Swedish Version of the Distress Thermometer: Validity Evidence in Patients With Colorectal Cancer

Authors:
Elisabeth Kenne SarenmalmResearch and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.

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Salmir NasicResearch and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.

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Cecilia HåkansonResearch and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.

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Joakim ÖhlénResearch and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.

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Eva CarlssonResearch and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.

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Monica E. PetterssonResearch and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.

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Richard SawatzkyResearch and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.
Research and Development, Skaraborg Hospital, Skövde, Sweden; Institute of Health and Care Sciences, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; University of Gothenburg Centre for Person-centred Care, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden; Department of Nursing Science, Sophiahemmet University, Stockholm, Sweden; The Palliative Centre, Sahlgrenska University Hospital, Gothenburg, Göteborg, Sweden; The Colorectal Unit, and The Vascular Department, Sahlgrenska University Hospital, Göteborg, Sweden; and School of Nursing, Trinity Western University, Langley, and Centre for Health Evaluation and Outcomes Sciences, Providence Health Care, Vancouver, British Columbia, Canada.

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Volume/Issue:
Volume 16: Issue 8
Online Publication Date:
Aug 2018
DOI:
https://doi.org/10.6004/jnccn.2018.7027
Full access

Background: The objective of this study was to validate the NCCN Distress Thermometer (DT), including the accompanying Problem List (PL), in a Swedish population of patients diagnosed with colorectal cancer (CRC). Methods: A total of 488 patients diagnosed with CRC completed the DT/PL and EORTC core quality-of-life questionnaire (QLQ-C30) before surgery. Construct validity of the PL was analyzed using a confirmatory factor analysis. Internal consistency reliability (ICR) was tested using Cronbach's alpha coefficient. Correlations between the reported PL areas and QLQ-C30 function scales were used to explore convergent validity. Discriminant validity was examined by evaluating associations between the DT and QLQ-C30 measures of overall health-related quality of life (HRQoL). Results: Findings showed that the Swedish translation of the DT/PL is consistent with the original English version. The DT has good ICR, with the total number of reported problems significantly correlating with DT scores (r=0.67; P<.001). Analysis of convergent validity indicated that the PL areas significantly correlated with QLQ-C30 function scales, with emotional problems showing the highest correlation (r=0.76; P<.001), and item-level correlation analyses showed significant correlations between symptoms. There was also good discriminant validity between the DT and the QLQ-C30 in terms of HRQoL, including overall health status (r=−0.49; P<.001) and overall quality of life (r=−0.57; P<.001). Furthermore, there was good discriminant validity between the DT and QLQ-C30 regarding poor, moderate, and excellent HRQoL. Conclusions: These findings provide validity evidence regarding the DT, including the PL. Findings also show that the DT has good potential for screening distress-related practical, family, emotional, and physical problems during the cancer trajectory in Swedish-speaking patients. Additionally, the DT seems to be an effective screening tool to detect patients with poor, moderate, and excellent HRQoL.

There is increasing recognition that psychosocial care, with its goal of relieving emotional distress and promoting well-being, is an essential component of the comprehensive care of patients diagnosed with cancer. Heightened distress is common1 and is associated with worse health-related quality of life (HRQoL),2 poorer adherence to treatment recommendations,3 and poorer survival in patients with cancer.4 Yet, evidence indicates that heightened distress often goes unrecognized.5

NCCN recommends that all patients be routinely screened for distress at appropriate intervals during the cancer trajectory,6 and the Distress Thermometer (DT) has been shown to be an effective screening tool in identifying distress in patients with cancer.6,7 The one-item DT was originally published by Roth et al8 in 1998, and appears in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) accompanied by a Problem List (PL), which categorizes sources of distress. The DT is widely used in the supportive and palliative care of patients with cancer across a diverse range of settings and various populations,9 and is systematically validated across countries and cultures.10–15 However, there are several challenges to translating these instruments. One such challenge with the DT is the translation of the core concept itself; for example, there is no relevant corresponding Swedish term for distress.

Several studies12,16,17 have tested the validity of the DT with the Hospital Anxiety and Depression Scale (HADS), also using HADS to determine specificity and sensitivity for identifying clinical cases.18 Based on a validation study examining a Swedish translation of an earlier version of the DT (version 1.2004) in relation to HADS, Thalén-Lindström et al17 suggested that, with a cutoff threshold for significance of ≥4, the DT is valid for screening purposes and has the ability to measure changes in distress over time.

