Glucocorticoid-trials in rheumatoid arthritis mostly study representative real-world patients: A systematic review and meta-analysis

Objective: Randomized controlled trials (RCTs) are considered the gold standard in clinical research due to credible causality. Their results, however, may not be generalizable to real-world populations. While glucocorticoids (GCs) remain a mainstay of rheumatoid arthritis (RA) treatment, it is unclear whether the results of GC-RCTs are generalizable to current real-world RA patients. Methods: MEDLINE was searched for RCTs and, as comparators, cohort studies (CSs) in RA evaluating systemic GCs. Random-effects meta-analyses were performed for descriptive baseline characteristics (including general demographics, comorbidities, and disease activity) that have been shown to be able to modify the benefit-risk-ratio of various RA therapeutics. These meta-analyses were stratified by study type (RCT and CS). Stratified estimates were subsequently compared. Further sensitivity analyses were performed stratifying by disease duration. Results: 56 RCTs (7053 participants) and 10 CSs (14,688 participants) were included. 12 characteristics were reported frequently enough to allow for comparative analysis. In 10/12 characteristics (83%), RCT estimates did not appear to differ from CS estimates. However, RCT participants were younger (-4.7 years [95% CI -7.2 to -2.1]; p < 0.001) and had higher erythrocyte sedimentation rates (11.8 mm/h [5.7 to 17.8]; p < 0.001) than CS participants. Comorbidities could not be assessed due to insufficient reporting. Conclusion: Our findings suggest that evidence from GC trials in RA is of acceptable generalizability to current real-world patients – especially compared to findings from biologic agents in RA. However, RCT participants were younger than real-world patients, potentially limiting the generalizability of trial results to elderly patients. Systematic review registration: PROSPERO (CRD42019134675)