CME Author: Zeena Nackerdien
Study Authors: Joshua J. Joseph, Aleena Bennett, et al.; Hareld Kemps, Nicolle Kränkel, et al.
Target Audience and Goal Statement:
Endocrinologists, cardiologists, and primary care physicians
The goal was to learn whether ideal cardiovascular health (CVH) is linked to lower diabetes risk across all glycemic levels, to explore racial differences, and to understand the role of exercise in heart disease and diabetes.
The following questions were addressed in this review of two papers:
- Does the association of ideal CVH with lower diabetes risk vary based on glycemic status (normal fasting vs impaired fasting glucose or IFG)?
- Was there a difference in the magnitude of ideal CVH components with lower diabetes risk among African-Americans versus whites?
- What are expert recommendations about implementation of a behavioral modification, such as exercise, in patients with both diabetes and heart disease?
Synopsis and Perspective:
Seven steps to ideal CVH were summarized by the American Heart Association (AHA) with “Life’s Simple 7” — manage blood pressure (BP), control cholesterol, reduce blood sugar, get active, eat better, lose weight, and stop smoking.
Improving factors beneficial to heart health can also lower the risk for diabetes; however, “recent analyses challenged the notion whether association of ideal CVH with diabetes risk differed for participants with higher levels of diabetes risk (i.e. IFG, African-Americans) compared with participants at lower baseline risk (i.e. normal fasting glucose, whites),” according to Joshua Joseph, MD, of Wexner Medical Center at the Ohio State University in Columbus, and colleagues in Diabetologia.
The authors embarked on a secondary analysis of data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study to assess whether whether the link between ideal CVH with diabetes risk differed for participants with higher levels of diabetes risk (IFG of 5.6-6.9 mmol/L, African-Americans) compared with participants at lower baseline risk (normal fasting glucose of <5.6 mmol/L, whites).
Data on stroke risk factors, sociodemographic, lifestyle, and psychosocial characteristics were collected from more than 30,000 African-American and white adults, ages ≥45, enrolled in the REGARDS study. The primary endpoint of the current secondary analysis was incident diabetes, defined as fasting glucose ≥7 mmol/L, non-fasting glucose ≥11.1 mmol/L, or diabetes medication use at the follow-up examination in those without prevalent diabetes at baseline.
“Baseline cholesterol, blood pressure, diet, smoking, physical activity and body mass index (BMI) were used to categorize participants based on the number (0-1, 2-3, and ≥4) of ideal CVH components,” according to the authors.
They found 891 incident diabetes cases among 7,758 participants (mean age 63, 56% female, 73% white, 27% African-American) without diabetes at baseline (2003-2007) followed over 9.5 years. Only 27.9% of the REGARDS participants had four or more out of seven ideal CVH metrics. As in other studies, African-American participants in the REGARDS cohort had a lower prevalence of ideal CVH at baseline versus white participants (17.2% vs 31.8%).
Participants with normal fasting glucose who practiced at least four of the “Simple 7” AHA behaviors (n=6,004) had a 80% lower risk of diabetes (risk ratio [RR] 0.20, 95% CI 0.10-0.37) compared with a subgroup with IFG at baseline (n=1,754) who had 13% lower risk (RR 0.87, 95% CI 0.58-1.30).
Joseph and colleagues stated that “the association of ideal CVH components with lower diabetes risk was stronger among whites than African-American participants (P=0.0338 for interaction). Racial differences were not evident for physical activity and dietary intake, but were noted for BP and BMI. In the latter two instances, ideal compared with poor levels of each were linked with lower diabetes risks among whites versus African-American participants, respectively:
- BP: 69% vs 37%, P=0.0194
- BMI: 81% vs 66%, P=0.0309
Study limitations included reliance on self-reports for diet and physical activity, possible misclassification of dietary data, lack of physical activity duration, genetic susceptibility measurements, and the inability to distinguish between type 1 and type 2 diabetes. However, given the rarity of type 1 diabetes in the age range of the study participants, the authors assumed a predominance of type 2 diabetes.
