Objective: To evaluate the safety and effectiveness of insulin pump therapy in children and adolescents with type 1 diabetes.
Research Design and Methods: All 95 patients who began insulin pump therapy at Johns Hopkins Hospital between January 1990 and December 2000 were included in the study. The mean age was 12.0 years (range 4-18), and 29% of the patients were <10 years old. Data were obtained by chart review beginning 6-12 months before pump start. The median duration of follow-up was 28 months.
Results: There was a small but significant decrease in HbA1c at 3-6 months after pump start (7.7 vs. 7.5%; P = 0.03). HbA1c levels then gradually increased and remained elevated after 1 year of follow-up; however, this association was confounded by age and diabetes duration, both of which were associated with higher HbA1c levels. After adjusting for duration and age, mean HbA1c after pump start was significantly lower than before pump start (7.7 vs. 8.1%; P < 0.001). The number of medical complications (diabetic ketoacidosis, emergency department visits) was similar before and after pump start. There were fewer hypoglycemic events after pump start (12 vs. 17, rate ratio 0.46, 95% CI 0.21-1.01).
Conclusions: This study suggests that pump therapy is safe and effective in selected children and adolescents with type 1 diabetes.
Continuous subcutaneous insulin infusion, or insulin pump therapy, has been used to treat diabetes since the late 1970s. Since the completion of the Diabetes Control and Complications Trial in 1993 and the introduction of lispro insulin in 1996, children and adolescents with diabetes, and their parents, have increasingly requested insulin pump therapy as an alternative to insulin injections. The Johns Hopkins Pediatric Diabetes Program has been using insulin pumps with children since the early 1980s.
The theoretical advantage of insulin pump therapy is its ability to mimic physiological insulin release and meet physiological insulin needs in people with insulin deficiency. The basal and bolus functions of the pump allow separate determination and adjustment of both these insulin requirements and also allow flexibility in timing and amounts of nutritional intake and physical activity, allowing for wide variations in lifestyle. In addition, use of short-acting insulin makes coverage of the early-morning glucose rise ("dawn phenomenon") possible, eases sick-day management, and matches nutrient absorption more physiologically, thereby reducing the risk of hypoglycemia.
Prior studies of pump users show a high degree of satisfaction, and most show a decreased risk of severe hypoglycemia. However, previous studies are mixed regarding safety and effectiveness. Some show a decrease in HbA1c, whereas others show no durable improvement. Some report that HbA1c improved in the first few months but returned to prepump status after 1 year. Some show an increased risk of diabetic ketoacidosis (DKA) and BMI. The inconsistency in the literature may be due in part to small sample sizes, short follow-up periods, and a failure to account for confounding factors.
Therefore, we reviewed data in our insulin pump population to evaluate safety and efficacy in children and adolescents and to identify predictors of metabolic control. We hypothesized that pump therapy would improve glycemic control without an increased risk of hypoglycemia or DKA.