Impact of transfer from animal-source insulins to biosynthetic human insulin (rDNA E coli) in patients with diabetes mellitus

Abstract

Six hundred forty-eight patients (50.5% men; 49.5% women) with diabetes mellitus on animal-source insulin therapy for at least five years were studied. In this patient population, approximately 68.7% had Type I insulin-dependent diabetes mellitus and 31.3% had Type II noninsulin-dependent diabetes mellitus, nonetheless requiring insulin therapy. Patients were voluntarily transferred from animal-source insulin to biosynthetic human insulin derived by recombinant DNA technology from genetically altered Escherichia coli [human insulin (rDNAE coli)] and were monitored regularly thereafter. At a mean interval of 14 months after transfer to human insulin (rDNAE coli), these patients had gained 0.8 kg in body weight (P less than 0.01). There was a significant decline in systolic (P less than 0.01) but not in diastolic blood pressure. Insulin requirements while on animal-source insulin averaged 47.6 +/- 22.9 U/day (mean +/- SD); this requirement was not significantly different after transfer to human insulin (rDNAE coli) (47.0 +/- 21.2 U/day). The distribution of regular and modified insulin types prescribed did not change after patients were transferred from animal-source insulin to human insulin (rDNAE coli). However, a significant increase in the number of insulin injections from 1.79 +/- 0.59 to 1.96 +/- 0.61 injections/day was observed (P less than 0.001). Fasting glucose levels declined significantly from 202 +/- 87 mg/dl on animal-source insulin to 178 +/- 66 mg/dl on human insulin (rDNAE coli) (P less than 0.001). Postprandial glucose levels (at two hours) also declined from 227 +/- 83 mg/dl to 212 +/- 80 mg/dl. Glycosylated hemoglobin (HbA1c) decreased from 9.57 +/- 2.01% while taking animal insulin to 8.97 +/- 2.00% on human insulin (rDNAE coli) (P less than 0.001) Serum cholesterol and triglyceride levels insulin (rDNAE coli). Serum high-density lipoprotein cholesterol (HDL-cholesterol) levels increased from 54.2 +/- 15.1 mg/dl on animal insulin to 57.2 +/- 15.5 mg/dl on human insulin (rDNAE coli) (P less than 0.001). These data demonstrate that transfer of patients from animal-source insulins to human insulin (rDNAE coli) was associated with: (1) an improvement in glycemic control parameters; (2) a slight increase in the number of insulin injections in some patients, but no overall alteration in insulin requirements; and (3) no adverse trends in indicators of cardiovascular risks, such as serum lipids. Indeed, overall cardiovascular risk may have declined not only as a result of improvement in glycemic control, but also owing to a reduction in systolic blood pressure and an elevation in HDL-cholesterol levels.