Prevalence of mixed dermatophyte and non-dermatophyte onychomycosis in surveillance of patients with diabetes living in a sub-tropical climate and association with selected diabetes foot ulcer risk factors

Abstract

Background: Onychomycosis (OM) is the infection of a fingernail or toenail by one or more of three types of pathogens: dermatophytic fungi, yeasts and non-dermatophytic moulds. Whereas previously dermatophytes were regarded as the primary causative agent, mixed infections of both dermatophyte onychomycosis (DOM) and non-dermatophyte onychomycosis (NDOM) have been reported with higher incidence in warm climates. Very few studies in Africa have tracked OM prevalence in populations living with diabetes.

Objectives: This study aimed to determine the prevalence of mixed OM and whether there was any association between mixed OM and four variables, namely, gender, pre-clinical peripheral arterial disease (prePAD), peripheral neuropathy (PN), and hallux dysfunction.

Method: A retrospective chart review was conducted on annual foot assessment records for 231 male and female adult diabetes patients in Umhlanga, KwaZulu-Natal.

Results: Prevalence of mixed OM was 54.5% and was associated with being male (p = 0.028). Patients presenting hallux dysfunction were less likely to have mixed OM (44% versus 61%). There was a strong association between prePAD and PN (p < 0.001) as those with prePAD were more likely to have PN (62.5% vs 30.8%). There was no association between mixed OM and the four variables captured in this small study.

Conclusion: A high prevalence of mixed OM exists in the diabetes population in this study. Mixed OM is less likely in hallux dysfunction and no association was found between mixed OM and the other variables. Pre-clinical PAD shows a strong association with PN.