INTRODUCTION
Primary hyperhidrosis is a chronic disorder of excessive sweating that can profoundly impact quality of life. Measuring hyperhidrosis severity is challenging. The absence of widely accepted, scientifically sound, patient-reported outcome (PRO) measures hinders development of better hyperhidrosis treatments.
The frequently used Hyperhidrosis Disease Severity Scale (HDSS) is a single question with four severity levels. Such “single-item†scales do not meet scientific and regulatory rigor as outcome measures because single questions cannot measure the extent of disease impact reliably, validly, or precisely.1,2 In addition, each HDSS response category combines two constructs: tolerability and impact on daily life. Thus, the HDSS does not allow patients to report different levels of effect for these two constructs. Quantitative axillary sweating measurements, such as gravimetric sweat production, are variable, difficult to interpret, and correlate poorly with patient experience.3,4
The Hyperhidrosis Disease Severity Measure-Axillary (HDSM-Ax) was developed to be an accurate, comprehensive measure of primary AHH severity satisfying scientific and regulatory requirements for treatment trials.1,3,5 Three planks underpin current PRO requirements: a clearly defined variable to measure, an explicit context of use, and robust measurement performance.1 When these criteria are met, it is reasonable to interpret scores and estimate clinically meaningful changes.
Previously, we reported conceptualization and item content development for HDSM-Ax.6 The result was an 11-item questionnaire with each item scored 0–4, yielding a total score of 0–44. HDSM-Ax was used as the primary efficacy endpoint in a randomized, controlled, double-blinded, phase IIb study of sofpironium bromide gel for treatment of AHH (NCT03024255).6 We now evaluate HDSM-Ax measurement performance and estimate clinically meaningful change scores from those data.
The frequently used Hyperhidrosis Disease Severity Scale (HDSS) is a single question with four severity levels. Such “single-item†scales do not meet scientific and regulatory rigor as outcome measures because single questions cannot measure the extent of disease impact reliably, validly, or precisely.1,2 In addition, each HDSS response category combines two constructs: tolerability and impact on daily life. Thus, the HDSS does not allow patients to report different levels of effect for these two constructs. Quantitative axillary sweating measurements, such as gravimetric sweat production, are variable, difficult to interpret, and correlate poorly with patient experience.3,4
The Hyperhidrosis Disease Severity Measure-Axillary (HDSM-Ax) was developed to be an accurate, comprehensive measure of primary AHH severity satisfying scientific and regulatory requirements for treatment trials.1,3,5 Three planks underpin current PRO requirements: a clearly defined variable to measure, an explicit context of use, and robust measurement performance.1 When these criteria are met, it is reasonable to interpret scores and estimate clinically meaningful changes.
Previously, we reported conceptualization and item content development for HDSM-Ax.6 The result was an 11-item questionnaire with each item scored 0–4, yielding a total score of 0–44. HDSM-Ax was used as the primary efficacy endpoint in a randomized, controlled, double-blinded, phase IIb study of sofpironium bromide gel for treatment of AHH (NCT03024255).6 We now evaluate HDSM-Ax measurement performance and estimate clinically meaningful change scores from those data.
