Association between Diabetes and Rheumatoid Arthritis: A Systematic Literature Review


 
 To examine the risk of diabetes mellitus (DM) in patients with rheumatoid arthritis (RA) and whether the risk is related to conventional risk factors, RA disease activity, and treatment.
 
 
 
 A systematic literature review (SLR) query was conducted using specified MeSH terms, searching PubMed and EMBASE databases from inception to March 2020. Both cohort or case-control design studies assessing the incidence or prevalence of DM in RA patients were included.
 
 
 
 Of the 1948 articles, 43 peer-reviewed observational studies were selected. A high degree of heterogeneity in study design and reporting was observed, precluding final conclusions.
 Based on the studies included, it was observed that DM prevalence ranged between 1% and 20% in RA patients, which was similar to controls (1–29%). The cumulative incidence of DM in RA patients ranged between 1.3% and 11.7% over different time frames. DM incidence rates in patients with RA per 1000 person-years ranged from 5.2 to 16.7. 
 RA patients may be at higher risk of DM, particularly among those receiving glucocorticoids (GC), while patients on hydroxychloroquine and biological disease-modifying anti-rheumatic treatments (DMARDs) may be at lower risk.
 
 
 
 DM incidence may be increased in patients with RA as a result of more concomitant traditional risk factors and GC exposure. It is unclear whether biologics may have a true protective effect or provide a GC-sparing effect. High-quality studies in large cohorts of RA patients with appropriate adjustment for covariates are warranted to fully investigate the interplay between DM and RA.
