Toenail Onychomycosis with or without Diabetes in Canada: Patient Treatment Preferences and Health State Utilities

Background

Toenail onychomycosis affects approximately 6.7% of Canadians. Symptoms include nail discolouration/disfiguration and pain; psychosocial impacts contribute to reduced health-related quality-of-life. Comorbid diabetes increases the risk of complications and exacerbates burden. Treatment may include topical therapy and/or oral agents.

Purpose

To understand toenail onychomycosis treatment preferences, and to quantify the impact of toenail onychomycosis, with or without diabetes, on patient well-being.

Methods

Adults living in Canada with self-reported, physician-diagnosed, toenail onychomycosis were recruited online. A discrete choice experiment was used to quantify treatment preferences. Scenarios were randomized; data were analyzed using conditional logit regression. Health state utilities were estimated using the Health Utilities Index Mark 3®. Results were stratified by diabetes status and toenail onychomycosis severity; the Wilcoxon Rank Sum test was used to assess between-group utility differences.

Results

Three-hundred thirteen participants with toenail onychomycosis were included (161 had comorbid diabetes; 61.3%, severe onychomycosis). The mean age was 57.7 years; 55.9% were male. Treatment attributes with statistically significant impacts on patient preferences were efficacy (odds ratio [OR],1.04; 95% confidence interval [CI], 1.02-1.05 per 1% increased treatment success), administration method (one pill versus topical nail lacquer reference, 1.14; 1.04-1.26; topical solution applicator versus reference: 1.15; 1.03-1.29), severe adverse events (0.85; 0.80-0.90 per 1% increased risk), and risk of potential pharmacodynamic (0.80; 0.76-0.85) and alcohol (0.93; 0.88-0.98) interactions; preferences were more pronounced for efficacy and avoiding severe adverse events among toenail onychomycosis patients with comorbid diabetes. The mean (95% CI) utility value was 0.73 (0.70-0.75) overall, and statistically significantly lower (p=0.02) for toenail onychomycosis patients with diabetes (0.70; CI, 0.66-0.73) than those without (0.76; CI, 0.72-0.79).

Conclusion

Among patients with toenail onychomycosis, the presence of diabetes was associated with differing treatment-related preferences. Utility values for patients with toenail onychomycosis represent a significant decline from full health that is exacerbated by comorbid diabetes.

Combination of Photodynamic Therapy and Oral Antifungals for the Treatment of Onychomycosis

Onychomycosis accounts for 50% of nail disorders, making it one of the most prevalent fungal diseases and a therapeutic challenge. Photodynamic therapy (PDT) could constitute a therapeutic alternative, owing to its good adherence, the low probability of resistance, the lack of interaction with antimicrobials, and its favorable adverse effect profile. This retrospective observational study included all patients with a microbiological diagnosis of onychomycosis treated with PDT at Miguel Servet University Hospital, Zaragoza (Spain), between January 2013 and June 2021. The protocol consisted of pre-treatment with 40% urea for 7 days, followed by 16% methyl-aminolevulinate (MAL) for 3 h and subsequent irradiation with a red-light LED lamp (37 J/cm²), every 1 or 2 weeks. Combined treatment with oral and/or topical antifungals was recorded. Of the 20 patients included (mean age, 59 ± 17 years), 55% were men. The most frequently detected microorganism was Trichophyton rubrum (55%). The most commonly affected location was the feet (90%): 50% of these cases were associated with tinea pedis. The median (standard deviation) number of PDT sessions was 6 (2.8). PDT was combined with systemic terbinafine (250 mg/day) in 10 cases (in 8 cases, this was administered for only 1 month), and with topical terbinafine in 3 cases. A complete clinical response was achieved in 80% (16) of cases and microbiological cure in 60% (12). PDT is a therapeutic alternative for onychomycosis, and can be administered either in monotherapy or combined with antifungals, allowing for a reduction in the duration and possible adverse effects of antifungal treatment and achieving higher cure rates than those obtained with either treatment alone.

A Practical Guide to Curing Onychomycosis: How to Maximize Cure at the Patient, Organism, Treatment, and Environmental Level

Onychomycosis is a fungal nail infection caused by dermatophytes, non-dermatophyte molds, and yeasts. Treatment of this infection can be difficult, with relapse likely to occur within 2.5 years of cure. The objective of this article is to review factors that can impact cure and to suggest practical techniques that physicians can use to maximize cure rates. Co-morbidities, as well as disease severity and duration, are among the many patient factors that could influence the efficacy of antifungal therapies. Furthermore, organism, treatment, and environmental factors that may hinder cure include point mutations, biofilms, affinity for non-target enzymes, and exposure to fungal reservoirs. To address patient-related factors, physicians are encouraged to conduct confirmatory testing and treat co-morbidities such as tinea pedis early and completely. To combat organism-focused factors, it is recommended that disruption of biofilms is considered, and drugs with multiple routes of delivery and unique mechanisms of action are prescribed when traditional agents are not effective. Extending follow-up periods, using combination treatments, and considering pulse regimens may also be of benefit. Through these practical techniques, physicians can maximize cure and limit the risk of relapse and re-infection.

Improving Cure Rates in Onychomycosis

Background:

Onychomycosis is a persistent fungal nail infection that is notoriously hard to treat. Approximately 20% to 25% of patients with onychomycosis do not respond to treatment, and 10% to 53% of patients relapse. As such, successful treatment is imperative for long-term disease management.

