Measurement properties of quality-of-life outcome measures for children and adults with eczema: An updated systematic review

Patient prioritisation of items to develop the Patient-Reported Impact of Dermatological Diseases measure: A global Delphi study

BACKGROUND

The Global Research on the Impact of Dermatological Diseases (GRIDD) project is developing the new Patient-Reported Impact of Dermatological Diseases (PRIDD) measure. PRIDD measures the impact of dermatological conditions on the patient's life.

OBJECTIVES

This study aimed to seek consensus from patients on which items to prioritize for inclusion in PRIDD.

METHODS

A modified, two-round Delphi study was conducted. Adults (≥18 years) with dermatological conditions were recruited. The survey consisted of a demographic's questionnaire and 263 potential impact items in six languages. Quantitative data used Likert-type ranking scales and analysed against consensus criteria. Qualitative data collected free text responses for additional feedback and a framework analysis was conducted.

RESULTS

1154 people representing 90 dermatological conditions from 66 countries participated. Items were either removed (n = 79), edited (n = 179) or added (n = 2), based on consensus thresholds and qualitative feedback. Results generated the first draft of PRIDD with 27 items across five impact domains.

CONCLUSION

This Delphi study resulted in the draft version of PRIDD, ready for psychometric testing. The triangulated data helped refine the existing conceptual framework of impact. PRIDD has since been pilot tested with patients and is currently undergoing psychometric testing.

Further refinement of the Patient-Reported Impact of Dermatological Diseases (PRIDD) measure using classical test theory and item response theory

BACKGROUND

Existing dermatology-specific Patient-Reported Outcome Measures (PROMs) do not fully capture the substantial physical, psychological and social impact of dermatological conditions on patients' lives and are not recommended for use according to the COSMIN criteria. Most were developed with insufficient patient involvement and relied on classical psychometric methods. We are developing the new Patient-Reported Impact of Dermatological Diseases (PRIDD) measure for use in research and clinical practice in partnership with patients.

OBJECTIVES

To examine the factor structure of PRIDD, determine the definitive selection of items for each subscale, and establish structural validity and internal consistency through classical and modern psychometric methods.

METHODS

Two cross-sectional online surveys were conducted. Adults (≥ 18 years) worldwide living with a dermatological condition were recruited through the membership network of the International Alliance of Dermatology Patient Organizations (GlobalSkin). They completed the PRIDD questionnaire and a demographics questionnaire via an online survey. We examined missing data and distribution of scores for each item. The factor structure was assessed using confirmatory and exploratory factor analysis (Survey 1). Internal consistency was examined using Cronbach's α. Rasch measurement theory analyses were conducted, including iterative assessment of rating scale function, fit to the Rasch model, unidimensionality, reliability, local dependence, targeting and differential item functioning (DIF) (Surveys 1 and 2).

RESULTS

Participants in Surveys 1 and 2 numbered 483 and 504 people, respectively. All items had ≤ 3% missing scores and all five response options were used. A four-factor model showed the best fit. PRIDD and all four subscales were internally consistent but showed some misfit to the Rasch measurement model. Adjustments were made to rectify disordered thresholds, remove misfitting items, local dependency and DIF, and improve targeting. The resulting 16-item version and subscales fit the Rasch model, showed no local dependency or DIF at the test level, and were well targeted.

CONCLUSIONS

This field test study produced the final PRIDD measure, consisting of 16 items across four domains. The data triangulated and refined the conceptual framework of impact and provide evidence of PRIDD's structural validity and internal consistency. The final step in the development and validation of the PRIDD measure is to test the remaining measurement properties.

Hospital quality of life for children: development of a new measurement tool for hospitalised children

Background

Hospitalisation affects children's quality of life (QoL) regardless of illness, treatment and care.

Aims

The objective of this study was to create an instrument for evaluating QoL of hospitalised children aged 7 to 18 years.

Methods

Initially, 46 items for the preliminary Hospital Quality of Life for Children Scale (HQL-children) were developed through a combination of literature reviews and individual interviews. The study was conducted with 230 participants from a general paediatric ward of a hospital. Exploratory and confirmatory factor analyses were conducted to examine the construct, convergent and discriminant validities of the measure. Criterion validity was assessed by confirming split-half reliability, whereas reliability was established using Cronbach's alpha coefficient.

