Mortality in patients with psoriatic arthritis in Sweden: a nationwide, population-based cohort study

ObjectivesTo compare all-cause mortality and causes of death between patients with psoriatic arthritis (PsA) and the general population in Sweden.MethodsAdults with at least one main PsA diagnosis (International Classification of Diseases-10: L40.5/M07.0-M07.3) from outpatient rheumatology/internal medicine departments 2001-2017 were identified from the National Patient Register. Each case was matched to five population comparator-subjects on sex/county/age at the case's first arthritis diagnosis. Follow-up ran from 1 January 2007, or from first PsA diagnosis thereafter, until death, emigration or 31 December 2018. Mortality was assessed overall, and stratified by sex and duration since diagnosis (diagnosis before/after 1 January 2007), using matched Cox proportional hazard regression (excluding/including adjustments for comorbidity) or Breslow test, as appropriate. Incidence rate ratios (IRR) of death, overall and stratified by sex/duration since diagnosis/age, as well as causes of death in PsA cases and comparator-subjects were also described.ResultsAll-cause mortality was elevated in PsA (HR: 1.11 (95% CI: 1.07 to 1.16); IRR: 1.18 (95% CI: 1.13 to 1.22)), mainly driven by increased risks in women (HR: 1.23 (95% CI: 1.16 to 1.30)) and cases with longer time since diagnosis (HR: 1.18 (95% CI: 1.12 to 1.25)). IRR of death were significantly increased for all ages except below 40 years, with the numerically highest point-estimates for ages 40-59 years. When adjusted for comorbidity, however, the elevated mortality risk in PsA disappeared. Causes of death were similar among PsA cases/comparator-subjects, with cardiovascular disease and malignancy as the leading causes.ConclusionsMortality risk in PsA in Sweden was about 10% higher than in the general population, driven by excess comorbidity and with increased risks mainly in women and patients with longer disease duration.

Automated summary

This study compared the all-cause mortality and causes of death between patients with psoriatic arthritis (PsA) and the general population in Sweden. The findings showed that PsA patients had a slightly higher all-cause mortality rate compared to the general population, mainly driven by increased risks in women and patients with longer disease duration. However, after adjusting for comorbidity, the elevated mortality risk in PsA disappeared. The leading causes of death were cardiovascular disease and malignancy.