A new study offers doctors another barometer to gauge the quality of care they give patients with diabetes. The study researchers are proposing an evaluation of diabetes care that tracks providers’ success over time instead of at a single moment.

“It’s kind of like a movie versus a snapshot,” said researcher Monika Safford, M.D. “Most of the ways we measure quality of care are looking at a snapshot.”

The study of 125 Veterans Health Administration facilities nationwide analyzed results of the blood glucose test A1c, the gold standard for monitoring how well patients have managed their diabetes in recent weeks and months.

America’s health care systems already receive a report card on the quality of their diabetes care — an assessment largely based on A1c testing. Health plans are evaluated on the percentage of diabetes patients who receive the A1c test each year and the proportion of patients whose diabetes is out of control, based on an A1c score higher than 9 percent.

The A1c test detects a hemoglobin protein in the blood that is bound with glucose. As A1c levels rise, the risks for diabetes complications also increase and can result in damage to the cardiovascular system, eyes, kidneys or other organs.

The Veterans Health study, published in the December Health Services Research journal, tracked changes in average monthly A1c levels for each facility during two years. The majority of the facilities lowered their average-patient A1c levels during the study period.

“It’s a demonstration across a population that you can get A1c levels under better control,” Safford said.

Even a modest drop across a patient population can translate into fewer of the medical problems commonly associated with diabetes and elevated A1c levels, she said.

To highlight differences, the researchers ranked each facility from worst to best based on average change in A1c levels. That kind of ranking could be used to identify the facilities that are the poorest performers and to determine those that need to improve the quality of their diabetes care, the study suggests.

Knowing how well a health plan is treating diabetes is valuable consumer information for anyone shopping for the best care, said Nathaniel Clark, M.D., national vice president of clinical affairs for the American Diabetes Association.

Because A1c levels are influenced by so many factors beyond quality of care — such as marital status, age or ethnicity — Safford said it is premature and unfair to link the rankings to accountability. But she said, “It’s a nice tool for health systems and physicians to monitor their performance against their peers.”

The study received grant support from the VA Health Services Research and Development program.

Thompson W, et al. Assessing quality of diabetes care by measuring longitudinal changes in hemoglobin A1c in the Veterans Health Administration. Health Services Research 40(6), 2005.