Supplementary Material for: Abnormal Baseline Lab Results Rarely Lead to Treatment Modification for Patients on Isotretinoin

Background: Treatment modification and clinical course for patients initiating isotretinoin with abnormal baseline lab results is currently unknown, and no recommendations exist for monitoring this patient group. Methods: We performed a retrospective review of patients prescribed isotretinoin for acne from 2008 to 2016 at Brigham and Women’s and Massachusetts General Hospitals to investigate the characteristics, clinical implications, and management of patients initiating isotretinoin for acne with baseline laboratory abnormalities. Results: We identified a low rate (7.2%) of treatment modification, including interruption (3.6%) and early termination (3.6%), during isotretinoin therapy due to lab abnormalities for patients with baseline lab abnormalities. Abnormal baseline total cholesterol, triglyceride, and liver function tests did not predict management changes, as only 2 of 10 total treatment modifications were due to a lab result that was abnormal at baseline. Treatment modification was driven by ALT elevation not present at baseline that occurred in patients with liver comorbidities. Conclusion: Emphasizing relevant comorbidities, including hepatic disease or alcohol use, to inform our monitoring may be a superior predictor of abnormalities during treatment, as our work demonstrates that the value of baseline lab data prior to isotretinoin is unclear.