Prognostic factors for mycological cure in patients with onychomycosis caused by Neoscytalidium dimidiatum: A retrospective cohort study.

BACKGROUND

The prognostic factors for cure have been derived from cases of dermatophyte onychomycosis. However, there are limited studies in non-dermatophyte onychomycosis. Neoscytalidium dimidiatum is the common causative agents of non-dermatophyte onychomycosis which has proven to be recalcitrant to treatment.

OBJECTIVE

This retrospective cohort study investigated mycological cure and prognostic factors in Neoscytalidium onychomycosis patients.

METHODS

Patients aged 18 or older with newly diagnosed Neoscytalidium onychomycosis were enrolled. All patients were treated and followed up for at least 1 year. Mycological cure was analysed with Cox proportional hazard regression. The hazard ratios (HRs) of previously reported potential prognostic factors were included in univariable and multivariable stratified Cox regression analyses.

RESULTS

From total 198 patients, mycological cure was achieved in 108 (54.6%) patients with a median of 490 (± SD 62.2) days. The poor prognostic factors for mycological cure were age ≥ 70 years (HR, 0.63; 95% CI, 0.41-0.97; p = .034); nail thickness ≥2 mm (HR, 0.20; 95% CI, 0.11-0.35; p < .001); and peripheral vascular disease (HR, 0.46; 95% CI, 0.28-0.77; p = .003). Combination therapy was associated with achieving a mycological cure (HR, 2.55; 95% CI, 1.49-4.38; p < .001).

CONCLUSIONS

Approximately half of the patients with onychomycosis caused by Neoscytalidium dimidiatum achieved a mycological cure, with a median time to cure exceeding 1 year. Combined topical and systemic antifungal treatments yield a higher chance of mycological cure than monotherapies. Advanced age, nail thickness and peripheral vascular disease are obstacle factors to cure.