JOURNAL OF MEDICAL INTERNET RESEARCH Hernandez et al Original Paper EuroQol (EQ-5D-5L) Validity in Assessing the Quality of Life in Adults With Asthma: Cross-Sectional Study Gimena Hernandez1,2,3, MD, MPH; Olatz Garin1,3,4, MPH, PhD; Alexandra L Dima5, PhD; Angels Pont1,3, BSc; Marc Martí Pastor1,2,3, MD, MPH; Jordi Alonso1,3,4, MD, PhD; Eric Van Ganse5,6, MD, PhD; Laurent Laforest6, MD, PhD; Marijn de Bruin7, PhD; Karina Mayoral1,2, MPH; Vicky Serra-Sutton3,8, PhD; Montse Ferrer1,2,3, MD, PhD; ASTRO-LAB Group 1 Health Services Research Group, Hospital del Mar Medical Research Institute, Barcelona, Spain 2 Department of Paediatrics, Obstetrics and Gynaecology and Preventive Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain 3 Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública, Madrid, Spain 4 Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain 5 Health Services and Performance Research, Université Claude Bernard Lyon 1, Lyon, France 6 Pharmaco-Epidemiology Lyon, Lyon, France 7 Institute of Applied Health Sciences, University of Aberdeen, Scotland, United Kingdom 8 Agència de Qualitat i Avaluació Sanitàries de Catalunya, Barcelona, Spain Corresponding Author: Montse Ferrer, MD, PhD Health Services Research Group Hospital del Mar Medical Research Institute Dr Aiguader 88 Barcelona, 08003 Spain Phone: 34 933160763 Fax: 34 933160797 Email: mferrer@imim.es Abstract Background: The EuroQol-5 Dimension (EQ-5D), developed in 1990, is a most widely used generic tool to measure the health-related quality of life (HRQoL) and considered suitable for patients with asthma. In 2009, the EuroQol Group developed a new EQ-5D version to overcome limitations related to its consistently reported high ceiling effect. To enhance the sensitivity for assessing the HRQoL in further patient populations, the number of responses of EQ-5D was increased from 3 to 5 levels (EQ-5D-5L). Moreover, the availability of well-defined requirements for its Web-based administration allows EQ-5D-5L use to monitor the HRQoL in electronic health (eHealth) programs. No study has evaluated the metric properties of the new EQ-5D-5L in patients with asthma yet. Objective: This study aims to examine the distribution, construct validity, and reliability of the new EQ-5D-5L questionnaire administered online to adults with asthma. Methods: We evaluated patients with asthma (age: 18-40 years) from a primary care setting in France and England, who self-completed the EQ-5D-5L questionnaire online. The inclusion criteria were persistent asthma defined as >6 months of prescribed inhaled corticosteroids and long-acting beta-agonists or inhaled corticosteroids alone during the 12 months prior to inclusion. The EQ-5D index was obtained by applying the English preference value set for the new EQ-5D-5L and the French 3L-5L crosswalk value set. Both value sets produced single preference-based indices ranging from 1 (best health state) to negative values (health states valued as worse than death), where 0=death, allowing the calculation of quality-adjusted life years. Responses to dimensions and index distribution, including ceiling and floor effects, were examined. The construct validity was assessed by comparing the means of known groups by analyses of variance and calculation of effect sizes. Results: Of 312 patients answering the baseline Web-based survey, 290 completed the EQ-5D-5L (93%). The floor effect was null, and the ceiling effect was 26.5% (74/279). The mean EQ-5D-5L index was 0.88 (SD 0.14) with the English value set and 0.83 (SD 0.19) with the French 3L-5L crosswalk value set. In both indices, large effect sizes were observed for known groups defined by the Asthma Control Questionnaire (1.06 and 1.04, P<.001). Differences between extreme groups defined by chronic http://www.jmir.org/2019/1/e10178/ J Med Internet Res 2019 | vol. 21 | iss. 1 | e10178 | p. 1 (page number not for citation purposes) XSL• FO RenderX JOURNAL OF MEDICAL INTERNET RESEARCH Hernandez et al conditions (P=.002 and P=.003 for the English value set and French 3L-5L crosswalk value set, respectively), short-acting beta-agonists (SABAs) canisters in the last 12 months (P=.02 and P=.03), or SABA use during the previous 4 weeks (P=.03 and P=.01) were of moderate magnitude with effect sizes around 0.5. Conclusions: The new EQ-5D-5L questionnaire has an acceptable ceiling effect, a good construct validity based on the discriminant ability for distinguishing among health-related known groups, and high reliability, supporting its adequacy for assessing the HRQoL in patients with asthma. EQ-5D-5L completion by most Web-based respondents supports the feasibility of this administration form. (J Med Internet Res 2019;21(1):e10178) doi: 10.2196/10178 KEYWORDS asthma; EQ-5D-5L; EuroQol; health-related quality of life; Web-based survey; validity; patient-reported outcome measures obstructive pulmonary disease [18], osteoarthritis [18], diabetes Introduction [19], and coronary heart disease [20]. The impact of asthma on the patients’ health