Respiratory complications following SARS-CoV-2 infection

Abstract

Since its emergence in late 2019 in Wuhan, the zoonotic disease caused by the coronavirus-19 (COVID-19) has rapidly spread worldwide. Although many cases are mild or asymptomatic, a proportion of patients develop Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pneumonia, which can lead to various long-term pulmonary complications, affecting both the lung parenchyma and the airways. Characterizing these complications is essential, as some cases may require treatment to prevent permanent sequelae. In this context, adequate follow-up after hospital discharge is crucial for these patients. This doctoral thesis aimed to study the presence of respiratory complications following SARS-CoV-2 pneumonia based on the viral involvement itself, the acute treatment administered, and the presence of comorbidities (such as bronchial asthma), as well as to evaluate the need for additional medical interventions for these complications. Five studies were conducted. First, the impact of dexamethasone during SARS-CoV-2 pneumonia on respiratory complications was assessed, revealing that patients treated with dexamethasone experienced less dyspnea, improved pulmonary function, and fewer signs of fibrosis in follow-up assessments. Second, the prevalence and characteristics of airway involvement were analyzed, revealing that it was common among patients hospitalized with COVID-19 and associated with older age, a history of smoking, lower body mass index (BMI), and cardiometabolic comorbidities. Third, the prevalence of tracheomalacia following hospitalization for SARS-CoV-2 pneumonia was examined, with findings indicating that 0.8% of patients exhibited this complication. Fourth, the incidence and severity of respiratory sequelae were compared between asthmatic and non-asthmatic patients; no significant differences were found in the frequency of sequelae between the two groups. However, asthmatic patients exhibited greater bronchial thickening and/or tracheomalacia, whereas bronchiectasis was more common among non-asthmatic individuals. Finally, a fifth study involved the design of a clinical trial to determine the optimal dosage of oral corticosteroids for one of the most common complications of COVID-19: organizing pneumonia. The study demonstrated that a descending regimen of 0.5 mg/kg/day over three months was equally effective but associated with fewer adverse effects compared to the conventional treatment regimens, which involve higher doses and an unrestricted duration of six months.

Date of Award	9 Oct 2025
Original language	English
Awarding Institution	Universitat Autònoma de Barcelona (UAB)
Supervisor	Xavier Muñoz Gall (Director) & Maria Jesus Cruz Carmona (Director)