Effect of switching medically vulnerable patients with uncontrolled diabetes from isophane insulin human to insulin glargine.

Purpose: The purpose of this observational study was to determine if switching from isophane insulin human (NPH) to insulin glargine would improve glycemic control in a medically vulnerable population with uncontrolled diabetes.

Methods: A retrospective cohort review of patients' medical records was performed that recorded events occurring between January 1, 2001, and December 31, 2003. The cohort consisted of patients with diabetes in an adult medicine clinic at a county hospital. Patients were included if they were receiving NPH insulin for a minimum of six months and subsequently switched to insulin glargine for a minimum of six months.

Results: The study included 43 patients. There was no significant difference in mean glycosylated hemoglobin (HbA(1c)) between NPH insulin (9.6%) and insulin glargine (9.7%) regimens (p = 0.78, 95% confidence interval, -0.62%, 0.82%). Neither was there a significant difference in the frequency or severity of hypoglycemic episodes between the two treatments. Patients experienced significantly fewer diabetes-associated visits over six months while on insulin glargine. Refill frequency did not differ significantly when patients were receiving NPH insulin versus insulin glargine. When analyzing patient characteristics, those of Hispanic ethnicity experienced HbA(1c) values significantly higher than white patients. Several characteristics were associated with refill frequency.

Conclusion: The results of our study indicate that both NPH- and glargine-based basal insulin regimens result in similar levels of glycemic control in a medically vulnerable population with diabetes, without significant differences in the number or severity of hypoglycemic episodes or in refill frequency.