Impact of non-ventilator healthcare-associated pneumonia on mortality and additional length of stay in adults admitted to an acute care hospital: a systematic review

BACKGROUND: Non-ventilator healthcare-associated pneumonia (NV-HAP), a subset of healthcare-associated pneumonia (HAP), is common and significantly increases patient mortality and hospital stay. However, no systematic review has been undertaken to synthesise the impact of NV-HAP on these outcomes. AIM: The aim of this study was to undertake a review of the evidence on the impact of NV-HAP on mortality and additional length of stay in adults admitted to an acute care hospital. METHODS: We performed a systematic search to identify research exploring and evaluating the impact of NV-HAP on mortality and additional length of stay in adults admitted to an acute care hospital. The electronic databases MEDLINE and CINAHL were searched, for peer-reviewed articles published between January 2004 and August 2025. An assessment of the study quality and risk of bias of included articles was conducted using the ROBINS-E (Risk of Bias in Non-randomized Studies - of Exposures) and ROBINS-I (Risk of Bias in Non-randomized Studies - of Interventions) tool. FINDINGS: A total of 6324 studies were initially identified, with 49 articles included in the review following the screening and full-text review. Twenty-six papers identified both mortality and additional length of stay results, 21 papers identified mortality results only and two papers reported additional length of stay results only. Inpatient mortality following NV-HAP ranged from 3.1 to 73.9%. Additional length of stay associated with NV-HAP was extended between 10 and 47.5 days. CONCLUSIONS: This systematic review highlights the impact of NV-HAP on patients admitted to hospital. NV-HAP was associated with patient mortality and additional length of stay. Results of this study will inform a larger planned program of research.