has been The traditional EQ-5D descriptive system, composed of 5 traditionally assessed by either clinical markers or functional dimensions with 3 levels of severity, defines 243 distinct health tests [1]. Patient-reported outcome measures, such as symptom states resulting from all the possible combinations (ie, 35); this control or health-related quality of life (HRQoL), have shown is a low number compared with other generic preference-based to be useful for clinical management, understanding disease instruments such as the Health Utilities Index [21] or the SF-6D impact on the patients’ functional status and well-being, and [22] with 972,000 and 18,000 possible combinations, cost-effectiveness analyses [2]. Hence, international guidelines respectively. To improve its sensitivity, the EuroQol Group for asthma diagnosis and treatment have emphasized that developed a new EQ-5D version, by increasing the number of treatment goals should include the improvement of the patients’ responses from 3 to 5 levels, known as EQ-5D-5L, with 3125 HRQoL [3]. health states (ie, 55) [23]. In asthma, disease-specific HRQoL measures have been more widely used than generic ones, as they could be more sensitive. The new EQ-5D-5L has already been tested in some Adding generic HRQoL domains important to patients with disease-specific samples, such as patients with cancer [24,25] asthma has been proposed [4] because asthma-specific HRQoL and with hepatitis [26], showing a better discrimination instruments measure similar contents to those covered by asthma capability and lower ceiling effects than the traditional 3-level control questionnaires [5,6] such as symptoms and activity version (11% vs 17% [24], 9.7% vs 16.8% [25], and 21.6% vs limitations. Generic HRQoL instruments are broad measures 38.3% [26]). However, to date, no study has evaluated metric that can be applied in patients with various conditions and the properties of the new 5-level EQ-5D in patients with asthma. general population. The EuroQol-5 Dimensions (EQ-5D), Hence, this study aims to examine the distribution, construct developed in 1990 by the EuroQol Group, is one of the most validity, and reliability of the new EQ-5D-5L administered widely used generic tools owing to its low respondent burden, online to adults with asthma. good psychometric properties, and econometric development [7-9]. In addition, the availability of well-defined requirements Methods for its Web-based administration by multiple devices, such as Setting and Study Population personal computer, tablet, or smartphones, makes this instrument adequate for monitoring the HRQoL in eHealth programs [10]. In this study, we analyzed baseline data of adults (age: 18-40 years) enrolled in the ASTRO-LAB cohort who completed the The EQ-5D was considered a suitable generic measure in a EQ-5D-5L questionnaire. The ASTRO-LAB project is a systematic review [11] of patient-reported outcome measures prospective longitudinal study of asthmatic patients designed for patients with asthma. This health status measure allows the to provide new evidence regarding the safety of long-acting calculation of quality-adjusted life years (QALYs) when society beta-agonists (LABAs) in routine primary care in France and preferences are applied and cost-utility analysis in economic the United Kingdom. Details of the study are described evaluations [12-14]. However, to the best of our knowledge, elsewhere [27]. only 3 studies have evaluated its psychometric properties in patients with asthma [15-17]. Garratt et al [16] showed a The inclusion criteria were as follows: persistent asthma and moderate EQ-5D association with asthma-specific HRQoL age <40 years. Patients were considered to have persistent instruments and external variables such as smoking status and asthma when they had >6 months of prescribed treatment with education level. Oga et al [15] and McTaggart-Cowan et al [17] inhaled corticosteroids (ICs) and LABAs or ICs alone during reported a high ceiling effect (59% and 50% of the sample with the 12 months prior to inclusion. Persistent asthma requires the maximum score, respectively) questioning the usefulness controller therapy on a regular basis, whereas intermittent of the EQ-5D in asthmatic patients. In fact, limitations related asthma can be treated with rescue medication as needed. The to the high ceiling effect have also been consistently reported ASTRO-LAB persistent asthma definition was based on a for the EQ-5D in other chronic conditions such as chronic minimal prescription duration level of antiasthmatic drugs because this method is considered less biased than the http://www.jmir.org/2019/1/e10178/ J Med Internet Res 2019 | vol. 21 | iss. 1 | e10178 | p. 2 (page number not for citation purposes) XSL• FO RenderX JOURNAL OF MEDICAL INTERNET RESEARCH Hernandez et al practitioner’s classification of asthma, and it is frequently used Patient-Completed Web-Based Survey in database studies [28]. The ASTRO-LAB project’s age limit Patients received instructions during the