All-Cause and Cause-Specific Mortality in Parkinson's Disease: A Meta-Analysis

Objectives: This study aimed to assess the overall and cause-specific standardized mortality ratios (SMRs) in patients diagnosed with Parkinson's disease (PD).

A systematic review was conducted, focusing on studies that evaluated SMRs for all-causes and specific causes in PD patients compared to the general population. Searches were performed extensively in Medline, Embase, and Cochrane databases to compile relevant literature. A meta-analysis was subsequently conducted to evaluate all-cause, sex-specific, region-specific, and cause-specific SMRs in individuals with PD.

Twenty-one studies including 26,114 PD patients and 10,247 deaths from 12 European, 4 Asian, 3 Oceanian, 1 North American, and 1 Middle Eastern country met the inclusion criteria. The overall SMR analysis revealed that PD patients exhibited a 1.617-fold higher risk of all-cause mortality compared to the general population (SMR 1.617, 95% confidence interval [CI] 1.295-2.020, p < 0.001). Region-specific analysis showed significant SMR increases across all regions. Sex-specific analysis indicated elevated SMRs for both women (SMR 1.702, 95% CI 1.426-2.033, p < 0.001) and men (SMR 1.588, 95% CI 1.365-1.848, p < 0.001). PD onset before 60 years of age was associated with a higher, albeit not statistically significant, SMR compared to onset after 60 (SMR 1.991, 95% CI 1.313-3.021 vs. SMR 1.589, 95% CI 1.109-2.277). Cause-specific analyses revealed significantly increased SMRs for pneumonia (SMR 3.414, 95% CI 2.227-5.234, p < 0.001), cerebrovascular accidents (CVAs) (SMR 1.484, 95% CI 1.048-2.102, p = 0.026), cardiovascular disease (SMR 1.449, 95% CI 1.156-1.816, p = 0.001), and suicide (SMR 2.049, 95% CI 1.383-3.035, p < 0.001), with no significant increase observed for cancer-related mortality.

These findings highlight the increased mortality risk in PD patients, particularly due to causes such as pneumonia and CVA.