Prevalence of Insulin Pump Therapy and Its Association with Glycemic Control: Results from the Canadian Study of Longevity in Type 1 Diabetes
Authors: Geneviève Boulet MD1, Elise M. Halpern MSc1, Leif E. Lovblom MSc1, Alanna Weisman MD1, Johnny-Wei Bai BHSc MD (Cand.)1, Devrim Eldelekli BM1, Hillary Keenan PhD2, Michael Brent MD3, Narinder Paul MD4, Vera Bril MD5, David Cherney MD PhD6*, Bruce A. Perkins MD MPH1*. *Co-senior authors
1Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Ontario, Canada.
2Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA.
3Department of Ophthalmology and Vision Sciences, Department of Medicine, University of Toronto, Ontario, Canada.
4Joint Department of Medical Imaging, Division of Radiology, University Health Network, Toronto, Ontario, Canada.
5Division of Neurology, Department of Medicine, University of Toronto, Ontario, Canada.
6Division of Nephrology, Department of Medicine, University of Toronto, Ontario, Canada.
OBJECTIVE: We aimed to determine cross-sectional insulin pump prevalence in a longstanding type 1 diabetes (T1DM) national cohort, its associated factors, and its association with glycemic control.
RESEARCH DESIGN AND METHODS: 305 Canadian participants with ≥50 years of T1DM were administered a comprehensive mail-based questionnaire including acquisition of contemporary laboratory results. Factors associated with pump use and HbA1c were analyzed by linear regression.
RESULTS: The 305 participants had median age 65[59, 71] years, median diabetes duration 54[51, 59] years, and mean HbA1c 7.5 ± 1.1%. Prevalence of pump use was 44% (133/305). Compared to the non-pump subgroup, the pump subgroup had similar HbA1c (7.4±0.9 vs. 7.6±1.2%; p=0.22), but were younger (64[59, 69] vs. 66[60, 73] years, p=0.04), more educated (85 vs. 73% level greater than high school, p=0.01), and had lower insulin requirements (0.47±0.16 vs. 0.56±0.27 U/kg/d, p=0.01). Daily glucose tests (6.0 vs. 4.0), use of carbohydrate ratios (62 vs. 12%), hyperglycemia correction doses (95 vs. 85%), computer data uploads (37 vs. 0%), and continuous glucose monitors (22 vs. 7%) were greater among pump subgroup (p<0.005 for each comparison). In multivariate regression analysis, more frequent daily glucose tests – but not pump therapy or its prescription parameters – was independently associated with lower HbA1c.
CONCLUSION: Though common in those with longstanding T1DM, insulin pump use was not shown to be associated with lower HbA1c. Rather, the key modifiable factor independently associated with better glycemic control was a higher frequency of daily glucose tests.