Risk of Traumatic Injury in Patients With Early-Onset Parkinson's Disease: A Population-Based Matched Cohort Study.

Introduction: Early-onset Parkinson's disease (EOPD) shares similar clinical features to the late-onset form, but the risk of injury remains unclear. This study aimed to evaluate the risk of traumatic injury, including fracture, in patients with EOPD. Methods: This matched cohort study used a Japanese administrative claims database to compare the risk of traumatic injury and fracture between EOPD patients and the general population. EOPD was defined by diagnosis between ages 21 and 49 together with the initiation of anti-PD medication. Crude incidence rates and adjusted hazard ratios (aHRs) were estimated using Poisson and Cox regression models. Subgroup analyses were performed by age and sex. Results: In 368 EOPD patients and 1586 matched individuals from the general population, the traumatic injury rate was slightly higher in EOPD patients (9.5 vs. 7.9 events per 100 person-years), but the difference was not substantial (aHR, 1.2; 95% confidence interval [CI], 0.9-1.5). Fracture risk in the groups was similar, at 1.4 events per 100 person-years (aHR, 0.9; 95% CI, 0.5-1.6). Subgroup analyses showed an increased traumatic injury risk in EOPD patients aged 40-49 years (aHR, 1.4; 95% CI, 1.0-1.8) and in females (aHR, 1.3; 95% CI, 1.0-1.8). No clear differences were observed in other comparisons. Conclusion: No major difference in traumatic injury or fracture risk was found between EOPD patients and the general population. However, preventive interventions may be warranted for patients aged 40-49 years and for females due to their elevated injury risk.