Objective:

To identify ways to improve cure rates for onychomycosis.

Method:

The literature on onychomycosis treatment and recurrence was reviewed to summarize treatment approaches and suggest strategies to increase cure rates.

Results and Conclusion:

To improve treatment success in onychomycosis, we suggest the following measures be followed: (1) onychomycosis must be correctly diagnosed, (2) the treatment regimen should be tailored to the individual patient, (3) the efficacy of antifungals must be maximized, and (4) recurrence must be prevented.

Review of Treatment for Onychomycosis: Consideration for Special Populations

This article provides a brief discussion of onychomycosis treatment in special populations such as children, the elderly, and patients with diabetes, human immunodeficiency virus (HIV), or Down syndrome. These subjects are generally not included in clinical trials, and few data on antifungal therapy are available in the literature. Issues with onychomycosis infection and treatment affecting each group are discussed, and where treatment reports exist, efficacy and safety data are presented. The discussion is restricted to agents approved for use in onychomycosis in Canada: oral terbinafine, oral itraconazole, and ciclopirox 8% nail lacquer. Although sparse, the literature demonstrates that onychomycosis therapies can be used safely and effectively in these special populations, although it is likely that the appropriateness of such treatment would have to be assessed on a case-by-case basis. Typically, oral medications are used reluctantly in these groups as the potential for adverse liver or kidney effects and medication interactions may be significant. Ciclopirox nail lacquer has recently become available for use and may offer an alternative to oral therapy in the future for mild to moderate cases of onychomycosis; however, the efficacy in these patients has not typically been reported. It remains to be seen what impact this medication will have for special populations. More knowledge of treatment in special populations must be accumulated in the literature before more formal treatment guidelines may be formulated.

Diagnosis of Trichophyton rubrum from onychomycotic nail samples using polymerase chain reaction and calcofluor white microscopy

BACKGROUND

A high rate of false-negative dermatophyte detection is observed when the most common laboratory methods are used. These methods include microscopic observation of potassium hydroxide-digested nail clippings and culture methods using agar-based media supplemented with cycloheximide, chloramphenicol, and gentamicin to isolate dermatophytes. Microscopic detection methods that use calcofluor white staining or periodic acid-Schiff staining may also be substituted for and have previously been reported to be more sensitive than potassium hydroxide-digested nail clippings.

METHODS

Trichophyton rubrum infections were detected directly from nails in a double-round polymerase chain reaction assay that uses actin gene-based primers. This method was compared with detection of fungal hyphae by using calcofluor white fluorescence microscopy of nail samples collected from 83 patients with onychomycosis who were undergoing antifungal drug therapy.

RESULTS

Twenty-six of 83 samples (31.3%) were found to be positive by calcofluor white fluorescence microscopy, and 21 of 83 samples (25.3%) yielded positive results for T rubrum when actin gene-based primers in a double-round polymerase chain reaction assay were used. When calcofluor white fluorescence microscopy and polymerase chain reaction assay were used, the combined detection was 46.9% compared with 31.3% when calcofluor microscopy and culture of nail samples on Sabouraud's dextrose agar supplemented with cycloheximide, chloramphenicol, and gentamicin were used.

CONCLUSIONS

These results suggest that the use of a direct DNA protocol is an alternative method for detecting Trichophyton infections. When this protocol is used, the presence of T rubrum DNA is directly detected. However, the viability of the dermatophyte is not addressed, and further methods need to be developed for the detection of viable T rubrum directly from nail samples.

Common nail disorders and fungal infections

PURPOSE

To provide the practitioner with current information on the most common nail disorders.

TARGET AUDIENCE

This continuing education activity is intended for physicians and nurses with an interest in wound care and related disorders.

OBJECTIVES

After reading this article and taking this test, the reader should be able to: 1. Describe the structures that compose the nail apparatus. 2. Identify the most common nail disorders, including etiology and treatment.

Co-prescriptions with itraconazole and fluconazole as a signal for possible risk of drug–drug interactions: a four-year analysis from Italian general practice

PURPOSE

To determine the prevalence of concomitant use of drugs potentially responsible for interactions among itraconazole and fluconazole users in general practice.

METHODS

During the years 1999-2002, we obtained information from the 'Health Search Database', (HSD) an Italian general practice research database. Among a total sample of 457 672 eligible patients, we included those aged >16 years, and whose diagnoses could be classified as mycosis. Itraconazole and fluconazole users were then selected. A potentially drug-drug interaction (DDI) occurred when the use of concomitant drugs were recorded within +/-30 days from the date of the first azoles prescription. Interacting drugs were classified according to the summary of product characteristics (SPC) as provided by the Italian Pharmaceutical Repertory (REFI).

RESULTS

From 18 323 cases of mycosis, we selected 4843 itraconazole and 1446 fluconazole users. Potentially interacting drugs were prescribed in 8.7% of itraconazole and 6.1% of fluconazole users. For itraconazole, calcium channel blockers were the most common interacting drugs (3.3%), followed by statins (1.7%) and clarithromycin (1.3%), whereas gestoden + ethynylestradiol (2.5%) and benzodiazepines (1.8%) resulted as the most common interacting drugs among fluconazole users.

CONCLUSION

Data indicate a relevant prevalence of concomitant use of medications potentially leading to drug interactions among azoles users. Because of the wide use of these medications in general practice, they should be used with clinical monitoring in view of their known side effects as well as their potential risk for drug interaction.