Results

The HQL-child scale consists of 17 items and the total variance is 51.14%. The scale is categorised into five sub-dimensions: illness, fear, activity, hospital and perception. The scale demonstrated construct, convergent and divergent validity, discriminant and split-half reliability, with Cronbach's alpha coefficient 0.75.

Conclusions

The scale is a promising instrument to determine children's perception by capturing their experiences on hospitalisation. Assessing the QoL in hospitalised children is crucial for enhancing patient satisfaction and facilitating the development of health policies based on patient self-reporting in Turkey.

Evidence of the content validity, acceptability, and feasibility of a new Patient-Reported Impact of Dermatological Diseases measure

Background

The Global Research on the Impact of Dermatological Diseases (GRIDD) team is developing the new Patient-Reported Impact of Dermatological Diseases (PRIDD) measure of the impact of dermatological conditions on the patient's life, in partnership with patients. To develop PRIDD, we conducted a systematic review, followed by a qualitative interview study with 68 patients worldwide and subsequently a global Delphi survey of 1,154 patients to ensure PRIDD items were meaningful and important to patients.

Objective

To pilot test PRIDD with patients with dermatological conditions, focusing on its content validity (comprehensiveness, comprehensibility, and relevance), acceptability, and feasibility.

Methods

We conducted a theory-led qualitative study using the Three-Step Test-Interview method of cognitive interviewing. Three rounds of semi-structured interviews were conducted online. Adults (≥ 18 years) living with a dermatological condition and who spoke English sufficiently to take part in the interview were recruited through the International Alliance of Dermatology Patient Organizations' (GlobalSkin) global membership network. The topic guide met the gold-standard COSMIN (Consensus-based Standards for the Selection of Health Measurement Instruments) standards for cognitive interviewing. Analysis followed the thematic analytical model of cognitive interviewing.

Results

Twelve people (58% male) representing six dermatological conditions from four countries participated. Overall, patients found PRIDD to be comprehensible, comprehensive, relevant, acceptable, and feasible. Participants were able to discern the conceptual framework domains from the items. Feedback resulted in: the recall period being extended from 1 week to 1 month; removal of the 'not relevant' response option; and changes to the instructions and item ordering and wording to improve clarity and increase respondents' confidence in their ability to respond. These evidence-based adjustments resulted in a 26-item version of PRIDD.

Conclusion

This study met the gold-standard COSMIN criteria for the pilot testing of health measurement instruments. The data triangulated our previous findings, in particular the conceptual framework of impact. Our findings illuminate how patients understand and respond to PRIDD and other patient-reported measurement instruments. The results of comprehensibility, comprehensiveness, relevance, acceptability, and feasibility of PRIDD provide evidence of content validity from the target population. The next step in the development and validation of PRIDD is psychometric testing.

Measurement properties of quality-of-life outcome measures for children and adults with eczema: A systematic review update 2.0

A systematic review on measurement properties of patient-reported outcome measures (PROMs) for the assessment of quality of life (QoL) in children and adults with eczema was published in 2016 and updated in 2019. We now aimed to systematically assess the measurement properties of PROMs based on recently published development and validation studies regarding quality-of-life skin- or disease-specific PROMs using the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) guidelines and integrate these findings with those from the 2019 update. A systematic literature search was conducted in PubMed and Embase. Eligible studies reported on measurement properties of QoL skin- or disease-specific PROMs for the assessment of QoL in children and adults with eczema. The methodological quality of the included studies was evaluated using the COSMIN Risk of Bias checklist. The methodological quality of the included PROMs was judged using updated criteria for good measurement properties, and the quality of evidence was graded. The new evidence was integrated into the results from the 2019 update. Finally, a recommendation for use of the identified PROMs was derived based on all evidence. We identified 12 studies fulfilling our inclusion criteria. Based on the newly generated evidence, the Childhood Atopic Dermatitis Impact Scale-short form (CADIS-SF) for infants and the Skindex for adults can be recommended for use. We identified three new PROMs, which have the potential to be used, but require further validation: the Pediatric Allergic Disease Quality of Life Questionnaire (PADQLQ), the Skindex-Mini, and the Scratch Intensity and Impact Scale (SIIS). All other assessed PROMs still have the opportunity to be recommended for use (except for the Dermatology Life Quality Index (DLQI)) but need further validation. Currently, two PROMs for the assessment of QoL in eczema can be recommended for use: the CADIS-SF for infants and the Skindex for adults. Many PROMs, including the recently developed and/or validated PROMs PADQLQ, Skindex-Mini and SIIS, need further validation.

