Supplementary Material for: How Much Do We Know about Maintaining Treatment Response after Successful Acne Therapy? Systematic Review on the Efficacy and Safety of Acne Maintenance Therapy

After cessation of successful initial acne therapy, patients often experience flares. Consecutive maintenance treatment after successful induction therapy is promoted by guidelines; however, little is known about the efficacy/safety of different maintenance regimens. A systematic review on acne maintenance treatments was conducted. We identified 5 randomized controlled trials [RCTs; adapalene vs. vehicle or vs. no treatment (3 RCTs), adapalene/benzoyl peroxide (BPO) vs. vehicle, combination/monotherapy of minocycline (systemic)/tazarotene/placebo] and 3 non-RCTs on systemic isotretinoin, adapalene/BPO and azelaic acid. The results of adapalene versus vehicle/no treatment varied depending on the reported outcome. The ‘number of patients maintaining at least 50% improvement' counting inflammatory lesions/non-inflammatory lesions with adapalene was superior to vehicle (risk ratio, RR 1.24, 95% confidence interval, CI 1.08-1.43/RR 1.34, 95% CI 1.18-1.59). However, no significant differences were found in 2 of 3 RCTs for maintaining ‘clear/almost clear' or ‘mild acne' or on the global grading score. For the combination regimens of minocycline/tazarotene/placebo, no significant differences were found. Adapalene/BPO was superior to vehicle counting inflammatory lesions/non-inflammatory lesions (RR 1.61, 95% CI 1.31-1.99; RR 1.80, 95% CI 1.44-2.26). Due to the scarcity of studies, few conclusions can be drawn. More homogeneous outcome measures and specific maintenance study designs may lead to more robust findings.