Respiratory muscle strength, lung function and persistent symptoms of COVID-19 in hospitalized and non-hospitalized individuals one year after infection

Introduction: COVID-19, emerging in 2019, caused millions of cases and left many patients with persistent symptoms, such as fatigue and shortness of breath, affecting daily functioning and quality of life. Objectives: To evaluate respiratory muscle strength, lung function, and persistent COVID-19 symptoms in hospitalized and non-hospitalized individuals one year after infection. Methods: A cross-sectional study included 160 participants (80 hospitalized, 80 non-hospitalized) in Fortaleza, Ceará (2021–2024). Assessments included manovacuometry, spirometry, and a questionnaire on persistent symptoms by organ system. Results: Participants’ mean age was 55.8 ± 15.87 years and BMI 28.85 ± 4.85 kg/m². Comorbidities were present in 37.5% of hospitalized participants, mainly cardiovascular diseases (27.5%). Persistent symptoms occurred in 42.5% of hospitalized and 45% of non-hospitalized individuals (p = 0.716). Fatigue was more frequent in non-hospitalized participants (42.5% vs. 16.2%, p = 0.032). Hospitalized individuals showed lower forced vital capacity (FVC) (60.01 ± 11.14%) compared to non-hospitalized (89.02 ± 10.94%, p = 0.021). Predictors of persistent symptoms included BMI (OR: 1.07, p = 0.001) and comorbidities (OR: 2.08, p = 0.040) in hospitalized participants, and acute-phase symptoms (OR: 4.05) and comorbidities (OR: 2.00) in non-hospitalized participants. Conclusions: One year post-infection, persistent symptoms were common, with fatigue predominating in non-hospitalized individuals. Hospitalized participants showed greater restrictive lung impairment. Predictors of prolonged symptoms differed between groups, highlighting the need for tailored follow-up strategies. Keywords: COVID-19. Post- Acute COVID-19 Syndrome. Respiratory Function Tests.