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

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.

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.

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.

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.

PROSPERO (CRD42019134675).