Low Bone Mineral Density and Calcium Levels as Risks for Mortality in Patients with Self-Discontinuation of Anti-Osteoporosis Medication

Abstract

Bone mass density (BMD) has been used universally in osteoporosis diagnosis and management. Adherence to anti-osteoporosis medication is related to mortality risk. This study aimed to investigate the relationship between mortality and low BMD of the femoral neck and vertebra among patients self-discontinuing anti-osteoporosis medication. Between June 2016 and June 2018, this single-center retrospective study recruited 596 participants who self-discontinued anti-osteoporosis medication. Patients were categorized into four groups by BMD of the right femoral neck and lumbar spine. Occurrence and causes of mortality were obtained from medical records. Independent risk factors and the five-year survival of various levels of BMD were analyzed by Cox regression and the Kaplan–Meier survival analysis. BMD value and serum calcium level were significantly lower in the mortality group (p < 0.001). Compared to the reference, the adjusted hazard ratio (HR) for all-cause mortality in patients with lower BMD of both the lumbar spine and femoral neck was 3.03. The five-year cumulative survival rate was also significantly lower (25.2%, p < 0.001). A low calcium level was also associated with mortality (HR: 0.87, 95% CI: 0.76–0.99, p = 0.033). In conclusion, lower BMD and calcium levels were associated with higher mortality risk in patients with poor adherence. Hence, patients self-discontinuing anti-osteoporosis medication should be managed accordingly.