In December 2005, in characterizing diabetes as an epidemic, the New York City Board of Health mandated the laboratory reporting of hemoglobin A1C laboratory test results. This mandate established the United States' first population-based registry to track the level of blood sugar control in people with diabetes. But mandatory A1C reporting has provoked debate regarding the role of public health agencies in the control of noncommunicable diseases and, more specifically, both privacy and the doctor-patient relationship. This article reviews the rationale for adopting the rule requiring the reporting of A1C test results, experience with its implementation, and criticisms raised in the context of the history of public health practice. For many decades, public health agencies have used identifiable information collected through mandatory laboratory reporting to monitor the population's health and develop programs for the control of communicable and noncommunicable diseases. The registry program sends quarterly patient rosters stratified by A1C level to more than one thousand medical providers, and it also sends letters, on the provider's letterhead whenever possible, to patients at risk of diabetes complications (A1C level >9 percent), advising medical follow-up. The activities of the registry program are similar to those of programs for other reportable conditions and constitute a joint effort between a governmental public health agency and medical providers to improve patients' health outcomes. Mandatory reporting has proven successful in helping combat other major epidemics. New York City's A1C Registry activities combine both traditional and novel public health approaches to reduce the burden of an epidemic chronic disease, diabetes. Despite criticism that mandatory reporting compromises individuals' right to privacy without clear benefit, the early feedback has been positive and suggests that the benefits will outweigh the potential harms. Further evaluation will provide additional information that other local health jurisdictions may use in designing their strategies to address chronic disease.