recruitment contact to was chosen to minimize the recruitment of patients with other self-complete a Web-based survey, which included the comorbid conditions frequent at older ages, most importantly EQ-5D-5L to measure the HRQoL and sociodemographic data, chronic obstructive pulmonary disease, often overlapped and such as their highest level of education and current work difficult to exclude without specific tests. situation, among others. The exclusion criteria were as follows: chronic oral The EQ-5D-5L is a brief, multiattribute, generic, health status corticosteroid use (≥15 consecutive days 3 months before measure composed of 5 questions with Likert response options inclusion), history of omalizumab therapy, and any other (descriptive system) and a visual analog scale (EQ-VAS). The concomitant chronic respiratory disease (chronic obstructive latter asks patients to rate their own health from 0 to 100 (the pulmonary disease, cystic fibrosis, pulmonary fibrosis, worst and best imaginable health, respectively). The descriptive bronchiectasis, or tuberculosis). Owing to ASTRO-LAB’s main system covers 5 dimensions of health (mobility, self-care, usual focus being LABAs safety, the abovementioned criteria based activities, pain or discomfort, and anxiety or depression) with on the administration of other medications aimed at avoiding 5 levels of severity in each dimension (no problems, slight confounding with their adverse effects, implying that most problems, moderate problems, severe problems, and unable to patients with severe persistent asthma were excluded. perform or extreme problems). The ASTRO-LAB study has been approved by the Ethics and Preference value sets used to obtain the index of the EQ-5D-5L Regulatory Boards in France and the United Kingdom and was were the 3L-5L crosswalk from the French 3L version [29], and conducted in accordance with the Declaration of the World the new EQ-5D-5L value set from England [30]. In both cases, Medical Association. In France, approval was obtained from single preference-based indices were produced ranging from 1 CCTIRS (Comité consultatif sur le traitement de l’information (the best health state) to negative values (health states valued en matière de recherche dans le domaine dela santé) on as worse than death), where 0=death. The minimal important November 21, 2012 (Dossier N°12702), and the authorization difference for the EQ-5D index was estimated as 0.07 [31]. from Commission Nationale d’Informatique et Liberté was obtained in May 17, 2013 (DR-2013-264). In the United Telephone Interviews Kingdom, according to the UK Research Governance The telephonic interviews were computer-assisted to standardize Framework, the study was submitted to The West London the process. Trained interviewers administered questions to Research Ethics Committee (REC), and the final approval was patients about their asthma control and treatment use, among obtained on April 15, 2013 (REC Reference 12/LO/20139). others. Asthma control is defined as the extent to which the Following the UK regulatory process, the ASTRO-LAB manifestations of asthma can be observed in a patient, or have consortium submitted the protocol to the National Institute for been reduced or removed by treatment [32,33]; it reflects the Health Research Clinical Research Network (NIHR CRN) to suitability of the asthma treatment. launch the review by Primary Care Trust local sites. The first local approval was granted by the West London Primary Care The Asthma Control Questionnaire (ACQ) is composed of 7 Consortium on May 22, 2013. Informed consent was obtained items—the top scoring 5 symptoms, FEV1% predicted, and from all participants prior to inclusion. daily rescue bronchodilator use. A shorter version called ACQ-symptoms only [34] was developed to use when it is not Measurement Instruments feasible to collect data about the last 2 items, as in Clinical data were extracted from medical records, and ASTRO-LAB. It assesses the frequency of the 5 asthma patient-reported information was obtained by the following 2 symptoms during the previous week on a 7-point Likert scale administration modes: patient-completed Web-based survey (0=no impairment, 6=maximum impairment). The overall score, and telephone interviews with patients performed by trained calculated as the mean of item responses, ranges from 0 to 6. interviewers. The EQ-5D-5L was only administered in the A score <0.75 was defined as well-controlled asthma; 0.75-1.5 Web-based survey. as intermediate control; and >1.5 as not well-controlled asthma [35]. The results generated by the short versions have shown Clinical Data to be very similar to those of the complete ACQ, as well as its Information on age, gender, body mass index, comorbidity, and measurement properties (reliability, responsiveness, internal treatment prescribed was obtained; in France, general consistency, construct validity, and interpretability) [34]. practitioners completed a Web-based survey at patient inclusion, while in the United Kingdom, this