Diabetes control: Big gains but far from optimal

The proportion of diabetics in the U.S. who met measures for controlling microvascular and cardiovascular risk factors rose dramatically between 1988 and 2010, but despite those gains, only 18.8 percent achieved all three goals. The results were published online Feb. 15 in Diabetes Care.

The American Diabetes Association (ADA) recommends that most adult diabetics meet what are called the ABCs of diabetes care: hemoglobin A1C lower than 7 percent; blood pressure less than 130/80 mmHg; and low-density lipoprotein (LDL) cholesterol of less than 100 mg/dL. It also recommends the use of statins in patients with cardiovascular disease (CVD); those 40 years old or older with one or more CVD risk factor; and lower-risk patients with LDL cholesterol greater than 100 mg/dL.

In a study conducted and funded by the National Institutes of Health and the Centers for Disease Control and Prevention, Sarah Stark Casagrande, PhD, of Social & Scientific Systems in Silver Springs, Md., and colleagues analyzed national data to assess the prevalence of people in the U.S. with diabetes who met ABC recommendations. The researchers also looked at results for people achieving less stringent measures for controlling glucose and blood pressure.

They used data from the National Health and Nutrition Examination Surveys (NHANES) from 1988-1994, 1999-2002, 2003-2006 and 2007-2010 to identify 4,926 participants with a previous diagnosis of diabetes. To be included in the analysis, participants had to be 20 years old or older who completed a household interview and took a physical examination. Within that group, 1,558 people had valid LDL levels.

Their analysis saw improvements in all three ABC measures and a spike in the use of statins.

• For A1C, 52.5 percent of people with diabetes achieved the measure in 2007-2010 compared with 43 percent in 1988-1994. When the measure was changed to A1C lower than 8 percent, 77.9 percent met the goal in 2007-2010 compared with 60.1 percent in 1988-1994.
• For blood pressure, 51.1 percent met the measure in 2007-2010 compared with 33.2 percent in 1988-1994. When the measure was changed to less than 140/90 mmHg, 72 percent met the goal in 2007-2010 compared with 62 percent in 1988-1994.
• For LDL cholesterol, 56.2 percent met the measure in 2007-2010 compared with 9.9 percent in 1988-1994.
• Statin use increased from 4.2 percent in 1988-1994 to 51.4 percent in 2007-2010.

But the proportion of people with diabetes who met all three ABCs in 2007-2010 was just 18.8 percent, according to the analysis, which was much lower than the proportion of people who met an individual goal (between 51.1 and 56.2 percent). Nonetheless, 18.8 percent was a significant increase over the 1.7 percent reported for 1988-1994.

“The greatest potential to reduce type 2 diabetes-related complications may lie in focusing on controlling A1C, BP and LDL, collectively,” Casagrande and colleagues wrote.

Their results also showed a trend of smaller improvement among younger people, particularly in the A1C and LDL cholesterol goals. The researchers suggested that younger people may have type 1 diabetes, which may be harder to control.

“Nevertheless, younger adults have more to gain from risk factor control because their life expectancy is longer and the potential for complications increases with the duration of diabetes,” the authors suggested. “Thus, the ADA recommends more stringent A1C goals for individuals with a longer life expectancy and shorter time since diagnosis and less stringent goals for those with longer time since diagnosis, established complications or conditions limiting life expectancy.”

They concluded that the steady improvement found in their study is likely to translate into a reduction in complications in patients with diabetes. They also pointed out limitations that might affect results, including the small number of people in a fasting LDL sample, changes in NHANES protocols for LDL measures for people taking insulin between sampling periods and discrepancies in self-reported statin use and documentation.