Although most studies tested the validity of the DT, few studies have validated the PL. The PL consists of a list of 39 items regarding responses to cancer and its treatment, which are categorized into 5 PL areas measuring practical, family, emotional, spiritual/religious, and physical problems.9 The PL also includes 1 open-ended item that allows respondents to indicate other problems not included in the list. Less is known about how these problems are associated with each other. To the best of our knowledge, no studies have validated the PL using the EORTC core quality-of-life questionnaire (QLQ-C30) function scales.

In patients with colorectal cancer (CRC), significant negative relationships have been found between mental health outcomes, as measured by HADS, and HRQoL, as measured using the QLQ-C30.19 However, the association between distress, measured with the DT, and HRQoL, measured by QLQ-C30, is less known, as is whether the DT can identify individuals with poor, moderate, or excellent HRQoL.

The main objectives of this study were to examine measurement validity and reliability with respect to the DT/PL in a Swedish population of patients diagnosed with CRC. We specifically examined construct validity, internal consistency reliability (ICR), and convergent and discriminant validity, by addressing the following questions:

  • Do the PL items cluster in a manner that is consistent with the PL areas?

  • What is the ICR of the PL areas and what are their correlations with the DT?

  • How do the PL items correlate with the HRQoL domains of the QLQ-C30?

  • To what extent does the DT distinguish groups of people with poor, moderate, or excellent HRQoL?

Methods

Ethical Approval

Ethical approval was granted by The Regional Ethical Review Board in Gothenburg, Sweden (Dnr:2012-08-13; T264-14).

Sample and Setting

The study sample was included in a large person-centered information and communication intervention among patients scheduled for elective CRC surgery. Patients were consecutively enrolled, and data were collected presurgery, including the intervention group and controls. Study exclusion criteria were nonelective surgery, metastasis, preoperative chemotherapy, long-term preoperative radiation, diagnosis of benign tumors postsurgery, reduced cognitive function, and lacking ability to communicate in Swedish. Patient sociodemographic and clinical characteristics are presented in Table 1.

Data Collection

Eligible patients received oral and written study information from nurses and surgeons at the hospitals' outpatient clinics. Following their written consent, participants completed questionnaires prior to surgery, measuring HRQoL, preparedness, distress, well-being, and coping. Medical diagnosis was obtained from patient medical records, whereas demographic variables were included in the questionnaire. Patient-reported outcome measures were the DT/PL and QLQ-C30.

Measures

The DT is a one-item, self-reported measure for distress. Respondents were instructed to indicate how

Table 1.

Patient Sociodemographic and Clinical Characteristics (N=488)
Table 1.
distressed they felt in the previous week using a visual analog scale ranging from 0 (“no distress”) to 10 (“extreme distress”). To identify the prevalence of distress, we used a cutoff score of 4.6 The DT is accompanied by a PL categorized into 5 areas: practical, family, emotional, spiritual/religious, and physical. The items for each 5 areas are listed in Table 2. Respondents were asked to indicate whether they have experienced any of the problems during the previous week. Although each PL item has 2 checkboxes to indicate “yes” or “no,” many people only checked off “yes” for problem items while not checking off “no” for other problem items. For our analyses, we assumed missing responses to any of the items listed on the PL indicated “no” for those who responded to at least one of the items.

For this study, the first author (E.K.S.) and a healthcare manager with expertise in cancer care quality development, translated the English version of the DT/PL published at that time (version 2.2013) into Swedish using a standard forward-translation procedure.20 These 2 versions were discussed and discrepancies solved through mutual consensus. The Swedish version was then submitted to 2 independent bilingual translators for back translations into English, and the original English version and the back-translated version were then analyzed for further discrepancies. When consensus was established, with an agreement to use the English term distress, a Swedish translation of the definition of distress according to NCCN was included. The Swedish approved translation of the NCCN DT/PL Screening Tool from the NCCN Guidelines for Distress Management is shown in Figure 1.

The DT/PL, as well as the definition of distress, were then evaluated in a pilot study in which 30 patients, diagnosed with different types of cancer (lung,

Table 2.

Frequencies and Loadings for PL Items (N=459)a
Table 2.
hematologic, gynecologic, and breast, and malignant melanoma), tested and confirmed the applicability of the Swedish version, including the use of the term distress. In the present study, a translation of the NCCN definition of distress was presented to participants before they were asked to respond to the DT/PL.

