Trends in cardiovascular risk factor management in type 1 diabetes by sex

Abstract

Aims

DCCT showed that intensive type 1 diabetes management reduces complication incidence but did not focus on other cardiovascular disease risk factors, whose control in type 1 diabetes has not been well-studied. We assessed trends in cardiovascular risk factors in type 1 diabetes and attainment of concurrent American Diabetes Association (ADA) guidelines/recommendations (for HbA1c, blood pressure, LDL cholesterol, triglycerides) for complication prevention.

Methods

Individuals with childhood-onset type 1 diabetes (n = 658; 49.4% women; baseline (1986–1988) median age 27 and duration 19 years) were followed biennially for up to 25 years, with surveys and/or examinations.

Results

At the latest recorded follow-up, achievement of concurrent ADA recommendations increased for HbA_1c (from 9.7 to 25.6%, p < .0001); was unchanged for blood pressure (from 89.7% to 87.4%, p = .36); and decreased for LDL cholesterol (from 62.3 to 39.7%, p < .0001). Adoption of intensive insulin therapy (from 5.9 to 64.4%, p < .0001) and hypercholesterolemia (from 67.3 to 78.9%, p = .0006) also increased. Overall, the proportion meeting all four recommendations was essentially unaltered (from 6.8% to 7.6%) (p = .69). Results were similar by gender.

Conclusions

Although the adoption of intensive insulin therapy and obtaining ADA HbA_1c recommendations are increasing, overall cardiovascular risk factor compliance remains low and merits further intervention.

Introduction

The incidence of type 1 diabetes continues to increase annually¹ and with that comes a growing concern for the burden posed by diabetes-associated microvascular and macrovascular complications.² Increased risk of cardiovascular disease (CVD) has been repeatedly recognized as a complication of type 1 diabetes, and recent data still suggest a 10-fold greater risk.³ There are multiple modifiable risk factors, such as HbA_1c, blood pressure, lipids, smoking, and obesity, which can be intervened upon to reduce CVD risk in type 1 diabetes.⁴ Indeed, results from the Diabetes Control and Complications Trial (DCCT) demonstrated that intensive management of hyperglycemia greatly reduces the development and progression of micro⁵- and macro-vascular⁶ disease in type 1 diabetes, transforming care for these individuals. Unfortunately, years after the advent of intensive insulin therapy, the rates of CVD are still higher in type 1 diabetes compared to the general population, suggesting that tighter control of non-glycemic factors might be beneficial. However, to what extent improvements in cardiovascular risk factor control have occurred in the general type 1 diabetes population and whether they may differ between men and women, is not clear. An earlier study suggested poor adherence.⁷ In the present study, we aimed to assess trends in CVD risk factors among men and women over the 25-year follow-up of a cohort study of individuals with childhood-onset type 1 diabetes.

For >20 years, the American Diabetes Association (ADA) has disseminated key recommendations for diabetes care standards and guidelines in an attempt to improve management.⁸ Understanding how well these guidelines are attained may give insight into what areas of care are needed to potentially reduce the continuing high CVD rates. We therefore aimed to determine the proportion of individuals within this type 1 diabetes cohort falling within the guidelines set by the ADA for the prevention and management of diabetes complications. We additionally assessed trends over time in the proportions adopting intensive insulin therapy as well as in the proportions of overweight/obesity, hypercholesterolemia and hypertension, given their close interrelation with ADA goal attainment.