Development of an international COVID-19 specific healthrelated quality of life questionnaire, phase III pretesting and validation

ABSTRACT

Aims: This study aimed to develop, pilot-test and psychometrically analyse a patient-reported health-related quality of life questionnaire for patients with current or previous coronavirus disease (COVID-19). A disease-specific instrument was not available before, even though the patients experience a wide range of symptoms and reduced functioning. Method(s) We used an internationally recognized methodology for questionnaire development consisting of four phases. Adults with current or previous COVID-19, in hospital, nursing home or at home were eligible. In phase I, relevant issues were gathered through literature review, interviews with health-care workers and patients, and operationalized into items in phase II. In the current study, participants completed the questionnaire and were interviewed as part of phase IIIA and, in phase IIIB, participants completed a revised questionnaire and a debriefing form. Validity and reliability were assessed by correlation-based methods, Cronbach's alpha and intra-class correlation coefficient. Result(s) We enrolled participants from 11 countries within and outside Europe, 54 in phase IIIA and 371 in Phase IIIB. The mean time needed to complete the 80-item questionnaire in Phase IIIA was 16 min (range 4-45). Predefined criteria for retention were fulfilled for 71 items of which five needed some rewording. In phase IIIB, 80% of participants completed the 71-item questionnaire within 15 min, on paper (n = 175) or digitally (n = 196). The final questionnaire includes 61 items that fulfilled criteria for retention or were important to subgroups of patients. The item-scale correlations were>0.7 for all but nine items;three of these were changed. The internal consistency (alpha range 0.68-0.92) and test-retest (all but one scale>0.7) results were acceptable. The final scale structure of the Oslo COVID-19 quality of life (QLQ) weekly (W) 61 consists of 15 multi-item scales and six single items covering e.g. acute and long-term physical symptoms, psychological distress, and physical, social functioning. Patient representatives expressed satisfaction with the content of the questionnaire. Conclusion(s) COVID-19 is a disease with a pleomorphic symptomatology. In addition to many items assessing symptoms, multiple functional items were included. The Oslo COVID-19 QLQ-W61 is a cross-cultural instrument, now ready for use in research and clinical practice.