Alpha and Beta Cell Dysfunction Improves With Effective Insulin Therapy in Treatment Naive Type 2 Diabetes - a Prospective Observational Study

Abstract: Type 2 diabetes mellitus is characterized by insulin resistance and progressive beta cell decline. Elevated glucagon levels and impaired incretin axis also contribute to the poor glycemic status. Early intensive glycemic control, reduces long-term vascular complications and may preserve β-cell function. Clinical studies of effect of early insulin therapy on combined alpha and beta cell function are lacking. Objective: To determine the effect of early insulin therapy on combined alpha and beta cell dysfunction (islet cell dysfunction) in newly diagnosed type 2 diabetes. Methods: 56 newly diagnosed type 2 diabetes patients, attending the endocrinology OPD at a tertiary teaching hospital were enrolled in this treatment related follow up study after institutional ethical committee clearance, conducted between May 2017 to December 2018. Patients with HbA1C > 8.5% to <12.5% (n=56) were included in the study. Metabolic (FPG, PPG, HbA1c), and Hormonal parameters (plasma glucagon levels,fasting and 2 hour mixed meal stimulated C peptide and levels) were assessed both at baseline and after 6 months of insulin treatment. Initiating dose of insulin was 0.5 U/kg/day and the dose was titrated according to FPG and 2 hr PPG in order to maintain glycemic goals as per ADA standards. Results: The study included 56 subjects with mean age of 41.24 ± 5.64 years and a mean BMI of 25.5 kg/m(2). At the end of 6 months of the study, a significant reduction in the mean FPG, PPG, HbA1C were observed,[FPG (139±14.47 mg/dl), PPG (179.89 ± 19.42mg/dl),HbA1c (7.54± 0.63%)] as compared to baseline mean FPG, (216.30 ± 42.35 mg/dl),2 hour PPG (338.44 ±62.89 mg/dl), HbA1C (10.39 ± 1.56 %) (p <0.001). Baseline glucagon levels were high (197.68± 49.09 pg/ml), and were significantly reduced at 6 months of insulin therapy (107.06±49.09 pg/ml).(p <0.001). In comparison to the baseline a significant increase in both fasting (0.73±0.27 ng/ml) and stimulated c-peptide (1.54±1.02 ng/ml) (p<0.001) levels was observed at end of the study. Conclusion: Combined alpha and beta cell (Islet) dysfunction prevails in newly diagnosed T2DM. And early insulin therapy significantly improves both these defects. The documentation of this novel beneficial effect on islet cell dysfunction in our study strengthens the concept of early insulin therapy in newly diagnosed Type 2 diabetes patients.