Secondary outcomes
Table 2 presents the risk factors for post COVID-19 symptoms and pulmonary function impairment shown in spirometry. The history of COVID-19 pneumonia significantly associated with the presence of post COVID-19 symptoms (OR = 6.00, 95% CI [1.54,23.33], p = 0.01). However, there was no statistically significant association between the pneumonia and subsequent pulmonary function impairment (OR = 0.79, 95% CI [0.15-4.32], p = 0.79). Other factors, including increasing age, being overweight or obese, and the interval between acute COVID-19 infection and assessment timepoint, did not show any significant association with post COVID-19 symptoms and pulmonary function impairment. FEV1 z-score was added to the analysis due to the significant difference between patients with and without respiratory sequalae. However, it did not significantly increase the presence of post COVID-19 symptoms.