Changes in Insulin Resistance with Different Weight Loss Methods in Patients with Type Two Diabetes Mellitus and Hypertension: A Comparative Clinical Trial

Background: The comparative effects of pharmacological treatment, bariatric surgery, and diet on insulin resistance (IR) remain unclear. Aim: To study the comparative effects of the methods on IR: pharmacologic, bariatric surgery, and very-low-calorie diet (VLCD) in patients with type 2 diabetes mellitus (T2DM) and hypertension. Methods. Design: a 90-day prospective, multicenter, comparative clinical trial including 130 adult patients divided in three groups: Drug, Surgical, and VLCD groups. Endpoints: HOMA-IR; weight loss; HbA1c, systolic/diastolic blood pressure (SBP/DBP). Results. At 90 days, weight lost in Surgery (-19.8%) and VLCD groups (-17.4%) (P< 0.0001), while in Drug group the loss was unsignificant (-6.5%; P=0.06). SBP/DBP in Drug group decreased by -9.5% (P=0.0002) and -4.1% (P=0.09), respectively. SBP/DBP in: Surgical group decreased by -13.6% and -10.6%, respectively (P< 0.001); VLCD group -23.3% and 21.3%, respectively (P< 0.0001). HOMA-IR in Drug, Surgery and VLCD groups decreased by -42.2% (P=0.004), -87.6% (P< 0.0001), and -88.7% (P< 0.0001), respectively. In Drug group HOMA-IR did not reach normal level. Correlation-regression-analysis revealed a direct correlation between weight-loss and a decrease in HOMA-IR (r=0.526; F=33.2, P< 0.0001). HOMA-IR decreases by 65% if weight decreases by 10%; if weight decreases by 25%, then HOMA-IR decreases by 83%. Conclusions. HOMA-IR was associated with weight loss: the greater the weight loss, the lower HOMA-IR. Weight loss leads to reduce the need for antidiabetic/antihypertensive drugs in the patients.