Male patients with rheumatoid arthritis have an increased risk of osteoporosis: Frequency and risk factors

Most previous research investigating osteoporosis in rheumatoid arthritis (RA) has focused on female patients and there is a lack of data regarding clinical characteristics of osteoporosis in male patients with RA. The aim of this study was to compare the frequency of osteoporosis between male patients with RA and healthy patients, and to identify the risk factors for osteoporosis and low bone mineral density (BMD) in male patients with RA. We conducted a retrospective, cross-sectional study including 76 South Korean male patients with RA aged over 50 years and 76 age-matched male healthy individuals. BMD was measured at the lumbar spine (L1-4) and left hip (femoral neck and total hip) using dual energy X-ray absorptiometry. Osteoporosis was defined as a T-score of ≤ −2.5 according to the World Health Organization (WHO) classification. The frequency of osteoporosis at either the spine or the hip among male patients with RA was significantly higher than that among controls (22.4% vs 10.5%, P = .049) and RA patients had a significantly lower total hip BMD than healthy individuals (0.92 ± 0.14 vs 0.96 ± 0.1 g/cm(2), P = .027). For male RA patients, the mean 28-joint Disease Activity Scores using erythrocyte sedimentation rate (DAS28-ESR) and body mass index (BMI) were 3.28 and 22 kg/m(2), respectively. In multivariable logistic regression models, BMI ≤ 22 kg/m(2) (odds ratio = 3.43, P = .043) and DAS28-ESR > 3.2 (odds ratio = 3.85, P = .032) were independent risk factors for osteoporosis at either site in male patients with RA. Our data demonstrate that male patients with RA had a 2.1 times higher risk for osteoporosis compared with healthy individuals. This suggests that appropriate management of osteoporosis in patients with RA is crucial not only for postmenopausal women but also for men aged over 50 years, especially those with low BMI and higher disease activity.