Weight Change Has Implications in Parkinson's

A change in body mass index (BMI) does not appear to affect survival in patients with Parkinson’s Disease (PD), according to recent research published in the JAMA Neurology. The study was conducted by Anne-Marie A. Wills, MD, MPH, of the Department of Neurology, at the Massachusetts General Hospital and Harvard Medical School in Boston, and colleagues.

The researchers set out to “explore the association between change in BMI, Unified Parkinson’s Disease Rating Scale (UPDRS) motor and total scores, and survival among persons with PD and to test whether there is a positive association between BMI at randomization and survival.” The main outcome measures were changes in UPDRS score and time to death.

There were 1673 participants included in the final analysis, of which 1074 were male. Only 158 (9.4%) lost weight, thereby decreasing BMI, and 233 (13.9%) gained weight. The majority, 1282 (76.6%) remained weight stable. Decreasing BMI was associated with worse UPDRS scores over time, while increasing BMI was associated with better UPDRS scores. The researchers say, “Although this does not imply causation, our results suggest that weight and BMI are important clinical biomarkers and that data on weight and BMI should be collected even in early PD.”

One unexpected result of this study was that the researchers may have identified “a subtype of PD associated with both decreasing BMI and higher increases in motor and total UPDRS scores.” They offer two theories regarding this potential discovery: “This subtype might represent a more severe, hypermetabolic form of PD or it might be a subtype of PD in which the patient has greater gastrointestinal autonomic symptoms, reduced appetite, and reduced oral intake.”

Because the participants were enrolled at an early stage of the disease, there were few deaths during the course of this trial, which represents a limitation of this study. Given the number of questions this study raised, the researchers say that there is a “need for further study of weight changes in PD.”