Osteoporosis in internal medicine outpatients: Sex-specific disparities in prevalence, risk stratification, and treatment in a large cohort

Abstract Background Osteoporosis is a major health problem linked to population aging. Internal medicine outpatients often have multiple comorbidities and a high osteoporosis risk; however, osteoporosis prevalence and treatment rates remain unclear. We investigated osteoporosis prevalence and treatment rates in a large cohort of internal medicine outpatients. Methods This single-center, cross-sectional study used baseline data from the ongoing JUSTICE-TOKYO prospective cohort study ( N = 1,078) of Japanese internal medicine outpatients aged ≥ 65 years. Demographic and clinical characteristics, osteoporosis prevalence, treatment rates, and risk assessment (Osteoporosis Self-assessment Tool for Asians [OSTA]) were assessed. Student’s t-test was used for between-sex comparisons of continuous variables and Pearson’s chi-square test for comparisons of categorical variables. Multivariable logistic regression analysis was performed to identify factors independently associated with osteoporosis. Results After excluding missing data, 1,040 cases were analyzed. The mean age was 78.2 ± 6.1 years. Overall osteoporosis prevalence was 28.3%, and differed significantly between men (15.8%) and women (38.0%) ( p < 0.001). The treatment rate was 29.3% among osteoporosis patients, with a significant difference between men (12.5%) and women (34.7%) ( p < 0.001). In the primary multivariable model adjusted for age, sex, and body mass index (BMI), older age, female sex, and lower BMI were independently associated with osteoporosis. In an exploratory model additionally including grip strength, lower grip strength was independently associated with osteoporosis, whereas the association with female sex was attenuated after adjustment. Conclusion In this cohort, osteoporosis was highly prevalent and substantially undertreated, particularly among men. Significant sex-specific disparities were observed in both osteoporosis prevalence and treatment rates.