Risk factors and evolution of weight loss in Parkinson's disease: A 9-year population-based study

Weight loss is considered a common complication of Parkinson's disease (PD), but there are few prospective longitudinal studies on weight loss in patients followed from time of PD diagnosis. We sought to determine the frequency, evolution and risk factors of weight loss in a representative incident PD cohort.

In this prospective population-based observational study, we followed 180 newly-diagnosed, initially drug-naïve PD patients and 161 controls with repetitive weight examinations over 9 years. We used Cox regression models with adjustment for potential confounders to identify independent risk factors of clinically significant (>10 %) weight loss.

Mean % weight change during follow-up was -3.9 (±11.2) in patients and -1.4 (±8.1) in controls (p = 0.016). Clinically significant weight loss was observed in 26.7 % of patients and 10.6 % of controls (RR 2.53; 95 % CI 1.52-4.21; p < 0.001). Age was the only independent baseline risk factor for weight loss (HR 1.06 per year; 95 % CI 1.03-1.10; p < 0.001). Additional time-dependent risk factors were presence of olfactory impairment (HR 2.42; 95 % CI 1.14-5.15; p = 0.021), presence of dyskinesias (HR 3.14; 95 % CI 1.58-6.23; p = 0.001), and cognitive impairment (HR per MMSE unit 0.90; 95 % CI 0.82-0.99; p = 0.036). Dopamine agonist use reduced the risk of weight loss during follow-up (HR 0.44; 95 % CI 0.24-0.82; p = 0.007).

The risk of weight loss is more than doubled in the general PD population and associated with both disease-related features and drug-related complications. This suggests a multifactorial nature of weight loss in PD, which is important to consider in research and clinical practice.