Comparing approaches to diabetes screening

The Buzz: ADA guidelines outperform the updated USPSTF approach to screening for diabetes

Citation: A Sheehy et. al. Analysis of Guidelines for Screening Diabetes Mellitus un an Ambulatory Population.  Mayo Clinic Proc. January 2010; 85(1):27-35

Summary: Of the estimated 25 million Americans currently with diabetes, approximately 40% continue to be undiagnosed, and determining the most effective screening method may prevent significant morbidity and mortality. Currently, the American Diabetes Association (ADA) and the US Preventative Services Task Force (USPSTF) have issued vastly different guidelines for screening for diabetes. This retrospective study included 28,842 patients from a large, Midwestern primary care practice, comparing the performance of both approaches to screening. The study found that adhering to USPSTF guidelines would have identified 33% fewer new cases of diabetes, and the authors recommended using the ADA guidelines due to their superior performance. One caveat is the population of patients under 45 who are non-obese with hypertension, for whom the USPSTF recommends screening and the ADA guidelines do not. Study authors point out this is an important group to screen as well.  The study also found that a history of pre-diabetes or polycystic ovarian syndrome conferred the highest risks for developing diabetes.

Commentary: This study suggests we combine USPSTF and ADA guidelines in an effort to identify more cases of diabetes.

By: Maxwell Jen, MSIII & Spencer Blackman, MD

Rosiglitazone (Avandia) and increased risk of CV events

The Buzz: FDA advisory committees recommend removing rosiglitazone
Citation: AAFP News Now, 7/20/2010
Summary: Members of two FDA advisory committees have expressed concerns over the safety of rosiglitazone (Avandia) and have recommended removing the medication from the list of approved drugs. While investigation into the safety of rosiglitazone has been ongoing since 2007, two recent studies from JAMA and the Archives of Internal Medicine
reported significant elevation in CV risk associated with its use. Of note, GlaxoSmithKline, the maker of Avandia, has said that it will record a $2.36 billion legal charge in the second quarter of fiscal year 2010 for settlements related to rosiglitazone.
Commentary: While FDA has yet to make a decision, we should consider getting our patients off rosiglitazone, and certainly not write new prescriptions for it. Pioglitazone (Actos) is considered safer than rosiglitazone, though it should be considered only in patients refractory to or intolerant of first- and second-line therapies.
By: Spencer Blackman MD

UPDATE (9/25/2010): Rosiglitazone has been pulled from the European market, and will only be offered to US patients in whom "every other" diabetes medication has been tried.

Should we use aggressive medical treatment to stop the progression of diabetic retinopathy?

The Buzz: In type 2 diabetics, intensive glucose and lipid control (but not intensive BP control) prevents the progression of diabetic retinopathy (DR), but the approach may harm more patients than it benefits.
Citation: NEJM 363;3 July 15, 2010
Summary: As part of a sub-study of the large multi-center RCT ACCORD trial, researchers evaluated 10,251 diabetic patients randomly assigned to intensive (A1c < 6.0%) vs standard therapy (A1c < 7.0-7.9%), and were followed to monitor progression of DR, including the need for laser surgery or vitrectomy. Decreased rates of progression of DR were seen in the intensive glucose (7.3 vs 10.4%, P = 0.003) and lipid (6.5 vs 10.2%, P = 0.006) groups, but not the intensive BP group (10.4 vs 8.8%, P = 0.29). However, the trial was halted early, and a large portion of patients with higher LDL levels and alb/creat scores and lower visual acuity scores did not receive 4 year follow-up.

Commentary: These findings need to be interpreted in conjunction with the ACCORD trial, since DR is only one CV endpoint that is seen in diabetics.  In fact, the trial was stopped early when results suggested intensive glucose lowering was found to have no benefit in MI/CVA prevention and increased all-cause mortality. These findings were not replicated in the newer ADVANCE trial, which used different glucose lowering agents.  However, despite this newer trial and the benefit seen in DR, it is likely most prudent to maintain an A1c goal of 7.0-7.9%. In addition, this study suggests adding fenofibrate therapy to a statin may be useful to slow DR progression, particularly if the patient is male and has high trigylcerides or low HDL, as CV risk reduction with fenofibrate was found in these subsets.

