[Switching of NPH insulin to glargine therapy in a cohort of diabetic patients: observational study]

Outcomes with insulin glargine in patients with type 2 diabetes previously on NPH insulin: evidence from clinical practice in Spain

AIM

We evaluated the effectiveness of insulin glargine (glargine)-based regimens in patients with type 2 diabetes mellitus (T2DM) in clinical practice in Spain.

METHODS

This was a retrospective, registry-based study of 1482 patients treated with neutral protamine Hagedorn (NPH) who were either switched to glargine or maintained on NPH at investigators' discretion. The primary outcomes were HbA(1c) change over a period of 4-9 months follow-up and incidence of hypoglycaemia.

RESULTS

Prior to switching treatment, mean ± standard deviation HbA(1c) was worse in the glargine vs. the NPH group (8.3 ± 1.2% vs. 7.9 ± 1.1% respectively; p < 0.0001). After 4-9 months of treatment, mean reductions in HbA(1c) were greater with glargine vs. NPH (-1.0 ± 1.0% vs. -0.2 ± 0.8% respectively; p < 0.0001) and the incidence of hypoglycaemia in the month prior to the study visit was lower (21.8% vs. 47.6% respectively; p < 0.0001). An expected reduction in dosing frequency, as well as in the basal insulin dose was reported for glargine vs. NPH, with 97.3% of glargine-treated patients on once-daily injections and 81.2% on NPH receiving twice-daily therapy. Improvements in treatment satisfaction were significantly higher with glargine (p < 0.0001).

CONCLUSIONS

In a Spanish clinical practice setting, patients with T2DM who switched to glargine from NPH experienced significantly greater reductions in mean HbA(1c) and a lower incidence of hypoglycaemia than patients maintained on NPH.

Clinical experience with insulin glargine in type 1 diabetes

The Diabetes Control and Complications Trial (DCCT) demonstrated the importance of optimal glycemic control achieved through intensive insulin therapy in reducing the microvascular complications associated with type 1 diabetes. However, the DCCT, which was conducted prior to the availability of insulin analogs, also reported a significant increase in severe hypoglycemia with intensive versus conventional therapy. Insulin analogs were developed to aid patients in achieving better diabetes control by providing insulins with optimized pharmacokinetic and pharmacodynamic characteristics. Insulin glargine was the first long-acting insulin analog with a 24-h duration of action, offering once-daily injection, and has now been in clinical use for over 10 years. The authors performed a systematic search of EMBASE, MEDLINE, and Web of Science (Science Citation Index) to determine the efficacy of insulin glargine in type 1 diabetes in basal-bolus insulin regimens. Randomized controlled trials have demonstrated that glycemic control with insulin glargine is at least comparable to that with neutral protamine Hagedorn (NPH) insulin in adults and in children and adolescents, and with continuous subcutaneous insulin infusion in adults. However, these same trials show a significantly lower risk for hypoglycemia with insulin glargine compared with NPH insulin in adults.

Improved glycaemic control by switching from insulin NPH to insulin glargine: a retrospective observational study

Background

Insulin glargine (glargine) and insulin NPH (NPH) are two basal insulin treatments. This study investigated the effect on glycaemic control of switching from a NPH-based regimen to a glargine-based regimen in 701 patients with type 1 (n= 304) or type 2 (n= 397) diabetes, using unselected primary care data.

Methods

Data for this retrospective observational study were extracted from a UK primary care database (The Health Improvement Network). Patients were required to have at least 12 months of data before and after switching from NPH to glargine. The principal analysis was the change in HbA_1c after 12 months treatment with glargine; secondary analyses included change in weight and total daily insulin dose. Inconsistent reporting of hypoglycemic episodes precludes reliable reporting of this outcome. Multivariate analyses were used to adjust for baseline characteristics and confounding variables.

Results

After adjustment, both diabetic cohorts showed statistically significant reductions in mean HbA_1c 12 months after the switch, by 0.38% (p < 0.001) in type 1 patients and 0.31% (p < 0.001) in type 2 patients. Improvement in HbA_1c was positively correlated with baseline HbA_1c; patients with baseline HbA_1c ≥ 8% had reductions of 0.57% (p < 0.001) and 0.47% (p < 0.001), respectively. There was no significant change in weight or total daily insulin dose while on glargine. The majority of patients received a basal-bolus regimen prior to and after the switch (mean 79.3% before and 77.2% after switch in type 1 patients, and 80.4% and 76.8%, respectively in type 2 patients, p > 0.05).

Conclusion

In routine clinical practice, switching from NPH to glargine provides the opportunity for improving glycaemic control in diabetes patients inadequately controlled by NPH.