Prevalence of clinical hip abnormalities in haemophilia A and B: an analysis of the UDC database

Clinical hip abnormalities, secondary to recurrent joint and/or muscle bleeding in persons with haemophilia, have not been well characterized and have the potential for significant morbidity. We aimed to examine the prevalence of clinical hip abnormalities in the US haemophilia population and to explore associations between these findings and putative risk factors. We conducted a study of hip abnormalities of 8192 subjects aged 2–69 years with haemophilia A and haemophilia B (54% of haemophilia A and haemophilia B are severe) currently enrolled in the Universal Data Collection (UDC) database. Associations between hip abnormality and type/severity of haemophilia A/B, current age, history of high‐titre (≥5 BU) inhibitor (HTinh), concomitant ankle (AA) and knee arthropathy (KA), overweight and obesity and prophylaxis were examined using logistic regression. Overall prevalence of hip abnormality at the last recorded UDC visit for all subjects was 16.7%. Haemophilia A (aOR = 1.3, 1.0–1.4), severe haemophilia (aOR = 1.3, 1.0–1.5), a history of HTinh (aOR = 1.4, 1.1–1.7), and concomitant AA (aOR = 1.7, 1.4–1.9) were each independently associated with hip abnormality. Older age (45–69 years) was significantly associated with hip abnormality prevalence only in subjects with KA (aOR = 3.4, 1.9–5.9). The presence of overweight (aOR = 1.4, 1.1–1.8) and obesity (aOR = 2.1, 1.6–2.8) was associated with hip abnormality only among subjects without KA. Hip abnormality prevalence was not influenced by prophylaxis (aOR = 0.9, 0.8–1.1). These data suggest that hip abnormalities in US patients with haemophilia are associated with haemophilia severity and type, HTinh, concomitant AA and, depending on the presence or absence of KA, advancing age and obesity.