Source Reference: Diabetologia, Jan. 15, 2019; DOI: 10.1007/s00125-018-4792-y; European Journal of Preventive Cardiology, Jan. 14, 2019; DOI: 10.1177/2047487318820420
Study Highlights: Explanation of Findings
The study demonstrated that higher levels of CVH were linked with a lower risk of dose-dependent diabetes, particularly among people with normal fasting glucose at baseline; however, this association was not observed among those with IFG. Strengths of the study included longitudinal analysis of a large, biracial population-based cohort over the course of nearly a decade.
“These findings suggest population-level public health promotion of the AHA 2020 ideal CVH metrics may be beneficial for primordial prevention of diabetes, but may not be as beneficial for preventing progression to diabetes from impaired fasting glucose,” the authors said. “The lower magnitude of risk reduction with ideal CVH among those with impaired fasting glucose warrants further investigation and suggests this group requires higher intensity interventions to lower long-term diabetes risk.”
Overall, an important implication of the study is that prevention efforts must be initiated early, Joseph said in a statement. “Healthy people need to work to stay healthy,” he said. “Follow the guidelines. Don’t proceed to high blood sugar and then worry about stopping diabetes. By that point, people need high-intensity interventions that focus on physical activity and diet to promote weight loss and, possibly, medications to lower the risk of diabetes.”
While a “risk plateau” was reached in the last 2 decades for whites, the authors were concerned over the lower magnitude of diabetes risk-lowering with ideal CVH in African Americans — one reason for the continued increase in incident diabetes in this racial group. Hormonal actions underlying hypertension and diabetes, such as aldosterone, may differ in African-American versus white participants.
“Given the high rates of hypertension and diabetes among African-Americans, further research exploring mechanistic links explaining pathophysiological racial differences is of paramount importance,” Joseph and colleagues added.
African-Americans form at least 12.7% of more than 100 million people in the U.S. estimated to have diabetes or prediabetes. Exercise is one of the modifiable lifestyle risk factors known to be associated with a lower risk of diabetes in all races, including African-Americans.
According to the 2016 American Diabetes Association’s position paper,”the adoption and maintenance of physical activity are critical foci for blood glucose management and overall health in individuals with diabetes and prediabetes,” in reference to incorporating a tailored physical regimen for patients regardless of race.
Exercise for patients with heart disease and diabetes
The recommendations from Joseph’s group was echoed by the European Society of Cardiology in a new position paper providing detailed recommendations on exercise training in patients with diabetes and cardiovascular disease.
“Regular physical activity has demonstrated consistent beneficial effects on glycemic control, with the highest gain in patients with higher glycated hemoglobin (HbA1c) values,” wrote Hareld Kemps, MD, of the Máxima Medical Centre in Veldhoven, the Netherlands, and colleagues in the European Journal of Preventive Cardiology, and on behalf of the European Association of Preventive Cardiology.
Kemps’ group concluded that:
- Personalized exercise parameters should be developed for each patient
- High-volume moderate-intensity training is safe and has been shown to improve glycemic control and cardiorespiratory fitness (CRF) in patients with type 2 diabetes and cardiac comorbidity
- High-intensity interval training is a promising strategy to improve CRF, glycemic control, body composition, and cardiac function
- Combined high-volume resistance training/aerobic exercise training may add to improvements in glycemic control and body composition
Lack of motivation and/or specific cardiac and diabetes-related training barriers such as cardiovascular autonomic neuropathy, silent ischemia, arrhythmias, diastolic heart failure, peripheral artery disease, hypertension, and hypoglycemia were among the barriers to exercise adherence cited by the authors.
“Just advising patients to exercise, which is what doctors typically do, is not enough,” Kemps said in a statement. “Patients must be assessed for comorbidities, risks related to exercise, and personal preferences. This will be cost effective in the long run so we have to wake up policy makers and healthcare insurers to pay for it. That needs clinicians to take the lead and call for programmes to be reimbursed.”
One key to the success of an exercise program is setting early goals for each patient that are achievable and measurable, according to Kemps. “For an elderly person, this could be climbing the stairs in their home or walking to the supermarket — achievements that will really improve their quality of life,” he said.