OBJECTIVES: Toenail onychomycosis (fungal infection) affects nearly 7% of Canadians. Symptoms are progressive and include nail discolouration, disfiguration, and pain. The presence of type I/II diabetes mellitus is associated with both an increased risk of onychomycosis infection and of experiencing complications secondary to onychomycosis. Onychomycosis, with and without diabetes, may impact overall health status and associated utility estimates; however, such estimates are lacking. This study sought to estimate utility values associated with toenail onychomycosis, among adult patients with or without comorbid diabetes, in Canada.

METHODS: Canadian adults with self-reported, physician-diagnosed, toenail onychomycosis were recruited online. The survey comprised a demographic questionnaire and the Health Utilities Index (HUI) 15-item questionnaire (HUI-15Q^®), from which individual utility values were estimated. Mean (95% confidence interval [CI]) utilities were estimated for the entire sample; and stratified by onychomycosis severity (mild/moderate, severe) and diabetes status (yes, no). Tests for between-group differences were conducted using the Wilcoxon Rank Sum test.

RESULTS: Three-hundred and seven onychomycosis participants were included (188 with severe onychomycosis; 158 with type I/II diabetes). The mean (standard deviation) age was 57.6 (14.7) years; 55.4% were male. The mean (95% CI) utility value for participants without diabetes (n=149; 0.76 [0.72-0.79]) was significantly higher than among those with diabetes (n=158; 0.70 [0.66-0.73]); (p=0.02). Utility values did not differ statistically by severity: overall (with and without diabetes), mild/moderate (n=119; 0.74 [0.70-0.78]) and severe (n=188; 0.72 [0.69-0.75]) toenail onychomycosis; without diabetes, mild/moderate (n=72; 0.76 [0.71-0.80]) and severe (n=77; 0.75 [0.70-0.80]) toenail onychomycosis; with diabetes, mild/moderate (n=47; 0.72 [0.65-0.79]) and severe (n=111; 0.69 [0.65-0.73]) toenail onychomycosis.

CONCLUSIONS: Utility values from Canadians with toenail onychomycosis with diabetes were significantly lower than among those without diabetes; and trended lower with higher disease severity (non-statistically significant). These estimates can be used to inform cost-utility analyses of onychomycosis therapies for Canadians both with and without comorbid diabetes.