FRI0240 HOSPITAL ANXIETY AND DEPRESSION SCALE AND SENSE OF COHERENCE 13-ITEM SCALE IN A SWISS COHORT OF SYSTEMIC SCLEROSIS PATIENTS: VALIDITY, RELIABILITY AND SENSITIVITY TO CHANGE

Abstract

Background: Depression, anxiety and distress affect the quality of life of patients with systemic sclerosis (SSc) [1]. The Hospital Anxiety and Depression Scale (HADS) and Sense of Coherence 13-item scale (SOC-13, measuring comprehensibility, manageability and meaningfulness) are screening tools used in patients with different medical conditions. However, their validity, reliability and sensitivity to change in SSc patients has not been evaluated yet. Objectives: To examine the psychometric properties of HADS and its subscales HADS-A and HADS-D (measuring anxiety and depression symptoms, respectively), and unidimensional SOC-13 in a large cohort of Swiss SSc patients. Methods: Consecutive patients fulfilling the ACR/EULAR 2013 classification criteria for SSc who completed the HADS, SOC-13, Short Form-36 Health Survey (SF-36) and Scleroderma Health Assessment Questionnaire (SHAQ) were included in a cross-sectional and longitudinal analysis. Cronbach's α, split-half reliability and construct validity were measured. Sensitivity to change (Cohen's d coefficient) was assessed in patients who worsened within 12±3 months, defined as occurrence of any of the following events: decline in forced vital capacity (FVC)≥10%, new diagnosis of interstitial lung disease (ILD) on high-resolution computed tomography (HRCT), progression of known ILD to >20% lung involvement on HRCT (ILD20), new-onset pulmonary hypertension (PH), increase in European Scleroderma Study Group activity index (EScSG-AI) >3 points, new active digital ulcers, increase in modified Rodnan skin score (mRSS) > 7 points. Results: Of 345 patients (aged 59.34±14.17, 82.9% female, 18.8% with diffuse cutaneous SSc, 47.6% anti-centromere Ab-positive, 23.5% anti-Scl-70 Ab-positive, 13% anti-U1RNP Ab-positive and 11.3% anti-RNA polymerase III Ab-positive) 85 participated with a second visit to the sensitivity to change analysis. Internal consistency was excellent for the HADS (Cronbach's α=0.91; split-half reliability r=0.92), and very good for HADS-A, HADS-D and SOC-13 (Cronbach's α=0.85-0.89; split-half reliability r=0.86-0.89). Regarding construct validity, all four scales showed a strong to very strong correlation to each other, as well as with the mental components of SF-36 (Spearman's r=0.63-0.85). There was a moderate to strong correlation with the SHAQ (Spearman's r=0.45-0.64). Regarding sensitivity to change: HADS-A showed a large to very large effect size (ES) for progression of ILD as assessed on HRCT and increase in EScSG-AI (Cohen's d=1-1.63), and a very small to small ES for changes in FVC, DU and mRSS (Cohen's d=0.02-0.45). HADS-D showed a large ES for changes in the ILD20, mRSS and EScSG-AI (Cohen's d=0.82-1), and moderate ES for changes of FVC, ILD, PH, DU (Cohen's d=0.1-0.49). SOC-13 showed generally a very small to small EF, except for change in mRSS (Cohen's d=0.56). Conclusion: The HADS(A/D) and SOC-13 are valid and easy-to-use tools to detect depression, anxiety and distress in SSc. However, their sensitivity to change might be limited by the respective type of organ involvement and its impact on the patients' psychological wellbeing.