information was directly The following question was asked to patients with SABA extracted from medical records. The history of 4 associated therapy prescription: “How often have you usually taken your pathologies (allergic rhinitis, nasal polyps, anxiety or depression, ‘reliever medication’ (brand name) in the past 4 weeks? Every and gastroesophageal reflux), was registered and transformed day; almost every day; once or twice every week; less than once into a count variable. The total number of short-acting a week; or I don’t know.” beta-agonist (SABA) canisters prescribed in the 12 months prior Analytic Strategy to inclusion was transformed into a variable of 3 categories—0, Sample characteristics were described by calculating 1-4, and ≥5 canisters. percentages, or mean (SD) values, according to the variable type (detailed in tables and figures). To examine the nonresponse http://www.jmir.org/2019/1/e10178/ J Med Internet Res 2019 | vol. 21 | iss. 1 | e10178 | p. 3 (page number not for citation purposes) XSL• FO RenderX JOURNAL OF MEDICAL INTERNET RESEARCH Hernandez et al bias, subjects who completed the Web-based survey were (66.9%, 184/275), and 72.6% (201/277) were employed in their compared with those who had not completed this survey by a t usual jobs. These 2 variables were only available for patients test and chi-square test. included in the analysis, as they were recorded in the Web-based questionnaire. Nonrespondents were younger (aged 29.8 vs 31.0 We calculated the percentages of responses to each EQ-5D-5L years, P=.03), and presented higher ACQ mean scores (worse dimension. To examine the distribution of the EQ-5D index, control) in comparison to respondents but did not differ in body we calculated statistics of central tendency, dispersion, mass index, treatment, number of other chronic conditions, asymmetry, and tail extremity, as well as the proportion and SABA canisters prescribed last year, and frequency of SABA 95% CI of the individuals in the best possible (ceiling) and the used in the previous 4 weeks. worst possible (floor) health states [36]. To assess the reliability based on the internal consistency, the Cronbach alpha coefficient 5-Level EuroQoL-5 Dimension Version Distribution was estimated. Figure 1 shows the percentages of responses to each EQ-5D-5L The construct validity examines whether the instrument dimension. Most subjects reported “no problems” in mobility adequately assesses the concept that it intends to measure [37], (81.0%, 226/279) and self-care (98.2%, 274/279) dimensions, in this case the HRQoL. The strategy to evaluate the construct while only around half of the subjects endorsed this category validity based on known groups consists of testing the ability in pain or discomfort (45.5%, 127/279) and anxiety or of the instrument to discriminate among groups previously depression (48.0%, 134/279) dimensions. The “extreme hypothesized as differing in the concept measured. The problems” category was endorsed by 1 subject for pain and 7 following variables were chosen to test the instrument’s capacity for anxiety or depression. to discriminate, as differences have been consistently shown in Table 2 shows the distribution characteristics of EQ-5D-5L the HRQoL among groups defined by them [1,15,38,39]—the indices. In our sample, the EQ-5D-5L index constructed with number of chronic conditions (as an indicator of general health), the English value set ranged from 0.16 to 1 and from –0.074 to number of SABA canisters prescribed in the previous year, 1 when constructed with the French 3L-5L crosswalk value set. frequency of SABA inhaler use during the previous 4 weeks, The mean was 0.88 (SD 0.14) for the English index and 0.83 and ACQ scores (as 3 indicators of asthma control). We (SD 0.19) for the French one. The Kurtosis statistics of 5.62 hypothesized that asthma patients with worse general health or and 3.26, with skewness of –2.06 and –1.63, indicated that the less asthma control report worse HRQoL. asymmetry to the right part of the distribution and the tail To evaluate the discriminative capacity of the EQ-5D index and extremity were greater in the index constructed with the English EQ-VAS among the known groups mentioned above, mean EQ-5D-5L value set. The floor effect was null, and the ceiling scores were compared using one-way analysis of variance and effect was 26.5% (74/279). Cronbach alpha coefficient was .69, the Tukey studentized range (honestly significant difference) achieving the recommended standard [36,37]. test for post-hoc comparisons; alpha was set at.05. To assess 5-level EuroQoL-5 Dimension Version Construct the magnitude of the differences Cohen effect sizes were Validity calculated. General guidelines define an effect size of 0.2 as small, 0.5 as moderate, and 0.8 as large [40]. All analyses were Table 3 presents results on the construct validity of the conducted using the statistical package SPSS (IBM SPSS EQ-5D-5L based on known groups. Both EQ-5D-5L indices Statistics for Windows, Version 23.0, IBM