By: Elizabeth Haskins, MD

Does substitution with whole grains reduce diabetes risk?

The Buzz:  Whole-grain carbohydrates are recommended in lieu of refined grains to help prevent T2D.
Citation: “White rice, brown rice, and risk of type 2 diabetes (T2D) in US Men and Women” Arch Intern Med. 2010;170(11):961-969

Summary:  Using pooled data from the Health Professionals Follow-up Study and the Nurses’ Health Study I and II, researchers found that substituting brown rice for white rice was consistently associated with a lower risk of developing T2D, and that this effect could be extrapolated to other whole grains.  These associations were independent of lifestyle and dietary risk factors for T2D, as well as ethnicity.  Glycemic index (GI) values differed by variety, but in general they found that white rice consumption generated a relatively stronger postprandial glucose response than the same amount of brown rice.

Commentary:  Recommending whole grains, and whole foods (as nature intended) in general is likely a matter of course for most of us at this point, but for those looking for further substantiation this may prove helpful.  It is also worthy of note as we work with increasing populations of gluten-intolerant patients – we need to ensure we’re not solving a GI related issue, and potentially creating another one in the form of T2D.
By: Karyn Duggan, CNC

Which oral medications are best for obese patients with DM2?

The Buzz: Multiple classes of oral diabetes medications are weight-neutral or even beneficial for weight loss.
Citation: "Managing Type 2 Diabetes: Balancing HbA1c and Body Weight " Postgrad Med  2010 May  122(3):106-117.
Summary: Attempts at managing type 2 diabetes in the obese are often sabotaged by weight gain as a side effect of therapy. Weight loss has been shown to improve insulin resistance, improve glycemic control, and decrease the need for medication. Appropriate choice of medications in this population can help minimize weight gain and perhaps lead to weight loss, thus improving glycemic control and hopefully leading to improvements in overall cardiovascular risk. This review revealed that the antihyperglycemic agents most likely to be weight neutral or to promote loss were the biguanides (e.g. metformin), α-glucosidase inhibitors (e.g. acarbose), incretin mimetics (e.g. exenatide), amylin mimetics (e.g. pramlintide), DPP4-inhibitors (e.g. sitagliptin/saxagliptin). In addition, providers may consider the use of orlistat and sibutramine to target weight loss as adjuncts to conventional antihyperglycemic therapies.

Commentary: Further studies are needed to determine if these effects will translate into clinically relevant improvements in CV outcomes.
By: Sue Kim MD

Hgba1c as an independent risk factor for diabetes, CVD and death?

The Buzz: Glycated hemoglobin may be a useful marker for predicting development of diabetes, cardiovascular risk and death
Citation:  "Glycated Hemoglobin, Diabetes and Cardiovascular Risk in Nondiabetic Adults." NEJM 362;9 March 4, 2010 800-11

Summary: This multi-center study followed 11,092 middle-aged adults without diabetes over a 15 year period in order to study the use of glycated hemoglobin to predict risk of diabetes, coronary heart disease and death. Using thawed blood samples taken during subjects' earlier visits, researchers calculated adjusted hazard ratios for those with HgbA1c values below 7.0%, ie nondiabetics. HgbA1c values were as good as fasting glucose values for predicting risk of developing diabetes, and appeared to be better than fasting glucose as a predictor of long-term macrovascular event risk. For A1c values of <5.0%, 5.0%-<5.5%, 5.5%-<6.0%, 6.0%-<6.5% and >6.5%, the multivariable-adjusted hazard ratios were 0.52, 1.00, 1.86, 4.48 and 16.47, respectively for developing diabetes, and 0.96, 1.00, 1.23, 1.78, and 1.95, respectively for coronary heart disease (all values significant). Similar findings were reported for stroke and death from any cause.The authors concluded that not only does this study further support the use of glycated hemoglobin values to predict diabetes risk, but that values over 6.0% may be an independent risk factor for cardiovascular disease and death.
Commentary: This study, while observational, suggests we have another tool to help establish risk for developing diabetes, heart disease and death. However, the authors do not suggest which patients this would be useful for, nor do these findings change the approach to patients at elevated risk. Modifying lifestyle factors is still key in this battle.
By: Spencer Blackman MD