Abstract 4124506: Short Physical Performance Battery as a Marker of Severity and Predictor of Clinical Outcomes in Transthyretin Amyloid Cardiomyopathy (ATTR-CM)

Abstract

Background: ATTR-CM has an age dependent prevalence and is a disorder that almost exclusively affects older adults. Objective evaluations of function are critical to assessing and managing ATTR-CM in older adults. The short physical performance battery (SPPB) is a valid measure of functional capacity that predicts morbidity and mortality in older adults but its utility in ATTR-CM remains unknown. Aims/hypothesis: To establish SPPB as a useful marker of disease severity and predictor of outcomes in ATTR-CM. We hypothesized that SPPB scores would correlate with validated markers of ATTR-CM severity and improve clinical prediction. Methods: This is a retrospective analysis of patients referred to the Columbia University Cardiac Amyloid Program. Patients were stratified into low (SPPB 0-6), moderate (7-9), and high (10-12) cohorts based on initial SPPB score and baseline characteristics were compared between groups. Cox proportional hazard models and Kaplan Meier (KM) curves were generated to assess associations with mortality as well as a composite of death and cardiovascular (CV) hospitalization in follow-up. Results: A total of 263 patients, age 78 years (IQR 73, 84), 86% male, 22% with ATTRv (variant) and 78% with ATTRwt (wild type) were studied. SPPB showed no limitation in 59%, mild limitation in 33%, and severe limitation in 8%. Lower SPPB was associated (p <0.05) with older age, prior stroke/TIA, shorter 6-minute walk test, elevated NT-proBNP and HS-troponin, worse quality of life metrics on Kansas City Cardiomyopathy Questionnaire, more advanced NYHA and Mayo stages, and higher Columbia scores. On multivariate regression (adjusted for age, sex, genotype, NYHA), SPPB was independently associated with the composite of mortality and CV hospitalization, with each point increase corresponding to 13% lower incidence of the outcome (HR 0.87, p=0.01). Chair stands score, one of three SPPB subdomains, was independently associated with the composite and mortality. KM curves showed significant association with SPPB and both the composite and mortality (Fig. 1). Conclusions: SPPB score is a marker of ATTR-CM severity, associated with validated biomarkers and staging systems, and independently predicts clinical outcomes.