Comorbid conditions associated with Parkinson's disease: A longitudinal and comparative study with Alzheimer disease and control subjects

Abstract Background and objective To study what comorbid conditions were present at baseline and 3years later in a cohort of Spanish Parkinson's disease (PD) patients, to compare comorbidity with both Alzheimer's disease (AD) and control groups and to analyze the role of comorbidity as predictor of mortality. Methods One hundred and forty-seven non-demented PD patients (57.1% males; 70.9±8.6years old) were included in this 36months follow-up (2012–2015), monocenter, evaluation study. The International Classification of Diseases, Tenth Revision (ICD-10), Charlson Index (CI), Comorbidity-Polypharmacy Score (CPS) and Elixhauser Comorbidity Measure (ECM) were used to assess comorbidity at baseline and at 3years. Forty-four AD patients and 44 control subjects were included as comparator groups. Results Total number of comorbidities (ICD-10) and polypharmacy at baseline were higher in PD and AD patients than controls (4.4±2.3 vs 5.2±2.4 vs 3.4±1.9 [ p =0.001] and 81.6% vs 75% vs 56.8% [ p =0.003], respectively). Diseases of the circulatory system (ICD-10/chapter-IX) and endocrine, nutritional and metabolic diseases (ICD-10/chapter-IV) were the most frequent in all groups. There was a significant increase in comorbidity (mean, +1.6±2.8) in all groups ( p p =0.017); CI, hazard ratio 1.462 (95% confidence interval, 1.045–2.047; p =0.027). Conclusions Comorbidity is frequent in PD patients, increases significantly over time and predicts mortality.