SAT0262 MODIFIED ACR COMPOSITE RESPONSE INDEX IN SYSTEMIC SCLEROSIS SCORE SHOWS SENSITIVITY AND EXTERNAL VALIDATION TO MEASURE MAGNITUDE OF RESPONSE AT 12 MONTHS IN DIFFUSE CUTANEOUS SYSTEMIC SCLEROSIS

Abstract

Background: The Composite Response Index in Systemic Sclerosis (CRISS) is a 2-step process for the probability of improvement of patients with diffuse cutaneous systemic sclerosis (dcSSc) ranging from 0.0 (no improvement) to 1.0 (1). The limitation of probability is that it does not measure magnitude of response and it cannot be negative, hence reflecting worsening. Objectives: Here we aimed to test the performance of CRISS numerator normalised by baseline values to assess% change at 12 months in an observational cohort. Methods: Consecutive dcSSc patients were included in the study at a single centre. Clinical data were collected at baseline and 12 months and CRISS calculated using the published formula. To explore the quantitative value of the numerator, each of the 5 domains was corrected for their baseline value (e.g (12 months baseline)/baseline = Delta%) while keeping their original relative weight in the formula. The weighted sum was then divided by the number of domains. The modified CRISS (mCRS) was then compared with the original CRISS score and with another composite score validated in randomized controlled trials, the Global Ranked Composite Score (GRCS) (2). Death and organ failure were also included and assigned the worst negative values. Spearman’s test was used for Prism 7 correlation analysis. P Results: Thirty-three dcSSc patients were enrolled. Twenty-one patients had a CRISS = 0%. Twelve patients had a positive CRISS ranging from 1% to 77%. 18/21 patients with CRISS = 0% showed a negative mCRS (negative response = worsening) ranging from -9% to -2500%. 10/12 with positive CRISS showed a corresponding positive mCRS ranging from 1% to 22%. mCRS had a significant correlation with CRISS (r = 0.5, p = 0.003) and GRCS (r = 0.7, p Conclusion: Normalization by baseline data within CRISS numerator offers a quantitative score to assess magnitude of response, considering the 5 domains and their relative weight within the original CRISS. The mCRS measures magnitude of response rather than probability of response and includes the possibility of measuring worsening of disease. Application of the simple formula to the results of RCTs adopting CRISS as explorative efficacy objective will determine the validity of mCRS in offering quantitative assessment of response in SSc. Reference [1] Khanna D, Berrocal VJ, Giannini EH, et al. The American College of Rheumatology Provisional Composite Response Index for Clinical Trials in Early Diffuse Cutaneous Systemic Sclerosis. Arthritis Rheumatol 2016;68:299-311. [2] Sullivan KM, Goldmuntz EA, Keyes-Elstein L, et al. Myeloablative Autologous Stem-Cell Transplantation for Severe Scleroderma. N Engl J Med 2018; 378:35-47. Disclosure of Interests: None declared