COPENHAGEN – Severe psoriasis is an independent risk factor for serious renal disease – and psoriatic arthritis multiplies that risk even further, according to a Taiwanese national study.
“We think this might be related to the higher inflammatory status associated with psoriatic arthritis. For those with mild psoriasis without psoriatic arthritis, the risk was not increased,” Dr. Ching-Chi Chi said at the annual congress of the European Academy of Dermatology and Venereology.
The past decade has brought a mountain of data documenting that psoriasis, a chronic inflammatory dermatosis, is associated with increased risks of cardiovascular disease, diabetes, and other metabolic abnormalities, noted Dr. Chi, professor of dermatology at Chang Gung University in Taoyuan.
Dr. Ching-Chi Chi
He presented a nationwide retrospective cohort study utilizing Taiwan’s national health insurance system, which covers more than 99% of the population. The study included 4,633 patients with psoriasis diagnosed by a dermatologist or rheumatologist since 2005 and 922,534 controls. A total of 453 patients were classified as having severe psoriasis based upon ever having received systemic treatment or phototherapy; the other 4,180 were classified as having mild psoriasis.
Among the controls there were 36,615 incident cases of chronic kidney disease (CKD) and 9,493 new cases of end-stage renal disease (ESRD) during the study period, translating to rates of 676 per 1,000,000 person-years and 172 per 1,000,000 person-years, respectively. In contrast, patients with severe psoriasis had an incident CKD rate of 2,160 per 1,000,000 person-years and an ESRD rate of 876 per 1,000,000 person-years.
In a Cox regression analysis adjusted for potential confounders including age, gender, comorbid cardiovascular disease, gout, hypertension, dyslipidemia, and use of NSAIDs, severe psoriasis was independently associated with a 1.9-fold increased risk of new-onset CKD and a 3-fold increased risk of ESRD.
Although mild psoriasis alone wasn’t associated with increased risk of renal disease, the 254 patients with mild psoriasis and psoriatic arthritis were at 1.3-fold increased risk of CKD and 2.5-fold increased risk of incident ESRD, compared with controls. Moreover, among the 93 patients with severe psoriasis plus psoriatic arthritis, the risks of incident CKD and ESRD were increased by 2.6- and 6.7-fold over the control subjects.
The new Taiwanese national study confirms earlier work by Dr. Joel M. Gelfand and his coinvestigators at the University of Pennsylvania, Philadelphia. Their population-based cohort study and nested cross-sectional study utilizing a huge U.K. electronic medical records database analyzed 136,529 patients with mild psoriasis, 7,354 with severe psoriasis, and nearly 690,000 matched controls and concluded that moderate to severe psoriasis is associated with an increased risk of stage 3-5 chronic kidney disease (BMJ. 2013 Oct 15;347:f5961).
He reported having no financial conflicts regarding this study.
This article was updated October 29, 2015.