An epidemiological study of the prevalence rate of inflammatory back pain and axial spondyloarthritis in a university in the south of China

Inflammatory back pain (IBP) is an important clinical feature for axial spondyloarthritis (SpA). Yet, little is known about their prevalences in China. We conducted an epidemiological study in a university to detect the prevalences of IBP and axial SpA according to the Assessment of SpondyloArthritis International Society (ASAS) criteria. We investigated 3770 participants from South China Agricultural University by face-to-face questionnaires and evaluated the prevalences of chronic low back pain (CLBP) and IBP. In addition, 333 students including all IBP patients volunteered to do HLA-B27 test, and we performed X-ray examination on students with suspect axial SpA. Axial SpA was confirmed by rheumatologists according to ASAS criteria. The mean (± SD) age of screened population was 19.48 (± 2.80) years, while female to male ratio was 1.45:1 (2229/1541). Seven hundred thirty-one (19.39%) of all participants had CLBP and 111 (2.94%) had IBP. Among the 333 students receiving HLA-B27 test, 13 (0.34%, 13/3770) fulfilled ASAS criteria for axial SpA. Nine students had sacroiliitis on imaging plus at least one SpA feature (IBP and positive HLA-B27 results). Four students had positive HLA-B27 plus at least two other SpA features (arthritis/enthesitis and good response to NSAIDs). For CLBP, female/male was 485/246. For axial SpA, female/male was 4/9(P = 0.014). In southern China, the prevalences of CLBP and IBP were respectively 19.39 and 2.94% in university, and the prevalence of axial SpA was 0.34%. Although more female students had CLBP, males were more likely to suffer from axial SpA.