How Do COVID-19 Pulmonary Sequelae Evolve Post Hospital Discharge?

Following hospital discharge for COVID-19, patients tend to show functional impairments in gas exchange and exercise capacity, which vary according to the severity of acute pneumonia during hospitalization. Patients generally improve within 2 to 6 months. These were among study findings recently published in Respiration.

The advent of COVID-19 is so recent that there are not many studies reporting a double-step follow-up for addressing the clinical and functional aftermath for patients after hospitalization. Researchers sought to assess the clinical, functional, and imaging evolution of COVID-19 after discharge in patients not involved in pharmacologic therapy or rehabilitation programs.

In the current study, researchers conducted a prospective observational monocentric follow-up of 100 patients (60±14 years of age; 55 male; 37% former smokers; 50% cardiovascular comorbidity; 22% respiratory comorbidity; 40% obese, plus 40% overweight). Patients were divided into 2 groups according to the level of respiratory support received: a group of 34 patients requiring a higher level of support, including 10 patients who underwent invasive mechanical ventilation and 24 who were supported with either noninvasive ventilation, continuous positive airway pressure, or high-flow nasal cannula; and a group of 66 patients who received standard oxygen or no support.

Among the group with higher ventilatory support, cardiovascular comorbidities were significantly more prevalent; impairment of gas exchange (lowest value of the ratio of arterial oxygen partial pressure [PaO₂ in mmHg] to fractional inspired oxygen [FiO₂]) PaO₂/FiO₂ nadir and high-resolution computed tomography (HRCT) extension score were worse; lactate dehydrogenase at hospital admission was higher; and more patients received therapies (hydroxychloroquine, azithromycin, steroids, antivirals, and tocilizumab), (all P <.001). Describing symptoms, spirometry, and exercise capacity at 2 and 6 months was the primary outcome.

After 2 months, 64% of patients remained symptomatic. At 6 months, patients reporting at least 1 symptom decreased to 42%. Between 2 and 6 months, forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and 6-minute walking test (6MWT) time improved (P <.001). At 2 months and 6 months, patients with PaO₂/FiO₂ < 200 during hospitalization performed worse at 6MWT (P <.05), and at 6 months the same patients reported more extended radiological abnormalities (P <.001) compared with patients with PaO₂/FiO₂ >200. More extended radiological abnormalities were related with worse 6MWT, diffusing capacity for carbon monoxide (DLCO), and total lung capacity at 6 months (P <.05), and, the most common 6-month functional alteration was patients with DLCO impairment (57%).

Results of this study suggest that patients who had been hospitalized with COVID-19 improve between 2 and 6 months following discharge. Researchers concluded, “A mild defect in gas exchange and of exercise capacity seems to be the functional hallmark of aftermath,” and “severity of acute pneumonia is related to the severity of functional and radiological alterations.” The investigators further noted that this correlation “endorses British Thoracic Society guidance to pay more attention at follow-up of patients with more severe pneumonia.”

The study was limited by the fact that there was no control group or pre-COVID-19 baseline pulmonary function tests or high-resolution computed tomography images.

Reference

Ferioli M, Prediletto I, Bensai S, et al. Spontaneous evolution of COVID-19 lung sequelae: Results from a double-step follow-up. Respiration. Published online January 18, 2022. doi:10.1159/000521316

This article originally appeared on Pulmonology Advisor