Excess risk of fracture in incident Parkinson's disease Medicare beneficiaries.

BACKGROUND: Parkinson's disease (PD) is the second most common neurodegenerative disease, characterized by both motor and non-motor symptoms. Falls and fractures are common in advanced PD but the risk of fractures in newly diagnosed people with PD and the impact of treatment with levodopa is understudied. METHODS: We investigated the risk of fractures among Medicare beneficiaries with incident PD age ≥ 67 compared to controls. Among PD cases only with continuous Part D medication coverage, we examined the effect of levodopa treatment on fracture risk. We identified incident PD cases (N = 68,150) within a population-based sample of 2017 Medicare beneficiaries. Controls (N = 272,600) were matched 4:1 on age, sex, and month/year of the date of PD diagnosis. We used claims data from 2017-2019 to follow cases and controls to identify new fractures. Our primary outcome was any fracture. We classified fractures secondarily by body region (spine/vertebral, torso, pelvis, upper extremity, lower extremity [and separately hip]). We used competing risks regression models to estimate subhazard ratios (SHR) and 95% confidence intervals (CI) for the association between fracture and PD after adjusting for covariates. Among PD cases with continuous medication coverage (N = 61,317), we examined the effect of levodopa treatment in PD cases ever prescribed levodopa for 90 days (≥ 1 prescription fill). RESULTS: Following PD diagnosis/control reference date, the most common fracture location in incident PD cases and controls was in the hip, followed by the spine. PD cases had a greater risk of any fracture in all body regions compared to controls at any given time: any fracture (SHR 1.35, 95% CI 1.31-1.39), spine (SHR 1.47, 95% CI 1.35-1.59), hip (SHR 1.36, 95% CI 1.30-1.44), and upper extremity (SHR 1.34, 95% CI 1.22-1.48). PD cases who used levodopa for 90 days had a lower risk of any fracture (SHR 0.76, 95% CI 0.72-0.81) than those without treatment. This was also true for individual fracture types in all body regions with the exception of the torso and pelvis. CONCLUSION: Medicare beneficiaries with incident PD have a greater risk of fracture in all body regions compared to controls and this risk may be reduced with levodopa use.