The QLQ-C30 was used to measure domains of HRQoL. This questionnaire was specifically developed to assess quality of life (QoL) in patients with cancer participating in clinical trials.21 The questionnaire consists of 5 function scales (physical, role, cognitive, emotional, and social), 3 symptom subscales (fatigue, pain, nausea/vomiting), and 6 single-item scales (dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties). The QLQ-C30 also generates a global health status based on 2 items regarding respondents' experiences of health (question [Q] 29) and QoL (Q30) during the past week. The QLQ-C30 scores were calculated according to the algorithm of the QLQ-C30 scoring manual.22 The reliability and validity of the QLQ-C30 have been established in several studies.21,23

Statistical Analyses

Construct validity was explored by conducting a confirmatory factor analysis (CFA) using mean- and variance-adjusted weighted least squares estimation and tetrachoric correlations to accommodate the binary variables.24 We specifically examined whether the PL items cluster in a way that corresponds with the 5 PL areas. Two items (child care and substance abuse) were excluded from this analysis because they were endorsed by only 1 person. Well-established CFA guidelines were followed.25 The CFA model was specified by uniquely associating the items (problems) of each area with 1 of 5 correlated latent factors (each representing 1 area). The variances of the latent factors were fixed at 1 for purposes of model identification. For the area that had only 1 factor, the item loading was fixed at 1. The following criteria were used to evaluate model fit: (1) a root mean square error of approximation (RMSEA) <0.06 indicated good model fit and between 0.06 and 0.08 indicated adequate fit, and (2) a comparative fit index (CFI) >0.95 indicated good model fit.26,27

The ICR of the 4 PL areas (spiritual/religious area was excluded because it consists of only 1 item) were assessed based on the ordinal version of Cronbach's alpha coefficient, which is appropriate for both binary and ordinal items, using the estimates of the CFA models with correlated latent factors.28 An α >0.70 was considered satisfactory for internal consistency.29

Figure 1.
Figure 1.

Distress screening tool Swedish version 2.2013.

Citation: Journal of the National Comprehensive Cancer Network J Natl Compr Canc Netw 16, 8; 10.6004/jnccn.2018.7027

Additionally, we explored the correlation between the total number of reported problems and the DT scores.

Convergent and discriminant validity were explored by examining correlations between the reported PL areas and EORTC function scales. Convergent validity tested whether these subscales, which were expected to be related, were in fact related. Discriminant validity tested whether the construct “Distress” (DT) had low or moderate correlation to “Global Health and QoL” (QLQ-C30). Spearman's correlations were used to accommodate the ordinal data.

The QLQ-C30 global health status (Q29) was used to create the following groups: poor health status (scores 1–2), moderate health status (scores 3–5), and excellent health status (scores 6–7). Similarly, the discriminant validity was examined with respect to QoL using the QLQ-C30 global QoL (Q30). For all analyses, P<.05 was considered statistically significant.

Results

A total sample of 488 eligible participants were included in the study. The DT/PL form was missing for 6% of the patients (n=29), yielding a 94% response rate. Partial missing data (missing of single items) varied between 1% and 3% except for the item “Substance abuse,” for which missing data was 4%. A total of 459 patients responded to at least one of the PL items, 422 responded to the DT (37 were excluded due to partial missing data), and 476 responded to the QLQ-C30 questionnaire.

A prevalence of distress (DT >0) was reported by 86% of patients; 59 patients (14%) reported a DT score of 0, 233 (55%) reported a DT score between 0 and 4, and 130 (31%) reported a DT score >4.6

Construct Validity

Percentages of respondents endorsing the PL items ranged from 0.2 for PL-Child care (item 1) and PL-Substance abuse (item 38) to 61.0 for PL-Worry (item 15). A CFA of the remaining 37 items and 5 correlated latent factors resulted in acceptable overall model fit (χ2 [df]=778 [620]; RMSEA=0.024; CFI=0.93; n=461). Factor loadings were <0.40 for PL-Changes in urination (item 21), PL-Mouth sores (item 31), and PL-Tingling in hands/feet (item 39), with the remaining factor loadings ranging from 0.40 for PL-Diarrhea (item 23) to 0.88 for PL-Worry (item 15) (Table 2). The latent factor correlations ranged from 0.24 to 0.74. The smallest and not statistically significant correlations were for “spiritual/religious concerns” with “practical problems” and “family problems” (Table 3).

Internal Consistency Reliability

The ICR ranged from 0.77 for practical problems to 0.92 for emotional problems. There was a moderate correlation between the DT and number of reported problems (r=0.67; P<.001) (Figure 2).

