Predictors of Mortality in Nondemented Patients With Parkinson Disease: Motor Symptoms Versus Nonmotor Symptoms

Abstract

Background and objective: The aim of this study is to identify risk factors for mortality in a community-based cohort of nondemented patients with Parkinson disease (PD) during prospective long-term follow-up, while also comparing the effect of motor complications to nonmotor symptoms (NMS) on risk of mortality.

Methods: One hundred forty seven nondemented patients with PD (57.1% males; 70.9 ± 8.6 years old) were included in this 48 month follow-up, longitudinal, single, evaluation study. Motor and therapy-related complications were assessed using the Unified Parkinson's Disease Rating Scale/part-IV (UPDRS-IV). Non-Motor Symptoms Scale (NMSS) total score was used to assess NMS burden. Cox proportional hazard models were applied to identify independent predictors of mortality during follow-up.

Results: Twenty-two patients of 146 (15.1%) died (1 case without information). Both UPDRS-IV and NMSS total scores were higher at baseline in patients with PD who died (3.5 ± 3.1 vs 2.4 ± 2.4, P = .049 and 96.9 ± 58.6 vs 61.9 ± 51.0, P = .004, respectively). Unadjusted hazard ratios (HRs) associated with UPDRS-IV and NMSS total scores among those who died during follow-up were 1.171 (95% confidence interval [CI]: 1.012-1.357; P = .035) and 1.008 (95% CI: 1.002-1.013; P = .006), respectively. Independent predictors of mortality during follow-up after adjusting for other covariates were UPDRS-IV (HR: 1.224; 95% CI: 1.002-1.494; P = .047), age (HR: 1.231; 95% CI: 1104-1.374; P < .0001), and comorbidity (Charlson Index; HR: 1.429; 95% CI: 1.023-1.994; P = .036), but not NMSS total score (HR: 1.005; 95% CI: 0.996-1.014; P = .263).

Conclusions: Both motor complications (UPDRS-IV) and NMS (NMSS) were associated with mortality at 4 years, being motor complications an independent predictor of it.

Keywords: Parkinson disease; comorbidity; mortality; motor complications; nonmotor symptoms; outcome.