Study on the associated factors of early-stage hip involvement in patients with ankylosing spondylitis based on magnetic resonance imaging / 中华风湿病学杂志

ABSTRACT

Objective:To evaluate the clinical characteristics and identify potential factors of the early-stage hip involvement in patients with ankylosing spondylitis (AS) based on the magnetic resonance imaging (MRI).Methods:A retrospective group control study was carried out in 570 AS patients who were consecutively admitted to our hospital from 2014 to 2018. Patients with hip pain or hip function limitation but lacking definitive evidence of hip involvement on radiography were underwent hip MRI. Patients were divided into three groups no hip involvement, early-stage hip involvement (hip involvement detected by MRI but with negative radiographs) and advanced-stage hip involvement (Bath Ankylosing Spondylitis Radiology Index-hip score ≥2). The study factors included demographic, laboratory, clinical and radiographic data. Simple and multiple ordinal logistic regression analysis were used to identify factors associated with the early-stage hip involvement and advanced-stage hip involvement.Results:A total of 236 patients (41.4%) presented with hip involvement, in which 146 cases (25.6%) were diagnosed with early-stage hip involvement, while 90 cases (15.8%) were diagnosed with advanced-stage hip involvement. Multivariate logistic regression analysis demonstrated that older age at onset [ OR=0.80, 95% CI (0.72, 0.90), P<0.01], more active inflammation in the sacroiliac joints [ OR=1.13, 95% CI(1.07, 1.18), P<0.01] and worse BASMI score [ OR=3.06, 95% CI(2.14, 4.13), P<0.01] were associated with the occurrence of early-stage hip involvement. Conclusion:MRI is superior to radiography in detecting early-stage hip involvement. MRI is more suitable for hip involvement assessment in AS patients with suspected symptoms or risk factors of hip involvement.