Insulin Therapy for Insulin Resistant Patients—Harm or Benefit?

Insulin therapy has been proven to be effective in the management of type 2 diabetes. However, in patients with known insulin resistance, additional exogenous insulin used to achieve glycemic control may further contribute to the underlying dysmetabolic process resulting in increased complications. We sought to compare clinical outcomes in patients with diabetes and high insulin resistance by insulin use status. Data from NHANES (2001-2010) was used for this study. Of the 52,195 individuals included in the survey, 1,470 were reported to have diabetes with available serum fasting insulin and glucose levels. Of these, 395 were on insulin. Individuals were categorized to have high or low insulin resistance based on HOMA IR being lower or greater than the population median. Outcomes of interest included mortality status, any reported major adverse cardiovascular event (MACE), chronic kidney disease (CKD), and LDL cholesterol levels. Stratified logistic regression were used for all dichotomous variables and survey normal regression was used for LDL. Regressions were adjusted for HbA1c level, demographics, and comorbidities. Results showed that patients with high HOMAIR who were receiving insulin therapy had a significantly greater risk of dying (OR 3.487, p<0.001) and of a MACE (OR 2.756 p=0.003) compared to those not on insulin. The risk of CKD was also increased by taking insulin in the high HOMA IR group. (OR 3.657 p<0.001). In patients with low HOMA IR, receiving insulin did not significantly impact risk for mortality, MACE, or CKD. No significant association was found between patients with high HOMA IR on insulin and LDL levels, however a significant negative correlation was found for LDL levels in the low HOMA IR group on insulin (-14.164 p=0.034).

In conclusion, results of this study suggest that insulin therapy for patients with high insulin resistance may result more harmful than beneficial. Future studies are warranted given the importance of these potential clinical implications.