Validating Intensive Care Risk Scoring Tests in the Oldest Patients admitted to Intensive Care

In this study we will be comparing the performance of four ICU risk prediction tools: Acute Physiology And Chronic Health Evaluation (APACHE) III, its derived risk of death (APACHE3ROD), the Australian and New Zealand Risk of Death (ANZROD), and the Sequential Organ Failure Assessment (SOFA) score in predicting mortality among nonagenarian and centenarian ICU patients. All these scores are entered as a routine data entry points in the Australian and New Zealand Intensive Care Adult Patient Database. They will be collected directly from the registry. The time period from which patient data will be collected from the database is between 1 Jan 2010 and 31 Dec 2023. The ANZROD model estimates the risk of hospital mortality for ICU patients in Australia and New Zealand. It uses physiological and clinical data from the first 24 hours after ICU admission to provide a risk-adjusted benchmark for outcomes, allowing meaningful comparisons between ICU. The APACHE Score is calculated by combining points assigned to abnormal values of various physiological measurements, patient age, and chronic health status collected within the first 24 hours of ICU admission. The SOFA Score is calculated by scoring the degree of dysfunction across six organ systems (respiratory, cardiovascular, liver, coagulation, kidney, and neurological), with higher scores reflecting greater organ failure severity. The APACHE3ROD score is calculated by integrating several components collected within the first 24 hours of a patient’s admission to the intensive care unit (ICU). The calculation combines points assigned to the most abnormal values from a broad range of physiological variables (such as vital signs and laboratory results), patient age, and pre-existing chronic health conditions. Additional factors—including the primary reason for ICU admission and the patient’s location prior to ICU entry—are incorporated. This composite score is then entered into a specific mathematical equation, producing an estimated risk of hospital mortality for the individual patient. The APACHE3ROD model is widely used for severity adjustment, benchmarking, and research in critical care outcomes in Australia and internationally Primary outcome: The primary outcome will be the comparative predictive performance of the ANZROD model, and SOFA, APACHE3ROD and APACHE III scoring systems for short-term and long-term mortality among nonagenarian and centenarian ICU patients. Predictive performance will be assessed with three key metrics: 1. Discrimination, measured with the Area Under the Receiver Operating Characteristic curve (AUROC) 2. Calibration, assessed with observed-to-expected mortality comparisons via Standardised Mortality Ratios (SMRs); and 3. Clinical utility, evaluated through ity comparisons via Standardised Mortality Ratios (SMRs); and evaluated through decision curve analysis to quantify net benefit across a range of threshold probabilities. Data will be extracted directly from the Australian and New Zealand Intensive Care Adult Patient Database for patients admitted to the ICU between 1 Jan 2010 and 31 Dec 2023.