Variability and Predictors of Isotretinoin Dosing in Acne Patients: A Retrospective Cohort Study

Isotretinoin prescription for acne varies widely, partially due to inconsistent guidelines. This leaves physicians to rely on clinical judgment, experience, and institutional practices.

We examined real-world isotretinoin prescribing patterns among dermatologists in a large healthcare system, focusing on dosing variability and predictors of total cumulative dosage.

This retrospective cohort study at Kaiser Permanente Northern California (KPNC) included 9,551 KPNC members aged 13-40 years who received ≥1 isotretinoin prescription for acne from January 1, 2016, through December 31, 2022. The primary outcome was cumulative isotretinoin dose (mg/kg). Secondary outcomes included starting and maximum daily doses, time-to-maximum dose, and total treatment duration.

Among 9,551 participants, most were <18 years old (N=5,609 (59%)), with an equal gender split (female: N=4,911 (51%)). Common starting doses were 0.5-0.75mg/kg/day (N=4,809 (52%)), with 35% reaching a maximum of 1-1.25mg/kg/day. Mean cumulative dose was 136.6 mg/kg (SD=62.5), with 25% of patients receiving 120-150 mg/kg, consistent with the 2016 American Academy of Dermatology guidelines. Doses >175mg/kg were used in 24.8%. Significant predictors of higher cumulative dosing included female sex, younger age, prior antibiotic use, and more acne-related visits. Additionally, Asian and White patients received significantly higher cumulative doses compared to Black patients.

This study highlights substantial variability in isotretinoin prescribing practices. Although medium-range cumulative doses aligned with previous guidelines, there was substantial variability in cumulative dosing. These findings highlight the need for comparative studies of alternate dosing strategies. More comprehensive guidelines incorporating alternative dosing models could optimize acne treatment and ensure equitable care.