Impact of endogenous and exogenous insulin on basal energy expenditure in patients with type 2 diabetes under standard treatment

Abstract

Background: Factors that affect resting energy expenditure or basal energy expenditure (BEE) in patients with type 2 diabetes under standard treatment have not been evaluated in detail.

Objective: We determined the clinical factors that affected BEE in addition to body composition in patients with type 2 diabetes under standard treatment.

Design: BEE was measured by using indirect calorimetry under a strict basal condition in 58 Japanese patients with type 2 diabetes after >7 d as inpatients under management of diabetes with medical nutrition therapy and medications. Insulin secretion was measured with a glucagon test. Stepwise regression was applied to explore determinants of BEE.

Results: In the stepwise estimation, insulin secretion (P = 0.015), insulin therapy (P = 0.012), and pulse rate (P = 0.011) were selected in addition to fat-free mass (FFM) (P < 0.001) and fat mass (P = 0.006) as significant independent determinants of BEE. Standardized partial regression coefficients of the additional 3 factors were -0.16, -0.15, and 0.15, respectively, whereas those for FFM and fat mass were 0.82 and 0.19, respectively. The additional 3 factors explained another 3.9% of the variability of BEE, and the adjusted coefficient of determination was 83.4%. Age, sex, other medications, and parameters of glycemic control were not significant determinants beyond the combined contribution of body composition, endogenous and exogenous insulin, and pulse rate.

Conclusion: Endogenous insulin secretion and exogenous insulin administered in treatment have significant independent effects in the lowering of BEE in patients with diabetes under standard management with medical nutrition therapy and medications.