Risk of mortality in patients with psoriatic arthritis, rheumatoid arthritis and psoriasis: a longitudinal cohort study

Background There are conflicting reports in the literature of the mortality risk among patients with psoriatic arthritis (PsA). The objective of this study was to examine the risk of mortality in patients with PsA compared with matched controls, patients with psoriasis and those with rheumatoid arthritis (RA). Methods A longitudinal cohort study was performed in a large UK medical record database, The Health Improvement Network, among patients with PsA, rheumatoid arthritis (RA) or psoriasis with data from 1994 to 2010. Unexposed controls were matched on practice and start date within the practice for each patient with PsA. Cox proportional hazards models were used to calculate the relative hazards for death. Results Patients with PsA (N=8706), RA (N=41752), psoriasis (N=138424) and unexposed controls (N=82258) were identified; 1442357 person-years were observed during which 21825 deaths occurred. Compared with population controls, patients with PsA did not have an increased risk of mortality after adjusting for age and sex (disease-modifying antirheumatic drug (DMARD) users: HR 0.94, 95% CI 0.80 to 1.10; DMARD non-users: HR 1.06, 95% CI 0.94 to 1.19) whereas patients with RA had increased mortality (DMARD users: HR 1.59, 95% CI 1.52 to 1.66; DMARD non-users: HR 1.54, 95% CI 1.47 to 1.60). Patients with psoriasis who had not been prescribed a DMARD had a small increased risk of mortality (HR 1.08, 95% CI 1.04 to 1.12) while those who had been prescribed a DMARD, indicating severe psoriasis, were at increased risk (HR 1.75, 95% CI 1.56 to 1.95). Conclusions Patients with RA and psoriasis have increased mortality compared with the general population but patients with PsA do not have a significantly increased risk of mortality.