Factors affecting improved glycaemic control in youth using insulin pumps

Abstract

The purpose of this study was to evaluate factors associated with insulin pump therapy resulting in lower HbA(1c) levels in young people with Type 1 diabetes mellitus. Insulin pumps were downloaded from 150 youth (81 male), ages 5-20 years. Consecutive insulin pump downloads, 3 months apart, were available for 85 (43 male) of the 150 youth and changes in pump use were correlated with changes (≥0.5%, ≥ 6 mmol/mol) in HbA(1c) levels. Using cross-sectional data, lower HbA(1c) values correlated with use of more frequent daily insulin boluses (r=-0.46, P<0.0001) and more frequent blood glucose checks/day (r=-0.35, P<0.0001). Young people with HbA(1c) levels <7.5% (58 mmol/mol) vs. values of 7.5-9.0% (58-75 mmol/mol) or ≥ 9.0% (75 mmol/mol) tested blood glucose more frequently/day (P<0.0001), bolused more frequently/day (P<0.0001), reported more grams of carbohydrates eaten/day (P<0.05) and had a higher per cent bolus insulin/day (P<0.05) compared with the ≥9.0% of youth. Using longitudinal data, 48 of 85 patients had a change in HbA(1c) level of ≥0.5% (6 mmol/mol) between downloads (24 improved). Increased bolus insulin (OR=1.15, P=0.03) and time of temporary basal rate use (OR=1.017, P=0.01) predicted ≥0.5% (6 mmol/mol) decrease in HbA(1c) in logistic regression. This study emphasizes the importance of blood glucose testing, of bolus insulin administration and of an increase in the time of temporary basal rate use in relation to improving glycaemic control.