Corp) showed statistically significant different means for all known groups evaluated, while EQ-VAS only showed statistically Results significant differences among groups defined by ACQ scores. The mean EQ-5D-5L index for asthmatic patients decreased Study Sample significantly with an increase in the number of other chronic Of 581 subjects with asthma aged 18-40 years composing the conditions from 0.91 to 0.82 with the English value set and from ASTRO-LAB cohort, 312 filled in the baseline Web-based 0.86 to 0.75 with the French 3L-5L crosswalk. The effect size survey (Web-based participation rate, 53.7%), but 22 of these between patients with none and those with ≥2 other chronic did not complete the EQ-5D-5L (questionnaire nonresponse conditions were 0.62 and 0.60 (moderate) with EQ-5D-5L rate, 7.0%). Of 290 who fulfilled the EQ-5D-5L, 11 were indices. In addition, effect sizes were moderate between extreme excluded because they had missing data on all the variables groups defined by SABA canisters prescribed in the previous selected to define known groups; hence, 279 patients were year (0.58 and 0.46), and by the SABA frequency during the finally included in this analysis. Table 1 shows patients’ baseline last 4 weeks (both 0.5). Finally, among groups defined by ACQ characteristics, comparing the included subjects with excluded scores, the effect size between well-controlled and ones (mainly because of not responding to the Web-based intermediately controlled asthma was moderate (0.44 and 0.47) survey). Most of the included subjects were from France and and large between well- and not well-controlled asthma (1.06 had been treated with fixed-dose combinations of LABA and and 1.04). IC. More than half of them had completed a bachelor degree http://www.jmir.org/2019/1/e10178/ J Med Internet Res 2019 | vol. 21 | iss. 1 | e10178 | p. 4 (page number not for citation purposes) XSL• FO RenderX JOURNAL OF MEDICAL INTERNET RESEARCH Hernandez et al Table 1. The characteristics of included and excluded subjects. Characteristics Included patients (n=279) Excluded patients (n=302) P value Age (years), mean (SD) 31.0 (6.7) 29.8 (6.7) .03 <25, n (%) 62 (22.2) 85 (28.1) .10 25-34, n (%) 119 (42.7) 133 (44.0) ≥35, n (%) 98 (35.1) 84 (27.8) Gender, n (%) .47 Male 110 (39.4) 128 (42.4) Female 169 (60.6) 174 (57.6) Country .01 France, n (%) 222 (79.6) 264 (87.7) United Kingdom, n (%) 57 (20.4) 37 (12.3) Missing (n) 0 1 Body mass index (kg/m2), mean (SD) 25.2 (6.2) 25.4 (5.8) .79 Missing (n) 127 107 Treatment with, n (%) .18 a 11 (3.9) 9 (3.0) LABA ICsb 71 (25.4) 60 (19.9) LABA+ICs in separate inhalers 37 (13.3) 33 (10.9) Fixed LABA and ICs combination 160 (57.3) 200 (66.2) Other chronic conditions .51 0 conditions, n (%) 66 (41.5) 80 (39.2) 1 condition, n (%) 62 (39.0) 91 (44.6) ≥2 conditions, n (%) 31 (19.5) 33 (16.2) Missing (n) 120 98 Number of SABAc canisters prescribed (last year) .75 0 canisters, n (%) 119 (53.6) 133 (50.2) 1-4 canisters, n (%) 78 (35.1) 100 (37.7) ≥5 canisters, n (%) 25 (11.3) 32 (12.1) Missing (n) 57 —d Frequency of SABA use reported by patient (last 4 weeks) .63 Less than once a week, n (%) 166 (61.9) 171 (65.5) Once or twice every week, n (%) 71 (26.5) 60 (23.0) Almost every day or every day, n (%) 31 (11.6) 30 (11.5) Missing (n) 11 41 Asthma Control Questionnaire, mean (SD) 1.01 (0.92) 1.35 (1.01) <.001 Well-controlled (<0.75), n (%) 119 (44.6) 89 (34.1) <.001 Intermediate (0.75-1.5), n (%) 82 (30.7) 63 (24.1) Not well-controlled (>1.5), n (%) 66 (24.7) 109 (41.8) Missing (n) 12 41 Highest education Not calculated Secondary school or less, n (%) 13 (4.7) — Sixth form or college, n (%) 41 (14.9) — http://www.jmir.org/2019/1/e10178/ J Med Internet Res 2019 | vol. 21 | iss. 1 | e10178 | p. 5 (page number not for citation purposes) XSL• FO RenderX JOURNAL OF MEDICAL INTERNET RESEARCH Hernandez et al Characteristics Included patients (n=279) Excluded patients (n=302) P value Bachelor degree, n (%) 184 (66.9) — Postgraduate, n (%) 37 (13.5) — Missing (n) 4 — Work status Not calculated Employed at usual job, n (%) 201 (72.6) — On light duty or restricted work, n (%) 1 (0.4) — Paid leave or sick leave, n (%) 4 (1.4) — Unemployed because of other reason, n (%) 23 (8.3) — Student (school, college, university), n (%) 35 (12.6) — Keeping house or homemaker, n (%) 7 (2.5) — Retired, n (%) 0 (0.0) — On disability, n (%) 6 (2.2) — Missing (n) 2 — a LABA: long-acting beta-agonist. b IC: inhaled corticosteroid. c SABA: short-acting beta-agonist. d Indicates missing data. Figure 1. The percentage of patients’ responses to each dimension. http://www.jmir.org/2019/1/e10178/ J Med Internet Res 2019 | vol. 21 | iss. 1 | e10178 | p. 6 (page number not for citation purposes) XSL• FO RenderX JOURNAL OF MEDICAL INTERNET RESEARCH Hernandez et al Table 2. The distribution of 5-level EuroQoL-5 dimension version indices (n=279). Cronbach alpha coefficient was .69. Statistics EQ-5D-5La (English value set) EQ-5D-5L (French 3L-5L crosswalk value set) Theoretical range –0.28097 to 1 –0.530 to 1 