Association of the admission albumin-hemoglobin index with postoperative outcomes in older adults with hip fracture: a post-hoc analysis of a prospective study

Background Older adults with hip fracture are at high risk of postoperative mortality and impaired health-related quality of life. The albumin–hemoglobin index (AHI) combines nutritional and anemia-related information, but its prognostic value remains unclear. We evaluated the associations of admission AHI with 3-year all-cause mortality and postoperative health-related quality of life. Methods Patients aged ≥65 years who underwent hip fracture surgery between November 2018 and November 2019 were prospectively enrolled. AHI was calculated from admission serum albumin and hemoglobin levels and analyzed continuously, by quartiles, and using an exploratory cutoff. The primary outcome was 3-year all-cause mortality; the secondary outcome was longitudinal change in EQ-5D utility. Kaplan–Meier analysis, Cox models, restricted cubic splines, linear mixed-effects models, and LASSO Cox regression were used. Results Among 1,092 patients screened, 947 were included. Lower AHI was associated with older age, lower body mass index, poorer prefracture mobility, and worse overall health status. Three-year survival differed significantly across quartiles, with the lowest survival in Q1 and the highest in Q4. Each 1,000-unit increase in AHI was associated with a 43% lower mortality risk (adjusted hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.47–0.70; P < 0.001). Compared with Q1, the adjusted HRs for Q2, Q3, and Q4 were 0.69 (95% CI, 0.48–0.98), 0.45 (95% CI, 0.28–0.70), and 0.28 (95% CI, 0.16–0.49), respectively. Patients with AHI >4673 had lower mortality than those with AHI ≤ 4673 (HR, 0.46; 95% CI, 0.32–0.66; P < 0.001). In the multivariable-adjusted restricted cubic spline analysis, the overall association was significant ( P for overall <0.001), with no evidence of nonlinearity ( P for nonlinearity = 0.855). Higher AHI was also associated with more favorable EQ-5D recovery, and LASSO sensitivity analysis supported the primary findings. Conclusions Lower admission AHI was independently associated with higher 3-year mortality and poorer recovery in health-related quality of life after hip fracture surgery. AHI may provide a simple tool for perioperative risk stratification and individualized management.