Clinical characteristics of COVID-19 complicated with pleural effusion

Abstract

Background: Epidemiological and clinical features of patients with corona virus disease 2019 (COVID-19) were well delineated. However, no researches described the patients complicated with pleural effusion (PE). In the present study, we aimed to clinically characterize the COVID-19 patients complicated with PE and to create a predictive model on the basis of PE and other clinical features to identify COVID-19 patients who may progress to critical condition.

Methods: This retrospective study examined 476 COVID-19 inpatients, involving 153 patients with PE and 323 without PE. The data on patients' past history, clinical features, physical checkup findings, laboratory results and chest computed tomography (CT) findings were collected and analyzed. LASSO regression analysis was employed to identify risk factors associated with the severity of COVID-19.

Results: Laboratory findings showed that patients with PE had higher levels of white blood cells, neutrophils, lactic dehydrogenase, C-reactive protein and D-dimer, and lower levels of lymphocytes, platelets, hemoglobin, partial pressure of oxygen and oxygen saturation. Meanwhile, patients with PE had higher incidence of severe or critical illness and mortality rate, and longer hospital stay time compared to their counterparts without pleural effusion. Moreover, LASSO regression analysis exhibited that pleural effusion, lactic dehydrogenase (LDH), D-dimer and total bilirubin (TBIL) might be risk factors for critical COVID-19.

Conclusions: Pleural effusion could serve as an indicator for severe inflammation and poor clinical outcomes, and might be a complementary risk factor for critical type of COVID-19.

Keywords: COVID-19; Pleural effusion; Predictive model; Prognosis; Risk factor.

Fig. 1

Flowchart of COVID-19 patient inclusion

Fig. 2

Imaging findings of COVID-19 patients with pleural effusion: a: Multifocal ground-glass opacities (red arrow on the coronal image) and pleural effusion (green arrow on the axial image). b: Multiple patchy consolidation in the upper left lobe (red arrow on the coronal image) and the lower two lobes with bilateral pleural effusion (green arrow on the axial image). c: Bilateral ground-glass opacities (red arrow on the coronal image) and pleural effusion (green arrow on the axial image) with pleural thickening (white arrow on the axial image). d: Bilateral ground-glass opacities (red arrow on the coronal image) with pleural (green arrow on the axial image) and pericardial effusion (blue arrow on the axial image)

Fig. 3

Associations between the presence of PE and clinical outcomes in patients with COVID-19. Disease conditions were different between patients with PE (a) and patients without PE (b). Length of hospital stay of patients with PE was longer than that of patients without PE (c). The mortality rate was significantly higher in patients with PE than in patients without PE(d)

Fig. 4

Risk factors were identified by LASSO regression to predict critical type in patients with COVID-19. a: LASSO coefficient profiles of the non-zero parameters of COVID-19. b: Mean-Squared Error curve of the lowest point in the red line corresponds to a four-variable model

Fig. 5

The discriminative power and calibration of the nomogram for predicting critical type in COVID-19 patients. a: A nomogram, containing LDH, D-dimer, PE and TBIL was created to predict critical type of COVID-19. b: The predicted probabilities by nomogram were coincident with the actual outcomes, indicating the calibration of the nomogram was good. c: decision curve analysis (DCA) highlighted the clinical utility of the nomogram. d: ROC curve exhibited good discriminative power (AUC = 0.817) for predicting critical type of COVID-19