Mortality in Patients with Rheumatoid Arthritis: A Retrospective Cohort Study and Systematic Review

Background and Objectives: Mortality rates among patients with rheumatoid arthritis (RA) have been reported to be higher than in the general population. The long-term prognosis of RA has improved in recent years due to early diagnosis, as well as effective pharmacological treatment, and this may be able to diminish the excess mortality risk. This study was designed to investigate mortality (a) in patients with RA in a retrospectively defined national RA cohort in comparison with the general Lithuanian population, and (b) to conduct a systematic review of the literature from different countries and meta-analysis. Materials and Methods: In this national retrospective cohort study, patients with a first-time diagnosis of RA in the period between 1 January 2013 and 31 December 2017 were identified from the Lithuanian Compulsory Health Insurance Information System database SVEIDRA. All cases were cross-checked with the Health Information Center at the Institute of Hygiene, for the vital status of these patients and date of death if documented. The standardized mortality ratios (SMRs) with 95% confidence intervals (CI) obtained for all-cause mortality in patients with RA adjusted for age, sex, and calendar year were calculated. The search for published studies using the combination of keywords “rheumatoid arthritis AND standardized mortality ratio” was performed in MEDLINE (via PubMed, OVID, and EBSCO), Science Direct, Taylor & Francis, and Springer databases. Studies were selected according to described inclusion and exclusion criteria listed in the paper, and a meta-analysis was conducted. A random-effect meta-analysis model was used to compute the pooled standardized mortality ratios (meta-SMRs). Results: Overall, 4623 patients with newly diagnosed RA during the 2013–2017 period were identified and enrolled in the Lithuanian population-based cohort. The mean age of patients at the time of RA diagnosis was 58.7 (standard deviation (SD) 15.1) years, and 77.1% of the patients were women. The estimated SMR for all-cause mortality was 1.15 (95% CI 1.02, 1.29). The SMR for men (SMR 1.14, 95% CI 0.94, 1.39) was higher than for women (SMR 1.03, 95% CI 0.89, 1.19). A systematic literature search revealed 12 studies meeting the inclusion criteria, starting from 2010 to 2020, representing 50,072 patients. The meta-SMR in patients with RA for all-cause mortality was 1.41 (95% CI 1.29, 1.55). All-cause mortality risk was higher for men (meta-SMR 1.53, 95% CI 1.31, 1.78) than for women (meta-SMR 1.46, 95% CI 1.2, 1.77). Conclusions: In a retrospectively defined population-based national RA cohort, a 15% excess risk of death was observed among patients with RA compared to the general Lithuanian population. Patients with RA have a higher mortality risk than the general population. Published data indicate that the risk of mortality is increased by 41% in patients with RA compared to the general population. Excessive all-cause mortality risk is higher in men than in women. National data showed lower standardized mortality compared to literature data.