Patients with dementia are less likely to survive Parkinson’s disease than non-dementia patients, a large U.S. study has revealed.

Researchers at Washington University School of Medicine in St. Louis examined the records of about 140,000 people with Parkinson’s disease throughout the U.S. who were also Medicare beneficiaries between 2002 and 2008.

Their findings, reported in the journal Archives of Neurology, include that men were more likely to die from Parkinson’s disease than women.

Approximately the same percentage of black and white patients died during that six-year time period (66 and 65 percent, respectively) – compared to 55 percent of Hispanic patients and 51 percent of Asian patients.

And patients with both Parkinson’s and dementia were less likely to survive, researchers found.

Dementia had the strongest effect on age-adjusted survival rates of Parkinson’s patients, the authors noted.

“Our data highlight the need for prevention of, or treatment, for dementia in patients with PD because of its effect on survival.”