NEW YORK (Reuters Health) ¿ Americans with diabetes are doing a better job of keeping their blood glucose under control, a new analysis shows.

The percentage of people with Type 1 or 2 diabetes who had poor glycemic control fell from 21 percent in 1999 to 12.4 percent in 2004, according to data from the National Health and Nutrition Examination Survey (NHANES).

During that same time, the percentage of diabetics with their blood glucose under good control rose from 36.9 percent to 56.8 percent, Dr. Thomas J. Hoerger of RTI International in Research Triangle Park, North Carolina and colleagues report.

"This trend may represent an important improvement in diabetes care and is encouraging for future reduction of diabetes-related complications," Hoerger and his team conclude in the journal Diabetes Care. The researchers looked at NHANES data for three time periods for levels of haemoglobin A1C, an indicator of long-term blood glucose control, in adults diagnosed with diabetes. An A1C below seven percent indicates optimal blood glucose control, while nine percent and above represents poor glycemic control. Average A1C levels were 7.82 percent in 1999-2000; 7.47 percent in 2001-2002, and 7.18 percent in 2003-2004, the researchers found.

Improvements were seen among people of all ages, weights, and education and income levels, with the exception of Hispanics who had an increase in A1C levels.

The percentage of people with A1Cs below seven percent rose from 36.9 percent to 56.8 percent from 1999 to 2004, while the proportion of people with A1Cs above nine percent fell from 21 percent to 12.4 percent.

People with diabetes may be more likely to take their medicines as described thanks to better diabetes education and newer drugs with fewer side effects, Hoerger and his colleagues note.

Between 1999 and 2004, they point out, Medicare also upped its reimbursements for diabetes-related supplies.

The findings suggest, the researchers say, "that diabetes care improved dramatically between 1999 and 2004."