Long-term body weight trajectories and metabolic control in type 1 diabetes patients on insulin pump or multiple daily injections: A 10-year retrospective controlled study

Abstract

Background and aims: Overweight/obesity is a clinical concern also in patients with Type 1 diabetes (T1DM). These patients' body weight may vary depending on whether treatment consists in continuous subcutaneous insulin infusion (CSII) or multiple daily injections (MDI), as these treatments lead to different blood glucose control, insulin doses, and eating behaviors. We compared long-term body weight trajectories in persons with diabetes on CSII or MDI regimens.

Methods and results: Annual changes in body weight, HbA1c, and daily insulin doses over 6-10 years were retrospectively analyzed in T1DM adult patients on CSII (n = 90) or MDI (n = 90), strictly matched for sex, age, BMI, and diabetes duration. Mean follow-up was 9.1 ± 1.4 years. Body weight increased linearly (∼0.5 kg per year) throughout the observation period (p = 0.001, repeated measures ANOVA) with no significant difference between the CSII and MDI cohorts (p = 0.74), in either normal-weight or overweight/obese patients. HbA1c over follow-up was lower with CSII than with MDI (p = 0.037), maintaining the initial reduction after starting pump therapy. Insulin doses over follow-up were stably lower than baseline (∼20%) with CSII, while linearly increasing (∼20% from baseline to the end of observation) with MDI (p = 0.002). Mean annual weight changes correlated directly with total insulin dose changes (r = 0.191; p = 0.011) and baseline HbA1c level (r = 0.267; p = 0.001), and inversely with HbA1c changes (-0.173; p = 0.021) and baseline age (r = -0.254; p = 0.001).

Conclusion: T1DM patients on CSII or MDI showed comparable body weight gain over a 10-year follow-up, despite improved glycemic control and decreased insulin doses with CSII.

Keywords: Body weight; HbA1c; Insulin pump; Obesity; Type 1 diabetes.