Influence of fat-based versus glucose-based enteral nutrition formulas on glucose homeostasis

Introduction

Trauma patients who receive fat-based parenteral nutrition (PEN) achieve better glucose control compared with those fed with glucose-based PEN [1, 2]. Therefore, we determined whether fat-based enteral nutrition (EN) has the same benefit on glucose control and exogenous insulin demand in medical intensive care patients compared with glucose-based EN. Here we present preliminary data for this ongoing randomized controlled cohort study.

Methods

Medical critically ill patients with need for mechanical ventilation and without contraindications for EN are included in the study. Patients are randomly assigned to receive either fat-based (n = 30) or glucose-based (n = 30) EN. To evaluate the individual calorie demand, indirect calorimetry is performed after an overnight fast. The determined amount of EN is administered continuously for 5 days. Glucose concentrations are measured at least three times per day and averaged. Furthermore, exogenous insulin demand per 24 hours and calorie achievement per 24 hours are evaluated daily.

Results

So far, 37 patients, 16 with fat-based, 21 with glucose-based EN have been included in the study. Both groups had similar age (62 ± 10 vs. 58 ± 16 years, P = 0.44), body mass index (26.7 ± 5.8 vs. 28.4 ± 4.4 kg/ m², P = 0.302), SAPS II score (62.4 ± 12.7 vs. 64 ± 12.3, P = 0.697), and fasting plasma glucose (132 ± 34 vs. 121 ± 26 mg/dl, P = 0.269). Furthermore, resting energy expenditure was similar in both groups (1,522 ± 365 vs. 1,573 ± 313 kcal/day, P = 0.647). Throughout the entire study period, average blood glucose, exogenous insulin demand, and calorie achievements per day were similar between the groups (day 1: gluc: 139 ± 30 vs. 127 ± 20 mg/dl, P = 0.143; ins: 27.8 ± 28.4 vs. 16.2 ± 19.4 IE, P = 0.155; EN: 52.9 ± 25.6 vs. 61.7 ± 25%, P = 0.304; day 3: gluc: 129 ± 17 vs. 133 ± 21 mg/dl, P = 0.578; ins: 35.1 ± 30.9 vs. 32.3 ± 30.5 IE, P = 0.802; EN: 78.3 ± 28.9 vs. 83.4 ± 29%, P = 0.617; day 5: gluc: 124 ± 16 vs. 132 ± 17 mg/dl, P = 0.276; ins: 25.7 ± 37 vs. 33 ± 26.4 IE, P = 0.562; EN: 73.9 ± 41.4 vs. 87.1 ± 23%, P = 0.354). Interestingly, the calorie achievement was not associated with insulin demand (day 1: R = 0.241, P = 0.156) or average blood glucose (day 1: R = 0.248, P = 0.14) throughout the study.

Conclusion

Medical critically ill patients with fat-based or glucose- based EN achieve similar glucose control. EN was not associated with glucose concentrations or insulin demand.