Convergent Validity

The number of emotional problems on the PL showed the highest correlation (r=0.76) with the emotional functioning scale on the QLQ-C30 (Table 4). The number of physical problems correlated with QLQ-C30–physical functioning (r=0.53), QLQ-C30–pain (r=0.55), QLQ-C30–social functioning (r=0.51), QLQ-C30–cognitive functioning (r=0.50), and QLQ-C30–emotional functioning (r=0.44). The number of family-related problems (according to the PL) correlated with all of the QLQ-C30 subscales, but correlations were not very strong, ranging between 0.17 and 0.30.

The number of practical problems on the PL correlated moderately with the 4 QLQ-C30 functioning subscales and the pain scale, with correlations ranging between 0.17 and 0.35. In addition, the DT correlated satisfactory with QLQ-C30 emotional functioning (r=0.74), cognitive functioning (r=0.42), and social functioning (r=0.42) subscales. All correlations

Table 3.

Correlations Among Problem List Areasa,b (N=459)
Table 3.
Figure 2.
Figure 2.

Correlations between the Distress Thermometer (DT) and number of reported problems.

Citation: Journal of the National Comprehensive Cancer Network J Natl Compr Canc Netw 16, 8; 10.6004/jnccn.2018.7027

were statistically significant (P<.001) (Table 4).

Because the PL does not have natural corresponding subscales to the QLQ-C30, some correlation analyses were performed at the item level. PL-Fatigue (item 25) correlated well with QLQ-C30–Fatigue (Q18; r=0.66); PL-Nausea (item 32) correlated with QLQ-C30–Nausea (Q14; r=0.60); PL-Pain (item 34) correlated with QLQ-C30–Pain (Q9; r=0.63, and Q19; r=0.61, respectively); PL-Sleep (item 37) correlated with QLQ-C30–Insomnia

Table 4.

Correlations of DT/PL Areas With EORTC Function Scales
Table 4.
(Q11; r=0.69), PL-Constipation (item 22) correlated with QLQ-C30–Constipation (Q16; r=0.71); PL-Diarrhea (item 23) correlated with QLQ-C30–Diarrhea (Q17; r=0.74); and PL-Insurance/Financial (item 3) correlated with QLQ-C30–Financial (Q28; r=0.59) (P<.001) (Table 5).

Discriminant Validity

As expected, DT scores were associated with QLQ-C30 overall health status (Q29; r=−0.492; P<.001; Figure 3) and QoL (Q30; r=−0.569; P<.001; Figure 4). There was a significant amount of dispersion with respect to DT scores at poor, moderate, and excellent overall HRQoL, which suggests good discriminant validity between the 2 measures.

Discussion

To our knowledge, this is the first study that has performed a CFA to validate the DT and accompanying PL. The CFA suggests that the PL items correspond acceptably well with the structure of the 5 correlated PL areas.

Our findings using the Swedish translation of the DT are consistent with those of the original English version. These results are in accordance with other studies aimed at translating and validating the DT in patients with cancer in different countries and cultures.15 Additionally, our results showed that the PL has good ICR. The total number of reported problems significantly correlated with DT scores, suggesting that there is good internal consistency in the instrument (ie, high numbers of symptoms/problems correlated with high scores on the DT). This could be considered an aspect of internal consistency of the questionnaire, because 2 different parts on the questionnaire, measuring the same construct, clearly correlate with each other.

The convergent validity, analyzed as the correlation between the PL areas and QLQ-C30 function scales, indicated that emotional problems (PL) showed the highest correlation with emotional functioning (QLQ-C30). Likewise, physical problems were associated with physical functioning (QLQ-C30). Also, item-level correlation analyses showed significant correlations between symptoms, financial difficulties, work/daily activities, and cognitive function. Others have examined the DT with respect to the HADS,12,16–18 and our study complements that

Table 5.

Correlations Between PL Items and Corresponding EORTC Symptom Queries
Table 5.
research by examining the DT in relation to other dimensions of HRQoL.

Research in psycho-oncology has made evident that cancer care involves more than clinical treatment of the disease, and patients' experiences of psychosocial concerns has gained a greater attention within the cancer community. Cancer survivors have impaired HRQoL, and a substantial proportion of these patients experience distress and may benefit

Figure 3.
Figure 3.

Association between distress and overall health.

Abbreviation: DT, Distress Thermometer.

Citation: Journal of the National Comprehensive Cancer Network J Natl Compr Canc Netw 16, 8; 10.6004/jnccn.2018.7027

from psychological interventions.30 Our study results suggest good discriminant validity between the DT and QLQ-C30, with a significant distribution, regarding poor, moderate, and excellent HRQoL. Our findings regarding the significant association between responses to the DT and HRQoL measured by the QLQ-C30 illustrate that the DT has the potential to identify individuals in need of interventions to improve their HRQoL.

