An Increase in Specialist Treatment for Onychomycosis: An Unexplained Tendency. A Retrospective Study of Patients Treated for Onychomycosis in Danish Hospitals from 1994 to 2018

Abstract

Onychomycosis is a common disease with a significant negative impact on quality of life. While the disease is usually manageable in general practice, a proportion of patients need specialist treatment in academic hospital clinics. However, it is an unknown question whether the incidence in those needing specialist treatments is changing. Furthermore, the comorbidity burden in this patient population severely affected by onychomycosis has never been characterized. We conducted a retrospective study on patients treated for onychomycosis in Danish hospitals from 1994 to 2018. The cohort was observed for 24 years, and the data comprise 7.2 million Danes and their hospital diagnoses. A disease trajectory algorithm was used to examine the comorbidity burden in the cohort. A total of 2,271 patients received hospital treatment for onychomycosis during the time period, of which 1358 (59.8%) were men. The data show an increase in the incidence of hospital-treated cases since 2012 and that the most common comorbidities in this patient population include cardiovascular disease, alcohol-related diagnoses, and diabetes. One explanation of the increase in specialist treatment may include a general increase in patients with decreased resilience to fungal disease. This lack of resilience may both include an increasing elderly population with atherosclerosis, diabetes, and immunosuppression but also a potential increase in patients treated with immunosuppressive agents. Another possible explanation may include a shift in patient expectations in the case of treatment failure. Thus, patients may have an increasing demand for specialist treatment. While our data document an increase in the number of patients in need of specialist treatment for onychomycosis, we suggest future research to examine the general incidence of onychomycosis but also whether this increase in an apparently recalcitrant disease may be attributed to increased antifungal resistance, more specialist treatment options, or increased attention to dermatomycoses.

Potential emergence of terbinafine resistance by squalene epoxidase gene mutations: An 18‐month cohort study of onychomycosis patients in the United States

“…46,47 Older patients, especially those with comorbidity burden affecting immune function or those with pre-existing nail damage, may represent a high-risk group amidst the spread of terbinafine-resistant dermatophyte infections. 35,48 To summarise, our findings further highlight the need for physicians to have a high index of suspicion when patients present with extensive dermatophytosis or onychomycosis that does not respond to terbinafine. We found SQLE mutations that potentially confer resistance to terbinafine, a commonly prescribed first-line antifungal agent, are increasing in prevalence among the US onychomycosis population.…”

“…Risk factors underlying the transmission of dermatophytes include population movements and migrations, 33 mistreatment or treatment delays, 34 increase in prevalence of potentially immunocompromised individuals (e.g. diabetics and the elderly), 35 contaminated fomites especially for individuals living in a shared household, 36,37 sexual contact 38 and animal contact including rodents and canines. 36,39 Analysis of the SQLE mutation pattern identified 479 samples harbouring Phe397Leu alone or in combination.…”

“…mentagrophytes 46,47 . Older patients, especially those with comorbidity burden affecting immune function or those with pre‐existing nail damage, may represent a high‐risk group amidst the spread of terbinafine‐resistant dermatophyte infections 35,48 …”

Global prevalence of onychomycosis in general and special populations: An updated perspective

“…Limited limb mobility may hinder patients from applying topical medications and maintaining hygiene; furthermore, this patient group is likely to have multiple risk factors including advanced age, and other co‐morbidities such as nail trauma due to immobility, diabetes and hypertension, that further increase the risk of onychomycosis 41 ; the management of other co‐morbidities may take priority and leave onychomycosis un‐treated. Amidst a concerning trend of onychomycosis patients being managed by specialists rather than general practitioners possible due to increasing comorbidity burdens 119 ; to our knowledge, there are no existent recommendations on the management of knee osteoarthritis with concomitant onychomycosis.…”

Clinical Diagnosis and Laboratory Testing of Abnormal Appearing Toenails: A Retrospective Assessment of Confirmatory Testing for Onychomycosis in the United States, 2022–2023

“…Consequentially, more than half of onychomycosis patients reported to have self-diagnosed and self-treated their condition, which likely contributed to a high treatment failure rate of 24.0% [15]. The current healthcare burden is further compounded by a high rate of misdiagnosis (25.5%) among general practitioners [16] and a growing number of patients seeking care from specialists rather than primary care providers [17].…”