Abstract
OBJECTIVE: Multimorbidity (the coexistence of two or more long-term conditions) is highly prevalent in people who have rheumatoid arthritis (RA). The present work systematically reviewed the literature to determine the effect of multimorbidity on all-cause mortality, functional status, and quality of life in RA. METHODS: Six electronic databases were searched: CINAHL, The Cochrane Library, Embase, Medline, PsycINFO, and Scopus. Full-text longitudinal observational studies in English were selected. Quality appraisal of studies was undertaken using the Cochrane-developed QUIPS tool and a narrative synthesis of findings conducted. RESULTS: The search strategy identified 5,343 articles, with 19 studies meeting the inclusion criteria. Nine studies had mortality as an outcome, 9 reported functional status and/or quality of life, and 1 study reported both mortality and functional status. The number of participants ranged from 183 to 18,485, with studies conducted between 1985 and 2018. The mean age of participants ranged from 52.0 to 66.6 years, and 60.0-88.0% were female. Nine studies showed a significant association between multimorbidity and higher risk of mortality in people with RA. Ten studies reported significant associations between multimorbidity and reduced functional status in RA. Three studies also showed a further association with reduced quality of life. Only one study investigated the influence of mental health comorbidities on outcomes. CONCLUSION: Our review findings indicate that multimorbidity is a significant predictor for higher mortality and poorer functional status/quality of life in people with RA and should be considered in clinical management plans.