Frequency, Risk Factors, Clinical Characteristics and Outcomes of Spontaneous Pneumothorax in Patients with COVID-19 Results of the UMC-19-S7

Objective: We investigated the incidence, risk factors, clinical characteristics and outcome of spontaneous pneumothorax (SP) in COVID-19 patients attended in emergency departments (ED) before hospitalization. Methods: We retrospectively reviewed all COVID patients diagnosed with SP (case group) in 61 Spanish EDs (20% of Spanish EDs), during the first two months of the COVID outbreak and compared them with two control groups: COVID patients without SP (control group A) and non-COVID patients with SP (control group B). Relative frequencies of SP were estimated in cases and control group B. Unadjusted comparisons between cases and controls included 52 clinical, analytical and radiological characteristics and 4 outcomes. Results: We identified 40 SP in 71,904 patients with COVID-19 attending EDs (0.56‰, 95%CI=0.40-0.76‰). This incidence was higher than that observed in non-COVID patients (387/1,358,134, 0.28‰, 95%CI=0.26-0.32; OR=1.93, 95%CI=1.41-2.71). In COVID patients the characteristics associated with a higher risk of SP were: male sex, shorter symptom length, less fever, greater dyspnea, tachycardia, tachypnea and hypoxia, higher hemoglobin, leukocyte count, D-dimer and LDH, and lower lymphocyte count. Compared to control group B, case group patients were older, more frequently had obesity, asthma, dyspnea, tachycardia, tachypnea, hypoxia and analytical disturbances, and less frequently diabetes mellitus, hypertension, smoker habit, and chest pain. All the outcomes measured, including in-hospital death, were worse in cases than in control groups A and B. Conclusions: SP as a form of COVID presentation is unusual (<1‰ cases) but is associated with worse outcomes than SP developed in non-COVID patients and in COVID patients without SP. Funding Statement: The present work was performed without any direct or indirect financial support. Declaration of Interests: No author reports any conflict of interest directly or indirectly connected with this manuscript. Ethics Approval Statement: The UMC-19 project was approved by the Ethics Committee of the Hospital Clinic of Barcelona (Spain), with the reference number HCB/2020/0534, and acted as the central ethical committee. Under the exceptional circumstances generated by the COVID-19 pandemic, the urgent need to obtain feasible data related to this new disease, and the non-interventional and retrospective nature of the project, the requirement of obtaining written patient consent to be included in the study was waived.