Association of laboratory and radiological findings during hospitalization with early post-COVID pulmonary function and exercise capacity: a retrospective study

This study aimed to retrospectively evaluate the relationship between demographic characteristics, chest CT findings, and laboratory parameters during hospitalization and post-COVID pulmonary function and exercise capacity. The retrospective study included 101 patients who were hospitalized with COVID-19, had CT findings consistent with COVID-19, and completed at least two months after discharge. In the study, Six-Minute Walk Test (6MWT), Pulmonary Function Tests (PFT), thorax CT and laboratory findings were evaluated. Statistical analyses were conducted using SPSS (v25.0); normality and variance homogeneity were assessed by Shapiro–Wilk and Levene tests, respectively, while group comparisons were performed using Student’s t, Mann–Whitney U, Chi-square, and one-way ANOVA with Tukey post-hoc tests, and correlations were evaluated by Spearman analysis. Patients with severe/critical COVID-19 had significantly higher age, BMI, length of hospital stay, time from diagnosis to admission, ferritin, CRP, D-dimer, neutrophil %, N/L ratio, and Charlson Comorbidity Index, and lower lymphocyte % ( p < 0.005). Severe/critical pneumonia was observed in 66.7% of CO-RADS 4 and 67.9% of CO-RADS 5 cases ( p = 0.002). Restrictive respiratory patterns were found in 32.7% of the severe/critical group ( p = 0.018). ICU patients had significantly shorter 6MWT distances, more frequent restrictive PFT results, and higher inflammatory markers at admission compared to non-ICU patients ( p < 0.05). No significant correlation was found between disease severity and 6MWT distance. Elevated inflammatory markers and ICU admission during hospitalization were associated with impaired pulmonary function and reduced exercise capacity in the early post-COVID period. In contrast, disease severity and CO-RADS classification were not predictive of functional outcomes. These findings highlight the role of inflammatory burden and critical illness as key predictors of post-COVID impairment.