Diabetes Care Disparities in Long-standing Type 1 Diabetes in Canada and the U.S.: A Cross-sectional Comparison

Diabetes Care. 2018 Jan;41(1):88-95. doi: 10.2337/dc17-1074. Epub 2017 Nov 8.

Abstract

Objective: To assess national differences in diabetes care and quality of life (QOL) between individuals with long-standing type 1 diabetes (≥50 years) in Canada and the U.S.

Research design and methods: Cross-sectional data from identical surveys administered in the Canadian Study of Longevity in Diabetes and the Joslin Medalist Study, collected in 2013-2016 and 2005-2011, respectively, were compared. Laboratory values and ophthalmic examination were completed by clinical care physicians for Canadians and the Joslin Clinic for Americans. Univariate comparisons and multivariable regression for HbA1c, QOL, insulin pump use, and coronary artery disease (CAD) were performed. Nephropathy, CAD, and peripheral arterial disease (PAD) were self-reported; neuropathy was defined by a Michigan Neuropathy Screening Instrument (Questionnaire component) score ≥3, and proliferative retinopathy was documented from ophthalmic examination. QOL was self-reported on an ordinal scale.

Results: Three hundred sixty-one Canadians and 668 Americans had similar ages (mean 65.78 years [SD 8.67] vs. 66.38 years [7.66], P = 0.27) and durations of diabetes (median 53.00 years [interquartile range 51.00, 58.00] vs. 53.00 years [51.00, 57.00], P = 0.51). Canadians had higher HbA1c (mean 7.53% [SD 1.03] [59 mmol/mol] vs. 7.22% [0.98] [55 mmol/mol], P < 0.0001), lower QOL (36.9% vs. 48.7% with "excellent" QOL, P = 0.0002), and less CAD (29.7% vs. 41.2%, P = 0.0003) and insulin pump use (43.3% vs. 55.6%, P = 0.0002). Other complication rates were similar. Residual differences for Canadians compared with Americans remained after adjustment for age, sex, CAD, PAD, education, and relevant a priori selected variables: 0.28% higher HbA1c (P = 0.0004); and odds ratios of 0.68 (95% CI 0.51, 0.90), 0.46 (0.31, 0.68), and 0.71 (0.52, 0.96) for higher QOL, CAD, and insulin pump use, respectively.

Conclusions: Although Canadians and Americans have similar rates of complications other than CAD, further research is required to understand why Canadians have higher HbA1c levels, lower QOL, and less insulin pump use.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Body Mass Index
  • Canada / epidemiology
  • Coronary Artery Disease / epidemiology*
  • Coronary Artery Disease / prevention & control
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 1 / complications
  • Diabetes Mellitus, Type 1 / drug therapy
  • Diabetes Mellitus, Type 1 / epidemiology*
  • Diabetic Retinopathy / epidemiology*
  • Diabetic Retinopathy / prevention & control
  • Dose-Response Relationship, Drug
  • Female
  • Glycated Hemoglobin A / metabolism
  • Healthcare Disparities*
  • Humans
  • Insulin / therapeutic use
  • Insulin Infusion Systems
  • Longevity
  • Male
  • Middle Aged
  • Peripheral Arterial Disease / epidemiology*
  • Peripheral Arterial Disease / prevention & control
  • Prevalence
  • Quality of Life
  • Surveys and Questionnaires
  • United States / epidemiology

Substances

  • Glycated Hemoglobin A
  • Insulin