Psychometric properties of the Spanish version of the EuroQol-5D-5L in previously hospitalized COVID-19 survivors with long COVID


This study included patients hospitalized with acute SARS-CoV-2 infection during the first wave of the pandemic (March 20 to June 30, 2020) in an urban hospital in Madrid (Spain). All subjects attending a specific post-COVID unit at the hospital between March 2021 and May 2021 were invited to participate in the study. Participants must have a diagnosis of SARS-CoV-2 infection with real-time PCR testing of nasopharyngeal/oral swab specimens and the presence of consistent clinical and radiological findings at hospital admission.

COVID-19 collection data

Demographics (eg, age, sex, height, weight), clinical data (eg, prior medical comorbidities), and hospitalization data (symptoms associated with COVID-19 experienced on admission to hospital, intensive care unit [ICU] admission, days of hospitalization) were collected from hospital medical records.

Participants who agreed to participate were scheduled for a face-to-face interview by trained healthcare researchers. Participants were asked to report the presence/absence of symptoms after hospitalization and whether symptoms persisted at the time of the interview. It was pointed out that the symptoms should have appeared after hospitalization. Participants were systematically asked to provide a predefined list of post-COVID symptoms such as dyspnea, fatigue, anosmia, ageusia, hair loss, chest pain, palpitations, diarrhea, rash , brain fog, eye/visual disturbances, cough and loss of concentration. ; however, they were free to report any persistent symptoms they deemed relevant.

Health-related quality of life

The EQ-5D-5L questionnaire includes five items assessing five dimensions of health (e.g., mobility, self-care, activities of daily living, discomfort/pain, and depression/anxiety), each with a response at five levels (1: no problem to 5: serious problems)17. The answers are converted into a single index between 0 and 1 where 0 corresponds to a state of health considered equivalent to death and 1 corresponds to optimal health, by applying concordance index values ​​for life in Spain18. In the present study, we used the version validated for the general Spanish-speaking population19.20.

All participants completed the EQ-5D-5L at a first appointment conducted an average of 12 months (SD 5) after hospital discharge. In addition, a standardized checklist including the following items was also collected: time taken to answer the EQ-5D-5L (assessed with a digital stopwatch), unanswered questions, and difficulty in understanding and answering to the questionnaire. For test-retest reliability, participants completed the EQ-5D-5L a second time after 3 to 4 weeks from the first appointment.

statistical analyzes

Statistical analysis was performed with SPSS 23.0 software (SPSS Inc, Chicago, IL, USA). Statistical significance was defined as a priori value proportions, means and standard deviations) were used to describe the study population. We tested the following properties of the EQ-5D-5L questionnaire21 according to the Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN)22:

1. Internal consistency, i.e. the extent to which the items measure the same underlying construct, was calculated by Cronbach alpha23 and Raykow’s Omega coefficient24. Values ​​between 0.70 and 0.95 are considered to reflect good internal consistency.

2. Reproducibility, that is, the extent to which repeated test-retest measures provide similar answers, relate to reliability and agreement. We calculated percentage agreement and kappa coefficients to estimate test-retest agreement on each question of the EQ-5D-5L. We interpreted the kappa values ​​according to Landis and Kock25: excellent (0.81–1.0), good (0.61–0.80), moderate (0.41–0.60), fair (0.21–0.40) or poor (0.0 –0.2). The test-retest reliability of the EQ-5D-5L total score was assessed using a consistency-type two-way mixed model intraclass correlation coefficient (ICC2.1). An ICC ≥ 0.70 was considered good to excellent reproducibility26.

3. The construction validity, that is, the extent to which the score relates to other measures was tested using maximum likelihood factor analysis fixing a single factor. The Kaiser-Meyer-Olkin measure of sampling adequacy and Bartlett’s test of sphericity were used to assess whether or not the data were suitable for factor analysis.

We also calculated the percentage of subjects obtaining the highest scores (floor effect) and the lowest scores (ceiling effect) on each question of the EQ-5D-5L. Additionally, chi-square tests were performed to assess whether there were significant differences by gender and age group (categorized as

Ethics approval

All methods were performed in accordance with relevant guidelines and following the Declaration of Helsinki. The current study was approved by the local ethics committee of the University Hospital Fundación Alcorcon (HUFA20/126).

Informed consent

The participants were informed of the objective of the study and gave their informed consent before their inclusion and before any data collection.

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