Coronavirus disease 2019 (COVID-19) is a new infectious disease that was first discovered in Wuhan, China, on the 31^st December 2019 [1]. It has subsequently spread to almost all countries around the world. According to the latest report by the World Health Organization (April 25^th, 2020), this disease has spread to 210 countries and territories around the world, and 2 international conveyances [2]. Iran, with more than 100,000 cases of COVID-19, and a deaths-to-infections ratio of 6.4%, is amongst the highest ranked countries in terms of outbreak and mortality [2]. The spread of COVID-19 through all 31 provinces of Iran was very rapid (less than a month) [3]. Yazd, located in center of Iran, had more than 1,500 confirmed cases of COVID-19 in Iran in June 2020.

COVID-19 is a serious disease that can significantly affect the daily lives of recovered patients and their families in terms of mental health problems such as post-traumatic stress [4], depression [5], anxiety [6] and insomnia [7], as well as the negative impact COVID-19 has on patients quality of life (QoL) [8]. Since the patients are not immune to future infection [9], it may lead to a more negative impact on patients’ QoL. Health-related quality of life (HRQoL) is an important measure that is used for assessing the impact of diseases, disorders, or disabilities on the physical, mental, and social domains of patient health. The assessment of HRQoL helps healthcare providers identify the factors affecting QoL and recognize the aspects of COVID-19 management that needs to be enhanced for improving the QoL of patients [10,11].

The EuroQol 5-dimensional-5 levels (EQ-5D-5L) questionnaire is one of the most commonly used instruments for measuring HRQoL in clinical and outcome research, and its use is recommended by the National Institute for Health and Clinical Excellence [12,13]. This instrument was translated into Persian and was confirmed by the EuroQol group [14]. This study used the EQ-5D-5L instrument to describe the HRQoL of COVID-19 patients who had been discharged from the only hospital dedicated to COVID-19 patients in Yazd, and assessed the impact of socio-demographic and clinical factors on COVID-19 patients’ HRQoL.

Out of 420 interviews, 11 interviews were excluded from the final analysis because data on many of the dimensions of the EQ-5D-5L questionnaire were not available. Table 1 shows the socio-demographic and clinical characteristics of patients. The mean age of patients was 58.4 ± 18.21 years, and the average of household occupancy was 2.10 ± 0.18. Among COVID-19 patients, the majority were males, aged 51 to 60 years, married, unemployed, with a primary level of education, and in a household of between 1 to 2 members, and those who worked did so in a crowded environment.

The clinical characteristics of patients are presented in Table 2. The mean duration of hospitalization and days following hospital discharge was 8 ± 7 and 21.6 ± 14.8 days, respectively. The majority of COVID-19 patients had a hospital duration of ≤ 10 days and the duration of days following hospital discharge was > 30 days. In this study, 30% of the patients who were treated in the intensive care unit (ICU) were more than 60 years old.

This study evaluated HRQoL of COVID-19 patients using the EQ-5D-5L questionnaire and assessed the effects of socio-demographic and clinical factors on HRQoL. The results of this study provided important insights of the HRQoL based on the characteristics of hospitalized COVID-19 patients that can be used in the management of the disease. The mean EQ-5D-5L score for the patients was 0.6125.

A study conducted on people (n = 4,029) with suspected COVID-19 symptoms (S-COVID-19-S) visiting outpatient departments and health centers in Vietnam, in 2020 reported a mean score of 0.621 for the assessment of HRQoL [8]. The overall EQ-5D-5L score for COVID patients (0.612) in this study was lower than Asian patients suffering from diabetes (0.84) [21], type 2 diabetes (0.84) [22], cardiovascular diseases (0.84) [23], acute coronary syndrome (0.75) [24] human immunodeficiency virus (0.8) [25], skin diseases (0.73) [26], and respiratory diseases (0.66) [27], but higher than frail elderly (0.58) [28] and elderly patients after a fall injury (0.46) [29].

The percentage of individuals reporting problems affecting their HRQoL in each EQ-5D-5L dimension showed the most common problem was anxiety. Similar results also were reported by Nguyen et al [8]. They showed that the odds ratio of depression for people with S-COVID-19-S was higher than that of the people without S-COVID-19-S (3.69 vs. 1) [8].

