Risk Factors for Fatality of Hospitalized Patients with Coronavirus Infection-2019

Introduction

The coronavirus disease 2019 (COVID-19) marked the first time most of the world’s population experienced a pandemic (Dasgupta and Crunkhorn 2020). It has triggered an unprecedented wave of illness and death worldwide, impacting millions of lives and overwhelming healthcare systems (Liu and Lou 2022).

The overall reported case fatality rate of COVID-19 rose to 7.2% by the 17th epidemiological week after the detection of severe acute respiratory syndrome coronavirus-2 (Hasan et al. 2021). In response, governments and healthcare authorities worldwide have developed and distributed COVID-19 vaccines. Vaccination programs have been implemented as a key strategy to reduce virus transmission and lessen the disease’s impact (Stefanelli and Rezza 2022). Through various production platforms, many vaccine candidates have been in preclinical and clinical development. By early September 2022, more than two-thirds of the global population had received at least one dose of a COVID-19 vaccine (Briciu et al. 2023).

Several risk factors for developing COVID-19 in adults have been identified, ranging from demographic factors (e.g., older age, male sex) to the presence of underlying health conditions (e.g., diabetes) (Zhang et al. 2023). Sayli (2020) argued that understanding an association between blood group types and COVID-19 may assist in its management and treatment. Zhao et al. (2020) reported that blood type [A] is linked to a higher risk of COVID-19 infection and death, while blood type [O] is linked to a lower risk of infection and death. Similarly, Zietz, Zucker, and Tatonetti (2020) found that blood type [A] is associated with increased odds of testing positive for the disease.

Aruffo et al. (2022) noted that exploring the risk factors and the impact of vaccination on the overall case fatality rates is an important area of research. However, little research has examined vaccination effects in hospitalized populations, patients who typically have the most severe COVID-19 disease (Baker et al. 2023). However, there is still a paucity of data regarding the relationship between several risk factors, such as vaccination status, ABO blood typing, and the outcome of COVID-19 disease.

Patients and methods

Results

The present study included 606 patients, of whom 352 (58.1%) were males. About one-third of patients (34.2%) were 41-50 years old, 44.9% were 51-60 years old, and only 6.3% were less than 40 years old. The majority of patients were Saudi (545, 89.9%). Almost one-fourth of the patients (24.6%) were smokers, while 27.7% were diabetic. Blood group [O] was the most prevalent type (48.5%), followed by blood group [A] (38.8%), and [B] (10.4%), while [AB] was the least prevalent (2.3%). On admission, 62.5% of the patients did not receive any vaccine doses against COVID-19, while 8.1% received one dose, 14.5% received two doses, and 14.9% received three doses. The condition of 51.3% of the patients was critical. Provided respiration assistance was mainly through intubation (45.2%), or oxygen mask (49.8%). On discharge, patients’ COVID-19-related case fatality was 53.1% ( Table 1).

Figure 1 shows that 53.1% of hospitalized COVID-19 patients died.

Figure 1. Patients’ outcome.

Patients’ case fatality was significantly higher among male patients (p<0.001). Patients’ case fatality differed according to their age groups (p<0.001), being significantly higher among older patients aged above 60 years. In addition, case fatality differed according to patients’ nationality (p<0.001), being significantly higher among non-Saudi patients. COVID-19 case fatality differed significantly according to patients’ ABO blood group types (p<0.001), being highest among blood group [O] patients (60.5%) and lowest among blood group B patients (33.3%). However, case fatality did not differ significantly according to patients’ Rh-factors. Patients’ case fatality differed according to their anti-COVID-19 vaccination status (p<0.001), being highest among unvaccinated patients. Case fatality was significantly higher among patients who were critically ill on admission (p<0.001), smokers (p=0.001), and those with associated chronic comorbidity (p=0.021). Moreover, patients’ case fatality was highest among those who received intubation or BiPAP/CPAP masks (96.7% and 83.3%, respectively, p<0.001) ( Table 2).

Significant odds ratios for patients’ outcomes were associated with patients’ vaccination status (129.733, p<0.001), their health status on admission (103.213, p<0.001), their age groups (0.067, p<0.001), and nationality (0.080, p<0.001). However, the odds ratios for patients’ gender, blood group, Rh-factor, and associated comorbidity (diabetes) were not statistically significant ( Table 3).

Discussion

The findings of this study showed that more than half of our hospitalized COVID-19 patients were males, and almost two-thirds were above 50 years old. Almost one-fourth were smokers, while more than one-quarter of the patients were diabetic. On admission, the condition of about half of our patients was critical, and most patients received respiratory assistance through intubation or an oxygen mask. On discharge, patients’ COVID-19-related case fatality was quite high (53.1%). The case fatality of our patients was significantly higher among males, older, non-Saudi patients, those with associated chronic comorbidity, and those who received intubation or BiPAP/CPAP masks. Multivariate logistic regression confirmed several risk factors for COVID-19 patients’ mortality, including their older age and being non-Saudi.

