Clinical features in early Parkinson disease and survival

Abstract

Objective: To examine the association between demographic and clinical features in early Parkinson disease (PD) and length of survival in a multiethnic population.

Design: Clinical features within 2 years of diagnosis were determined for an inception cohort established during 1994-1995. Vital status was determined through December 31, 2005. Predictor variables included age at diagnosis, sex, race/ethnicity, as well as clinical subtype (modified tremor dominant, postural instability gait difficulty), symmetry, cognitive impairment, depression, dysphagia, and hallucinations. Cox proportional hazards regression analysis was used to identify factors associated with shorter survival.

Setting: Kaiser Permanente Medical Care Program, northern California.

Patients: Five hundred seventy-three men and women with newly diagnosed PD.

Results: Three hundred fifty-two participants in the PD cohort (61.4%) had died in the follow-up period. Older age at diagnosis (hazard ratio [HR], 1.1; 95% confidence interval [CI], 1.09-1.12), modified postural instability gait difficulty subtype (HR, 1.8; 95% CI, 1.3-2.7), symmetry of motor signs (HR, 2.0; 95% CI, 1.1-3.7), mild (HR, 1.7; 95% CI, 1.3-2.2) and severe (HR, 2.7; 95% CI, 1.9-3.9) cognitive impairment, dysphagia (HR, 1.4; 95% CI, 1.1-1.9), and hallucinations (HR, 2.1; 95% CI, 1.3-3.2) were associated with increased all-cause mortality, after adjusting for age, sex, and race/ethnicity. None of the other factors altered mortality risk. In an empirical predictive analysis, most previous significant predictors remained associated with shorter survival.

Conclusions: Both motor and nonmotor features in early PD predict increased mortality risk, particularly postural instability gait difficulty, cognitive impairment, and hallucinations. These predictors may be useful in clinical practice and when designing clinical trials.