Comparing the psychometric properties of the EQ-5D-3L and EQ-5D-5L descriptive systems and utilities in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a common chronic inflammatory skin disorder affecting up to 10% of adults. The EQ-5D is the most commonly used generic preference-accompanied measure to generate quality-adjusted life years (QALYs) for economic evaluations.

OBJECTIVES

We aimed to compare psychometric properties of the three-level and five-level EQ-5D (EQ-5D-3L and EQ-5D-5L) in adult patients with AD.

METHODS

In a multicentre cross-sectional study, 218 AD patients with a broad range of severity completed the EQ-5D-3L, EQ-5D-5L, Dermatology Life Quality Index (DLQI) and Skindex-16. Disease severity outcomes included the Investigator Global Assessment, Eczema Area and Severity Index and the objective SCORing Atopic Dermatitis.

RESULTS

A good agreement was established between the two EQ-5D versions with an intraclass correlation coefficient of 0.815 (95% CI 0.758-0.859, p < 0.001). Overall, 33 different health state profiles occurred in the EQ-5D-3L and 84 in the EQ-5D-5L. Compared to the EQ-5D-3L, ceiling effect was reduced for the mobility, self-care, usual activities and pain/discomfort dimensions by 4.6-11.5%. EQ-5D-5L showed higher average relative informativity (Shannon's evenness index: 0.64 vs. 0.59). EQ-5D-5L demonstrated better convergent validity with EQ VAS, DLQI and Skindex-16. The two measures were similar in distinguishing between groups of patients based on disease severity and skin-specific quality of life with a moderate or large effect size (η² = 0.083-0.489).

CONCLUSION

Both instruments exhibited good psychometric properties in AD; however, the EQ-5D-5L was superior in terms of ceiling effects, informativity and convergent validity. We recommend the use of the EQ-5D-5L to measure health outcomes in clinical settings and for QALY calculations in AD.

A systematic review of patient-reported outcome measures in paediatric endocrinology

CONTEXT

Patient reported outcome measures (PROMs) are useful tools in paediatric endocrinology to gauge health status in children, especially since they are often unable to clearly communicate it themselves. We aimed to systematically search and appraise all available PROMs relevant to paediatric endocrinology and provide a curated resource for health professionals to utilise.

EVIDENCE ACQUISITION

We identified PROMs in paediatric endocrinology by systematically searching the Cochrane Library, MEDLINE, World Health Organisation International Clinical Trials Registry Platform, and the Cumulative Index to Nursing and Allied Health Literature on May 20, 2022. Additional studies were located through hand searching and content area expert contributions. We assessed the quality of each PROM using the COSMIN risk of bias checklist.

EVIDENCE SYNTHESIS

We identified 5003 papers in the initial search. After applying exclusion criteria we included seven PROMs in the review. Six PROMs were specific to Type I Diabetes and one to Hypothyroidism. We gave all studies an overall COSMIN score of 'inadequate' due to poorly detailed PROM development.

CONCLUSION

The scope and quality of PROMs in paediatric endocrinology is limited. Further research and development of PROM tools are required in paediatric endocrinology to allow for improved patient care.

General and Skin-Specific Health-Related Quality of Life in Patients With Atopic Dermatitis Before and During the COVID-19 Pandemic

BACKGROUND

Few studies have investigated health-related quality of life (HRQoL) in patients with atopic dermatitis (AD) during the COVID-19 pandemic.

OBJECTIVES

The objectives of this study were to compare HRQoL in adult AD patients before and during the pandemic and to assess measurement performance of 4 HRQoL measures.

METHODS

Between 2018 and 2021, a multicenter, cross-sectional survey was conducted, involving 218 adult AD patients. Health-related quality of life outcomes included the EQ-5D-5L, Skindex-16, Dermatology Life Quality Index (DLQI), and DLQI-Relevant (DLQI-R). Severity was measured using objective SCORing Atopic Dermatitis, Eczema Area and Severity Index, and Investigator Global Assessment.

