Prevalence and risk factors of osteoporosis in patients with chronic obstructive pulmonary disease

Background: Osteoporosis is a significant comorbidity in patients with chronic obstructive pulmonary disease (COPD). This study examined the prevalence and risk factors associated with osteoporosis in patients with COPD. Methods: The bone mineral densities (BMDs) of the lumbar spine and femoral bone were measured in 53 patients with clinically stable COPD and 41 age- and gender-matched control subjects showing a normal lung function. Osteoporosis was defined as a T-score ≤-2.5. The subjects' clinical characteristics and laboratory data were reviewed, and multiple logistic regression analysis was used to identify the risk factors associated with osteoporosis in COPD patients. Results: The prevalence of osteoporosis was 47% and 32% in the COPD patients and controls, respectively. In particular, using the femoral neck T-score, the prevalence of osteoporosis in COPD patients was higher than that in the controls (26% vs. 5%; p=0.006). The average T-score of the lumbar spine (p=0.025) and femoral neck of COPD patients were significantly lower than those of the controls (p=0.001). The forced expiratory volume in the 1 second (FEV ₁) % predicted (p=0.019; odds ratio [OR], 0.955; 95% confidence interval [CI], 0.919-0.993) and age (p=0.024; OR, 1.144; 95% CI, 1.018-1.287) were independently associated with osteoporosis in patients with COPD. Conclusion: Using the femoral neck T-score, the prevalence of osteoporosis in patients with COPD was higher than the age-and gender-matched controls. A lower FEVi and older age further increase the risk of osteoporosis in patients with COPD.