The frequency of sacroiliitis on MRI in subjects over 55years of age.

Abstract

To evaluate the frequency of sacroiliitis in older subjects. Consecutive MRI examinations of the sacroiliac joints (SIJs) performed for suspected sacroiliitis (2005-2019) in patients ≥ 18years were retrospectively evaluated for the presence of active/structural lesions and were categorized for the presence/absence of sacroiliitis. Clinical and imaging parameters were compared between subjects with sacroiliitis according to age groups < 40years, 40-55, and > 55years. Clinical parameters including inflammatory back pain (IBP) and other spondyloarthritis (SpA) features were retrieved from the medical records. A total of 431 patients with SIJs MRI were evaluated: median age, 44 [IQR 35-54]; female:male 267(62%):164(38%). Sacroiliitis was diagnosed in 89 (20.6%) subjects-median age, 41years [IQR 32-54], 52% females- and was equally prevalent among the different age groups: > 40years old, 23.6%; 40-55, 20%; and > 55years old, 17%, p = 0.43, with active/structural lesions equally dispersed. Older patients (> 55) started suffering from back pain at an older age and had a longer delay in diagnosis. Gender distribution, the presence of IBP, and other SpA features were no different in patients < 45 and > 55years of age. The frequency of sacroiliitis on SIJs-MRI in subjects > 55years is similar to its frequency in younger subjects and is associated with the same type and magnitude of active and structural MRI lesions. Clinical parameters such as IBP and additional SpA features are similarly prevalent in older and younger subjects suggesting they suffer from the same disease and differing only in age of presentation.