“Keep it simple – a lesson from COVID-19”: highlighting the utility of chest X-rays in ARDS-associated illnesses through the Zonal Scoring System

Introduction
The post-pandemic era calls for appropriate literature on chest X-ray score cut-offs, enabling swift categorization and faster radiological reporting of patients with acute respiratory distress syndrome (ARDS)-like illnesses, hence prompting healthcare equity in low-resource centres where extortionate modalities of imaging such as computed tomography (CT) are unavailable. In this study, we aim to bridge the literature gap using the versatile zonal scoring system.

Material and methods
This retrospective cohort study uses data from 751 COVID-19 RT-PCR+ patients. Concordant chest radiograph (CXR) scores were reported, and inter-rater reliability was measured using kappa indices. receiver operating characteristic curves were used to establish cut-off scores for the outcomes of interest: mild or severe disease, admission to an intensive care unit (ICU), and intubation. Categorical data were expressed using means and percentages, and  or t-tests were used for comparison at an χ² level of 0.05. Unadjusted odds ratios for each outcome of interest vs. CXR score and comorbidity were then calculated using binary logistic regression.

Results
CXR findings included infiltrates (46.07%), pleural effusions (7.05%), consolidation and fibrosis (4.43%), pneumothoraces (2.71%), and cardiomegaly (2.26%). Most patients had an index CXR score of 0 (54.19%). The index cut-off score of ≤ 1 (82.95, 81.68) was established for mild disease, ≥ 4 for severe disease (85.71, 83.99), ≥ 3 for ICU admission (86.90, 71.91), and ≥ 4 for intubation (87.61, 72.90). Hypertension, type 2 diabetes mellitus, hypothyroidism, history of ischaemic heart disease, and history of tuberculosis were independent risk factors for a high CXR index score, intubation, and ICU admission.

Conclusions
CXR scores can be effectively used in low-resource settings for triaging patients, maintaining records, and disease prognostication.