Complications of insulin pump therapy: the effect of insulin preparation.

Complications of insulin infusion pump therapy include ketoacidosis related to interruption of insulin delivery and infected infusion sites. To determine if the type of insulin used in insulin pumps is a factor influencing these complications, we compared the occurrence of inflammation and infection at infusion sites and obstruction of infusion tubing in a 6-mo crossover study of 28 patients using two different insulin preparations. The use of buffered purified pork insulin was associated with less infusion site inflammation (P = 0.0039) and infusion set obstruction (P = 0.0215) than use of unbuffered beef-pork insulin. Infected infusion sites occurred less often with buffered pure pork insulin than with unbuffered beef-pork insulin, but the difference was not statistically significant. We conclude that the type of insulin selected for use in insulin pumps influences the occurrence of adverse reactions to insulin pump therapy: buffered purified pork insulin is associated with less infusion site inflammation and infusion set obstruction than unbuffered beef-pork insulin.

Factors related to discontinuation of continuous subcutaneous insulin-infusion therapy.

To determine the factors related to discontinuation of continuous subcutaneous insulin-infusion (CSII) therapy in patients with insulin-dependent diabetes mellitus, we analyzed clinical data from a group of 177 patients followed for up to 5 yr. Fifty-one (29%) of the patients made a decision to terminate CSII during the study. Of the clinical characteristics present before the onset of treatment with an insulin pump, the most important variable to predict a future decision to terminate CSII was pregnancy, followed by female gender. In addition, there was a greater percentage of smokers, single or divorced patients, and patients with a history of treatment for mental illness in the dropout group, although none of these differences was statistically significant. There was no correlation between discontinuation of CSII and age, duration of diabetes, or prepump concentrations of HbA1c. Events occurring during CSII were also analyzed for predictive value. Patients who discontinued CSII had a higher incidence of ketoacidosis and a lower incidence of hypoglycemic coma while using a pump. The most common reason reported by patients for terminating CSII therapy, cited by 24 (47%) of the 51, was discomfort, irritation, or infection at the infusion site.

Malfunction of continuous subcutaneous insulin infusion systems: a one-year prospective study of 127 patients.

Malfunction of portable continuous subcutaneous insulin infusion (CSII) systems may result in either ketoacidosis or serious hypoglycemia. To determine the types and frequencies of infusion system failure and the resulting clinical consequences, we recorded their occurrences in a 1-yr prospective study of 127 patients who were using insulin infusion pumps in a clinical practice setting. Of the 127 patients, 109 (86%) experienced at least one infusion system failure during the study. Most of the infusion system failures (96%) occurred in the syringe, infusion tube and connections, or subcutaneous infusion site. Virtually all malfunctions resulted in interruption of insulin flow, and most were associated with temporary loss of diabetes control. Equipment malfunction was documented in 6 of 7 patients who used insulin pumps and were treated in our hospital for diabetic ketoacidosis during the study. Pump "runaway" was not observed. We conclude that infusion system malfunction resulting in interruption of insulin flow is a common occurrence, is often associated with temporary hyperglycemia, and may account for some of the increased incidence of diabetic ketoacidosis previously described in these patients.

Long-term metabolic control with insulin pump therapy. Report of experience with 127 patients.

To determine the long-term efficacy of insulin-pump therapy, we analyzed trends in glycosylated hemoglobin concentrations in 127 patients with Type I diabetes using insulin pumps for periods ranging from 13 to 47 months. In the first year of pump therapy the average glycosylated hemoglobin concentration improved in 83 per cent of the patients, as compared with the value before pump therapy. Although only 11 of the 127 subjects had normal glycosylated hemoglobin values before pump therapy, 33 had a normal average value during the first full year of pump use (P = 0.0001). This favorable trend persisted for the three-year duration of the study. Seventeen of the 19 patients who subsequently discontinued insulin-pump therapy had improved glycosylated hemoglobin values during the period of pump use. Eleven of the 19 patients remained available for follow-up study; the glycosylated hemoglobin concentration became worse in 7 when they returned to conventional treatment. We conclude that the improvement in metabolic control repeatedly demonstrated in short-term studies with the insulin pump can be maintained for a period of years.