Prevalence of bone mineral density loss and potential risk factors for osteopenia and osteoporosis in rheumatic patients in China: logistic regression and random forest analysis.

Background: The objective of this study was to explore the prevalence of change in bone mineral density (BMD) and the potential risk factors for osteopenia and osteoporosis in rheumatic patients.

Methods: An analytical cross-sectional study design was carried out. For this study, one thousand and seven rheumatic patients were recruited and further accepted for data collection and blood and BMD tests. The potential risk factors for osteopenia and osteoporosis in rheumatic patients were further analyzed by using both logistic regression analysis and random forest (RF) analysis.

Results: 41.1% of the male patients aged 50 years or above and 50.8% of postmenopausal patients were osteoporotic in their lumbar spine. Among these patients, the prevalence of osteoporosis in the femoral neck and total hip was 19.4% and 8.9% in men, and 27.6% and 16.5% in women respectively, while more than half of the rheumatic patients had osteopenia in the femoral neck and total hip. For men younger than 50 years and premenopausal women, BMD were lower than the health population in the femoral neck (16.5% and 18.3% respectively) and the total hip (17.4% and 10.4% respectively). Older age, body mass index (BMI) <18.5 kg/m, female sex and glucocorticoid use were associated with lower BMD in the lumbar spine, femoral neck, and total hip of patients. In RF analysis, age was ranked as the most important factor for osteopenia in the lumbar spine, femoral neck, and total hip of patients, followed by glucocorticoid use and BMI.

Conclusions: More interventions should be given to osteopenia patients because of the higher prevalence when compared with osteoporosis patients. Older age, BMI <18.5 kg/m, female sex and glucocorticoid use were associated with lower BMD in rheumatic patients. The results from the logistic regression can be supplemented by random forest analysis.