Endocrine Abstracts

Background: Weight gain in type 1 diabetes (T1D) patients has become a clinical problem due to less strict diets and more stringent glycemic targets. Thus, the number of overweight T1D in the USA increased from 3.4% in 1988 to 22.7% in 2007. Hyperinsulinism is involved in the genesis of obesity but in T1D, the impact of insulin therapy in weight gain is not established. Islet transplantation, now reimbursed in France, makes it possible to interrupt insulin. The aim of this work was to study weight evolution in an islet-transplanted population after obtention of insulin-independence and to determine the weight predictive factors.

Methods: monocentric retrospective study comparing the evolution of anthropometric and metabolic parameters before and 1, 3, 5 and 10 years after islet transplantation alone performed between 2003 and 2017, in 41 patients.

Results: The population (21 women, 20 men), aged (median (IQR)) 48 (42-55) years, had a weight of 71.4 (66-78) kg, a BMI of 24.7 (22.9-26) kg/m², a body fat percentage (DEXA) of 26.3 (20.0-31.5) %, and a daily insulin requirement of 41.3 (30.5-47.0) IU/day. The median weight loss at 1, 3, 5 and 10 years was 6.6 (P=0.003), 4.9 (P=0.007), 5.0 (P=0.043), and 5.4 kg (P=0.418) respectively, and correlated with the decrease in insulin doses (r²=0.295; P=0.0005) at 5 years. In the 18/41 patients with a pre-transplantation BMI >25 kg/m², 10-year weight loss was permanent, unlike in the 23/41 patients with pre-transplantation normal BMI. The glycemic balance was identical between the 2 groups.

Conclusions: A weight loss is observed with islet transplantation, more marked in initially overweight subjects and correlated with the insulin dose decrease. These results suggest a role of exogenous insulin therapy in the weight gain of T1D patients, that is likely to limit their access to islet transplant, since a BMI below 28-30 is usually required is a favorable factor to gain insulin-independence after islet transplantatin. The latter, however, could be modulated by the level of insulin-sensitivity.