Unravelling the complexity of ventilator-associated pneumonia: a systematic methodological literature review of diagnostic criteria and definitions used in clinical research.

BACKGROUND: Ventilator-associated pneumonia (VAP) is a prevalent and grave hospital-acquired infection that affects mechanically ventilated patients. Diverse diagnostic criteria can significantly affect VAP research by complicating the identification and management of the condition, which may also impact clinical management. OBJECTIVES: We conducted this review to assess the diagnostic criteria and the definitions of the term "ventilator-associated" used in randomised controlled trials (RCTs) of VAP management. SEARCH METHODS: Based on the protocol (PROSPERO 2019 CRD42019147411), we conducted a systematic search on MEDLINE/PubMed and Cochrane CENTRAL for RCTs, published or registered between 2010 and 2024. SELECTION CRITERIA: We included completed and ongoing RCTs that assessed pharmacological or non-pharmacological interventions in adults with VAP. DATA COLLECTION AND SYNTHESIS: Data were collected using a tested extraction sheet, as endorsed by the Cochrane Collaboration. After cross-checking, data were summarised in a narrative and tabular form. RESULTS: In total, 7,173 records were identified through the literature search. Following the exclusion of records that did not meet the eligibility criteria, 119 studies were included. Diagnostic criteria were provided in 51.2% of studies, and the term "ventilator-associated" was defined in 52.1% of studies. The most frequently included diagnostic criteria were pulmonary infiltrates (96.7%), fever (86.9%), hypothermia (49.1%), sputum (70.5%), and hypoxia (32.8%). The different criteria were used in 38 combinations across studies. The term "ventilator-associated" was defined in nine different ways. CONCLUSIONS: When provided, diagnostic criteria and definitions of VAP in RCTs display notable variability. Continuous efforts to harmonise VAP diagnostic criteria in future clinical trials are crucial to improve quality of care, enable accurate epidemiological assessments, and guide effective antimicrobial stewardship.

Clinical trials of pneumonia management assess heterogeneous outcomes and measurement instruments.

OBJECTIVES: To inform clinical practice guidelines, randomized controlled trials (RCTs) of the management of pneumonia need to address the outcomes that are most important to patients and health professionals using consistent instruments, to enable results to be compared, contrasted, and combined as appropriate. This systematic review describes the outcomes reported in clinical trials of pneumonia management and the instruments used to measure these outcomes. STUDY DESIGN AND SETTING: Based on a prospective protocol, we searched MEDLINE/PubMed, Cochrane CENTRAL and clinical trial registries for ongoing or completed clinical trials evaluating pneumonia management in adults in any clinical setting. We grouped reported outcomes thematically and classified them following the COMET Initiative's taxonomy. We describe instruments used for assessing each outcome. RESULTS: We found 280 eligible RCTs of which 115 (41.1%) enrolled critically ill patients and 165 (58.9%) predominantly noncritically ill patients. We identified 43 distinct outcomes and 108 measurement instruments, excluding nonvalidated scores and questionnaires. Almost all trials reported clinical/physiological outcomes (97.5%). Safety (63.2%), mortality (56.4%), resource use (48.6%) and life impact (11.8%) outcomes were less frequently addressed. The most frequently reported outcomes were treatment success (60.7%), mortality (56.4%) and adverse events (41.1%). There was significant variation in the selection of measurement instruments, with approximately two-thirds used in less than 10 of the 280 RCTs. None of the patient-reported outcomes were used in 10 or more RCTs. CONCLUSION: This review reveals significant variation in outcomes and measurement instruments reported in clinical trials of pneumonia management. Outcomes that are important to patients and health professionals are often omitted. Our findings support the need for a rigorous core outcome set, such as that being developed by the European Respiratory Society.