Acne Relapse Rate and Predictors of Relapse Following Treatment with Oral Isotretinoin

Background: Relapse rates in patients with acne after treatment with oral isotretinoin vary between 10% and 60% depending on the dosage regimen used, the length of follow-up, and the characteristics of the study population. The aim of this study was to determine the acne relapse rate within 2 years of completion of isotretinoin therapy and to identify the prognostic factors associated with relapse. Material and methods: We studied a series of patients with cystic acne who had received a cumulative therapeutic dose of at least 120 mg/kg of oral isotretinoin. Data were analyzed using descriptive and analytical statistical methods. The relapse rate was expressed as the number of events divided by the amount of person-time. Factors predicting relapse were identified using multivariate Cox regression analysis. Results: A total of 142 patients were followed up for 24 months or until relapse occurred. The relapse rate was 15 events per 100 person-years of follow-up. The risk of relapse was twice as high among men. The protective effect of maintenance treatment with topical retinoids was 32% for each month of use. The risk of relapse was 3.5 times higher among women not receiving antiandrogen therapy. Conclusions: The relapse rate in our study was high and similar to that reported in the literature, Maintenance treatment with topical retinoids in men and women and androgen treatment in women helped to prevent relapse. (C) 2011 Elsevier Espana, S.L. and AEDV. All rights reserved.