Cause-specific mortality in patients with psoriatic arthritis and rheumatoid arthritis

Abstract

Objective: The objective of this study was to examine cause-specific mortality in patients with PsA compared with the general population and compared with patients with RA.

Methods: A cohort study was performed using The Health Improvement Network among patients aged 18-89 years with data from 1994 to 2010. PsA and RA were defined by medical codes, and up to 10 unexposed controls were matched on practice and start date within the practice. Cause of death was classified using categories from UK death statistics. Each death was manually reviewed to ensure appropriate classification. Age- and sex-adjusted hazard ratios (HRs) and multivariable adjusted HRs were calculated using competing risks survival regression.

Results: Among patients with PsA (8706), RA (41 752) and unexposed controls (81 573), 470, 7004 and 5269 deaths were observed, respectively. The most common causes of death among all patients were cardiovascular disease, followed by malignancy, respiratory deaths and infection. Cause of death was unknown in ∼25%. Among PsA patients, cardiovascular (1.09, 0.91-1.32), respiratory (0.97, 0.79-1.20), malignancy (1.03, 0.86-1.25) and infection deaths (1.05, 0.79-1.39) were not elevated. Among patients with RA, cardiovascular (1.55, 1.44-1.66), respiratory (1.85, 1.72-2.01), malignancy (1.18, 1.08-1.28) and infection deaths (2.21, 2.00-2.44) were significantly elevated compared with population controls. Although less common, suicide deaths were elevated in PsA and RA (HR 3.03 and 2.47, respectively).

Conclusion: Overall mortality and cause-specific mortality risk were not elevated among patients with PsA except for suicide deaths. Patients with RA were at increased risk of deaths from cardiovascular, respiratory, cancer and infectious diseases.

Keywords: epidemiology; mortality; psoriatic arthritis; rheumatoid arthritis; suicide.