Endocrine Abstracts

Aim: Despite multiple dose injections some patients still fail achieving HbA1c target. We aimed to evaluate the effect of sitagliptin add on therapy to multiple dose insulin injections.

Method: Data of 47 (seven males and 40 females) type 2 diabetic patients who had HbA1c over 7% were retrospectively evaluated. They were already treated with premix lispro or aspart insulin (n=28), glargine plus premeal regular or aspart or lispro insulin (n=15), and detemir plus premeal aspart insulin (n=2), and glargine plus premix lispro insulin (n=2) for at least 3 months before sitagliptin add on therapy. The insulin scheme was intensified (glargine plus premeal regular or aspart or lispro insulin (n=32), and detemir plus premeal aspart insulin (n=2), and NPH twice daily plus regular or lispro insulin (n=13)).

Results: The patients were aged 56.26±8.69 years. Mean duration of diabetes was 14.41±7.57 years. Mean BMI 37.75±6.08 kg/m² (28.81–53.78 kg/m²). One patient had sleeve gastrectomy and still continued sitagliptin afterwards. Duration of insulin therapy before sitagliptin therapy ranged between 3 months and 22 years. Before sitagliptin therapy total daily dose was 91.13±34.22 units (32–204 units) (n=46). HbA1c level within 6 months preceding sitagliptin therapy was 9.65±1.70% (7.25–14.37%). Duration of sitagliptin therapy ranged between 1 and 25 months. The patients who used sitagliptin <6 months were the ones who were lost follow-up. Neither of them discontinued sitagliptin due to side effects. Weight change was 3.01 (gain)±3.47 kg (−2.30 to 15.00). Only 43 had follow-up total daily insulin dose data. Mean change was 20.72 units increment±29.86 (−48 to 90 units). According to the available follow-up records, mean HbA1c change was 0.95±1.48% (−4.32 to 2.58%). When data of the patient who had undergone sleeve gastrectomy was deleted, mean weight change was 2.63 (gain)±2.74 kg (−2.30 to 6.60). Mean total daily insulin dose change was 23.90 units increment±30.68 (−48 to 90 units). Mean HbA1c change did not differ significantly (0.93±1.48%; range: −4.32 to 2.58%). HbA1c change was correlated neither with total daily insulin dose change nor with weight change. Total daily insulin dose change also did not correlate with weight change.

Conclusion: Adding sitagliptin to intensive insulin therapy do not cause consistent significant change in terms of weight change, HbA1c change, and total daily insulin dosage change.