Introduction: Persistent symptoms, abnormalities in lung function and imaging have been described after one year of follow-up for severe COVID-19, however, the information in Mexican population is limited. Objective: To analyze persistent symptoms, lung function abnormalities and tomographic abnormalities at one year of follow-up in Mexican patients with severe COVID-19.

Methods: This is a longitudinal, prospective study including patients who survived severe COVID-19 in Mexico. They were evaluated at 3, 6 and 12 months; at each visit, a symptom questionnaire, spirometry (FVC), lung diffusion (DLco) and a 6-minute walk test (6MWT) were performed based on current ATS/ERS standards. A CT-scan of the chest was performed at the 12-months visit. Continuous variables were analyzed using ANOVA and categorical variables using Fisher's exact test.

Results: 100 patients were included, median age 49 years (IQR 19), 56% male. At the 12-month evaluation, the most frequent symptoms were fatigue (56%), dyspnea (51%), and myalgia (33%). The lung function trajectory showed a significant linear trend in recovery over time in FVC (p<0.0007) and DLco (p<0.0013). However, at 1-year of follow-up, 52% of patients have a FVC <80%p and 41% with Dlco <60%p. Finally, chest imaging findings at 430 days (IQR 141) showed 35% of patients with persistent abnormalities according to the Goh scale, with inflammatory predominance 33.5% (IQR 33).

Conclusions: at 1-year follow-up, a significant proportion of Mexican patients have persistent symptoms, around 50% have lower lung function and by imaging, the cases persist with tomographic abnormalities characterized by predominantly ground glass opacities.