Among the demographic factors, univariate analyses showed that the mean EQ-5D-5L scores were significantly different depending on gender, age, education level, employment status, and workplace of the patients. The findings were similar to the findings reported in the study by Nguyen et al [8]. They reported the difference between mean HRQoL scores for people with S-COVID-19-S was significant depending on age, gender, marital status, education level, occupation status, ability to pay for medication, social status, comorbidity, and physical activity [8].

The older age groups of patients had lower scores of HRQoL compared with the younger patients. This may reflect the fact that COVID-19 impacts more on older patients. Sommer et al [30] reported that severe cases of COVID-19 (involving ICU admission) skewed towards patients who were > 60 years old. This current study revealed that women had lower scores for HRQoL than men. This finding may be due to a difference in the level of physical activity between men and women in developing countries, as women have a lower level of physical activity than men [31]. Another reason may be due to the fact that women are more worried about disease and may have less ability to cope. It was also observed that the difference between mean HRQoL scores in patients with different levels of education was significant. Lower scores of HRQoL were observed in patients with a higher level of education a greater level of awareness and concern of COVID-19 and its impact on life. Nguyen et al [8] observed that people with a college/university education had a higher prevalence of depression during the pandemic that created a burden of stress which further affected their HRQoL. The present study also showed that employed patients had higher scores of HRQoL. This could be due to the fact that the employed patients had not lost their income; therefore, they had more opportunity to have better healthcare [32]. A significant difference between HRQoL mean scores was also observed in workplaces of the patients. The patients who worked in crowded environments such as factories, shopping malls, and banks, had lower scores of HRQoL compared with people who worked in an uncrowded environment. The majority of the patients in crowded environments reported high anxiety of re-infection. We asked the patients to state their anxiety/depression regarding re-infection using the 5-Likert scale (no anxiety, slight anxiety, some anxiety, a lot of anxiety, or very anxious/depressed). In contrast to the results of this study, executives in Chongqing, China (n = 122) were reported to have a lower prevalence of depression and anxiety when they returned to work during COVID-19 pandemic [33]. There is an urgency to redesign training programs and communication activities for a more effective dissemination of information related to the COVID-19 [34].

Among clinical factors, the difference between mean scores of HRQoL was significant for ICU admission, having diabetes, and heart failure in this study. The mean HRQoL scores were different between the patients who had been admitted to hospital wards. The patients admitted to the ICU for COVID-19 treatment had lower scores of HRQoL than those admitted to a hospital wards, probably because ICU patients experienced more severe problems related to COVID-19. The mean scores of HRQoL were lower in the patients with diabetes than those without diabetes. This is because the disease was more severe in the patients with diabetes and it exacerbates their diabetes symptoms [35]. These results are consistent with the findings of a recent study conducted in critical care COVID-19 patients in the US. The study reported that COVID-19 in cases severe enough to require ICU admission, skewed the patient population towards patients with medical comorbidities, such as hypertension, diabetes mellitus, or cardiovascular diseases [30]. Furthermore, the patients with heart failure had lower HRQoL scores compared with those without heart failure.

The regression analysis showed that amongst demographic factors, age had the most marginal effect therefore, it has the most impact on HRQoL. It can be explained by the direct relationship between aging and increasing incidence of problems in patients. Among the clinical factors, having diabetes had the most marginal effect on HRQoL. Diabetes has been reported as a comorbidity of COVID-19 [35].

One limitation of the study was that the design was not cross-sectional, which did not allow the determination of the exact effects of patients’ socio-demographic and clinical factors on HRQoL. Further research is required using a longitudinal study to understand how these factors may affect the HRQoL. Another limitation is the use of crosswalk to calculate the Iranian EQ-5D-5L value set. The value set based on crosswalk is less reliable than the one obtained directly from the general public-preference. However, crosswalk is currently the only available technique to generate the EQ-5D-5L value set for countries that do not have the EQ-5D-5L value set based on their own context.

The mean score of HRQoL for the patients was 0.6125 in this study. Identifying strategies to improve the HRQoL in patients, especially in aging and diabetic patients, is therefore of particular importance. This study showed that gender, among demographic factors, and diabetes, among clinical factors, had the most marginal effect on the dimensions of EQ-5D-5L.