Persistence of Symptoms Following Hospitalization for COVID-19 in Oman: 
A Bidirectional Observational Study.

Objectives: This study sought to assess the prevalence of persistent COVID-19-related symptoms in patients with mild, severe, and critical disease. Methods: We conducted a bidirectional cohort observational study that included all adult patients ≥ 18 years, admitted to Armed Forces Hospital, Muscat between July 2020 and June 2022, with COVID-19 infection and discharged alive. Patients were requested to attend outpatient clinic at weeks six and 12 post-discharge, where they filled out a questionnaire and underwent a chest X-ray. Additionally, blood tests were performed if necessary. Healthcare workers with mild infections were also requested to fill out a questionnaire about their initial symptoms, persistent symptoms, and comorbidities. Results: The study included 468 patients, comprising 261 hospitalized patients and 207 healthcare workers. On follow-up, 39.7% of patients presented with residual symptoms, such as cough, breathlessness, and joint pain. These symptoms were more common in patients with medical comorbidities, particularly hypertension, diabetes, and dyslipidemia. Notably, these symptoms were also observed in patients with mild disease. Post-COVID-19 pulmonary fibrosis was observed in 21 patients, mainly among those admitted to the intensive care unit or requiring prolonged hospitalization. Conclusions: This study highlights the persistence of symptoms and the prevalence of post-COVID-19 syndrome at two months post-discharge, especially among patients with severe and critical disease during the acute phase. Various predictors of post-COVID-19 syndrome were identified, including female gender, older age, presence of comorbidities, disease severity, and hypertension. Therefore, patients in these categories require thorough evaluation and long-term follow-up to manage residual symptoms.