Diabetes Overview: New Diagnosis and Treatment Options
In the United States, 18.8 million people are diagnosed with diabetes, accounting for more than 6% of the population.1 Another 7 million people have undiagnosed diabetes and an additional 79 million people have prediabetes, according to estimates from the Centers for Disease Control and Prevention (CDC).1
“There’s a significant burden,” said Steven Milligan, MD, a faculty member at Southern Colorado Family Medicine in Pueblo, CO.
PREDIABETES
At the 2013 Cardiometabolic Risk Summit, Milligan discussed the importance of diagnosing and treating prediabetes—defined as having blood glucose or hemoglobin A1c (HbA1c) levels higher than normal but not high enough to meet the criteria for diabetes.2 The Expert Committee on Diagnosis and Classification of Diabetes Mellitus indicates that patients with prediabetes have HbA1c of 5.7% to 6.4%, fasting plasma glucose levels of 100 mg/dL to 125 mg/dL, and 2-hour values in the oral glucose tolerance test of 140 mg/dL to 199 mg/dL.3
Each year, 5% to 10% of people with prediabetes progress to diabetes, and up to 70% eventually have diabetes, according to an expert panel from the American Diabetes Association (ADA). Milligan added that CDC research found patients with diabetes are twice as likely to have premature death, and 2 to 4 times higher risk for stroke and heart disease deaths as compared to those without diabetes.4
Although several models have been developed to predict people who are at risk of having diabetes, they are not applicable to people outside of that particular population, noted Milligan. Potential risk factors include age, sex, body mass index (BMI), diet, physical inactivity, smoking, family history of diabetes, hypertension, cardiovascular disease, low high-density lipoprotein (HDL) cholesterol, high triglycerides, and uric acid.
Screening Recommendations
Milligan stressed that all patients with risk factors for diabetes should receive regular screenings. In 2013, the ADA recommended screening for all adults with a BMI >25 kg/m2 and more than 1 of the following risk factors: physical inactivity, first-degree relative with diabetes, high-risk race/ethnicity, women who have delivered a baby weighing more than 9 pounds or have a history of gestational diabetes, hypertension, HDL cholesterol <35 mg/dL, and trigylcerides >250 mg/dL.5
In addition, the ADA recommended screening for all adults with a BMI >25 kg/m2 and more than 1 of the following risk factors: women with polycystic ovary syndrome, HbA1c >5.7%, impaired glucose tolerance, or impaired fasting glucose on a previous test, a history of cardiovascular disease, or other clinical conditions such as obesity that is associated with insulin resistance.5
All other patients should start screening at 45 years of age. If the results are normal, screenings should be scheduled every 3 years. Milligan pointed out that the optimal screening interval is not known, although patients with prediabetes should be monitored at least once a year.
The US Preventive Services Task Force (USPSTF) recommends 3 screening tests: fasting plasma glucose, 2-hour postload plasma glucose, and HbA1c.6 Milligan noted that fasting plasma glucose is best because it is easier and faster to perform, more convenient and acceptable for patients, and less expensive than other options.
The USPSTF found that moderate screening for diabetes in adults with hypertension leads to a substantial benefit, although the benefit is uncertain for other patient populations.
• For adults with sustained blood pressure >135/80 mm Hg: The USPSTF found that lowering blood pressure below targeted values in patients with hypertension and diabetes
reduces the incidence of cardiovascular events and cardiovascular mortality.
• For adults with sustained blood pressure <135/80 mm Hg: The USPSTF found that people with clinically detected diabetes who have intensive glycemic control can have a reduction in the progression of microvascular disease.
For patients with impaired glucose tolerance, impaired fasting glucose, or those with an HbA1c from 5.7% to 6.4%, the ADA suggests they lose 7% of their body weight to prevent or delay the onset of diabetes.7 The ADA also suggests people walk or have moderate activity for 150 minutes per week.
Diet, exercise, and metformin are the best treatments for diabetes, according to Milligan. He added that the number to remember is 40 for patients undergoing an improved diet and exercise regimen: Healthcare professionals need to treat 40 people to prevent 1 case of diabetes. That number increases to 50 with metformin and 70 with thiazolidines.
