Insulin Pump Therapy Bests Injection Therapy in Large Study

Marlene Busko

August 19, 2013

Continuous subcutaneous insulin injection (pump therapy) provided better glycemic control with a lower rate of hypoglycemia than therapy with insulin injections, in the largest, longest study of insulin-pump use in children with type 1 diabetes, researchers report.

This observational, case-control study compared 345 children receiving insulin-pump therapy vs 345 children receiving insulin-injection therapy for type 1 diabetes. During follow-up (to 7 years­), the mean HbA1c level was 0.6% lower among patients on insulin-pump therapy than among control patients.

This "mean improvement of 0.6% in HbA1c will be expected to have a significant clinical impact on reducing long-term microvascular complications," senior author Elizabeth A. Davis, MBBS, from Princess Margaret Hospital for Children, Perth, Australia, told Medscape Medical News in an email.

"Pump therapy has now been shown to not only improve glycemic control over 7 years but also [to] reduce hospital admissions with diabetic ketoacidosis and reduce severe hypoglycemia (coma/convulsion) in children with diabetes," she continued. "We believe every child with diabetes [of any age] should be given the opportunity to have access to the insulin pump."

The study was published online August 19 in Diabetologia.

Pump vs Injections

The use of insulin-pump therapy has increased over the past 15 years due to improved pump technology, the availability of insulin analogs, and favorable results from the Diabetes Control and Complications Trial (DCCT), the investigators write.

In 1999, their center, which serves all pediatric patients with diabetes in Western Australia, began offering insulin-pump therapy to suitable patients, as assessed by a multidisciplinary team. The pumps are paid for by private insurance or donations, and the pump supplies are paid for by the Australian government. According to Dr. Davis, about 30% to 35% of the children and adolescents seen in their center are on pump therapy, but few children use continuous glucose monitors, because these are not subsidized.

In Australia, the treatment target for children with diabetes is an HbA1c below 7.5%, as recommended by the International Society for Pediatric and Adolescent Diabetes (ISPAD) guidelines, she added.

Children with diabetes are seen at their center until age 18, when they transition to adult care. Data are entered into the Western Australian Diabetes Database.

The researchers previously reported favorable results from 2-year follow-up of the first 100 children at their clinic who started on insulin-pump therapy.

The current study looked at 345 boys and girls who attended their clinic from 1999 to 2011 and were on insulin-pump therapy and matched them with control children who received either multiple daily injection (MDI) insulin therapy or insulin injections given 2 or 3 times daily.

At baseline, the children had an average age of 11.5 years (range, 2 to 19 years) and a mean HbA1c of 8.0% and had had diabetes for a mean of 4.1 years (range, 6 months to 15.5 years).

Patients With Poor Glycemic Control Benefit From Pump

The mean HbA1c level for patients in the pump cohort dropped to its lowest level, 7.6%, at 3 months, rose to 8.1% at 2 years, and then remained at 7.7% to 8.1% during the rest of the study. The mean HbA1c level for patients in the injection cohort increased from 8.0% to 8.8% at 7 years.

The rate of hypoglycemia dropped from 14.7 to 7.2 events per 100 patients per year with pump therapy but increased from 6.8 to 10.2 events per 100 patients per year with injection therapy. This finding confirms previous studies that showed a reduction in hypoglycemic episodes with pump therapy.

The rate of hospitalization for diabetic ketoacidosis was lower in the pump cohort than in the injection cohort (2.3 vs 4.7 per 100 patients per year) during follow-up.

About 1 in 10 children stopped pump therapy during the study, which was not surprising, according to Davis. Children may want to take a break from intense blood glucose monitoring, they may have body-image issues about being attached to the pump, or they may be cared for by a parent who, as a result of a recent separation/divorce, is unfamiliar with the device.

Among children with an initial HbA1c of 8.5% or greater, those on pump therapy had as much as a 0.9% greater reduction in HbA1c levels than those on injection therapy, for up to 4 years. This shows that, contrary to a common perception, children with poorer glycemic control appear to benefit most from pump therapy, so "clinicians need to note this when considering children for pump therapy," Dr. Davis said.

The authors have reported no relevant financial relationships.

Diabetologia. Published online August 19, 2013. Full text


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