Prevalence and characteristics of hip involvement in spondyloarthritis: a single-centre observational study of 275 patients

Hip involvement is a classic feature of spondyloarthritis (SpA). The aim of the present paper is to study the prevalence, clinical and radiological features of hip involvement, and the association with criteria for severity, in a cohort of patients with SpA in a tertiary care centre. retrospective single centre observational study in 2010 of patients with definite SpA who underwent direct interview by a physician. Hip involvement was defined as hip pain considered related to SpA inflammation and confirmed radiographically. Other data collection: demographic data, SpA characteristics, treatments performed for hip involvement. prevalence of hip involvement was analysed according to disease duration (Kaplan-Meyer). Multivariate Cox analysis compared patients with vs. without hip involvement over time. In all, 275 SpA patients were assessed. The median age was 45 (IQR 35-55) years, the median SpA symptom duration 14 (7-25) years, 61% (169) were men, and 79% were HLA-B27 positive. Hip involvement was found in 18% (49) SpA patients, with already 13% after 5 years of disease duration and with frequent bilateral involvement (61%). Hip involvement was associated with non-Caucasian origin (p=0.05). Thirty-three percent (16/49) needed surgery (23 total joint replacements in all) with good functional results. Hip involvement is a frequent manifestation in SpA (18%), often bilateral, and associated with non-Caucasian origin. One third of the patients needed total joint replacement. Physicians should be wary of hip pain in SpA patients and implement rapid diagnostic procedures in such cases.