Chest Radiographic Scores at Admission Correlated to the Mortality of Covid-19 Patients at the Kenyatta National Hospital

Abstract

Background: The chest radiograph is a common diagnostic modality used in the assessment and management of pulmonary infections. Chest radiography is therefore, often the first imaging investigation obtained in the diagnostic workup of admitted COVID-19 patients. This allows an assessment of the degree of pulmonary disease and also an early evaluation of the patient’s prognosis. This study determined the effectiveness of chest radiography in the early prognostication of COVID-19 disease by correlating the chest radiographic scores at admission with the mortality of RT-PCR confirmed COVID-19 patients. Objective: Correlation of the chest radiographic scores at admission to the in-hospital mortality of COVID-19 patients. Materials and Methods: A retrospective cross-sectional study was carried out in the Radiology Department and the Health Information Department of the Kenyatta National Hospital from 1st May 2020 to 31st April 2021. A total of 246 RT-PCR confirmed COVID-19 patients aged above 18 years were recruited into the study and their initial chest radiographs at admission were evaluated. A modified RALE chest radiograph severity score, of 0–8 was used to quantify the extent of pulmonary involvement. Correlation of the chest radiographic scores and the in-hospital mortality was done using chi-square tests. Results: A total of 246 patients with COVID -19 PCR positive were included in this study. The male to female ratio was 1:5:1. The mean age was 47.6 years (SD=14.3). The admission chest radiographs evaluated in this study were 246 of which 43.1% (106/246) were normal chest radiographs and the remaining 56.9% (140/246) radiographs had positive findings. Among the chest radiographs with positive findings, 45.7% (64/140) chest radiographs demonstrated a Modified RALE score of (1-4) while 54.3% (76/140) chest radiographs had a score of (5-8). The overall mortality rate was 12.6%. The mean age of the in-hospital mortalities was 55.3±17.4 whereas the mean age of the discharged patients was 46.5±13.5, (p-value of 0.011). Patients with RALE scores of 7 and 8 were 4.3 times (95% CI, 1.3 – 13.8, p=0.015) and 3.5 times (95% CI, 1.3 – 9.7, p=0.014) more likely to have in-hospital mortality when compared with the reference group of patients with RALE scores of between 0 to 4. Conclusion: This study shows that the highest RALE scores of 7 and 8 at admission posed a statistically significant increased risk of mortality at 4.3 times and 3.5 times respectively in comparison to the scores of 0-4. The Modified RALE chest radiographic scoring can be an invaluable tool in high- volume, resource constrained settings in providing rapid and objective prognostic information in the management of COVID-19 patients.