Finally, the present study used the English term distress. Originally, this term was chosen for its lack of associated psychological implications and ability to be defined and measured.31 As opposed to a single physical or psychological symptom, this broad concept highlights its multifactorial etiology and multidimensionality. Instead of using adjacent Swedish words, which would not capture the core concept “distress,” we provided a translation of the definition.

Limitations

Although we found support for the use of DT/PL in a large sample of Swedish patients diagnosed with CRC, measurement validity with respect to other Swedish cancer populations are unknown. However, the DT has been successfully evaluated in a variety of settings and in patients with different cancer diagnoses.15 It would have been desirable to test the repeatability over time with a test/retest method. Therefore, further prospective research applying a test/retest of the DT/PL is recommended.

Figure 4.
Figure 4.

Association between distress and quality of life.

Abbreviation: DT, Distress Thermometer.

Citation: Journal of the National Comprehensive Cancer Network J Natl Compr Canc Netw 16, 8; 10.6004/jnccn.2018.7027

Conclusions

Due to the importance of cancer-related distress, its high prevalence, and its significant impact on patient HRQoL, the availability of psychometrically sound screening instruments is critical. Our analysis provides general support for the measurement validity of the DT/PL in a sample of patients scheduled for CRC surgery. Further, the results pertaining to the Swedish translation of the DT indicate its potential usefulness for evaluating distress during the cancer trajectory in Swedish-speaking patients. In addition, our findings indicate that the DT can also be used as a rapid screening tool to identify individuals in need of interventions to improve their HRQoL.

Acknowledgments

The authors wish to acknowledge all patients who participated in this study.

The authors have disclosed that they have no financial interests, arrangements, affiliations, or commercial interests with the manufacturers of any products discussed in this article or their competitors.

Grants supporting this research were received from University of Gothenburg Centre for Person-centred Care and the Health & Medical Care Committee of the Regional Executive Board in Region Västra Götaland. This research was undertaken, in part, thanks to funding from the Canada Research Chairs program. Dr. Sawatzky holds a Canada Research Chair (Tier 2) in Patient-Reported Outcomes.

References

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    Zabora J, BrintzenhofeSzoc K, Curbow B et al.. The prevalence of psychological distress by cancer site. Psychooncology 2001;10:19–28.

  • 2.↑

    Skarstein J, Aass N, Fossa SD et al.. Anxiety and depression in cancer patients: relation between the Hospital Anxiety and Depression Scale and the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire. J Psychosom Res 2000;49:27–34.

    • Search Google Scholar
    • Export Citation
  • 3.↑

    Kennard BD, Stewart SM, Olvera R et al.. Nonadherence in adolescent oncology patients: preliminary data on psychological risk factors and relationships to outcome. J Clin Psychol Med Settings 2004;11:31–39.

    • Search Google Scholar
    • Export Citation
  • 4.↑

    Steel JL, Geller DA, Gamblin TC et al.. Depression, immunity, and survival in patients with hepatobiliary carcinoma. J Clin Oncol 2007;25:2397–2405.

    • Search Google Scholar
    • Export Citation
  • 5.↑

    Fallowfield L, Ratcliffe D, Jenkins V et al.. Psychiatric morbidity and its recognition by doctors in patients with cancer. Br J Cancer 2001;84:1011–1015.

    • Search Google Scholar
    • Export Citation
  • 6.↑

    Holland JC, Deshields TL, Andersen B et al.. NCCN Clinical Practice Guidelines in Oncology: Distress Management. Version 2.2018. Accessed: March 8, 2018. To view the most recent version of these guidelines, visit NCCN.org.

    • Search Google Scholar
    • Export Citation
  • 7.↑

    Jacobsen PB. Screening for psychological distress in cancer patients: challenges and opportunities. J Clin Oncol 2007;25:4526–4527.

  • 8.↑

    Roth AJ, Kornblith AB, Batel-Copel L et al.. Rapid screening for psychologic distress in men with prostate carcinoma: a pilot study. Cancer 1998;82:1904–1908.

    • Search Google Scholar
    • Export Citation
  • 9.↑

    Holland JC, Bultz BD. The NCCN Guideline for distress management: a case for making distress the sixth vital sign. J Natl Compr Canc Netw 2007;5:3–7.

    • Search Google Scholar
    • Export Citation
  • 10.↑

    Ozalp E, Cankurtaran ES, Soygur H et al.. Screening for psychological distress in Turkish cancer patients. Psychooncology 2007;16:304–311.

  • 11.

