Risk factors for the development of tinea pedis and onychomycosis: Real‐world evidence from a single‐podiatry center, large‐scale database in Japan

Dermatomycosis, including tinea pedis and onychomycosis, is frequently encountered in routine medical care in Japan. Identifying the risk factors for tinea pedis and onychomycosis development is important to encourage hospital visits by patients who may have these diseases but who are not undergoing any treatment. This approach may lead to the prevention of disease progression and the spread of infections to others. Risk factors for onychomycosis development have been reported both in and outside of Japan. However, most of the risk factors were identified based on a multicenter, questionnaire survey study and included evidence obtained from unclear or inconsistent diagnostic criteria for tinea pedis, onychomycosis, and identified risk factors. The current study analyzed the risk factors for developing tinea pedis and onychomycosis in real-world practice in Japan using a single-center, large-scale database that included the data of patients managed with consistent diagnostic criteria at the Podiatry Center of Juntendo University Hospital. A total of 2476 patients (1012 males, 1464 females) with a mean age of 63.4 years were included. Among these patients, 337 (13.6%) had tinea pedis and 346 (14.0%) had onychomycosis. A total of 259 patients (~ 75% of each patient population) had both diseases concomitantly. Multivariate logistic regression analysis adjusted for the possible risk factors of age (per 10 years), sex, diabetes, dialysis, visual impairment, ulcer history, lower-limb ischemia (LLI), and diabetic peripheral neuropathy (DPN) revealed that advanced age, male sex, diabetes, and LLI were independent risk factors for the development of tinea pedis. In addition, DPN was an independent risk factor for developing onychomycosis. We believe that these data are useful for identifying patients who are at high risk of developing tinea pedis and onychomycosis, which may result in disease prevention and suppression in real-world clinical practice in Japan.