Clinical characteristics and initial C-reactive protein (CRP) levels associated with COVID-19 pneumonia in hospitalized patients at Huataphan Hospital, a primary care setting in Thailand

Background Rapid diagnosis of pneumonia in COVID-19 infection patients is crucial for early effective management to reduce mortality. A challenge exists for the few radiologists in community hospitals in primary care settings in Thailand, in that general practitioners usually read chest X-rays themselves and may misdiagnosed COVID-19 pneumonia. Objective To evaluate the initial clinical characteristics and initial CRP values associated with COVID-19 pneumonia, confirmed by two radiologists, in proven COVID-19 hospitalized patients. Methods A retrospective cohort study was conducted between 1 July 2021 and 31 October 2021 at Huataphan Hospital in a primary care setting in Thailand. 412 hospitalized COVID-19 patients, 51% female with a median age of 34 (IQR 24, 46) years and 15.8% of them had at least one comorbidity were evaluated. The results showed that prevalence of chest X-rays (CXR) revealed COVID-19 pneumonias were diagnosed and confirmed by two radiologists was 63%. Female sex, older age patients, and pre-existing comorbidities were more common in COVID-19 pneumonia than those without COVID-19 pneumonia. C-reactive protein (CRP) values were statistically significantly higher in COVID-19 pneumonia compared to those without COVID-19 pneumonia (median CRP 10.8 vs. 2.3 mg/dL, p < 0.001). CRP cut-off value of 4 mg/dL was associated with radiographically confirmed COVID-19 pneumonia with the area under the curve (AUC) 66.8% (95% CI, 62.0%-71.5%), sensitivity 66.7% (95% CI, 60.6%-72.4%) and specificity 66.9% (95% CI, 58.8%-74.3%). Every 1 mg/dL increase in CRP was associated with a 4% increase in presentation of COVID-19 pneumonia (aOR 1.04, 95%CI 1.02–1.06, p = 0.001). Conclusions Initial CRP value in hospitalized COVID-19 infections can be used in the primary care hospital setting in combination with clinical assessment and chest X-ray for early diagnosis of COVID-19 pneumonia.