Randomized trial of infusion set function: steel versus teflon

Abstract

Background: This study compared infusion set function for up to 1 week using either a Teflon(®) (Dupont(™), Wilmington, DE) catheter or a steel catheter for insulin pump therapy in type 1 diabetes mellitus.

Subjects and methods: Twenty subjects participating in a randomized, open-labeled, crossover study were asked to wear two Quick-Set(®) and two Sure-T(®) infusion sets (both from Medtronic Minimed, Northridge, CA) until the infusion set failed or was worn for 1 week. All subjects wore a MiniMed continuous glucose monitoring system for the duration of the study.

Results: One subject withdrew from the study. There were 38 weeks of Sure-T wear and 39 weeks of Quick-Set wear with no difference in the survival curves of the infusion sets. There was, however, a 15% initial failure rate with the Teflon infusion set. After 7 days, both types of infusion sets had a 64% failure rate. Overall, 30% failed because of hyperglycemia and a failed correction dose, 13% were removed for pain, 10% were pulled out by accident, 10% had erythema and/or induration of>10 mm, 5% fell out because of loss of adhesion, and 4% were removed for infection. The main predictor of length of wear was the individual subject. There was no increase in hyperglycemia or daily insulin requirements when an infusion set was successfully used for 7 days (n=25 of 77 weeks).

Conclusions: We found no difference between steel and Teflon infusion sets in their function over 7 days, although 15% of Teflon sets failed because of kinking on insertion. The strongest predictor of prolonged 7-day infusion set function was the individual subject, not the type of infusion set.

FIG. 1.

Survival curves for infusion sets: (A) infusion set failure due to uncorrectable hyperglycemia (when the end point was hyperglycemia [>250 mg/dL] and the meter blood glucose level did not decrease by at least 50 mg/dL an hour after a correction bolus and/or blood ketone levels were greater than 0.6 mmol/L) and (B) for all causes of infusion set failure (uncorrectable hyperglycemia with or without ketonemia, pain, infusion set fell out [loss of adhesion], pulled out accidentally, erythema and induration, and infection). The solid line is the Teflon catheter (Quick-Set [QS]), and the dotted line is the steel needle catheter (Sure-T [ST]).

FIG. 2.

Length of wear in days for all infusions sets worn per subject. Teflon (Quick-Set) sets that failed shortly after insertion because of kinking were excluded. Data are mean±SD values.

FIG. 3.

Sensor glucose and total daily insulin doses for each of the 7 days of infusion set wear when either a Teflon (n=13) or steel (n=12) infusion set was worn for 7 days. Data are mean±SD values. P<0.001 refers to the linear correlation between mean length of wear with the ordered subjects.