Observed range 0.160 to 1 –0.074 to 1 Mean (SD) 0.88 (0.14) 0.83 (0.19) Median (interquartile range) 0.92 (0.84 to 1.00) 0.91 (0.71 to 1.00) Kurtosis (SE) 5.62 (0.29) 3.26 (0.29) Skewness (SE) –2.06 (0.15) –1.63 (0.15) Floor effect (%) 0 0 Ceiling effect (%) 26.5 26.5 a EQ-5D-5L: EuroQol-5 Dimensions-5 Levels. Table 3. The construct validity of 5-level EuroQoL-5 dimension version. Constructs EQ-5D-5La index (English value EQ-5D-5L index (French 3L-5L EuroQol visual analog scale set) crosswalk) Mean (SD) Effect size (95% CI) Mean (SD) Effect size (95% CI) Mean (SD) Effect size (95% CI) Other chronic conditions 0 chronic conditions 0.91 (0.11) Reference 0.86 (0.14) Reference 78.91 (14.85) Reference 1 chronic condition 0.89 (0.10) 0.14 (–0.21 to 0.48) 0.85 (0.15) 0.05 (–0.26 to 0.36) 79.08 (13.23) 0.06 (–0.25 to 0.37) ≥2 chronic conditions 0.82 (0.13) 0.62 (0.18 to 1.06) 0.75 (0.20) 0.60 (0.18 to 1.02) 72.94 (17.22) 0.37 (–0.04 to 0.79) P value .002 b,c — d .003 b,c — .12 — Number of SABAe canisters prescribed (last year) 0 canisters 0.89 (0.11) Reference 0.85 (0.15) Reference 78.84 (12.90) Reference 1-4 canisters 0.87 (0.14) 0.11 (–0.18 to 0.39) 0.82 (0.19) 0.19 (–0.07 to 0.45) 76.64 (17.93) 0.21 (–0.06 to 0.47) 5 or more canisters 0.81 (0.17) 0.58 (0.14 to 1.01) 0.76 (0.22) 0.46 (0.05 to 0.86) 72.00 (24.52) 0.47 (0.07 to 0.88) P value .02b — .03b — .15 — Frequency of SABA use reported by patient (last 4 weeks) Less than once a week 0.82 (0.19) Reference 0.74 (0.23) Reference 71.45 (19.85) Reference Once or twice a week 0.87 (0.15) 0.17 (–0.11 to 0.44) 0.81 (0.21) 0.29 (0.03 to 0.55) 78.08 (12.92) 0.07 (–0.19 to 0.32) Almost every day or every 0.89 (0.12) 0.50 (0.11 to 0.89) 0.85 (0.16) 0.50 (0.15 to 0.84) 78.61 (16.26) 0.37 (0.03 to 0.71) day P value .03b — .01b — .07 — Asthma Control Questionnaire Well-controlled (<0.75) 0.93 (0.10) Reference 0.91 (0.13) Reference 81.65 (13.80) Reference Intermediate (0.75-1.5) 0.87 (0.11) 0.44 (0.15 to 0.72) 0.81 (0.15) 0.47 (0.22 to 0.73) 79.18 (11.92) 0.15 (–0.11 to 0.40) Not well-controlled (>1.5) 0.78 (0.19) 1.06 (0.74 to 1.38) 0.69 (0.24) 1.04 (0.75 to 1.32) 68.39 (20.23) 0.79 (0.51 to 1.08) P value <.001b,c,f — <.001b,c,f — <.001b,c — a EuroQol-5 Dimensions-5 Levels. b First category (reference) versus third category. c Second category versus third category. d P value not necessary as the CI was calculated. e SABA: short-acting beta-agonist. f First category (reference) versus second category. http://www.jmir.org/2019/1/e10178/ J Med Internet Res 2019 | vol. 21 | iss. 1 | e10178 | p. 7 (page number not for citation purposes) XSL• FO RenderX JOURNAL OF MEDICAL INTERNET RESEARCH Hernandez et al option when compared with results from previous studies with Discussion the EQ-5D-3L suggests that the “no problems” category (level Principal Findings 1 out of 3) is partially redistributed to the following intermediate category, “slight” problems (level 2 out of 5), in the new 5-level To the best of our knowledge, this is the first study evaluating version. However, head-to-head studies are needed to ensure metric properties of the new EQ-5D-5L in patients with asthma. that the new 5L version’s better properties we have observed, In this study, this generic preference-based instrument showed compared with results from previous EQ-5D-3L studies [15,17], adequate distribution and reliability, with 26.5% (74/279) of are not explained by differences in patients’ characteristics or patients reporting the best possible health state (ceiling effect). design issues. In addition, it showed good construct validity, given its capacity of discriminating among groups differing in the number of Studies that directly elicit preferences from representative chronic conditions and symptom control. The distribution of general population samples to derive value sets for the new the EQ-5D-5L index was less skewed than the previously EQ-5D-5L, using a harmonized protocol, have already been published one for the 3-level version owing to its lower ceiling published for several countries [30,47-51], but they are not yet effect [15,17]. developed in many others, including France. The EuroQol Group developed the 3L-5L crosswalk value sets as a temporary Comparison of Web-Based Participation Rate With solution to estimate the EQ-5D-5L in such a situation [29]. The Prior Work difference between both indices in the negative extreme of the In this study, 53.7% (312/581) of participants completed the theoretical range (–0.28 and –0.53) is explained by the method Web-based baseline survey, and almost all of these completed used for the elicitation of the societal preference values to derive the EQ-5D-5L (92.9%, 290/312). The internet era has led to the value set: time trade-off in the French general population implementing Web-based surveys to take advantage of the for the 3L version [52], and the composite method of time known benefits such as completeness [41,42], low expenses trade-off with discrete choice experiments in the UK general [43], and better data