Cause-specific mortality in patients with psoriasis and psoriatic arthritis

Background There are limited data regarding causes of mortality in patients with psoriasis or psoriatic arthritis (PsA). Objectives This retrospective cohort study evaluated the risk and leading causes of mortality in patients with psoriasis or PsA. Methods Individuals with a hospital-based diagnosis of PsA or psoriasis were identified using the Danish National Patient Registry. Matched control individuals were identified from the general population. The main outcome measures were risk of death and cause-specific mortality in patients with psoriasis or PsA. Results Death rates per 1000 patient-years (with 95% confidence intervals) vs. controls were 22.3 (19.7-24.9) vs. 13.9 (11.8-16.0) for patients with psoriasis and 10.8 (8.9-12.8) vs. 11.6 (9.6-13.6) for patients with PsA. Survival, according to stratified hazard ratios (HRs), was significantly lower in patients with psoriasis than in controls (HR 1.74, P < 0.001), but not in patients with PsA (HR 1.06, P = 0.19). Significantly increased risk of death was observed in patients with psoriasis vs. controls due to a number of causes; the highest risks were observed for diseases of the digestive system; endocrine, nutritional and metabolic diseases; and certain infectious and parasitic diseases (HRs 3.61, 3.02 and 2.71, respectively). In patients with PsA, increased mortality was observed only for certain infectious and parasitic diseases (HR 2.80) and diseases of the respiratory system (HR 1.46). Patients with psoriasis died at a younger age than controls (mean age 71.0 vs. 74.5 years, P < 0.001). Conclusions Patients with severe psoriasis have increased mortality risk compared with matched controls, due to a number of causes. Evidence to support an increased risk for patients with PsA was less convincing.