POS0972 CLUSTER ANALYSIS OF ANKYLOSING SPONDYLITIS PATIENTS REVEALS DIFFERENTIAL DRUG SURVIVAL OF ANTI-TNF AGENTS ACCORDING TO DISTINCT CLINICAL PHENOTYPE

Abstract

Background:Previous studies using cluster analysis technique in ankylosing spondylitis (AS) patients have consistently identified distinct groups of patients in terms of their clinical characteristics: those with pure axial symptoms and those with a high frequency of peripheral manifestations [1,2]. Due to the cross-sectional nature of these studies, however, prognostic information such as drug survival of anti-TNF agents in these group were not provided.Objectives:Using the data retrieved from Korean College of Rheumatology Biologics (KOBIO) registry, which includes longitudinal data of AS patients using anti-TNF agents, this study aims to perform cluster analysis to differentiate AS patients in terms of clinical phenotypes and to examine the differential drug survival of anti-TNF agents in these groups.Methods:Clinical characteristics and demographic data of AS patients in KOBIO registry were analyzed using hierarchical clustering analysis. After clustering, drug survivals of anti-TNF agents were compared between these groups.Results:1,046 patients were included in the study with no missing data. The hierarchical cluster analysis classified patients in two groups; one with predominant isolated axial manifestations (axial group, n=823) and the other with more frequent extra-axial symptoms (extra-axial group, n=223). Almost all extra-axial symptoms (peripheral arthritis, enthesitis, uveitis, dactylitis, and psoriasis) were more frequently observed in extra-axial group than axial group. In addition, patients with shorter disease duration, late disease onset, and high disease activity were classified in extra-axial group (Table 1). Interestingly, the extra-axial group had lower drug survival probability than the axial group (p=0.008, Figure 1).Conclusion:Cluster analysis of AS patients using anti-TNF agents classified two distinct groups of patients in terms of their clinical phenotypes and revealed that the patients with prominent extra-axial manifestations had lower drug survival with anti-TNF agents.