Diagnostic accuracy of the Dutch version of the Somatic Symptom Disorder - B Criteria Scale (SSD-12) compared to the Whiteley Index (WI) and PHQ-15 in a clinical population

Health anxiety in cancer patients, assessed with the Whiteley Index

OBJECTIVE

Health anxiety (HA) is frequently observed in patients suffering from a severe disease such as cancer. This study aimed to test the psychometric properties of the Whiteley Index-7 (WI-7) measuring HA and to identify prognostic factors for heightened HA in cancer patients.

METHODS

A sample of 1723 cancer patients, treated in a German rehabilitation clinic, completed the Whiteley Index-7, the Generalized Anxiety Disorder screener GAD-7, the Patient Health Questionnaire PHQ-9, the Fear of Progression questionnaire FoP-Q-12, the Concerns About Cancer Recurrence questionnaire CARQ-4, and two subscales of the EORTC QLQ-SURV100.

RESULTS

The internal consistency of the WI-7 was good (Cronbach's α = 0.85), and the correlations between the WI-7 and other scales were as follows: 0.64 (GAD-7), 0.63 (PHQ-9), 0.75 (FoP-Q-12), 0.71 (CARQ-4), 0.66 (SURV-HD), and 0.75 (SURV-NHO). Women showed markedly higher levels of HA than men (effect size: d = 0.40), and patients aged 60 years and above reported lower levels of HA than younger patients (d = -0.32). Melanoma patients showed the highest HA mean score (M = 10.9), and patients receiving antibody therapy showed heightened levels of HA (M = 10.7). When considering age and sex, the effects of tumor type and treatment become smaller than in the univariate analyses.

CONCLUSION

The WI-7 is a suitable instrument for assessing HA in cancer patients. When evaluating the effects of cancer type or treatment on HA, one has to take into account the age and sex distribution. Younger patients and women deserve special attention regarding HA.

Measurement Properties of the Patient Health Questionnaire-15 and Somatic Symptom Scale-8: A Systematic Review and Meta-Analysis

Importance

The subjective experience of somatic symptoms is a key concern throughout the health care system. Valid and clinically useful instruments are needed.

Objective

To evaluate the measurement properties of 2 widespread patient-reported outcomes: the Patient Health Questionnaire-15 (PHQ-15) and Somatic Symptom Scale-8 (SSS-8).

Data Sources

Medline, PsycINFO, and Web of Science were last searched February 1, 2024.

Study Selection

English-language studies reporting estimates pertaining to factor analysis, taxometric analysis, internal consistency, construct validity, mean scores in relevant groups, cutoffs, areas under the receiver operating characteristic curves (AUROCs), minimal clinically important difference, test-retest reliability, or sensitivity to change.

Data Extraction and Synthesis

Search hits were reviewed by independent raters. Cronbach α, Pearson r, means, and between-group effect sizes indicative of sensitivity to change were pooled in random-effects meta-analysis. Study quality was assessed using 3 instruments. Reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 reporting guideline.

Main Outcomes and Measures

Comprehensive overview of evidence pertaining to the measurement properties of the PHQ-15 and SSS-8.

Results

A total of 305 studies with 361 243 participants were included. Most concerned routine care (178 studies) and the general population (27 studies). In factor analyses, both scales reflected a combination of domain-specific factors (cardiopulmonary, fatigue, gastrointestinal, pain) and a general symptom burden factor. The pooled PHQ-15 α was 0.81 (95% CI, 0.80-0.82), but with low item-total correlations for items concerning menstrual problems, fainting spells, and sexual problems (item-total correlations <0.40), and the SSS-8 α was 0.80 (0.77-0.83). Pooled correlations with other measures of somatic symptom burden were 0.71 (95% CI, 0.64-0.78) for the PHQ-15 and 0.82 (95% CI, 0.72-0.92) for the SSS-8. Reported AUROCs for identification of somatoform disorders ranged from 0.63 (95% CI, 0.50-0.76) to 0.79 (95% CI, 0.73-0.85) for the PHQ-15 and from 0.71 (95% CI, 0.66-0.77) to 0.73 (95% CI, 0.69-0.76) for the SSS-8. The minimal clinically important difference on both scales was 3 points. Test-retest reliability could not be pooled and was inconsistent for the PHQ-15 (PHQ-15: r = 0.65-0.93; ICC, 0.87; SSS-8: r = 0.996, ICC = 0.89). The PHQ-15 showed tentative sensitivity to change (g = 0.32; 95% CI, 0.08-0.56), but data for the SSS-8 were lacking.

Conclusions and Relevance

In this systematic review and meta-analysis, findings supported use of the PHQ-15 and SSS-8 for the assessment of symptom burden, but users should be aware of the complex, multifactorial structures of these scales. More evidence is needed concerning longitudinal measurement properties.

Reliability and Validity of the Korean Version of the Somatic Symptom Disorder-B Criteria Scale in a Clinical Population

OBJECTIVE

This study aimed to develop and validate the Korean version of the Somatic Symptom Disorder-B Criteria Scale (SSD-12) in outpatients at a psychiatric clinic and assess its diagnostic accuracy.

METHODS

A total of 207 patients completed SSD-12. For the diagnostic accuracy of SSD-12, the somatic symptom disorder (SSD) section of the structured clinical interview for DSM-5 disorders-research version (SCID-5-RV) was used. The SSD-12 construct and concurrent validity were assessed by examining the correlations with Generalized Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9), PHQ-15, 5-level EQ-5D version (EQ-5D-5L), and World Health Organization Quality of Life Brief Version (WHOQOL-BREF).

RESULTS

The SSD-12 had excellent internal consistency (Cronbach α=0.90). Confirmatory factor analysis revealed good fit indices for a general factor model (comparative fit index [CFI]=0.92, Tucker-Lewis index [TLI]=0.88, root mean square error of approximation [RMSEA]=0.10; 95% confidence interval [CI], 0.08-0.11) and a three-factor model (CFI=0.94, TLI=0.91, RMSEA=0.08; 95% CI, 0.07-0.10). The total SSD-12 score was significantly correlated with anxiety (GAD-7: r=0.53, p<0.001), depression (PHQ-9: r=0.52, p<0.001), physical symptom burden (PHQ-15: r=0.36, p<0.001), and quality of life (EQ-5D-5L: r=-0.40, p<0.001; WHOQOL-BREF: r=-0.51, p<0.001). SSD-12 demonstrated good accuracy (area under the curve=0.75, standard error=0.04; 95% CI, 0.68-0.82) with an optimal cut-off of 29.

CONCLUSION

The Korean SSD-12 demonstrates reliability and validity for diagnosing SSD in clinical setting.