Clinical and functional predictors of response to a comprehensive pulmonary rehabilitation in severe post-COVID-19 patients

Abstract

Background: Pulmonary rehabilitation (PR) following severe and very severe COVID-19 infection is known to be effective, according to typical assessments. However, not all patients benefit from PR to the same extent. This analysis aimed to identify the impact of different factors on PR outcomes in post-COVID-19 patients. Methods: This prospective observational study included 184 post-COVID-19 patients. The achievement of the predicted reference walking distance (6 min walking distance (6-MWD)) served as a parameter with which to identify responders and non-responders to PR. Several parameters (e.g., Functional Independent Measurement (FIM); pulmonary function testing (Forced Vital Capacity, FVC); 6MWD) were assessed in order to estimate their impact on PR success. Logistic regression models and classification and regression trees were used for multivariate analysis. Results: A total of 94 patients (51%) reached their reference 6MWD by the end of PR. FVC (0.95 (0.93–0.97)), 6MWD at admission (0.99 (0.99–1.00)), and FIM motoric (0.96 (0.93–0.99)) correlated with the risk not reaching the reference distance. The most important variable was the 6MWD at admission. Classification and regression tree identified 6MWD ≥ 130 m at admission and FVC predicted of >83% as the strongest predictor for reaching predicted 6-MWD. Conclusion: Post-COVID-19 patients with lower 6MWD, lower motoric FIM scores and lower FVC at admission have a high risk of not reaching their target values of physical performance despite intensive rehabilitation. As well as identifying them, it is of utmost importance to develop optimal PR concepts for these patients.