› Aim for a glycated hemoglobin of <7% for most nonpregnant patients with type 2 diabetes, with a less stringent target for those with severe hypoglycemia, limited life expectancy, advanced micro- or macrovascular complications, and/or extensive comorbidities. B
› Attempt to treat patients with diabetes and hypertension to a target blood pressure<140/90mm Hg. B
› Prescribe statin therapy regardless of baseline lipid levels for all patients who have diabetes and are between the ages of 40 and 75years. A
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
CASE › Dennis D, age 63, was recently diagnosed with diabetes. his glycated hemoglobin (HbA1c) is 7.8%, his blood pressure (BP) is mildly elevated (145/95 mm Hg), and his body mass index (BMI) is 28.5, but his low-density lipoprotein (LDL) cholesterol is 100 mg/dl, his high-density lipoprotein (HDL) cholesterol is 52 mg/dL, and he has no history of cardiovascular disease (CVD). After an unsuccessful attempt to treat him with lifestyle modification, it is time to initiate diabetes therapy.
Other than an alpha-blocker for benign prostatic hyperplasia and a prostaglandin for glaucoma, Mr. D takes no other medications. You prescribe metformin 500 mg twice daily and consider what else to add to keep his diabetes well controlled. Should you prescribe an antihypertensive? And, despite the patient’s normal lipid levels, should he begin taking a statin?
Type 2 diabetes has been extensively studied in rigorous randomized controlled trials (RCTs). While studies have provided ample evidence in support of optimal treatment, differing interpretations of the findings are reflected in consensus guidelines developed by expert panels that don’t always see eye to eye on what diabetes treatment targets should be and how best to prevent micro- and macrovascular complications.
What’s more, recommendations continue to be updated as new data emerge. In February 2014, the Joint Committee on Prevention, Evaluation, and Treatment of High Blood Pressure (JCN 8) revised its target for patients with diabetes to <140/90 mm Hg (from <130/80 mm Hg).1 This is likely to lead to revisions in other leading consensus guidelines, as well.
Thus, primary care physicians managing the care of patients with diabetes face the challenge of using the latest recommendations in a manner that addresses the entire clinical picture, considering each patient’s age and overall health status, priorities, and preferences. We developed this evidence-based review and guide- line summary with that in mind.
HbA1c target: How low should you go?
The Diabetes Control and Complications Trial (DCCT), published nearly 20 years ago, studied patients with type 1 diabetes, and found that intensive insulin therapy (HbA1c ≤6%) delayed the onset of retinopathy, nephropathy, and neuropathy.2 However, there was an important adverse effect of such intensive therapy: Patients in this group suffered from severe hypoglycemic episodes 3 times more frequently than those in the usual care group. Nonetheless, the microvascular benefits of intensive control observed in those with type 1 diabetes were thought to be similar for patients with type 2 diabetes.
The United Kingdom Prospective Diabetes Study (UKPDS), published in 1999, was the first major study to investigate targets for glucose control in patients with type 2 diabetes.3 Participants treated intensively (mean HbA1c goal, 7%) had a 25% reduction in microvascular complications, including the need for retinal photocoagulation, com- pared with those on standard control (mean HbA1c, 7.9%). There was also a nonsignificant trend toward a reduction in macrovascular complications in the intensive therapy group, but no difference in overall mortality rate.3
A 10-year follow-up of the UKPDS showed that while baseline differences in HbA1c between the 2 groups were lost by one year, reductions in microvascular complications continued to occur in the intensive treatment group.4 Reductions in myocardial infarction (MI) and death emerged over time, a possible legacy effect (ie, the result of intense treatment early in the course of the disease).
The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, published in 2008, studied patients at risk for CVD, defined by either a prior history of CVD or ≥2 other cardiovascular risk factors.5 Participants, all of whom had poorly controlled type 2 diabetes (mean HbA1c, 8.1%), were randomized to either intensive treatment (HbA1c goal, <6%) or standard therapy (HbA1c goal, 7%-7.9%). The study was discontinued after a mean follow-up of 3.5 years, when those in the intensive therapy group were found to have a higher mortality rate.5