    Bulli F, Miccinesi G, Maruelli A et al.. The measure of psychological distress in cancer patients: the use of Distress Thermometer in the Oncological Rehabilitation Center of Florence. Support Care Cancer 2009;17:771–779.

    • Search Google Scholar
    • Export Citation
  • 12.↑

    Bidstrup PE, Mertz BG, Dalton SO et al.. Accuracy of the Danish version of the ‘distress thermometer’. Psychooncology 2012;21:436–443.

  • 13.

    Grassi L, Johansen C, Annunziata MA et al.. Screening for distress in cancer patients: a multicenter, nationwide study in Italy. Cancer 2013;119:1714–1721.

    • Search Google Scholar
    • Export Citation
  • 14.

    Martinez P, Galdon MJ, Andreu Y et al.. The Distress Thermometer in Spanish cancer patients: convergent validity and diagnostic accuracy. Support Care Cancer 2013;21:3095–3102.

    • Search Google Scholar
    • Export Citation
  • 15.↑

    Donovan KA, Grassi L, McGinty HL et al.. Validation of the distress thermometer worldwide: state of the science. Psychooncology 2014;23:241–250.

  • 16.↑

    Gessler S, Low J, Daniells E et al.. Screening for distress in cancer patients: is the distress thermometer a valid measure in the UK and does it measure change over time? A prospective validation study. Psychooncology 2008;17:538–547.

    • Search Google Scholar
    • Export Citation
  • 17.↑

    Thalén-Lindström A, Larsson G, Hellbom M et al.. Validation of the Distress Thermometer in a Swedish population of oncology patients; accuracy of changes during six months. Eur J Oncol Nurs 2013;17:625–631.

    • Search Google Scholar
    • Export Citation
  • 18.↑

    Tavernier SS. Translating research on the distress thermometer into practice. Clin J Oncol Nurs 2014;18(Suppl):26–30.

  • 19.↑

    Tsunoda A, Nakao K, Hiratsuka K et al.. Anxiety, depression and quality of life in colorectal cancer patients. Int J Clin Oncol 2005;10:411–417.

  • 20.↑

    Maneesriwongul W, Dixon JK. Instrument translation process: a methods review. J Adv Nurs 2004;48:175–186.

  • 21.↑

    Aaronson NK, Ahmedzai S, Bergman B et al.. The European Organization for Research and Treatment of Cancer QLQ-C30: a quality-of-life instrument for use in international clinical trials in oncology. J Natl Cancer Inst 1993;85:365–376.

    • Search Google Scholar
    • Export Citation
  • 22.↑

    Fayers P, de Haes H. Quality of life. Lancet 1995;346:444.

  • 23.↑

    Borghede G, Karlsson J, Sullivan M. Quality of life in patients with prostatic cancer: results from a Swedish population study. J Urol 1997;158:1477–1485; discussion 1486.

    • Search Google Scholar
    • Export Citation
  • 24.↑

    Finney SJ, DiStefano C. Non-normal and categorical data in structural equation modeling. In: Hancock G, Mueller R, eds. Structural Equation Modeling: A Second Course. Greenwich, CT: Information Age Publishing; 2006:269–314.

    • Search Google Scholar
    • Export Citation
  • 25.↑

    Byrne BM. Structural Equation Modeling With Mplus: Basic Concepts, Applications and Programming. New York, NY: Routledge Academic; 2012.

    • Search Google Scholar
    • Export Citation
  • 26.↑

    Vandenberg RJ, Lance CE. A review and synthesis of the measurement invariance literature: suggestions, practices, and recommendations for organizational research. Organ Res Methods 2000;3:4–70.

    • Search Google Scholar
    • Export Citation
  • 27.↑

    Yu CY. Evaluating cutoff criteria of model fit indices for latent variable models with binary and continuous outcomes [dissertation]. Los Angeles: University of California; 2002.

    • Search Google Scholar
    • Export Citation
  • 28.↑

    Zumbo BD, Gadermann AM, Zeisser C. Ordinal versions of coefficients alpha and theta for Likert rating scales. J Mod Appl Stat Methods 2007;6:21–29.

    • Search Google Scholar
    • Export Citation
  • 29.↑

    Reeve BB, Wyrwich KW, Wu AW et al.. ISOQOL recommends minimum standards for patient-reported outcome measures used in patient-centered outcomes and comparative effectiveness research. Qual Life Res 2013;22:1889–1905.

    • Search Google Scholar
    • Export Citation
  • 30.↑

    Group AS. Health-related quality of life and psychological distress among cancer survivors in Southeast Asia: results from a longitudinal study in eight low- and middle-income countries. BMC Med 2017;15:10.

