Confounding by Indication in Observational Studies Investigating Glucocorticoid-Associated Adverse Events in Rheumatoid Arthritis: A Protocol for a Systematic Review

Background Glucocorticoids (GCs) are regularly used drugs in rheumatoid arthritis (RA), but they can cause adverse events (AEs). Observational studies provide important real-world evidence but can be biased. Observational studies investigating the association between AEs and GCs in RA are

particularly susceptible to confounding by indication as patients with higher disease activity are more likely to suffer from AEs and more likely to receive GCs.

Objective To assess how often observational studies in RA which investigate the association between GCs and certain AEs adjust for disease activity (such as the disease activity score-28 joints) and/or systemic inflammation (such as serum C-reactive protein levels).

Methods A systemic literature review will be conducted and reported in compliance with the 2020 PRISMA statement.

Protocol.pdf