Surgical urgency and outcomes in nonagenarian and centenarian patients admitted to the ICU after hip replacement: a binational multicenter cohort study

INTRODUCTION: The global population of nonagenarians and centenarians is expected to quadruple by 2050, resulting in increasing numbers of the oldest-old undergoing procedures such as hip replacement to maintain mobility and independence. Despite this trend, evidence on how surgical urgency affects outcomes in this population remains limited. METHODS: We conducted a retrospective cohort study using data from the ANZICS Adult Patient Database (2010-2023), which captures 98% of intensive care units (ICUs) in Australia and 68% in New Zealand. The study included 1,578 nonagenarian and centenarian patients who underwent non-traumatic hip replacement and were admitted to intensive care. Outcomes examined were mortality at three time intervals (<30 days, 30-365 days and >365 days) and ICU and hospital length of stay. Analytical methods included propensity score matching, Cox regression, Kaplan-Meier curves and time-dependent area under the receiver operating characteristic curve analyses to assess the prognostic value of clinical scores and biomarkers. RESULTS: Non-elective operation was associated with significantly higher mortality across all time points (HR 2.87 at <30 days; 3.02 at 30-365 days; 1.84 beyond 365 days). It was also linked to a 13.1% longer ICU stay (p=0.034). Acute Physiology and Chronic Health Evaluation III and Sequential Organ Failure Assessment scores showed strong predictive performance for short-term mortality, whereas age and sex had minimal prognostic value. CONCLUSION: Among nonagenarians and centenarians undergoing hip replacement, non-elective procedures were consistently associated with poorer outcomes, including higher mortality and longer ICU stay. Early risk stratification using routine clinical markers, together with proactive goals-of-care discussions, may improve perioperative management in this vulnerable population. LEVEL OF EVIDENCE: Level II Therapeutic/Care Management.