These results are in agreement with those reported by several studies in Saudi Arabia (Al-Omari et al. 2020; Alhumaid et al. 2021; Aljuaid et al. 2022). The higher incidence of COVID-19 among males and older patients is possibly due to more prevalent associated comorbidities and lower immunity states. Therefore, the identification of these risk factors is important for preventive and tailored healthcare and to minimize complications among these vulnerable groups (Alghamdi 2021; Al-Otaiby et al. 2022).

It is to be noted that the significantly higher case fatality among non-Saudi hospitalized COVID-19 patients may be explained by the relatively more delayed presentation for receiving health care among non-Saudi patients. Moreover, it has been reported that associated chronic comorbidities among COVID-19 patients (e.g., diabetes mellitus) are common (Zhang et al. 2023).

The high prevalence of diabetes among our hospitalized COVID-19 patients is in line with that reported by other studies in Saudi Arabia, where almost half of COVID-19 patients were diabetic (Hindawi et al. 2023; Jarrar et al. 2023). Dondorp et al. (2020) added that ventilatory support is vital for the survival of COVID-19 patients, with oxygen saturation <93%, respiratory rates >30/min, or those with respiratory failure.

Our study showed that blood group [O] was the most prevalent type among our hospitalized COVID-19 patients, followed by blood groups [A and B], while group [AB] was the least prevalent (2.3%). Moreover, most of our patients were Rh-positive.

These findings are in accordance with those reported by a study conducted in the northern area of the Aseer region, with 45.9% of the population having a blood group [O] (Belali 2022). In addition, the study of Al-Bshabshe et al. (2023) reported similar findings, with 51% of COVID-19 patients possessing blood group [O].

Case fatality among our patients differed according to patients’ ABO blood group types, being highest among patients with blood group [O], and lowest among those with blood group [B]. However, multivariate logistic regression analysis indicated an insignificant adjusted odds ratio (1.522, p=0.170). Moreover, case fatality did not differ significantly according to patients’ Rh factors.

Previous studies have identified associations between ABO blood groups and several different infections or disease severity following infections, including SARS-CoV-1, P. falciparum, H. pylori, Norwalk virus, hepatitis B, and N. gonorrhoeae (Degarege et al. 2012; Chen et al. 2016; Batool, Durrani & Tariq 2017; Murugananthan et al. 2018).

Zhao et al. (2020) reported that individuals with blood group [A] showed a significantly higher risk of COVID-19 infection compared with those with other blood groups, while individuals with blood group [O] showed a significantly lower risk for COVID-19 infection compared with those with other blood groups. Moreover, some other studies have suggested that those with blood type [A] were at a higher risk of contracting the disease, while those with blood type [O] were less prone to it (Solhpour et al. 2020; Al-Ansari et al. 2021; Franchini et al. 2021; Liu et al. 2021; Zhang et al. 2021).

However, several local (Jawdat et al. 2022; Nasif et al. 2022), and international studies (Latz et al. 2020; Levi et al. 2021; Niles et al. 2021) failed to establish significant associations between blood type and COVID-19 susceptibility or case fatality. Also, studies in several countries failed to establish a correlation between Rh-type and ICU admission, mechanical ventilation support, or case fatality rates among COVID-19 patients in Sudan (Taha et al. 2020), Iran (Dal et al. 2021), or Turkey (Abdollahi et al. 2020).

Our study showed that almost two-thirds of our patients did not receive any vaccine against COVID-19, 8.1% received only one dose, while 14.5% received two doses, and 14.9% received three doses. Patients’ case fatality differed significantly according to their anti-COVID-19 vaccination status, being highest among unvaccinated and incompletely vaccinated patients.

Briciu et al. (2023) noted that by the end of 2020, several vaccines against COVID-19, utilizing different production platforms, had already received emergency use approval. They emphasized that vaccination against COVID-19 is the most reliable method to avoid severe disease and reduce mortality. Haider et al. (2023) reported that following the second booster dose of the COVID-19 vaccine, both incidence and case fatality are significantly reduced. Additionally, De Gier et al. (2023) and Mendoza-Cano et al. (2023) confirmed the considerable public health benefits of primary and booster COVID-19 vaccinations and found high effectiveness against COVID-19 mortality.

The present study provided a significant understanding of the favorable impact of vaccination against COVID-19, in addition to the weight of several risk factors associated with hospitalized COVID-19 patients’ case fatality. However, the researchers admit the presence of certain limitations. First, this is a single-center study, which limits the generalizability of its findings. Moreover, due to the retrospective nature of the present study, a few limitations should be considered. The risk of bias (e.g., selection and information bias) cannot be fully overcome, and only associations should be regarded since causality cannot be established.

In conclusion, vaccination against COVID-19 has a significant preventive impact on patients’ case fatality. Several risk factors related to higher case fatalities among hospitalized COVID-19 patients have been identified, such as older age, being non-Saudi, or being critically ill. Moreover, patients with blood group [B] may have a lower case-fatality than those with blood group [O], but this finding remains to be explained.