Supplementary Material for: Patient Characteristics, Diagnostic Testing Utilization and Antifungal Prescribing Pattern for Onychomycosis in the United States: A Cohort Study Using DataDerm, 2016-2022

Introduction: Onychomycosis is a complex nail disease that is commonly seen in daily practice.

Methods: Electronic health records of clinically diagnosed onychomycosis patients were extracted using DataDerm – a dermatology data registry hosted by the American Academy of Dermatology – spanning from the year 2016 to 2022.

Results: Regardless of age, an increasing trend in patient volume was observed in the Southern U.S. region, which accounted for 50.7-56.9% of onychomycosis patients in 2022. A co-infection of tinea pedis was present among 15.6-22.5% of patients. Diagnostic testing was infrequently utilized with less than one quarter of patients having a histopathologic examination (12.7-21.9%) followed by fungal culture (5.5-8.2%) and direct microscopic examination (3.3-6.0%). Treatments were infrequently prescribed accounting for less than one quarter of patients (orals, terbinafine: 20.8-29.1%, fluconazole: 12.9-16.5%; topicals, efinaconazole: 3.2-13.8%); over 30% of treated patients received a combination regimen or experienced switching of treatments. Prescribing patterns did not significantly differ in vulnerable patient groups such as elderly patients and in patients with concomitant tinea pedis. Patients receiving a topical and/or oral antifungal prescription were frequently not tested to confirm the onychomycosis diagnosis (76.9%).

Conclusion: Our findings add to a growing body of literature calling for the improvement of onychomycosis management practices.