Sacroiliac joint involvement in systemic sclerosis

AimOne of the major problems for systemic sclerosis (SSc) patients is suggested to be articular involvement. Mostly involved joints in SSc were reported as wrist, carpometacarpal-interphalangeal, foot, knee, hip and shoulder; however, there has been little knowledge on the sacroiliac joint. Our aim was to evaluate sacroiliac joint involvement in SSc. MethodsFifty-seven SSc patients, 54 rheumatoid arthritis patients and 64 healthy subjects were included. Anteroposterior pelvic radiographs were obtained and graded twice by three blinded rheumatologists. One competent radiologist has re-evaluated the X-ray results. The ASAS (Assessment of Spondylo Arthritis International Society) scoring method was applied for grading sacroiliac involvement. Inflammatory back pain was also evaluated. Other clinical and laboratory data were collected as proposed by the European Study Group. ResultsIn the SSc group sacroiliitis was found in 13 patients (23%) and was significantly different from RA patients (two patients, 4%), P=0.003; and the healthy control group (one participant, 2%), P<0.001. The frequency of inflammatory back pain in SSc patients with sacroiliitis (8/13 patients, 62%) was significantly higher in SSc patients without sacroiliitis (4/44 patients, 9%), P<0.001. The SSc patients with sacroiliitis and with inflammatory back pain (8/57 patients, 14%) were regarded as axial spondyloarthritis overlap. Male gender, diffuse subtype, inflammatory back pain and high C-reactive protein levels (odds ratio: 1.069, 1.059, 1.059 and 3.698, respectively) were found to be the significant risk factors for sacroiliitis. ConclusionWe suggest that, sacroiliitis may be a concern to be considered in SSc practice.