Efficacy of Thrice-daily versus Twice-daily Insulin Regimens on Glycohemoglobin (Hb A1c) in Type 1 Diabetes Mellitus: A Randomized Controlled Trial

Abstract

Objectives: To improve glycemic control and prevent late complications, the patient and diabetes team need to adjust insulin therapy. The aim of this study is to evaluate the efficacy of thrice-daily versus twice-daily insulin regimens on HbA1c for type 1 diabetes mellitus by a randomized controlled trial in Hamedan, west of Iran.

Methods: The study included 125 patients under 19 years of age with type 1 diabetes mellitus over a 3-month period. All patients with glycohemoglobin (HbA1c) ≥8% were followed prospectively and randomized into two trial and control groups. The control group received conventional two insulin injections per day: a mixture of short-acting (regular) + intermediated acting (NPH) insulins pre-breakfast (twice daily), and the trial group was treated by an extra dose of regular insulin before lunch (three times daily). Main outcome measure was HbA1c at baseline and at the end of 3 months. The mean blood glucose level and number of hypoglycemia were recorded. All patients underwent monthly intervals follow up for assessing their home blood glucose records and insulin adjustment.

Results: Overall, 100 patients completed the study protocol. 52% were females, mean ±SD of age of 12.91 ± 3.9 years. There were no significant differences in baseline characteristics including age, gender, pubertal stage, adherence to diet, duration of disease and total daily insulin dose (p>0.05). There was a significant decrease individually in both groups in HbA1c level (p<0.05), but there was no significant difference in HbA1c reduction in patients on twice-daily insulin injections and those on thrice-daily insulin injection groups (1.12 ± 2.12 and 0.98±2.1% respectively, p>0.05).

Conclusion: Compared with twice daily insulin, a therapeutic regimen involving the addition of one dose regular insulin before lunch caused no significant change in the overall glycemic control of patients with type 1 diabetes mellitus. Our results emphasize that further efforts for near normoglycemia should be focused upon education of patients in terms of frequent outpatient visits, more blood glucose monitoring and attention to insulin adjustments.

Keywords: HbA1C; Type 1 diabetes mellitus; insulin.