RESULTS

The mean ± SD EQ-5D-5L utility, Skindex-16, DLQI, and DLQI-R scores were 0.82 ± 0.22, 56.84 ± 27.46, 13.44 ± 8.46, and 13.76 ± 8.60, respectively. The patients reported more problems during the pandemic (P < 0.05) regarding pain/discomfort (odds ratio [OR], 1.78), worrying (OR, 1.89), concerns about persistence/reoccurrence of disease (OR, 1.88), and social relationships (OR, 1.69). The HRQoL outcomes showed strong correlations with each other (range of rs, |0.69| to |0.99|). The Skindex-16, DLQI, and DLQI-R were able to discriminate between severity groups with large (η2 = 0.20-0.23), whereas the EQ-5D-5L with moderate effect sizes (η2 = 0.08-0.11).

CONCLUSIONS

Atopic dermatitis patients experienced significantly more problems in some areas of HRQoL during the pandemic. The EQ-5D-5L, Skindex-16, DLQI, and DLQI-R demonstrated good convergent and known-group validity and can be suitable instruments for HRQoL assessment in clinical and research settings.

Differences in Psychometric Properties of Clinician- and Patient-Reported Outcome Measures for Atopic Dermatitis by Race and Skin Tone: A Systematic Review

The psychometric validity and reliability of widely used atopic dermatitis (AD) outcome measures across different races and ethnicities are unclear. We describe the rates of reporting race, ethnicity, and skin tone in studies testing the psychometric properties of AD outcome measures and compare the psychometric analyses across race, ethnicity, and skin tone. We systematically reviewed MEDLINE and EMBASE for studies reporting psychometric properties of clinician-reported or patient-reported outcome measures in AD (International Prospective Register of Systematic Reviews: CRD42021239614). Overall, 16,100 nonduplicate articles were screened; 165 met inclusion criteria. Race and/or ethnicity were reported in 55 (33.3%) studies; of those, race was assessed by self-report in 10 studies (6.1%) or was unspecified in 45 (27.3%). A total of 16 studies (9.7%) evaluated psychometric property differences by race, and only five (4.4%) of those did not recognize it as a limitation. Properties assessed across race, ethnicity, or skin tone were differential item functioning, convergent validity feasibility, inter-rater reliability, intrarater reliability, test‒retest reliability, and known-groups validity. Multiple instruments demonstrated performance differences across ethnoracial groups. This review highlights the paucity of race/ethnicity consideration for psychometric property testing in AD outcome measurement instruments. More AD outcomes instruments should be validated in diverse populations.

Common patient-reported outcomes across ICHOM Standard Sets: the potential contribution of PROMIS®

BACKGROUND

The International Consortium for Health Outcomes Measurement (ICHOM) develops condition-specific Standard Sets of outcomes to be measured in clinical practice for value-based healthcare evaluation. Standard Sets are developed by different working groups, which is inefficient and may lead to inconsistencies in selected PROs and PROMs. We aimed to identify common PROs across ICHOM Standard Sets and examined to what extend these PROs can be measured with a generic set of PROMs: the Patient-Reported Outcomes Measurement Information System (PROMIS®).

METHODS

We extracted all PROs and recommended PROMs from 39 ICHOM Standard Sets. Similar PROs were categorized into unique PRO concepts. We examined which of these PRO concepts can be measured with PROMIS.

RESULTS

A total of 307 PROs were identified in 39 ICHOM Standard Sets and 114 unique PROMs are recommended for measuring these PROs. The 307 PROs could be categorized into 22 unique PRO concepts. More than half (17/22) of these PRO concepts (covering about 75% of the PROs and 75% of the PROMs) can be measured with a PROMIS measure.

CONCLUSION

Considerable overlap was found in PROs across ICHOM Standard Sets, and large differences in terminology used and PROMs recommended, even for the same PROs. We recommend a more universal and standardized approach to the selection of PROs and PROMs. Such an approach, focusing on a set of core PROs for all patients, measured with a system like PROMIS, may provide more opportunities for patient-centered care and facilitate the uptake of Standard Sets in clinical practice.

