Measuring the impact of onychomycosis on patient quality of life

According to survey research, onychomycosis, a fungal infection of the toenail or fingernail, affects quality of life including physical and social functioning and emotional health. We developed an onychomycosis disease-specific questionnaire (ODSQ) that sensitively assessed symptom distress, functional impact, and social stigma associated with the disease. Samples of patients enrolled in a randomized controlled clinical trial were used for the psychometric evaluations. The multi-item scales were internally consistent (alpha greater than or equal to 0.80) and reproducible (ICC > 0.85). Interscale correlations between the ODSQ and generic scales were moderate and consistent with the hypothesized magnitude and directions. Construct validation, employing known groups analysis, supported the hypothesized impact of onychomycosis on three domains of quality of life: physical functioning, emotional health, and social functioning. Significant differences were found between clinically "cured", "improved", or "failed" patients, and between mycologically "eradicated" and "persistent" patients. The ODSQ was responsive to clinical change and more sensitive than derived Medical Outcomes Study Short Form-36 scales. The ODSQ provides reliable, validated and responsive information about the consequences of onychomycosis and its treatment.