Clinical factors associated with early multidomain symptomatic recovery in hospitalized patients with chronic lung disease and post-COVID conditions: a secondary analysis of a prospective controlled cohort

Abstract Background Early symptom improvement after SARS-CoV-2 infection is heterogeneous among patients with chronic lung disease (CLD) and post-COVID conditions (PCC). The parent cohort previously reported the investigator-defined composite early recovery outcome and its unadjusted comparison between management pathways. The present post hoc secondary analysis addressed a narrower knowledge gap: which characteristics available at hospital admission were associated with improvement in at least two respiratory symptom domains during hospitalization? Methods This secondary analysis included 360 hospitalized adults with CLD and PCC from a single-center prospective controlled cohort. Early multidomain symptomatic recovery was defined as an investigator-defined score ≥ 2, based on cough relief within 7 days, sputum relief within 7 days, and dyspnea relief within 14 days. Associations with baseline demographic, clinical, physiological, radiological, inflammatory, functional, sleep, and psychological variables were examined using univariable and multivariable logistic regression. Management pathway was evaluated separately as a post-baseline exposure in a secondary adjusted model and was not treated as a baseline prognostic characteristic. Results Of 360 patients, 152 (42.2%) achieved early multidomain symptomatic recovery. In the baseline-only multivariable model, female sex was associated with lower odds of early recovery (OR 0.64, 95% CI 0.42–0.99; P = 0.047), whereas ILD/other phenotype (OR 1.73, 95% CI 1.04–2.89; P = 0.036), lower CT residual abnormality extent (OR 0.79 per 5% of lung involvement, 95% CI 0.65–0.96; P = 0.020), and higher ESR (OR 1.21 per 10 mm/h, 95% CI 1.03–1.41; P = 0.018) were associated with higher odds of early recovery. In a secondary model, integrated pathway management remained associated with early recovery (OR 1.86, 95% CI 1.17–2.94; P = 0.008), but this observational association was not interpreted as a causal treatment effect. Conclusions This post hoc secondary analysis identifies admission characteristics associated with early improvement in at least two respiratory symptom domains among hospitalized patients with CLD and PCC. The contribution beyond the parent publication lies in characterization of these baseline associations rather than re-estimation of the previously reported composite outcome or pathway comparison. These exploratory associations do not represent complete recovery from PCC, do not establish a causal effect of the integrated pathway, and require confirmation in independent cohorts.