Systemic therapy cuts risk of Parkinson’s disease in psoriasis patients

Psoriasis patients taking systemic anti-inflammatory agents have a significantly lower risk of Parkinson’s disease, a recent study has shown.

The authors conducted a nationwide population-based cohort study to determine the incidence rates and risk factors of Parkinson’s disease in patients with psoriasis. They analysed data from a total of 548,327 patients with psoriasis aged ≥20 years (53.32 percent men) and from 2,741,635 age- and sex-matched controls without psoriasis.

The incidence rates of Parkinson’s disease were 0.768 per 1,000 person-years in the psoriasis group and 0.673 per 1,000 person-years in the control group. Patients with psoriasis were at significantly higher risk of developing Parkinson’s disease (hazard ratio [HR], 1.091, 95 percent confidence interval [CI], 1.029–1.115) than controls.

In addition, the risk of Parkinson’s disease was significantly greater among patients with psoriasis who did not receive systemic therapy (HR, 1.093, 95 percent CI, 1.031–1.159) and lower among those on systemic therapy (HR, 1.04, 95 percent CI, 0.806–1.316).

In an earlier study by Jau-Jiuan Sheu and colleagues in Taiwan, patients with psoriasis were found to have a significantly increased risk of parkinsonism. In stratified Cox proportional hazards regression, psoriasis patients had a 74-percent higher risk for parkinsonism than controls during the 5-year follow-up (HR, 1.74, 95 percent CI, 1.35–3.20). [J Am Acad Dermatol 2013;68:992-999]

The current study had certain limitations, including its retrospective design, patient inclusion based solely on diagnostic codes, and unavailability of data on confounding factors, according to the authors.