Retrospective analysis of the impact of a low glycaemic index diet on hospital stay following coronary artery bypass grafting: a hypothesis

OBJECTIVE: Glucose tolerance and insulin resistance influence medical outcome in subjects with coronary artery disease, these metabolic parameters also influence general perioperative surgical outcome. We hypothesize that glucose tolerance and insulin resistance can be favourably modified by reducing the glycaemic index of the diet. DESIGN: The present study is a retrospective analysis of a low and high glycaemic index diet on glucose tolerance, insulin resistance and perioperative outcome, as assessed by the length of hospital stay following coronary artery bypass surgery. Thirty-five adults awaiting bypass surgery were randomized, for the 4 weeks prior to surgery, to either a low glycaemic index diet (17 subjects) or high glycaemic index diet (18 subjects). Glucose and insulin responses during a 75 g oral glucose tolerance test were assessed before and after dietary intervention and insulin-mediated glucose uptake was assessed in isolated adipocytes obtained at surgery. RESULTS: The patients who consumed a low glycaemic diet had improved glucose tolerance and significantly greater in vitro adipocyte insulin sensitivity at the time of surgery compared with the high glycaemic diet group (78.87 +/- 10.64% versus 41.11 +/- 7%, respectively). The total length of stay in the patients on the low glycaemic diet was less than patients consuming the high glycaemic diet (7.06 +/- 0.38 days versus 9.53 +/- 1.44 days, P < 0.5). CONCLUSION: This study provides further support that carbohydrate and fat metabolism influence cardiac outcome and provides new evidence that dietary modification prior to coronary artery bypass surgery can shorten hospital stay.