Objective: To study how corticosteroid therapy is planned and described in reports of systemic disease trials and estimate the impact of the between-arm difference in corticosteroid dose on treatment effect.
Methods: We performed a systematic review of PubMed and Cochrane databases on all reports of randomized systemic disease trials with corticosteroids as a cointervention. Data were extracted on the trial characteristics and results, planning of corticosteroid use, and dose. Success rates were adjusted for corticosteroid use for studies with available data and a binary outcome. Because the exact impact of between-arm differences in corticosteroid dose on success rates is unknown, we tested different values for the impact of a difference of 1 unit (1 mg for daily dosage or 250 mg for cumulative dose at the end of the trial).
Results: A total of 139 trials were identified, including 79 investigating lupus and 30 investigating vasculitis. Planned management of corticosteroid use was specified in 101 reports (72.7%), with a fully described tapering scheme in 33 (23.7%). Corticosteroid consumption for each arm was given in 60 reports (43.2%), with a comparison of daily or cumulative dosage at the end of the trial in 32 (23.0%). An attempt to adjust for corticosteroid use was described in 2 (1.5%). With a value of 2.5% for the impact of a 1-unit difference in corticosteroid dose, adjustment yielded changes in success rate differences exceeding 10% in 11 (46%) of the 24 reports analyzed.
Conclusion: For systemic disease trials, use of corticosteroids as a cointervention is often inadequately planned and reported and could affect treatment effect.