FROM THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
Patients with both psoriasis and major depressive disorder face an adjusted 37% greater risk of developing psoriatic arthritis (PsA) over a median follow-up of 5.1 years, a new study finds.
The findings don’t definitively prove that depression plays a role in PsA. Still, “physicians managing patients with psoriasis must make efforts to identify and address depression, as this comorbidity may have a downstream impact,” study coauthor Cheryl Barnabe, MD, MSc, said in an interview.
Researchers have linked psoriasis to a greater risk of depression. Another study found that patients with psoriasis had twice the odds of developing major depression, although there was no sign that increased severity boosted the risk (odds ratio, 2.09; 95% confidence interval, 1.41-3.11; P less than .001). Almost 17% of 351 patients with psoriasis showed signs of the condition ( JAMA Dermatol. 2016 Jan;152:73-9 ).
For the new study published by the Journal of Investigative Dermatology, researchers tracked 73,447 people in the United Kingdom with psoriasis through a primary care medical records database for up to 25 years. The study statistics come from the years 1987-2012, reported Ryan T. Lewinson of the Cumming School of Medicine, in Calgary, Alta., and his associates (J Invest Dermatol. 2017. doi: 10.1016/j.jid.2016.11.032 ).
The median age at psoriasis diagnosis was 49.5 years (range, 20-90 years) and the median follow-up time was 5.1 years; 2% of the patients developed PsA and 7% developed major depression.
Via an unadjusted model, those with signs of depression were 1.56 times more likely to develop PsA (hazard ratio; 95% CI, 1.28-1.90; P less than .0001). In a model adjusted for factors such as age, gender, and obesity status, the extra risk of PsA was 1.37 (HR; 95% CI, 1.05-1.80; P = .021).
“The study draws into question the biological mechanisms by which depression increases the risk for developing psoriatic arthritis,” said Dr. Barnabe, an associate professor with the departments of medicine and community health sciences at the University of Calgary and a rheumatologist with Alberta Health Services.
The study notes that depression is linked to poor diet and lack of exercise, factors that could contribute to PsA. The authors also point out that researchers have linked depression to inflammation, a crucial component of both psoriasis and PsA, although they note that the study doesn’t examine systemic inflammation.
What’s next? “Mental health in chronic inflammatory diseases is not well addressed at the present time, in our system anyway, and should be a prime area of focus,” Dr. Barnabe noted. “Depression occurs at elevated rates in both psoriasis and psoriatic arthritis, and there is certainly a role for treatment to assist with disease management.”
The study authors reported no specific study funding and no relevant financial disclosures.