Recommended core outcome instruments for health-related quality of life, long-term control and itch intensity in atopic eczema trials: results of the HOME VII consensus meeting

Background

The Harmonising Outcome Measures for Eczema (HOME) initiative has established a core outcome set of domains for atopic eczema (AE) clinical trials. Previous consensus meetings have agreed on preferred instruments for clinician‐reported signs (Eczema Area and Severity Index, EASI) and patient‐reported symptoms (Patient‐Oriented Eczema Measure, POEM). This paper reports consensus decisions from the HOME VII meeting.

Objectives

To complete the core outcome set for AE by agreeing on core outcome instruments for the domains of quality of life (QoL), long‐term control and itch intensity.

Methods

A face‐to‐face consensus meeting was held in Tokyo, Japan (8–10 April 2019) including 75 participants (49 healthcare professionals/methodologists, 14 patients, 12 industry representatives) from 16 countries. Consensus decisions were made by presentations of evidence, followed by whole and small group discussions and anonymous voting using predefined consensus rules.

Results

It was agreed by consensus that QoL should be measured using the Dermatology Life Quality Index (DLQI) for adults, the Children’s Dermatology Life Quality Index (CDLQI) for children and the Infant’s Dermatology Quality of Life Index (IDQoL) for infants. For long‐term control, the Recap of Atopic Eczema (RECAP) instrument or the Atopic Dermatitis Control Test (ADCT) should be used. Consensus was not reached over the frequency of data collection for long‐term control. The peak itch numerical rating scale (NRS)‐11 past 24 h was recommended as an additional instrument for the symptom domain in trials of older children and adults. Agreement was reached that all core outcome instruments should be captured at baseline and at the time of primary outcome assessment as a minimum.

Conclusions

For now, the core outcome set for clinical trials in AE is complete. The specified domains and instruments should be used in all new clinical trials and systematic reviews of eczema treatments.

What is already known about this topic?

Core outcomes sets improve the design and reporting of clinical trials, reduce selective outcome reporting bias and facilitate meta‐analysis of results in systematic reviews.

The HOME core outcome set for eczema recommends the inclusion of four core domains in all atopic eczema trials: clinician‐reported signs, patient‐reported symptoms, health‐related quality of life (HrQoL) and long‐term control.

Clinician‐reported signs should be captured using the Eczema Area and Severity Index (EASI) and patient‐reported symptoms using the Patient‐Oriented Eczema Measure (POEM).

What does this study add?

The HOME core outcome set is now complete and recommended core outcome instruments have been agreed on for all four domains.

Core outcome instruments for HrQoL: Dermatology Life Quality Index (DLQI) for adults, Children’s Dermatology Life Quality Index (CDLQI) for children and Infant’s Dermatology Quality of Life Index (IDQoL) for infants.

Core outcome instruments for long‐term control: either the Recap of Atopic Eczema (RECAP) or the Atopic Dermatitis Control Test (ADCT).

In addition, itch intensity should be measured using the peak NRS‐11 past 24 h for trials including older children and adults.

What are the clinical implications of this work?

If all future trials of eczema treatments include the HOME core outcome instruments, then trial results will be more readily incorporated into meta‐analyses in systematic reviews and clinical care will be informed by the best available evidence.

Linked Comment: D.F. Murrell and C.F. Paul. Br J Dermatol 2021; 185:13–14.

Association between hospital-diagnosed atopic dermatitis and psychiatric disorders and medication use in childhood

BACKGROUND

While adult atopic dermatitis (AD) is associated with anxiety and depression, and paediatric AD is linked to attention deficit hyperactivity disorder (ADHD), the relationship between AD in childhood and other psychiatric disorders is largely unknown.

OBJECTIVES

To determine the relationship between AD and diagnosis and treatment of psychiatric disorders in children.

METHODS

All Danish children born between 1 January 1995 and 31 December 2012 with a hospital diagnosis of AD (n = 14 283) were matched 1 : 10 with children without a hospital diagnosis of AD. Endpoints were psychotropic medication use, hospital diagnoses of depression, anxiety, ADHD, or self-harming behaviour, accidental/suicidal death, and consultation with a psychiatrist or psychologist.

