Responsiveness of the NAIL-Q Patient-Reported Outcome Measure.

BACKGROUND

Nail conditions account for ~10% of dermatological conditions and can significantly impact quality of life. The NAIL-Q is a patient-reported outcome measure that was developed to measure outcomes that matter to patients treated for any type of fingernail or toenail condition. The ability of the NAIL-Q to detect change (ie, responsiveness) has not yet been established.

OBJECTIVE

To evaluate the responsiveness of the NAIL-Q in patients undergoing treatment for nail psoriasis, onychomycosis, brittle nails, and retronychia.

METHODS

This prospective validation study included patients newly diagnosed at an urban dermatology clinic in the United States. Participants completed the NAIL-Q at baseline, 3, and 6 months. Responsiveness was evaluated by testing predefined hypotheses of the change score. Minimally important differences (MIDs) were calculated using anchor and distribution-based methods.

RESULTS

Of 166 eligible participants, 142 completed a baseline assessment and 79 (56%) and 55 (39%) completed the 3 and 6 month follow-ups, respectively. Mean age of study participants was 56 years (standard deviation = 19). Toenail conditions predominated (54%), with onychomycosis being the most common condition (54%). Hypothesis acceptance rates demonstrated validity of the change score for the Appearance 88% (15/17), Nail Symptoms 80% (16/20), and Outcome (treatment-related) 91% (10/11) scales. Effect sizes were moderate for Appearance, Nail Distress, and Outcome scales (0.6-0.7). MID values for the 3 scales ranged from 9 to 14.

CONCLUSIONS

The NAIL-Q demonstrated sufficient evidence of responsiveness in patients undergoing treatment for nail psoriasis, onychomycosis, brittle nails, or retronychia.