    • Search Google Scholar
    • Export Citation
  • 31.↑

    Holland JC, Andersen B, Breitbart WS et al.. Distress management. J Natl Compr Canc Netw 2007;5:66–98.

Author contributions: Study planning: Kenne Sarenmalm, Håkanson, Öhlén, Carlsson, Pettersson, Sawatzky. Study implementation: Kenne Sarenmalm, Håkanson, Öhlén, Carlsson, Pettersson, Sawatzky. Data analysis: All authors. Manuscript preparation: All authors.

Correspondence: Elisabeth Kenne Sarenmalm, RN, PhD, Research and Development, Skaraborg Hospital, Skövde, and Institute of Health and Care Sciences, and University of Gothenburg Centre for Person-Centred Care, Sahlgrenska Academy at the University of Gothenburg, Sweden, SE-416 85 Göteborg, Sweden. Email: elisabeth.kenne.sarenmalm@vgregion.se
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  • View in gallery

    Distress screening tool Swedish version 2.2013.

  • View in gallery

    Correlations between the Distress Thermometer (DT) and number of reported problems.

  • View in gallery

    Association between distress and overall health.

    Abbreviation: DT, Distress Thermometer.

  • View in gallery

    Association between distress and quality of life.

    Abbreviation: DT, Distress Thermometer.

Distress screening tool Swedish version 2.2013.

Correlations between the Distress Thermometer (DT) and number of reported problems.

Association between distress and overall health.

Abbreviation: DT, Distress Thermometer.

Association between distress and quality of life.

Abbreviation: DT, Distress Thermometer.
  • 1.

    Zabora J, BrintzenhofeSzoc K, Curbow B et al.. The prevalence of psychological distress by cancer site. Psychooncology 2001;10:19–28.

  • 2.

    Skarstein J, Aass N, Fossa SD et al.. Anxiety and depression in cancer patients: relation between the Hospital Anxiety and Depression Scale and the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire. J Psychosom Res 2000;49:27–34.

    • Search Google Scholar
    • Export Citation
  • 3.

    Kennard BD, Stewart SM, Olvera R et al.. Nonadherence in adolescent oncology patients: preliminary data on psychological risk factors and relationships to outcome. J Clin Psychol Med Settings 2004;11:31–39.

    • Search Google Scholar
    • Export Citation
  • 4.

    Steel JL, Geller DA, Gamblin TC et al.. Depression, immunity, and survival in patients with hepatobiliary carcinoma. J Clin Oncol 2007;25:2397–2405.

    • Search Google Scholar
    • Export Citation
  • 5.

    Fallowfield L, Ratcliffe D, Jenkins V et al.. Psychiatric morbidity and its recognition by doctors in patients with cancer. Br J Cancer 2001;84:1011–1015.

    • Search Google Scholar
    • Export Citation
  • 6.

    Holland JC, Deshields TL, Andersen B et al.. NCCN Clinical Practice Guidelines in Oncology: Distress Management. Version 2.2018. Accessed: March 8, 2018. To view the most recent version of these guidelines, visit NCCN.org.

    • Search Google Scholar
    • Export Citation
  • 7.

    Jacobsen PB. Screening for psychological distress in cancer patients: challenges and opportunities. J Clin Oncol 2007;25:4526–4527.

  • 8.

    Roth AJ, Kornblith AB, Batel-Copel L et al.. Rapid screening for psychologic distress in men with prostate carcinoma: a pilot study. Cancer 1998;82:1904–1908.

    • Search Google Scholar
    • Export Citation
  • 9.

    Holland JC, Bultz BD. The NCCN Guideline for distress management: a case for making distress the sixth vital sign. J Natl Compr Canc Netw 2007;5:3–7.

    • Search Google Scholar
    • Export Citation
  • 10.

    Ozalp E, Cankurtaran ES, Soygur H et al.. Screening for psychological distress in Turkish cancer patients. Psychooncology 2007;16:304–311.

  • 11.

    Bulli F, Miccinesi G, Maruelli A et al.. The measure of psychological distress in cancer patients: the use of Distress Thermometer in the Oncological Rehabilitation Center of Florence. Support Care Cancer 2009;17:771–779.

    • Search Google Scholar
    • Export Citation
  • 12.

    Bidstrup PE, Mertz BG, Dalton SO et al.. Accuracy of the Danish version of the ‘distress thermometer’. Psychooncology 2012;21:436–443.

  • 13.

