Spondyloarthropathy is underestimated in inflammatory bowel disease: prevalence and HLA association.

To determine the overall prevalence of spondyloarthropathy (SpA) among patients with inflammatory bowel disease (IBD) [Crohn's disease (CD) and ulcerative colitis (UC)].One hundred three consecutive patients with IBD from a gastroenterology unit were questioned and examined for SpA symptoms. Patients previously diagnosed with SpA were excluded. All patients were questioned and examined for SpA symptoms such as inflammatory back pain, joint swelling, enthesitis, and psoriasis or a specific family history. Radiographs were taken of all sacroiliac joints. HLA loci A, B, C, and DR were determined in all patients.Thirty-nine percent of the patients with IBD had clinical articular manifestations: 30% had inflammatory back pain, 10% had synovitis, and 7% had a peripheral enthesopathy. The majority (90%) of patients with rheumatic complaints fulfilled the classification criteria for SpA and 10% fulfilled the criteria for ankylosing spondylitis. Asymptomatic sacroiliitis was found in an additional 18% of the patients. Moreover, sacroiliitis, symptomatic or asymptomatic, was related to the disease duration. HLA-B27 conferred an additional risk for inflammatory low back pain in patients with IBD.Articular involvement in IBD can be classified as SpA. The appearance of SpA occurs irrespective of the extent of the bowel disease. Moreover, asymptomatic sacroiliac involvement is a common manifestation in IBD and it is related to disease duration, suggesting evidence for a related pathogenic mechanism.