Exploring changes in placebo treatment arms in hidradenitis suppurativa randomized clinical trials: A systematic review

Background: Hidradenitis suppurativa (HS) is characterized by recurrent, painful nodules in flexural areas. Objective: The objective of this study was to explore the placebo response in HS randomized clinical trials and to compare it briefly with the placebo response in psoriasis and atopic dermatitis. Methods: A Cochrane Review on interventions in HS was used as a starting point, and a systematic review was then undertaken by using the PubMed database, yielding 7 HS randomized clinical trials for inclusion in this study. Results: This review demonstrates that there is a robust placebo response in HS that is most marked in physical signs but also marked in pain responses. Limitations: Multiple outcome measures utilized in these studies and reporting bias limited this review. Conclusion: This large placebo response has implications for clinical trial design. This knowledge can also help deliver improved clinical care by forming the basis of nonpharmacologic treatments and help optimize current medication use to maximize the placebo effect.