management. Nevertheless, there are still population for the new 5L version [23,30]. Our findings show some barriers to Web-based self-completion, which could that the mean EQ-5D-5L indices obtained with both value sets produce low response rates and selection bias. Although the are quite similar (0.88 and 0.83), supporting that the 3L-5L reported participation rate varied a lot across Web-based surveys crosswalk is a good interim solution to calculate the EQ-5D-5L [41,44,45], the 53.7% in this study is similar to those reported index, until definitive EQ-5D-5L value sets are available. by other studies comparing different modes of data collection, The EQ-5D-5L index could discriminate among different known such as 64.2% and 53.3% participation rates reported by groups in the hypothesized direction. In all the variables Kongsved et al [41] and Hohwu et al [46] studies. Remarkably, evaluated, differences between extreme groups ranged from both studies showed a slightly better response rate with the 0.07 to 0.2, therefore being equal to or higher than the minimal paper mode—73.2% versus 64.2% [41] and 56.2% versus 53.3% important difference, previously estimated as 0.07 [31]. The [46]. In the ASTRO-LAB cohort, the high overall respondent magnitude was moderate for differences among groups defined burden (participants were asked to respond to yearly Web-based by the presence of other chronic conditions and SABA use or surveys, 4-monthly telephone interviews, and monthly short prescription and large for differences between patients with message service text messages) could have affected the response well- and not well-controlled asthma measured with the ACQ. rate. McTaggart-Cowan et al [17], with the traditional EQ-5D-3L in Comparison With Prior Studies Evaluating the patients with asthma, also showed differences between extreme EuroQoL-5 Dimension Version in Patients With groups >0.07, ranging from 0.07 to 0.18. It was not possible to Asthma directly compare effect sizes with this study [17], as the variables to define known groups were different. Mc Despite being higher than the 15% [36] established for the Taggart-Cowan et al reported a correlation of 0.37 for the ACQ ceiling effect, 26.5% (74/279) of patients with mild-to-moderate with the EQ-5D-3L index [17], similar to the 0.43 found in our persistent asthma in the best possible health state in our sample study with the EQ-5D-5L index. These findings indicate a good was considerably lower than that reported in prior studies using construct validity for the EQ-5D-5L index, which, in general, the traditional EQ-5D-3L in paper-and-pencil administration presented a greater discriminant capacity than the EQ-VAS [15,17]. A ceiling effect of 59% was described in Japanese among the known groups evaluated. patients with mild-to-severe asthma treated with ICs [15], and 50% in Canadian patients with mainly mild-to-moderate Limitations and Strengths self-reported asthma [17]. In addition, our findings showed a Some potential limitations of this study need to be considered. lower proportion of patients with no problems in most First, a direct comparison with the EQ-5D-3L was not possible. dimensions than those reported by the 3-level version Although previous EQ-5D-3L studies in asthma patients [15-17] [15]—81.0% (226/279) versus 90.7% in mobility, 77.1% showed higher ceiling effects and lower discriminatory (215/279) versus 85.2% in activity, 45.5% (127/279) versus properties than ours with the EQ-5D-5L, differences among 74.1% in pain or discomfort, and 48.0% (134/279) versus 77.8% studies regarding patients’ and design characteristics cannot be in anxiety or depression. The other 2 studies on the EQ-5D-3L discarded. Second, as no asthma-specific HRQoL measure was in asthma [16,17] did not report percentage distributions for included in this study, we were unable to compare the generic each dimension. This lower endorsement of the top response EQ-5D-5L with them. Studies evaluating the EQ-5D-3L in http://www.jmir.org/2019/1/e10178/ J Med Internet Res 2019 | vol. 21 | iss. 1 | e10178 | p. 8 (page number not for citation purposes) XSL• FO RenderX JOURNAL OF MEDICAL INTERNET RESEARCH Hernandez et al comparison to the Asthma Quality of Life Questionnaire [15-17] evaluating the EQ-5D-5L’s construct validity in patients with or the Newcastle Asthma Symptoms Questionnaire [16] showed asthma. The relationship between comorbid chronic conditions that these disease-specific instruments were more sensitive to and health is well established, and the associations of symptoms change. Further head-to-head studies comparing the EQ-5D-5L control [53] with the HRQoL have been extensively studied in with disease-specific instruments are needed, mainly to compare this population. Furthermore, the ACQ, validated in 50 responsiveness. Third, the usability of online versus other languages, is one of the most widely accepted instruments for methods of survey administration could not be evaluated because measuring asthma control [54]. all patients