Table 2.

Randomised clinical trials investigating the effect of preoperative carbohydrate on insulin resistance

Study	n	Type of surgery	Intervention groups	Technique	Conclusions	p-value
Okabayashi, 20105	26	Hepatic resection	1. Control – no additional dietary supplement2. Aminoleban® EN (mixture of carbohydrate and BCAAs) – 50g given orally twice a day started 2 weeks prior to surgery	Artificial pancreas with a closed loop system (STG-22)	IS better in Aminoleban® EN group	0.039
Kaska, 20106	221	Colorectal resection	1. Control – overnight fasting2. IV 500ml 10% glucose with 10ml 7.45% KCl and 10ml 20% MgSO4 – pm and am3. Oral 400ml potion containing maltodextrin and electrolytes – pm and am	Quantitative insulin sensitivity check index	IS reduced in control group	0.05
Faria, 20097	21	Laparoscopic cholecystectomy	1. Overnight fasting2. CHO 200ml – am	HOMA-IR	IS higher in CHO group than fasted group	0.03
Svanfeldt, 20078	12	Colorectal resection	1. High CHO group – 125mg/ ml CHO2. Low CHO group – 25mg/ml CHO 800ml – pm, during the waiting period on the day of surgery: 200ml portion given every hour. In total, 3 or 4 portions (600–800ml) ingested, with last portion no later than 2 hours before premedication.	HN clamp – measured before and on the first postoperative day	No effect seen on postoperative peripheral IS	0.049
Svanfeldt, 20059	6	Simulated preoperative setting; no surgery	1. Overnight fasting2. CHO 800ml – pm3. CHO 400ml – am4. CHO 800ml – pm, 400ml – am	HN clamp – measured 120 minutes after the morning drink	IS increased by 50% 3 hours after morning drink	<0.01
Nygren, 199910	30	Colorectal surgery (n=14), THR (n=16)	1. CHO 800ml – pm, 400ml – am2. Placebo – similar protocol	HN clamp THR -1 week before surgery and immediately after completion of surgeryColorectal surgery – day before surgery and 24 hours postoperatively	THR: 37% reduction in IS in placebo group immediately after surgery. No significant reduction in IS found in CHO group.Colorectal surgery: 24% greater reduction in IS in fasted group than in CHO group at 24 hours after surgery	<0.05
Ljungqvist, 199411	12	Laparoscopiccholecystectomy	1. Control – overnight fasting2. Overnight glucose infusion 5mg/kg/min	HN clamp – measured 3 days preoperatively and on first day postoperatively	IS reduced in control patients compared with treatment group	<0.01

BCAAs = branched chain amino acids; IS = insulin sensitivity; pm = evening before surgery; am = morning of surgery; CHO = carbohydrate drink; HOMA-IR = homeostatic model assessment – insulin resistance; HN = hyperinsulinaemic normoglycaemic; THR = total hip replacement