Study suggests insulin analogs pose lower CV risk than human insulin
According to a study published in the journal Therapeutic Advances in Endocrinology and Metabolism, insulin analogs (IAs) have lower cardiovascular (CV) risk compared to human insulin (HI) in patients with type 1 diabetes mellitus (T1DM). [2017;8(11):149–157]
There are retrospective observation studies on the influence of different IAs on CV risk in patients with type 2 diabetes mellitus (T2DM), but none on T1DM. As such, this study is the first of its kind. Type 1 diabetics with impaired renal function—defined as estimated glomerular filtration rate of less than 90 mL/min—had lower CV complication rates when treated with IAs compared to those treated with HI and HI/IA (25 percent vs 28 percent vs 38 percent, p=0.06). The finding is similar for type 1 diabetics without renal impairment.
The borderline significance may be due to several factors. For instance, the mean treatment duration with IA—3 years—may be too short for the detection of the influence of these insulins on macroangiopathic complications. Another reason could be the low incidence rate of CV events in the younger T1DM patients.
Another interesting study finding was that complication rates were the lowest with insulin lispro (5.9 percent) and lispro/glargine (16 percent). However, the CV risk difference in types of IA used was not statistically significant, the authors wrote.
Demographic and clinical data from 509 patients with T1DM were analyzed. All patients received treatment in an outpatient clinic from 2006 to 2012. The researchers studied the association between type of insulin therapy and prevalence of CV complications; the CV complications that were studied were coronary heart, cerebrovascular and peripheral arterial diseases.
The study findings were consisted with the finding from studies involving patients with type 2 diabetes; treatment with IA is associated with lower CV risk, compared with HI. The mechanism for the CV protective influence of IA in diabetes is still unclear. One possible explanation is that short-acting IAs cause decreased glycaemic variability, leading to a reduction in oxidative stress for blood vessels and improved endothelial function.
There were four limitations in the study. First, the participants were assigned to the diabetes outpatient clinic or diabetic day clinic from general medical or diabetes centres. This could have led to a selection bias. Second, treatment duration with respective IAs could not be exactly as defined in the study. Third, factors that influence the development of macroangiopathic complications such as cigarette and alcohol consumption, were not systematically recorded. Lastly, the cross-sectional nature of the study design. As such, further research in confirmative, prospective studies is necessary to translate the findings into clinical practice, the authors concluded.