Associations between the Composite Response Index in Diffuse Cutaneous Systemic Sclerosis (CRISS), survival and other disease measures.

OBJECTIVE

Diffuse cutaneous systemic sclerosis (dcSSc) is a multifaceted disease for which the Composite Response Index in dcSSc (CRISS) was developed as a global outcome measure. We aimed to further validate the CRISS by examining its association with other disease measures, patient reported quality of life (QoL), and mortality.

METHODS

DcSSc patients with ≤5 year disease duration were recruited from multinational registries. CRISS improvers (score ≥0.6) and non-improvers (score <0.6) were identified after one year. Median changes in European Scleroderma Group Activity Index (EScSG-AI), Medsger Disease Severity Scale (DSS), Scleroderma Clinical Trials Consortium Damage Index (SCTC-DI), and Short Form 36 physical component score (SF-36 PCS) after one year was compared between CRISS groups. Kaplan Meier and adjusted Cox analyses compared SCTC-DI damage accrual and mortality between CRISS groups.

RESULTS

Of 212 patients, 68 (32.1%) were CRISS improvers. CRISS improvers had improved median EScSG-AI (-1.1 points [IQR -2.6, -0.3] vs. 0 [-1.1, 1.0], p<0.001), DSS (-1 [-3, 1] vs. 0 [-2, 2], p = 0.015), and SF-36 PCS (+3.6 [-1.0, 8.9] vs. -0.3 [-5.9, 4.5], p<0.001) compared to non-improvers. CRISS improvers were less likely to accumulate damage on the SCTC-DI (hazard ratio [95% confidence interval] 0.68 [0.47, 0.96]) adjusting for age, sex, disease duration, and immunosuppression use. CRISS improvers had a trend towards better survival.

CONCLUSION

CRISS improvers had more favourable changes in measures of disease activity, disease severity, and QoL compared to non-improvers. These findings support the construct validity of a CRISS outcome after one year in early dcSSc.