The association between uncontrolled hyperglycemia (Type-2 Diabetes) and cardiovascular sequelae in patients with and without insulin

Introduction

Despite the availability of new cardio-protective oral hypoglycemic drugs, insulin is often recommended as an add-on therapy for type-2 diabetes with hemoglobin A1C (HbA1C) ≥ 9. Introducing insulin as a choice for patients with uncontrolled hyperglycemia (HbA1C≥9) has been questionably associated with cardiovascular sequelae. This study aims to examine the association between insulin use and cardiovascular effects in type-2 diabetic patients with uncontrolled hyperglycemia.

Methodology

A retrospective observational cohort study was conducted to identify cardiovascular complications between the two groups (patients with HbA1C≥9% on insulin versus those with HbA1C≥9% without insulin) at King Saud University Medical City (KSUMC). Patients with type-2 diabetes whose HbA1C was ≥ 9 during the period from 2015 to 2018 and who were followed up within the hospital for at least 5 years until the end of 2022 were included in the study.

Results

A total of 366 patients were included in the study; 286 patients were on insulin, while 80 patients were not. The median baseline HbA1C levels were comparable between the two groups (10.2 versus 9.8). After 5 years of follow-up, there was no significant difference between the groups (29.4 % of insulin users versus 18.8 % of non-insulin users; p = 0.065). However, the incidence of other diabetes complications, such as retinopathy, nephropathy, and neuropathy, was significantly higher among patients who were on insulin compared to those not on insulin (50.7 % versus 27.5 %; p = 0.005). Additionally, the average of the last three HbA1C readings and the overall average HbA1C readings were significantly higher among patients who were on insulin (9.67 % versus 9.07 %; p = 0.001) compared to those not on insulin (9.64 % versus 9.11 %; p = 0.005).

Conclusion

Our study did not find a significant association between the use of insulin and cardiovascular complications. The association between insulin therapy and the development of other diabetes complications warrants further investigation.