completed the Web-based EQ-5D-5L. Fourth, because the ASTRO-LAB project only included patients with Conclusions mild-to-moderate persistent asthma, the generalizability of our In summary, our results provide support to the construct validity results to those with intermittent or severe persistent asthma is of the EQ-5D-5L administered online to patients with asthma, uncertain. The generalizability is also uncertain to patients older based on its discriminant ability for distinguishing among than 40 years. Finally, it is important to note that 46.3% health-related known groups, as well as its lower ceiling effect (269/581) of participants in the ASTRO-LAB project did not than previously reported for the traditional 3-level version answer the Web-based survey. No differences in [15,17]. The completion of the EQ-5D-5L by most of the sociodemographic characteristics, treatment, and comorbidity Web-based survey respondents supports the feasibility of this were found between respondents and nonrespondents, and administration form. As it was developed as a preference-based differences detected in asthma control were minor. However, health status measure, the EQ-5D-5L index allows combining there could be differences in other characteristics, which have both length and quality of life, and calculates QALYs to measure not been measured such as personality or other psychological health outcomes in economic evaluations. All these findings traits. suggest that the new EQ-5D with 5 levels is a promising instrument to compare the efficiency of different programs or This study has several strengths that need to be highlighted. treatment strategies for asthma patients. Nevertheless, further First, embedding this study in an observational cohort in routine studies are recommended to evaluate the responsiveness over care allowed us to select several appropriate known groups for time of the EQ-5D-5L among patients with asthma. Acknowledgments Financial support for this study was provided by the European Union Seventh Framework Programme FP7 (ASTROLAB project EC HEALTH-F5-2011-282593), Instituto de Salud Carlos III FEDER (PI12/00772), Fondo de Investigación Sanitaria, ISCIII (PI15/00449), Fondo de Investigación Sanitaria, ISCIII (PI16/00130), Fondo de Investigación Sanitaria, ISCIII (FI16/00071), ISCIII (Río Hortega, CM15/00167), and DIUE of Generalitat de Catalunya (2017 SGR 452, 2014 SGR 748). The funding agreement ensures the authors’ independence in designing the study, interpreting the data, and writing and publishing the report. The authors would like to acknowledge Aurea Martin for her help in the English editing and proofreading process, and in finalizing this manuscript. Members of the ASTRO-LAB group are: Sandrine Herbage, Manon Belhassen, Marine Ginoux (LBBE, University Claude Bernard Lyon 1, France); Stéphane Schück, Nathalie Texier, Sandy Leproust, Hélène Le Cloarec (Kappa Santé, France); Richard Hubbard (University of Nottingham, England); Alison Bourke, Mary Thompson, Delphine Vial, David Ansell (Cegedim Strategic Data, England); Javier Olaiz, Ana Valcarcel Orti (Lyon Ingénierie Projet, France); and authors MdB, ALD, EVG, LL, MF, OG, and GH. Authors' Contributions GH contributed to the conception and design of the paper, conceptualized and oversaw analyses, contributed to the interpretation of data, and wrote the paper. AP contributed to the analysis and gave statistical support. ALD, OG, MMP, JA, EVG, LL, MdB, and KM oversaw all aspects and reviewed the paper for important intellectual content. 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NPJ Prim Care Respir Med 2014 Jun 26;24:14020 [FREE Full text] [doi: 10.1038/npjpcrm.2014.20] [Medline: 24964767] Abbreviations ACQ: Asthma Control Questionnaire EQ-5D-5L: 5-level EuroQoL-5 dimension version EQ-VAS: EuroQol-visual analog scale HRQoL: Health-Related Quality of Life IC: inhaled corticosteroid LABA: long-acting beta-agonists SABA: short-acting beta-agonists Edited by G Eysenbach; submitted 14.03.18; peer-reviewed by T Poder, D Williams, M Duplaga; comments to author 03.08.18; revised version received 27.09.18; accepted 03.10.18; published 23.01.19 Please cite as: Hernandez G, Garin O, Dima AL, Pont A, Martí Pastor M, Alonso J, Van Ganse E, Laforest L, de Bruin M, Mayoral K, Serra-Sutton V, Ferrer M, ASTRO-LAB Group EuroQol (EQ-5D-5L) Validity in Assessing the Quality of Life in Adults With Asthma: Cross-Sectional Study J Med Internet Res 2019;21(1):e10178 URL: http://www.jmir.org/2019/1/e10178/ doi: 10.2196/10178 PMID: 30672744 ©Gimena Hernandez, Olatz Garin, Alexandra L Dima, Angels Pont, Marc Martí Pastor, Jordi Alonso, Eric Van Ganse, Laurent Laforest, Marijn de Bruin, Karina Mayoral, Vicky Serra-Sutton, Montse Ferrer, ASTRO-LAB Group. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 23.01.2019. This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included. http://www.jmir.org/2019/1/e10178/ J Med Internet Res 2019 | vol. 21 | iss. 1 | e10178 | p. 12 (page number not for citation purposes) XSL• FO RenderX