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Researchers Report New Insights Into Parkinson’s Disease-Related Mortality

A Dutch study in JPD identifies risk factors associated with increased mortality in patients with PD compared to the general population

November 8, 2019
Amsterdam, NL – By following a group of newly diagnosed patients with Parkinson's disease (PD) for a decade or more, researchers have been able to identify several factors never before reported that appear to be associated with higher mortality rates in PD patients compared to the general population. As reported in the Journal of Parkinson's Disease, these factors are early onset of PD, early impairment of memory and thinking, and early motor symptoms requiring the start of drug therapy.

“The reduced life span of patients with PD has been reported earlier, but research on factors associated with this decline has been scarce and of limited scope. While life expectancy is a crude outcome, it is clearly a relevant one, and its association with PD-specific characteristics might help to further understand the heterogeneity of disease often reported in PD,” explained Rob M.A. de Bie, MD, PhD, of the Department of Neurology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.

This study differed from previous studies of mortality in PD patients because of its focus on factors affecting mortality related to PD. In this study, 129 newly diagnosed patients (median age 68.2 years) were followed for an average of 13 years or until death. The median survival time was 11.8 years and 85 patients died during the study. The majority of patients were already on levodopa therapy when the study began.

The investigators found that earlier onset of PD, early impairment of memory and thinking, and higher daily antiparkinson medication use (measured in levodopa equivalent dose) were all associated with PD-related mortality. Other factors, such as male sex, poor scores on the Unified Parkinson’s Disease Rating Scale (UPDRS), and general cognitive ability (assessed by the Mini Mental State Examination) did not contribute significantly to the findings.

Dr. de Bie emphasized that the findings do not suggest that levodopa exerts a harmful effect on patients. He maintained that the most plausible explanation is that progressive disease in terms of motor impairment leads to both early levodopa treatment and increased mortality.

The investigators stressed that applying the results from population studies to individuals must be done cautiously. “While we found life expectancy in PD to be decreased on average, accurate prediction of individual life expectancy is a more difficult endeavor. Nonetheless, individualized care starts with a better understanding of differences between patients, and our findings show that individual differences in the manifestation of PD are associated with life expectancy,” noted lead author Jeroen Hoogland, MSc, who is also affiliated with the Department of Neurology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.

PD is a slowly progressive disorder that affects movement, muscle control and balance. It is the second most common age-related neurodegenerative disorder affecting about 3% of the population by the age of 65 and up to 5% of individuals over 85 years of age. PD is associated with an increased mortality ratio of approximately 1.5 when compared to the general population.

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NOTES FOR EDITORS
Full open access study: “Overall and Disease Related Mortality in Parkinson’s Disease – A Longitudinal Cohort Study” by Jeroen Hoogland, MSc; Bart Post, MD, PhD; and Rob M.A. de Bie MD, PhD (DOI: 10.3233/JPD-191652). The article is published in the Journal of Parkinson’s Disease, Volume 9, Issue 4 (October 2019) by IOS Press. It is openly available at: content.iospress.com/articles/journal-of-parkinsons-disease/jpd191652.

This study was funded by ZonMw (Dutch organization for health research and innovation) and the Dutch Parkinson’s Disease Foundation.

Contact
For additional information, contact Diana Murray, IOS Press (+1 718 640-5678 or d.murray@iospress.com). Journalists wishing to interview the study’s authors should contact Rob de Bie (+44 20 566 63842 or r.m.debie@amsterdamumc.nl).

About Journal of Parkinson’s Disease
Launched in 2011, the Journal of Parkinson’s Disease (JPD) is dedicated to providing an open forum for original research in basic science, translational research and clinical medicine that will expedite our fundamental understanding and improve treatment of Parkinson’s disease. The journal is international and multidisciplinary and aims to promote progress in the epidemiology, etiology, genetics, molecular correlates, pathogenesis, pharmacology, psychology, diagnosis and treatment of Parkinson’s disease. JPD publishes research reports, reviews, short communications, and letters-to-the-editor and offers very rapid publication and an affordable open access option. journalofparkinsonsdisease.com

About IOS Press
IOS Press is headquartered in Amsterdam with satellite offices in the USA, Germany, India and China and serves the information needs of scientific and medical communities worldwide. IOS Press now publishes more than 80 international peer-reviewed journals and about 75 book titles each year on subjects ranging from computer science, artificial intelligence, and engineering to medicine, neuroscience, and cancer research. iospress.com