Evaluation of a statewide non-name-based HIV surveillance system.

Recent advances in AIDS-related therapies have delayed the onset of AIDS-defining illnesses and reduced the usefulness of AIDS surveillance in assessing the incidence of early HIV disease and estimating future needs of the HIV-infected population. These changes have prompted renewed interest in expanding surveillance to include HIV and have engendered national debate on whether an HIV surveillance system should be based on reports of the names of infected individuals or employ non-name-based data codes. In 1994, the state of Maryland implemented a program to require HIV surveillance by unique identifier (UI) patient code. This evaluation of Maryland's program found that when complete, the 12-digit UI number provided a virtually unduplicated count 99.8% unique, was 99.9% unique with only the last four digits of the U.S. government Social Security Number (SSN), date of birth (DOB), and race, and 77.7% unique if the last four digits of the SSN were missing. Health care providers were willing to create the UI, with DOB and gender present 98.3% and 98.8% of the time, race was complete 84.1% and last four digits of SSN were complete 72.4%. The overall completeness of reporting for HIV tests was 87.8%.and 84.8%, respectively, using different methodologies. Evidence from the Maryland UI evaluation demonstrates that a non-name-based system can provide accurate, timely and valid data concerning the scope of the HIV epidemic, without the creation of state-wide name-based registry.