Subcutaneous Insulin Pumps: Tighter Control for the Long Run

Continuous subcutaneous insulin infusion (CSII, also called the insulin pump) was developed and became clinically available in the 1970. Most research in this area compared patients who use CSII with those who administer multiple daily injections, and much of the research is confined to children. These studies have documented improvements in acute outcomes, but until now, long-term results in adults have not been reported. A study in Diabetes Technology & Therapeutics fills that void. It reports that adult patients with type 1 diabetes who have CSII pumps maintains lower HbA1c values over a 1-10-year period compared with pre-CSII values.

This retrospective observational study enrolled 200 patients with type 1 diabetes. All participants received their first CSII pump at a single outpatient clinic between January 1998 and December 2012. The researchers reviewed data collected from 3 months before patients received pumps to up to 15 years after.

Patients’ mean age was 35 years, and the average patient had been a diagnosed diabetic for 22 years and used an insulin pump for 6 years.

At the start of the study, patients’ HbA1c averaged 8.7%. Within six months, that value decreased to a low of 7.5%. Average HbA1c increased over time (range, 7.8—8.2%), but was consistently lower than patients’ pre-pump value. The researchers attribute improvements in the study’s early months to high initial adherence to recommended insulin pump practices. In this population, like all others, adherences declines over time.

The greatest reduction in HbA1c level occurred in patients who had the highest pre-pump HbA1c levels (greater than >10%).

Patients who were diagnosed with diabetes more recently (i.e. had a shorter disease duration), had missed appointments, experienced comorbid mental illness, and those who smoked were less likely to have lower HbA1c values.

The researchers conclude that CSII pump therapy maintains lower HbA1c values over 10-years. They write, “Any reduction in HbA1c level is associated with a reduction in risk of microvascular complications. The benefits accrued with insulin pump therapy may be especially significant in this vulnerable population.”