Baseline C-Reactive Protein Levels and Life Prognosis in Parkinson Disease.

Abstract

BackgroundC-reactive protein (CRP) is a biomarker of inflammation, and high levels of CRP correlate with vascular death. Chronic inflammation is considered to be involved in neurodegeneration, although there is no evidence linking it with the process of neurodegenerative diseases.ObjectiveTo determine the role of baseline CRP levels in the prognosis of patients with Parkinson disease (PD).MethodsA cohort of 313 patients with a mean age of 69.1 and mean PD duration of 7.9 years was retrospectively followed for a mean observation time of 1,753 days. CRP was measured when patients were not diagnosed with any infections, and levels were repetitively measured to investigate a tendency of “regression to mean.” The primary outcome measure was a survival time from study enrollment to death.ResultsDuring the observation period 56 patients died. Baseline CRP was log-linearly associated with a risk of death in PD. Mean survival time was 3,149 (95% confidence interval; 3,009-3,289) days in patients with CRP ≤ 0.8mg/L (lower two thirds) and 2,620 (2,343-2,897) days in those with CRP > 0.8 mg/L (top third, p < 0.001, log-rank test). The adjusted hazard ratio (HR) per two-fold higher CRP concentration for all deaths was 1.29 (1.10-1.52), and after excluding PD-unrelated deaths, such as cancer or stroke, HR was 1.23 (1.01-1.49) (adjusted for age, sex, PD duration, modified Hohen-Yahr stages, MMSE scores, and serum albumin).ConclusionsBaseline CRP concentrations were associated with the risk of death and predicted life prognosis of patients with PD. The associations were independent from PD duration, PD severity, cognitive function, ages, and nutritional conditions, suggesting the possibility that subclinical chronic inflammation is associated with a neurodegenerative process in PD.