Chinese herbal medicine as adjunct therapy improves clinical recovery and reduces multidrug-resistant bacterial load in older adults with pulmonary infection: a retrospective cohort study

Objective Pulmonary infections are common and challenging in older adults due to immune decline, comorbidities, and antimicrobial resistance. This study aimed to evaluate the effects of Chinese herbal medicine as an adjunct therapy to improve immune function and infection outcomes. Methods This retrospective cohort study was conducted at the Department of Geriatrics, the Second Hospital of Shandong University, China, and included 372 older adults who were admitted between 1 January 2024 and 30 June 2024. Patients were divided into two groups: those who received CHM treatment and those who received conventional treatment. Data were retrieved from the hospital’s information system, including patient demographics, clinical status, laboratory results, and treatment outcomes. Outcomes included hospital stay time, febrile duration, symptom recovery, SpO 2 recovery, CPIS recovery, laboratory parameter recovery, MDR-related indicators and mortality. Propensity score matching and E-values were performed as a sensitivity analysis to address baseline confounding, with covariate balance assessed by standardized mean differences. Results CHM treatment was associated with significantly reduced hospital stay and febrile period, as well as a higher fever resolution rate compared to conventional treatment. Inflammatory markers improved in the CHM group, suggesting a potential immunomodulatory effect. CHM-treated patients also exhibited greater reductions in MDR bacterial counts. These beneficial effects remained consistent in the PSM-matched cohort and were further validated by E-value analysis for robustness against unmeasured confounding. However, no significant differences were found in overall mortality or MDR bacterial reversal. Subgroup analysis showed greater benefits in frail, malnourished, immunocompromised, disabled, and patients with altered consciousness. Conclusion CHM offers clinical benefits as an adjunct therapy for older adults with pulmonary infections, particularly in improving recovery time and managing MDR bacteria. Further research is required to confirm its efficacy and optimize treatment protocols.