Active AIDS surveillance: hospital-based case finding in a metropolitan California county.

OBJECTIVES: Health departments that use passive surveillance alone cannot be sure of the level of complete and accurate reporting of acquired immunodeficiency syndrome (AIDS) cases. We sought to develop a model of active AIDS case reporting using limited county resources. METHODS: A validation study of AIDS case reporting using discharge diagnosis codes was undertaken to assess underreporting. Hospital-specific protocols for active surveillance were developed. RESULTS: The validation study revealed that 24% of AIDS cases in all hospitals were not reported through passive surveillance in 1990. In the first 3 months of 1991, active surveillance identified nine unreported cases (69% of the total cases reported) in one hospital. These underreporting estimates far exceed the 15% national underreporting rate estimated by the Centers for Disease Control. CONCLUSIONS: A method of hospital-based case finding was developed and serves as the model for implementing an ongoing program of active surveillance needed to ensure complete, accurate, and timely reporting of diagnosed AIDS cases. Application of this model may be helpful in attempts to minimize underreporting.