Association between preoperative frailty and 30-day functional disability after surgery: a prospective cohort study using the Edmonton Frail Scale

Background: Frailty is a known predictor of adverse surgical outcomes, yet its influence on functional recovery trajectories in South Asian settings remains underexplored. This study evaluated the association between preoperative frailty and achieving a clinically meaningful improvement in disability 30 days after elective surgery. Methods: A prospective cohort study was conducted at a tertiary hospital in Karachi, enrolling 146 patients aged > 50 years undergoing elective general or orthopedic surgery. Preoperative frailty was assessed using the Edmonton Frail Scale (EFS). Disability was measured using the WHODAS-12 at baseline and 30 days postoperatively. The primary outcome was a meaningful functional improvement, defined as a decrease of ≥ 3.5 points on the WHODAS-12 scale. Results: Among 146 patients (mean age 64.1 ± 9.4 years), 76.7% (n = 112) were categorized as frail. Frail patients had significantly higher baseline disability than non-frail patients (17.74 ± 6.70 vs. 12.29 ± 7.84; p < 0.001). At 30 days, overall disability improved significantly (mean change: −1.99 ± 8.12, p = 0.036), driven primarily by the frail group (− 2.66 ± 7.33, p = 0.007) compared to the non-frail group (+ 0.35 ± 10.34, p = 0.89). In the multivariable model, higher baseline WHODAS scores were significantly associated with a greater likelihood of improvement (OR 1.18 per point; 95% CI: 1.02–1.35; p = 0.022). Conversely, patients aged > 75 years were 89% less likely to achieve improvement (OR 0.11; 95% CI: 0.01–0.98; p = 0.048). Subgroup analysis indicated that improvement rates peaked in the Moderate frailty category (47.62%) compared to those classified as Vulnerable (12.50%). Conclusion: Preoperative frailty identifies patients with the greatest potential for functional gain, though this recovery is significantly limited by advanced age. These results suggest that surgery provides a “functional dividend” for frail individuals with high baseline impairment. Routine frailty screening should be utilized to manage expectations and tailor recovery pathways in aging surgical populations.