Preoperative Whey Protein Supplementation and Early Postoperative Outcomes in Older Adults Undergoing Total Hip Arthroplasty

Background Surgical stress induces metabolic and inflammatory responses that may contribute to postoperative insulin resistance and delayed recovery, particularly in older adults. Preoperative nutritional optimization strategies have been proposed to improve perioperative metabolic stability. Objective This randomized controlled trial aimed to evaluate the effects of preoperative whey protein supplementation on early postoperative metabolic markers and recovery quality in older adults undergoing total hip arthroplasty. Methods Sixty-two patients aged 50–70 years scheduled for total hip arthroplasty under spinal anesthesia were randomly assigned to either the intervention group (n = 30), who received 600 mL of oral whey protein solution six hours before surgery, or the control group (n = 32), who received 600 mL of water. Blood samples were collected 24 hours before surgery, immediately before surgery, and 24 hours postoperatively to measure glucose, insulin, HOMA-IR, cortisol, albumin, and C-reactive protein levels. Postoperative recovery quality was assessed using the QoR-15T scale. Analyses were performed using intention-to-treat principles. Between-group comparisons were adjusted for baseline metabolic values using ANCOVA. Results Unadjusted analyses indicated lower insulin and HOMA-IR levels in the whey protein group. However, after adjustment for baseline values, no statistically significant group effect was observed for postoperative insulin (F = 0.98, p = 0.327) or HOMA-IR (F = 0.969, p = 0.002) levels. No significant differences were observed between groups in glucose, cortisol, CRP, albumin levels, or postoperative recovery quality. Conclusion Preoperative whey protein supplementation did not significantly improve early postoperative metabolic or inflammatory outcomes after adjustment for baseline metabolic status. Early postoperative insulin resistance appears to be primarily influenced by pre-existing metabolic conditions rather than a single preoperative whey protein dose.