Observational Study of the Impact of Infusion Set Replacement in Insulin Pump Users on Glycemic Management

Abstract

Background: Although several studies have evaluated the impact of prolonged infusion set use in insulin pump users on glycemic management with the use of continuous glucose monitoring (CGM), real-world assessments without intervention have been unavailable.

Methods: This retrospective observational study recruited individuals with type 1 diabetes who received insulin pump therapy with real-time CGM. Insulin pump and CGM logs were extracted from the Medtronic CareLink system, and a dataset was constructed programmatically, counting tracking days from infusion set replacement every 24 hours up to day 4. The primary outcome was mean sensor glucose (SG) level, and the impact of infusion set usage duration on glycemic management was assessed.

Results: The study enrolled 45 individuals with a median age of 40 (interquartile range = 32-51) years and median body mass index of 22.5 (21.2-23.8) kg/m². Mean SG was significantly higher on day 4 (median of 151.9 [136.5-173.7] mg/dL) than on day 2 (144.4 [124.0-162.9] mg/dL, P = .024). Similarly, time above range (TAR), time in range (TIR), and time in tight range (TITR) had worsened on day 4 compared with day 2. The TAR increased from a median of 22.0% (7.3%-35.8%) on day 2 to 27.6% (17.7%-44.9%) on day 4, whereas TIR decreased from 74.2% (59.9%-87.1%) to 66.5% (52.0%-79.8%) and TITR decreased from 47.6% (37.1%-67.5%) to 42.2% (34.6%-54.1%).

Conclusions: Our evaluation of the real-world impact of prolonged infusion set use revealed an association between longer use and worsening of glycemic management.

Keywords: continuous glucose monitoring; infusion set; insulin pump therapy; observational study; type 1 diabetes.

Figure 1.

Overview of data analysis workflow. Abbreviation: rtCGM, real-time continuous glucose monitoring.

Figure 2.

Derivation of the study population. Abbreviation: T1D, type 1 diabetes; rtCGM, real-time continuous glucose monitoring.

Figure 3.

Changes in continuous glucose monitoring metrics and insulin dose across different days of infusion set wear: (a) mean sensor glucose, (b) standard deviation (SD) of sensor glucose, (c) coefficient of variation (%CV), (d) total daily dose of insulin (TDD), (e) time above range (TAR), (f) time in range (TIR), (g) time in tight range (TITR), and (h) time below range (TBR). Data are presented as box-and-whisker plots, with the boxes indicating median and upper and lower quartile values and the whiskers indicating the range excluding outliers. Outliers are defined as data points beyond 1.5 times the interquartile range from the upper or lower quartiles and are shown as individual points. *P < .05 (post hoc analysis).

Figure 4.

The median and interquartile range of the hyperglycemia component and hypoglycemia component on days 1, 2, 3, and 4: (a) all participants, (b) the hemoglobin A_1c ≥7% group, and (c) the hemoglobin A_1c <7% group. Zones A to E were defined based on a previously published study. Abbreviation: GRI, glycemia risk index.

Figure 5.

Changes in continuous glucose monitoring metrics and insulin dose across different days of infusion set wear stratified by hemoglobin A_1c level (≥7% [shaded boxes] vs <7% [open boxes]): (a) mean sensor glucose, (b) standard deviation (SD) of sensor glucose, (c) coefficient of variation (%CV), (d) total daily dose of insulin (TDD), (e) time above range (TAR), (f) time in range (TIR), (g) time in tight range (TITR), and (h) time below range (TBR). Data are presented as box-and-whisker plots, with the boxes indicating median and upper and lower quartile values and the whiskers indicating the range excluding outliers. Outliers are defined as data points beyond 1.5 times the interquartile range from the upper or lower quartiles and are shown as individual points. *P < .05 (post hoc analysis).