Rinaldo Bellomo's seminal contribution to observational research using the ANZICS CORE registry.

Rinaldo Bellomo advanced critical care not only through randomised trials but also through rigorous use of observational data, particularly from the ANZICS Centre for Outcome and Resource Evaluation (ANZICS CORE) Registry. At a time when retrospective analyses were often confined to hypothesis generation, he showed that carefully curated, clinically grounded registry studies could inform policy and change practice. Recognising early the potential of ANZICS CORE to become a leading registry, he worked to strengthen its data architecture and published in journals such as The New England Journal of Medicine and JAMA, helping to spark global dialogue and shape guidelines. Using the Adult Patient Database, he described epidemiological trends, identified clinically relevant questions, designed, justified and evaluated randomised trials, and monitored the uptake of evidence-based practice. His work addressed key challenges in sepsis, acute kidney injury, glycaemic control, temperature management and health equity, and was marked by clear case definitions, extensive sensitivity analyses and transparent reporting. This article reviews selected contributions using ANZICS CORE data and outlines how his legacy endures through the value of these datasets and the many researchers he mentored.