COVID-19 Quality of Life (CO-19_QoL) Questionnaire for Investigation of Health-Related Quality of Life of COVID-19 Patients in Selangor: A Translation and Validation Study

The impact of Coronavirus Disease 2019 (COVID-19) on quality of life (QoL) appears to be substantially underestimated. In Malaysia, Selangor consistently ranked among the states with the highest reported COVID-19 cases. Generic QoL instruments typically assessed broad domains such as mental well-being, physical function, social function and pain, which can all be impacted by any disease. Hence, diseasespecific tools are more sensitive in detecting clinical changes or differentiating patients according to disease severity. This study aims to assess the validity and reliability of the Malay version of the COVID-19 Quality of Life (CO-19_QoL) questionnaire for the use in the Malaysian context. A cross-sectional study involving 330 adult COVID-19 patients was conducted in the state of Selangor. The questionnaire was translated and culturally adapted following International Society for Pharmacoeconomics and Outcomes Research (ISPOR) guidelines, including forward backward translation and expert review to ensure conceptual and linguistic equivalence. It demonstrated excellent content validity (Kappa > 0.8), confirming that the items are relevant to COVID-19 symptoms and accurately translated. Internal consistency was high (Cronbach’s alpha = 0.919), while test-retest showed excellent reliability [Intraclass Correlation Coefficient (ICC) = 0.896, p < 0.001]. Construct validity analyses identified a single 15-item domain to be reliable and valid to measure the QoL of COVID-19 patients. The CO-19_QoL is a promising new instrument for measuring disease-specific QoL. It is easy to use, acceptable to patients, and meets rigorous reliability and validity standards. Also, CO-19_QoL enables a more thorough evaluation of HRQoL among COVID-19 patients in Selangor when used together with a generic QoL instrument.