Coronavirus Disease 2019 (COVID-19) is a novel viral disease with person-to-person transmission that has spread to many countries since the end of 2019. Although many unknowns were resolved within a year and the vaccine is available, it is still a major global health problem.
ObjectiveCOVID-19 infection may present with a considerably wide spectrum of severity and host factors play a significant role in determining the course of the disease. One of these factors is blood groups. Based on previous experience, it is believed that the ABO blood group type affects prognosis, treatment response and length of stay in the hospital. In this study, our aim was to evaluate whether the blood group had an effect on the length of the hospital stay. To the best of our knowledge, no previous studies have assessed the effect of ABO blood groups, as well as age, on the length of the hospital stay in these settings.
MethodsIn this retrospective cohort study, 969 patients admitted to our hospital between March 15, 2020 and May 15, 2020 were evaluated. The patients were divided into 4 groups according to ABO blood groups. The effect of the ABO blood group by age on the course of the disease, need for intensive care, duration of hospitalization and mortality in patients with COVID-19 infection, especially in geriatric patients, was evaluated.
ResultsOf all the patients, 9.1% required admission to the intensive care unit (ICU), of whom 83% died. The average length of ICU stay was 11 days (0 - 59). The observed mortality rates in blood groups A, B, AB and 0 were 86.4%, 93.3%, 80.0% and 70.8%, respectively, indicating similar death rates in all ABO blood types. When the Rh phenotype was taken into consideration, no significant changes in results were seen.
ConclusionAs a result, we could not observe a significant relationship between blood groups and clinical outcomes in this study, which included a sample of Turkish patients with COVID-19.
The new coronavirus disease that started in Wuhan, China in December 2019 has rapidly become a pandemic that remains a major global health problem despite the scientific efforts to provide effective treatments. The COVID-19 infection may present with a considerably wide spectrum of severity and host factors play a significant role in determining the course of the disease.
While most patients have an asymptomatic or mild disease, older patients or those with comorbid conditions such as diabetes, hypertension, chronic lung disease, cardiac disorders or malignancy are known to have a more unfavorable disease course.1 In addition to comorbid conditions and host-related thrombo-inflammatory responses, genetic factors, such as the ABO blood group, are also believed to affect the prognosis, treatment response and length of hospital stay. A close link between blood groups and the predisposition to infectious disease has been previously described in H. pylori, Plasmodium falciparum, HBV, SARS-COV and MERS-COV.2-6 Again, while some investigators reported a significant correlation between the ABO type and acquisition, prognosis and mortality of the SARS-CoV-2 infection during the COVID-19 pandemic,7,8 others failed to observe an association between the course of the COVID-19 infection and blood groups.9,10
It is important to estimate the duration of the hospital stay in COVID-19 patients not only to predict the demand for patient beds, but also to plan the allocation of resources. Therefore, many studies have been performed to assess the risk factors that have an impact on the length of the hospital stay of these patients.11-13 In these studies, a prolonged hospital stay among COVID-19 patients was found to be associated with the female gender, high fever, presence of hepatic or renal disease at presentation, elevated creatinine levels, lymphopenia and presence of bilateral findings in chest CT scan.11,12 However, the effect of some other risk factors have been elusive until now.
In this study, our aim was to evaluate whether the blood group had an effect on the length of the hospital stay. To the best of our knowledge, no previous studies have assessed the effect of ABO blood groups, as well as age, on the length of the hospital stay in these settings.
MethodsIn this retrospective cohort study, patients admitted to our pandemic reference hospital between March 15, 2020 and May 15, 2020 were eligible if they had blood group data available. The 969 patients included in the study were categorized into the following 4 groups based on their ABO blood groups: A, B, O and AB. The ABO blood group distribution according to age, Rh status, demographic data, comorbid conditions, hematological and inflammatory parameters, PCR and imaging findings, treatments received, duration of hospital stay, need for intensive care unit admission and discharge and mortality rates were analyzed. Patients admitted to clinical wards or the intensive care unit were included if they presented a known blood group, positive PCR test, and/or suspected COVID-19 infection (PCR negative, but presenting with the following symptoms: high fever, sore throat, shortness of breath and/or typical bilateral ground-glass appearance in thoracic CT images consistent with pulmonary involvement of the COVID-19 disease). Patients under 18 years of age, treated on an outpatient basis or having missing data, were excluded.
The study protocol was approved by the local ethics committee at the SBU Bursa Yuksek Ihtisas Research and Training Hospital (date, 10.06.2020; no, 2011-KAEK-25 2020/06-06) and the study was conducted in accordance with the principles of the Declaration of Helsinki. In addition, the study protocol was approved by the Turkish Ministry of Health for COVID-19 research. This study used the data collected during the routine clinical practice for COVID-19 patients and the data were handled anonymously.
Statistical analysisThe IBM SPSS Statistics version 21.0 software (SPSS Inc., Chicago, IL) was used for the analysis of the data. The descriptive data are presented in number (percentage), median (min-max) or mean ± standard deviation, where appropriate. Categorical variables were compared using the Pearson's chi-square test or Fisher's exact test. The ANOVA or Kruskal-Wallis was used, where appropriate, in comparing demographics, comorbidities and medications across blood types. A univariate screen between the blood type and demographics, comorbidities and the outcomes of interest were performed using the Chi-square test for categorical variables and the Student's t-test or the Wilcoxon rank-sum for continuous variables, as appropriate. The blood type, sex, age, comorbidities, inflammatory markers and length of stay in the hospital were determined for adjustment, as these covariates were thought to be potential confounders. The model was run for each blood type against all others. Logistic regression was performed for univariate analysis of hematological/inflammatory parameters and blood types for their association with mortality. Two-sided p-values < 0.05 were considered an indication of statistical significance.
ResultsThere were 969 participants with a mean age of 53.4 ± 19 years. Fifty percent of the patients were female and approximately one-third were over 65 years of age. The ABO blood group type distribution was as follows: type A, 461 subjects (47.6%); type O, 279 patients, (28.8%); type B, 145 subjects (15 %), and; type AB (8.6%). The most common comorbidity was hypertension (HT), which was present in 42.5% of the patients. The ABO groups were comparable with respect to the distribution of comorbid conditions. Of all the patients, 81.4% had no lymphopenia, while 18.6% had lymphopenia and 3.3%, severe lymphopenia. Again, hematologic/inflammatory parameters at presentation did not differ significantly among the ABO blood groups. Of the 508 patients in whom thorax CT results were available, 96.5% had imaging findings consistent with the COVID-19 infection. Additionally, there were no significant differences in terms of pulmonary involvement among the patients with different ABO types. The most commonly utilized agent for treatment was hydroxychloroquine in 99.4%, followed by oseltamivir in 50.1%. Additional enoxaparin was administered to 60.8% of the patients during the course of the treatment (Table 1).
Demographic characteristics according to blood type.