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Hyperhidrosis Quality of Life Index (HidroQoL©): further validation and clinical application in patients with axillary hyperhidrosis using data from a phase III randomized controlled trial *
Author(s) -
Gabes M.,
Jourdan C.,
Schramm K.,
Masur C.,
Abels C.,
Kamudoni P.,
Salek S.,
Apfelbacher C.
Publication year - 2021
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/bjd.19300
Subject(s) - medicine , hyperhidrosis , quality of life (healthcare) , intraclass correlation , cronbach's alpha , dermatology life quality index , physical therapy , randomized controlled trial , placebo , discriminant validity , clinical trial , surgery , psychometrics , patient satisfaction , clinical psychology , disease , internal consistency , pathology , alternative medicine , nursing
Summary Background The Hyperhidrosis Quality of Life Index (HidroQoL©) is a validated patient‐reported outcome measure capturing the quality of life of people affected by hyperhidrosis. Objectives We aimed to extend the validity evidence to physician‐confirmed diagnosis of primary axillary hyperhidrosis. Methods Data from a phase III randomized placebo‐controlled clinical trial were used ( n = 171). Confirmatory factor analysis was carried out to confirm the a priori two‐factor structure of the HidroQoL. Internal consistency was assessed using Cronbach’s α. Intraclass correlation coefficients (ICCs) were calculated to evaluate test–retest reliability after days –7 to –4. Convergent validity was assessed using correlations with the Dermatology Life Quality Index (DLQI), the Hyperhidrosis Disease Severity Scale (HDSS) and gravimetric sweat production. Known groups were analysed to evaluate discriminative validity. Responsiveness after 29 days was assessed and minimal important difference (MID) values were calculated using both anchor‐ and distribution‐based approaches. All analyses were carried out for total HidroQoL and its two domains. Results The two‐factor structure of the HidroQoL was confirmed. Internal consistency and test–retest reliability were strong (Cronbach’s α 0·81–0·90; ICCs 0·89–0·93). Correlations with other outcome measures were in line with a priori hypotheses. The HidroQoL discriminated between different severity groups ( P ≤ 0·001) and showed sensitivity to change towards improvement ( P < 0·001). An MID value of 4 is proposed for the total scale. Conclusions This study supports excellent measurement properties including clinical applicability of the HidroQoL in primary axillary hyperhidrosis and suggests a MID of 4 be applied to clinical trial data.