Outcomes of nonagenarians undergoing hip fracture surgery: a multicentre observational study across Asia-Oceana

Nonagenarians with hip fracture represent a rapidly growing, highly vulnerable subgroup, yet comparative data across diverse health‑care systems in Asia‑Oceania are scarce. We aimed to describe mortality, postoperative complications, and perioperative care patterns in nonagenarians undergoing hip fracture surgery in Australia and Malaysia, and to explore associations between key perioperative factors and mortality. We conducted a binational, retrospective, multicentre observational study of consecutive nonagenarians (aged ≥ 90 to < 100 years) who underwent surgery for unilateral femoral neck, intertrochanteric, or subtrochanteric fractures at four tertiary training hospitals (one in Australia, three in Malaysia) between January 2016 and January 2021. Patient demographics, comorbidities, frailty, surgical and anaesthetic details, and postoperative complications were extracted from electronic records; complications were graded using the Clavien–Dindo classification. Primary outcomes were in‑hospital, 30‑day, and 1‑year mortality; secondary outcomes were number and severity of postoperative complications, length of hospital stay, and 30‑day readmission. Statistical analyses focused on descriptive comparisons and cohort-stratified exploratory analyses to explore associations between perioperative factors and mortality. Among 510 patients, 394 (77.3%) were treated in Australia and 116 (22.7%) in Malaysia; median age was 92.0 years (interquartile range 91.0–94.0). Baseline profiles and perioperative care differed substantially: Malaysian patients more often had hypertension, diabetes, and chronic kidney disease, whereas Australian patients more frequently had congestive heart failure and dementia, and underwent emergency surgery within 48 h. In‑hospital and 30‑day mortality were similar between Australia and Malaysia (6.3% vs. 6.9% and 8.6% vs. 10.3%, respectively), but 1‑year mortality was higher in Malaysia (36.0% vs. 14.7%; P < 0.001). Overall, 86.0% of patients experienced at least one postoperative complication, with higher rates in Australia than Malaysia (98.3% vs. 49.1%), while severe complications (Clavien–Dindo grade ≥ III) were comparable (15.0% vs. 15.5%). Median length of stay was similar (8 days in both cohorts), but 30‑day readmission was more frequent in Malaysia (28.7% vs. 2.7%; P < 0.001). In cohort‑stratified models, factors associated with mortality differed by country and time point; no single perioperative factor was consistently associated with mortality across settings. In this binational cohort of nonagenarians undergoing hip fracture surgery, short‑term mortality was comparable across four tertiary hospitals in Australia and Malaysia, whereas 1‑year mortality and early readmission were substantially higher in Malaysia. These findings suggest that system‑level factors, including delayed access to surgery and limited coordinated post‑acute care, may be important determinants of longer‑term outcomes in this very old population, and highlight the need for context‑specific strategies to optimise hip fracture care in resource‑diverse settings.