RESULTS

Significant associations were observed between hospital-diagnosed AD and antidepressant [adjusted hazard ratio (aHR) 1·19, 95% confidence interval (CI) 1·04-1·36], anxiolytic (aHR 1·72, 95% CI 1·57-1·90), and centrally acting sympathomimetic (aHR 1·29, 95% CI 1·18-1·42) medication use. Consultation with a psychiatrist (aHR 1·33, 95% CI 1·16-1·52) or psychologist (aHR 1·25, 95% CI 1·11-1·41) was also associated with AD. No association with a hospital diagnosis of depression (aHR 0·58, 95% CI 0·21-1·56), anxiety (aHR 1·47, 95% CI 0·98-2·22) or self-harming behaviour (aHR 0·88, 95% CI 0·27-2·88) was observed, but a diagnosis of ADHD (aHR 1·91, 95% CI 1·56-2·32) was significantly associated with AD. The absolute risks were generally low.

CONCLUSIONS

The increased risk of treatment, but not of a hospital diagnosis of psychiatric disorders in children with hospital-diagnosed AD, suggests that psychiatric issues in children with AD could be of a transient, reversible or mild-moderate nature.

Responsiveness of quality of life measures in children with peripheral vascular malformations: The OVAMA project

Background

The OVAMA (Outcome Measures for VAscular MAlformations) project determined quality of life (QoL) as a core outcome domain for evaluating treatment effect in vascular malformations. To correctly evaluate treatment effect on QoL, patient-reported outcome measures (PROMs) are needed that are responsive to changes. In children with vascular malformations, we explored if two widely used PROMs were responsive to changes: the Pediatric Quality of Life Inventory (PedsQL) and the Children's Dermatology Life Quality Index (CDLQI).

Methods

In an international multicenter prospective study, conservatively and invasively treated children completed the PedsQL and CDLQI at baseline and after follow-up of 6-8 weeks. At follow-up, change in health was assessed by a global rating of change (GRC) scale. Responsiveness was assessed by testing hypotheses on expected correlation strength between change scores of the PROMs and the GRC scale, and by calculating the area under the receiver operating characteristics curve (AUC). The PROMs were considered responsive if ≥75% of the hypotheses were confirmed or if the AUC was ≥0.7.

Results

Twenty-nine children were recruited in three centers in the Netherlands and United States, of which 25 completed all baseline and follow-up measurements. For both the PedsQL and CDLQI, less than 75% of the hypotheses were confirmed and the AUC was <0.7.

Discussion

The results suggest that these PROMs are not sufficiently responsive for evaluating treatment effect in peripheral vascular malformations. Our study emphasizes the need for assessing responsiveness before using a PROM in evaluating treatment effect.

Current measures are not sufficient: an interview-based qualitative assessment of quality of life in cutaneous T-cell lymphoma

BACKGROUND

Cutaneous T-cell lymphoma (CTCL) negatively impacts quality of life (QoL), but existing QoL questionnaires may not comprehensively reflect patients' experience.

OBJECTIVES

To identify the aspects of QoL that are most meaningful to patients with CTCL and to evaluate existing QoL instruments in this context.

METHODS

Semistructured interviews were conducted between May and June 2019 using purposive sampling of patients with CTCL. Data were analysed by an inductive thematic approach using Dedoose Version 8.0.35.

RESULTS

One-on-one interviews lasting a median of 43 min were completed by 18 patients [median age 62 years (interquartile range 52-70); 39% advanced-stage (IIB-IV)]. Itch was the most common clinical symptom reported (16 of 18 patients), followed by pain (12 of 18), skin breaks (11 of 18) and skin flaking (10 of 18). Eleven patients reported that their symptoms interfered with sleep, which impacted daily functioning. Patients also noted a lack of understanding of the disease in the community and felt uncertain (12 of 18), depressed (11 of 18), suicidal (four of 18) and hopeless (nine of 18). Nearly all patients (17 of 18) reported a sense of 'otherness' (not feeling 'normal' or 'like themselves'), and most patients (16 of 18) specifically mentioned concern about their physical appearance. Patients also noted substantial treatment burden. Salient patient concerns, including individual clinical symptoms, concern about appearance and problems with sleep, were not adequately or consistently represented in generic, skin-specific or CTCL-specific QoL measures.

CONCLUSIONS

Incorporating the concerns and priorities that distinguish patients with CTCL from other patient populations will be of paramount importance in developing a comprehensive CTCL-specific measure of QoL that adequately captures patients' experience.

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

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.