To assess effects of caffeine on Parkinson disease (PD).Methods:
In this multicenter parallel-group controlled trial, patients with PD with 1–8 years disease duration, Hoehn & Yahr stages I–III, on stable symptomatic therapy were randomized to caffeine 200 mg BID vs matching placebo capsules for 6–18 months. The primary research question was whether objective motor scores would differ at 6 months (Movement Disorder Society–sponsored Unified Parkinson's Disease Rating Scale [MDS-UPDRS]–III, Class I evidence). Secondary outcomes included safety and tolerability, motor symptoms (MDS-UPDRS-II), motor fluctuations, sleep, nonmotor symptoms (MDS-UPDRS-I), cognition (Montreal Cognitive Assessment), and quality of life.Results:
Sixty patients received caffeine and 61 placebo. Caffeine was well-tolerated with similar prevalence of side effects as placebo. There was no improvement in motor parkinsonism (the primary outcome) with caffeine treatment compared to placebo (difference between groups −0.48 [95% confidence interval −3.21 to 2.25] points on MDS-UPDRS-III). Similarly, on secondary outcomes, there was no change in motor signs or motor symptoms (MDS-UPDRS-II) at any time point, and no difference on quality of life. There was a slight improvement in somnolence over the first 6 months, which attenuated over time. There was a slight increase in dyskinesia with caffeine (MDS-UPDRS-4.1+4.2 = 0.25 points higher), and caffeine was associated with worse cognitive testing scores (average Montreal Cognitive Assessment = 0.66 [0.01, 1.32] worse than placebo).Conclusion:
Caffeine did not provide clinically important improvement of motor manifestations of PD (Class I evidence). Epidemiologic links between caffeine and lower PD risk do not appear to be explained by symptomatic effects.Clinicaltrials.gov identifier:
NCT01738178.Classification of evidence:
This study provides Class I evidence that for patients with PD, caffeine does not significantly improve motor manifestations.