One year into a landmark diabetes monitoring program, hemoglobin A1c test results are streaming from New York City laboratories into the city's health department and, in a sampling of cases, on to medical directors for distribution to clinicians.
City health officials, in the meantime, are working with a national advisory group of diabetes experts to analyze the data in the city's novel hemoglobin A1c (Hb A1c) registry—900,000 HbA1c test results covering 600,000 individuals, as of last month—and to design subsequent interventions.
The registry, which was launched in January 2006, is being watched by health officials across the country who want to reduce diabetes complications and control what they increasingly view as one of their largest public health crises.
The New York City program mandates that laboratories already reporting communicable diseases must also report results of HbA1c tests directly to the city's Department of Health and Mental Hygiene. As the program develops, the health department plans to routinely provide information to clinicians on their patients with diabetes and offer services and interventions to patients with poor glycemic control.
“The essence [is] to have it be more than just a surveillance system,” said Dr. Diana Berger, medical director of the city's Diabetes Prevention and Control Program.
“We already have a robust system to establish the prevalence of diabetes,” she said. “We wanted a two-pronged initiative: surveillance plus some sort of intervention.”
For now, in a pilot phase of the program, the city has begun sending quarterly reports to medical directors of seven practices in Manhattan and the South Bronx. The medical directors are then responsible for distributing the practice reports—which list patients stratified by HbA1c levels—to the 274 clinicians in the practices, Dr. Berger said.
The city plans to expand the pilot project to cover all of the South Bronx (approximately 100 practices) this summer, followed by other high-risk neighborhoods later in the year—a roll-out that officials hope will be helpful for fine-tuning reports and eventually designing interventions.
Interpreting the growing body of registry data, in the meantime, has been a significant undertaking.
Test results come in with the patient's full name, date of birth, and address, as well as the date the test was taken and the name and location of the ordering facility and clinician. This information may be enough for providing profiles to providers, but it's probably not enough to fully understand the epidemic and design optimal interventions, Dr. Berger said.
“The problem is, there's no diagnostic code attached to [the results],” she said. “We don't know whether a patient has diabetes or not [or what type of diabetes it is]. … The database needs a lot of cleaning [and interpretation]—it's a complex process.”
Also complicating the analysis is the fact that the registry, by including all HbA1c test results, captures tests used for diabetes screening as well as for monitoring, Dr. Berger said.
“There's a current practice of using A1c [levels] to screen for diabetes,” even though it's not recommended by the American Diabetes Association, she said. “We're estimating that anywhere from 10%–20% of the A1c results [coming in] are for screening purposes … We need to be able to wean these out.”
Another unanswered question is how much HbA1c testing is left out of the registry.
As of last month, almost three-fourths of the clinical laboratories required to report all results of blood test HbA1c—28 of 38 labs—are now doing so, and Dr. Berger said she anticipates that 100% will be reporting test results shortly.
The registry does not, however, include results obtained in office laboratories. Dr. Zachary Bloomgarden, clinical professor of medicine at the Mount Sinai School of Medicine, New York, said his practice is excluded from the program because he does blood draws and HbA1c testing right in his office lab.
Dr. Bloomgarden said he doesn't “have any real sense” of how many other practices perform in-office HbA1c testing, and Dr. Berger said she's actively seeking an answer to that question. “I'm in the process of studying that, trying to get a sense of what we're missing,” Dr. Berger said.
Some practices, she said, utilize finger-stick HbA1c testing to be able to present results immediately to patients, “but just anecdotally, I know that some robust endocrinology practices don't actually trust their figures from the A1c machines and will also get a [blood] draw.”
Dr. Berger said that she hopes to release the first “surveillance report”—a description, in essence, of all the data in the registry—later this spring, after she and others involved in the program have finished analyzing the data with the help of the advisory group.