Background The Ankylosing Spondylitis Registry of Ireland (ASRI) is a web-based database established in 2013, the objectives of which are to provide descriptive epidemiological data on the ankylosing spondylitis (AS) population in Ireland and to establish a registry for potential future studies of genetics, aetiology and therapeutics. The prevalence of osteoporosis is higher in AS patients than age- and sex-matched controls, with potential for vertebral fractures increased. However, the true prevalence is unknown. There is no data on the prevalence of osteoporosis in an Irish cohort.
Objectives To determine the prevalence of low bone mineral density (BMD) in an Irish AS cohort.
Methods A standardised detailed clinical assessment was performed on each patient. Disease activity was assessed by Bath AS Disease Activity Index (BASDAI), function by the Bath AS Functional Index (BASFI) and Health Assessment Questionnaire (HAQ) and quality of life by AS Quality of Life (ASQoL). Structured interviews provided patient-reported data. Presence or absence of dual-energy x-ray absorptiometry (DXA) testing and result was recorded. Bone mineral density (BMD) was categorised according to the World Health Organisation criteria into normal BMD, osteopenia or osteoporosis. Statistical analysis was performed using SPSS.
Results As of October 2015, 416 patients are enrolled in ASRI: 78.1% males, mean age 47.95 (SD 12.4), mean disease duration 20.9 years (SD 12.2), average delay to diagnosis of 8.8 years (SD 8.3). Mean BASDAI is 3.8 (SD 2.5), BASFI 3.7 (SD 2.7), HAQ 0.53 (SD 0.51) and ASQoL 6.15 (SD 5.5). DXAs have been performed in 24.75% (n=103) of the cohort, of which 39.8% (n=41) have osteopenia and 10.7% (n=11) have osteoporosis. Low BMD is significantly correlated with men and advancing age. There is no association with disease activity or duration. Low BMD is more prevalent in patients treated with one or more biologics compared to those never treated. The self-reported prevalence of osteoporosis is 6.4% (n=27; 19 males).
Conclusions There is an elevated prevalence of low BMD in this cohort, with no association with disease severity. The majority of affected patients were unaware, as demonstrated by the low self-reported prevalence. More research and education is needed.
Disclosure of Interest None declared