The novel coronavirus disease 2019 (COVID-19) was declared a global pandemic by the World Health Organization (WHO). The virus that causes COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was identified in December 2019 in the Wuhan province of China. ¹ The virus has since spread rapidly around the world, affecting more than 235 million people by October 2021, and causing approximately 4.8 million deaths, with the highest number of positive confirmed cases in America reaching 90 million. The first case of COVID-19 in Indonesia was detected on 2 March 2020. ² COVID-19 cases in Indonesia had reached approximately 4.2 million, with 143,299 deaths by 27 October 2021. During this period, East Java became the fourth province with the highest number of confirmed cases, having a total of 396,001 positive patients. Among them, 29,464 people died, 365,340 recovered, and 1,197 were in the process of being treated or undergoing self-isolation. Moreover, the case fatality rate from COVID-19 in East Java is known to be the highest in Indonesia, having reached 7.44%.

The national trend of COVID-19 cases in Indonesia shows that adults aged 31–45 years are more prone to infection, followed by young adults aged 19–30 years; however, those ≥ 46 years of age show the highest number of deaths and a low recovery rate. ² These patterns are similar to current trends in both high-income and developing countries, which report as many as 5% more deaths in patients between 20–39 years old, and up to 23% in those between 40–59 years old. ^{3 – 6} Supporting these findings, several studies in 2021 revealed that the mortality of COVID-19 increases with age, which is considered to be associated with deteriorating health status or pre-existing comorbidities. ^{7 – 9}

In addition to age-related factors, mortality from COVID-19 has also been correlated with other factors, such as gender, comorbidities, and clinical condition. ^{9 – 11} Many studies have focused on analysing the risk factors for mortality in hospitalised patients, ^{7 , 12 – 14} and these were mainly associated with clinical treatment, existing chronic disease(s), type of treatment unit, and complications. However, very few studies have focused on determining the factors associated with mortality from COVID-19 in non-hospitalised patients.

Therefore, the aim of this study was to analyse the predictors of mortality among hospitalised and non-hospitalised patients with COVID-19 in East Java, Indonesia.

Table 1 shows the results of a univariate analysis of the sociodemographic characteristics of respondents. According to the findings, the prevalence of death from COVID-19 in patients aged 18-59 years in East Java, Indonesia is 4.8%. (1065). The proportion of male and female mortality differed by 1.1%, with male patients (5.3%) having a higher prospect of succumbing to the disease than the female patients (4.2%). In addition, patients who were hospitalised on a ventilator are more likely to die (52.6%). The severity category showed that the more severe the disease is, the more patients tend to die (63.3%). Based on travel history, patients who have a high history of travelling are more likely to die (6.3%), compared to those who have no traveling history.

Furthermore, patients with a history of being in contact with a confirmed COVID-19 case are less likely to die (4.7%). Based on the results of bivariate analysis, the chi-square test revealed that four independent variables were significant (p ˂ 0.05) in relation to the mortality risk in patients aged 18–59 years caused by COVID-19. Nonetheless, sex, treatment status, severity category, and travel history were significant factors associated with the incidences of COVID-19 deaths. The data are depicted in Table 1.

The determinants of mortality risk among patients aged 18–59 years are shown in the multivariate analysis table ( Table 2). According to the data, older patients with COVID-19 were 1.08 times more likely to die than the younger patients with the range aged of 18–59 years. Patients with COVID-19 on ventilators were 130.75 times more likely to die than patients receiving other treatment strategies. The disease category indicated that patients with a severe form of the disease were more likely to die than those with a mild or moderate diagnosis (AOR = 15.24, 95% CI = 11.51–20.17). Based on travel history, patients with a history of travelling prior to symptom onset had a higher (1.36 times) probability of dying from the disease than those without a travel history.

The present study findings showed that age is associated with mortality from COVID-19, with the older generation being more vulnerable than the younger population. This finding is supported by studies from various countries, including New York, Mexico, and Pakistan. ^{12 , 13 , 15 , 16} In Mexico, the prevalence of COVID-19 survivors and non-survivors was compared and the findings showed that the majority of the non-survivors were 10 years older than those who survived. ¹² The reason for this is that natural immunity and organ function tend to decline gradually with age. ⁹ In addition, the social factors of adults, such as work activity, habits, and lifestyle might influence their susceptibility to death. ¹⁷ Thus, it can be postulated that adult patients with COVID-19 are likely to develop more opportunistic infections, and in turn be at higher risk of mortality than the younger population group.

Patients with COVID-19 who were on ventilator support had a high mortality rate because of reduced pulmonary function. This finding is consistent with that of a study from Pakistan, which reported that 86% of patients that died from COVID-19 required invasive ventilator support. ¹⁶ Several countries, states, and provinces reported a high mortality rate in COVID-19 patients on ventilators, including Italy (53.4%), the United Kingdom (67%), New York (88%), and Wuhan (97%). ^{18 – 21} Based on these findings, the use of ventilators in the management of COVID-19 should be aligned with patient symptoms since acute respiratory failure in COVID-19 is unique and poorly understood. ^{22 , 23} This suggests that clinicians must understand the different settings of the ventilator to match disease severity when treating patients with acute respiratory symptoms associated with COVID-19.

Patients with severe COVID-19 had a higher probability of dying than those in the moderate and mild categories. Patients with severe illness might have been exposed to SARS-CoV-2 longer than those in the other disease categories, resulting in the development of an inflammatory response. ²⁴ The progression of disease in patients with severe infection is important in understanding disease prognosis because these patients tend to experience several symptoms, including acute respiratory distress, coagulopathy, acute respiratory failure, and metabolic acidosis. ²⁵ A study confirmed more patients with severe disease required intensive care and treatment, the lack of which resulted in their death. ²⁶

Lastly, the majority of deaths in patients aged 18–59 years with COVID-19 were associated with having a travelling history, meaning that infection from SARS-CoV-2 occurred during travelling. Study findings from research in Iran is in accordance with this observation, in which Iranian women with a travelling history had 8.8% higher infection rate than those who did not travel, especially those who visited high-risk areas. ²⁷ Other studies concluded that mobility could be a contributing factor in the transmission of COVID-19 among people. ^{28 , 29}

Since our study used secondary data, the use of specific built-in variables could have led to focus bias. In addition, some individuals who might have developed symptoms and did not report to treatment centres could not be included in the study.

Mortality risk from COVID-19 among patients aged 18–59 years has been correlated with various factors, specifically, age, treatment, severity of illness, and travelling history. Reduction in mortality rate might be achieved by enhancing precision treatment and broadening prevention at both clinical and community levels.