Gout in elderly individuals is associated with a modest increase in the risk of Parkinson’s disease (PD), according to a new study.
From a 5% random sample of Medicare claims data, Jasvinder A. Singh, MD, and John D. Cleveland, MD, of the University of Alabama at Birmingham, found 22,636 patients with PD: 1129 with and 21,507 without gout. The crude incidence rates of incident PD was higher in patients with gout than without it (3.7 vs 2.2 per 1000 person-years), the investigators reported in BMC Neurology. In multivariable analysis, gout was associated with a significant 14% increased risk of PD overall. Among patients at least 65 but less than 75 years of age, gout was associated with a significant 27% increased risk of PD. Gout was not associated with PD among patients aged 75 years or older.
The mean time from gout diagnosis to development of PD was 2.38 years.
Drs Singh and Cleveland observed no significant difference in PD risk by gender or race/ethnicity.
As for how gout might influence PD risk, the authors noted that inflammatory arthritis conditions common in the elderly, such as gout, are associated with increased oxidative stress and chronic inflammation, which has the potential to increase PD risk. Previous studies have demonstrated an antioxidant effect of urate, they noted, but acute and chronic inflammatory states in gout patients could negate these antioxidant effects of urate, if this exists physiologically.
With regard to study limitations, the authors noted that misclassification bias is possible “since we used database diagnosis of PD and gout, and both under-diagnosis and over-diagnosis are possible.” In addition, their study was observational, and this “puts our finding at the risk of confounding bias, despite our attempt to include several covariates and potential confounders, including medications and disease conditions.”
Previous studies looking at an association between gout and PD have yielded inconsistent findings. A study conducted in the United Kingdom found an 11% increased of PD among gout patients, whereas a study of Canadians aged 65 years and older found a 30% decreased risk of PD among gout patients.
Singh JA, Cleveland JD. Gout and the risk of Parkinson’s disease in older adults: a study of U.S. Medicare data. BMC Neurol. 2019;19:4.
Pakpoor J, Seminog OO, Ramagopalan SV, Goldacre MJ. Clinical associations between gout and multiple sclerosis, Parkinson’s disease and motor neuron disease: record-linkage studies. BMC Neurol. 2015;15:16.
De Vera M, Rahman MM, Rankin J, et al. Gout and the risk of Parkinson’s disease: a cohort study.Arthritis Rheum. 2008;59:1549-1554.