    Grassi L, Johansen C, Annunziata MA et al.. Screening for distress in cancer patients: a multicenter, nationwide study in Italy. Cancer 2013;119:1714–1721.

    • Search Google Scholar
    • Export Citation
  • 14.

    Martinez P, Galdon MJ, Andreu Y et al.. The Distress Thermometer in Spanish cancer patients: convergent validity and diagnostic accuracy. Support Care Cancer 2013;21:3095–3102.

    • Search Google Scholar
    • Export Citation
  • 15.

    Donovan KA, Grassi L, McGinty HL et al.. Validation of the distress thermometer worldwide: state of the science. Psychooncology 2014;23:241–250.

  • 16.

    Gessler S, Low J, Daniells E et al.. Screening for distress in cancer patients: is the distress thermometer a valid measure in the UK and does it measure change over time? A prospective validation study. Psychooncology 2008;17:538–547.

    • Search Google Scholar
    • Export Citation
  • 17.

    Thalén-Lindström A, Larsson G, Hellbom M et al.. Validation of the Distress Thermometer in a Swedish population of oncology patients; accuracy of changes during six months. Eur J Oncol Nurs 2013;17:625–631.

    • Search Google Scholar
    • Export Citation
  • 18.

    Tavernier SS. Translating research on the distress thermometer into practice. Clin J Oncol Nurs 2014;18(Suppl):26–30.

  • 19.

    Tsunoda A, Nakao K, Hiratsuka K et al.. Anxiety, depression and quality of life in colorectal cancer patients. Int J Clin Oncol 2005;10:411–417.

  • 20.

    Maneesriwongul W, Dixon JK. Instrument translation process: a methods review. J Adv Nurs 2004;48:175–186.

  • 21.

    Aaronson NK, Ahmedzai S, Bergman B et al.. The European Organization for Research and Treatment of Cancer QLQ-C30: a quality-of-life instrument for use in international clinical trials in oncology. J Natl Cancer Inst 1993;85:365–376.

    • Search Google Scholar
    • Export Citation
  • 22.

    Fayers P, de Haes H. Quality of life. Lancet 1995;346:444.

  • 23.

    Borghede G, Karlsson J, Sullivan M. Quality of life in patients with prostatic cancer: results from a Swedish population study. J Urol 1997;158:1477–1485; discussion 1486.

    • Search Google Scholar
    • Export Citation
  • 24.

    Finney SJ, DiStefano C. Non-normal and categorical data in structural equation modeling. In: Hancock G, Mueller R, eds. Structural Equation Modeling: A Second Course. Greenwich, CT: Information Age Publishing; 2006:269–314.

    • Search Google Scholar
    • Export Citation
  • 25.

    Byrne BM. Structural Equation Modeling With Mplus: Basic Concepts, Applications and Programming. New York, NY: Routledge Academic; 2012.

    • Search Google Scholar
    • Export Citation
  • 26.

    Vandenberg RJ, Lance CE. A review and synthesis of the measurement invariance literature: suggestions, practices, and recommendations for organizational research. Organ Res Methods 2000;3:4–70.

    • Search Google Scholar
    • Export Citation
  • 27.

    Yu CY. Evaluating cutoff criteria of model fit indices for latent variable models with binary and continuous outcomes [dissertation]. Los Angeles: University of California; 2002.

    • Search Google Scholar
    • Export Citation
  • 28.

    Zumbo BD, Gadermann AM, Zeisser C. Ordinal versions of coefficients alpha and theta for Likert rating scales. J Mod Appl Stat Methods 2007;6:21–29.

    • Search Google Scholar
    • Export Citation
  • 29.

    Reeve BB, Wyrwich KW, Wu AW et al.. ISOQOL recommends minimum standards for patient-reported outcome measures used in patient-centered outcomes and comparative effectiveness research. Qual Life Res 2013;22:1889–1905.

    • Search Google Scholar
    • Export Citation
  • 30.

    Group AS. Health-related quality of life and psychological distress among cancer survivors in Southeast Asia: results from a longitudinal study in eight low- and middle-income countries. BMC Med 2017;15:10.

    • Search Google Scholar
    • Export Citation
  • 31.

    Holland JC, Andersen B, Breitbart WS et al.. Distress management. J Natl Compr Canc Netw 2007;5:66–98.

Copyright:
Copyright © 2018 by the National Comprehensive Cancer Network 2018
Page Numbers:
8
Article Category:
Research Article
Received:
26 Nov 2017
Accepted:
19 Mar 2018
Print Publication Date:
01 Aug 2018
Online Publication Date:
Aug 2018
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