Clinical features, diagnostic, aetiology and outcome of hospitalised solid organ recipients with community-acquired pneumonia: a retrospective cohort analysis

Background Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality worldwide. Limited evidence is available on the most effective diagnostic approaches, management strategies, and long-term outcomes for CAP in patients who have undergone solid organ transplantation. Research Question What is the acute and long-term morbidity and mortality after CAP in organ transplant recipients? Study Design and Methods We retrospectively analysed hospitalisations for CAP in solid organ recipients at the largest German transplant centre. The study included patients admitted between 1 January 2010 and 31 May 2021. The reported outcomes are in-hospital and 1-year mortality, risk of cardiovascular events during hospitalisation and at one year, admission to the intensive care unit, and risk of pneumonia with P. aeruginosa. Multivariable binary logistic regression using stepwise forward selection was performed to determine predictive factors for pneumonia with P. aeruginosa. Results We analysed data from 403 hospitalisations of 333 solid organ recipients. In over 60% of cases, patients had multiple comorbidities, with cardiovascular and chronic kidney disease being the most prevalent. More than half of the patients required oxygen supplementation after admission. In-hospital mortality (13.2%) and the death rate at one year post-event (24.6%) were higher than data reported from immunocompetent patients. We also observed high rates of acute cardiovascular events and events occurring one year after admission. Early blood cultures and bronchoscopy in the first 24 hours significantly increased the odds of establishing an aetiology. In our low-resistance setting, the burden of antimicrobial resistance was driven by bacteria from chronically colonised patients, mostly lung transplant recipients. Interpretation This comprehensive analysis highlights the high morbidity associated with CAP after transplantation. It also emphasises the need for prospective multicenter studies to guide evidence-based practices and improve outcomes for these vulnerable patients.