Impact of Bolus/Basal Insulin Ratio on HbA1c and Lipid Profile in Adult Patients with Type 1 Diabetes Mellitus.

Objective: To evaluate the existence of any relationship between the bolus/basal (B/b) insulin ratio and HbA1c and lipid profile in patients with Type 1 Diabetes mellitus (T1DM) on a basal-bolus treatment regimen.

Study design: Retrospective observational study. Place and Duration of the Study: University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey, from January 2015 to March 2020.

Methodology: This retrospective-observational study included 181 adult patients with T1DM. They were divided into two groups with <1.5 and ≥1.5 B/b insulin ratios, and the parameters were compared.

Results: The subjects comprised 94 females and 87 males with a mean age of 30.1 ± 9.2 years. Microvascular complications and dyslipidaemia were found in 30.9% and 68.5% of the patients, respectively. B/b insulin ratio of ≥1.5 was observed in 65.1% of the patients. The HbA1c level was <58 mmol/mol in 11.6% of the patients. A positive correlation was found between the B/b insulin ratio and HbA1c level. Fasting Plasma Glucose (FPG) and HbA1c levels were higher in those with ≥1.5 B/b insulin ratio. The rate of patients who reached the optimal HbA1c level was 3.57-fold lower in those with ≥1.5 B/b ratio.

Conclusion: A higher B/b insulin ratio was associated with higher HbA1c levels in patients with T1DM treated with intensive insulin therapy. Prospective studies are needed to define a causal relationship between the B/b insulin ratio, glycaemic parameters, and lipid profile.

Key words: Bolus/basal insulin ratio, Type 1 Diabetes mellitus, HbA1c, Low-density lipoprotein, Lipid profile.