Consensus on the definition, components, and grading of composite postoperative pulmonary complication outcomes (PrECiSIOn): insights from an international Delphi expert panel

Postoperative pulmonary complications (PPCs) are common after surgery and contribute substantially to morbidity, mortality, and health-care burden, and are frequently used as endpoints in clinical studies. However, absence of standardised definitions and heterogeneity in component selection limit comparability across studies and might bias estimates of treatment effects. The Postoperative Pulmonary Complications-Evaluation for Consensus on Standardised Outcomes (PrECiSIOn) study was an international, mixed-method consensus study using a Delphi process to establish a standardised definition of PPCs, determine severity-based ranking of individual components, and define approaches for their assessment. A multidisciplinary panel of experts in PPCs was recruited and candidate PPC components were identified through a focused literature review, structured into domains, and evaluated across iterative Delphi rounds using a seven-point Likert scale, with consensus predefined as ≥75% agreement. Patient and patient care representative perspectives were incorporated through interviews and surveys, and panellists assigned severity weights to components reaching consensus. Input from 44 panellists and five patients and patient representatives informed the prioritisation of clinically meaningful outcomes. Consensus was achieved on a standardised PPC construct comprising components grouped into four domains: symptoms, diagnoses, therapies, and outcomes. Panellists supported the use of routinely collected clinical data and a standardised in-hospital monitoring approach but did not reach consensus on the optimal follow-up period or need for post-discharge surveillance. Severity-based rank ordering enabled hierarchical organisation of PPC components according to their clinical importance, supporting the development of ordinal composite outcomes that account for differences in severity between individual complications. This international consensus-based framework provides a standardised definition of PPCs incorporating severity-based rank ordering, addresses important limitations of existing composite outcomes, and might facilitate more consistent and clinically meaningful evaluation of perioperative interventions. Further work should focus on external validation, implementation in clinical trial analyses, and assessment of applicability across diverse patient populations and health-care settings.