BARRIERS TO TREATMENT
Kevin A. Peterson, MD, professor and director of research at the University of Minnesota Medical School, said there are plenty of options available to treat diabetes, although they are not always used correctly and are ineffective in some cases. He cited a 2011 report from the National Committee for Quality Assurance that found 27% of people with commercial insurance had HbA1c greater than 9%, 66% had systolic blood pressure of at least 130 mm Hg, 34% had systolic blood pressure of at least 140 mm Hg, and 52% had low-density lipoprotein of at least 100 mg/dL.8
Peterson defined clinical inertia as the failure to intensify the treatment of a patient who has not reached their evidence-based HbA1c goal. He noted a study that found 58% of patients in a Veterans Affairs hospital with an HbA1c of 8% or higher and 57% of patients with LDL cholesterol of 100 mg/dL or higher experienced clinical inertia.9
More people have resistance to insulin than they do to other drugs, noted Peterson. However, there are issues with insulin. Patients with type 2 diabetes on average begin insulin therapy 11 years after diagnosis and 7.7 years after they failed oral therapy.
Patients do not start insulin treatments for a variety of reasons, including an inadequate understanding of diabetes, a fear of injections, a preference for other therapies, and an inability to afford the medications. Physicians do not prescribe insulin because they may have a lack of understanding of its benefit and clinical guidelines and may fear patients will have hypoglycemia if they receive insulin.
Although primary care physicians are responsible for 90% of diabetes care, Milligan suggested that patients receive support from other healthcare professionals and receive counseling on diet, nutrition, exercise, and weight reduction. Diabetes educators and physicians can work together to ensure better patient outcomes.
“You can’t do this alone anymore,” Peterson said. “It takes a team to do this.”
Another barrier to effective treatment is a lack of health literacy, which Peterson defined as the ability to obtain, process, and understand basic health information and services needed to make appropriate health decisions. Nearly 90% of people are not health literate, according to Peterson, who added that the highest risk groups are older adults, racial and ethnic minorities, non-native English speakers, those with a low income, those with a compromised health status, and those with less than a high school degree or GED certificate.
NEW THERAPEUTIC OPTIONS
Mark E. Molitch, MD, professor in the division of endocrinology, metabolism and molecular medicine at Northwestern University, said drugs for type 2 diabetes have different targets, including the pancreas, muscle and fat, gut, and liver. He discussed glucagon-like peptide-1 (GLP-1) receptor agonists, such as exenatide and liraglutide, as well as dipeptidyl peptidase-4 (DPP-4) inhibitors, such as sitagliptin, saxagliptin, linagliptin, and alogliptin.
The DPP-4 inhibitors “are all quite similar in their effects,” according to Molitch. They each reduce HbA1c by approximately 0.8%, are well-tolerated with few adverse effects, and are effective when used with other oral antidiabetic agents.
Pharmaceutical companies are developing numerous other diabetes drugs, including longer-acting basal insulins (insulin degludec, LY2605541, and insulin glargine U300), more rapid-acting prandial insulins, inhaled insulin, closed loop pumps, and insulin patch-pumps. Molitch said the FDA could soon approve insulins that last for 48 hours or longer.
There are also additional GLP-1 receptor agonists, DPP-4 inhibitors, and subtype 2 sodium-glucose transport protein (SGLT2) inhibitors in the pipeline. As of November 2013, canagliflozin was the only FDA-approved SGLT2 inhibitor. ■
References:
1.2011 National Diabetes Fact Sheet. Centers for Disease Control and Prevention. Available at: http://www.cdc.gov. Accessed February 2014.
2.Prediabetes. Centers for Disease Control and Prevention. Available at: http://www.cdc.gov. Accessed February 2014.
3.Tabák MD, Herder C, Rathmann W, et al. Prediabetes: a high-risk state for diabetes development. Lancet. 2012;379(9833):2279-2290.
4.Diabetes report card 2012: national and state profile of diabetes and its complications. Centers for Disease Control and Prevention. Available at: http://www.cdc.gov. Accessed February 2014.
5.Standards of medical care in diabetes—2013. American Diabetes Association. Available at: http://care.diabetesjournals.org/content/36/Supplement_1/S11.full . Accessed in February 2014.
6.U.S. Preventive Services Task Force. Screening for type 2 diabetes mellitus in adults: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2008;148:846-854.
7.Diagnosing diabetes and learning about prediabetes. American Diabetes Association. Available at: http://www.diabetes.org/diabetes-basics/diagnosis/ . Accessed February 2014.