Date of first positive HIV test: Reliability of information collected for HIV/AIDS surveillance in the United States

Objectives. This study examined the reliability of the first positive HIV test date reported in the U.S. HIV/AIDS Reporting System (HARS). This date is essential to determine case counts for resource allocation for HIV treatment and prevention efforts. Methods. The dates of first positive HIV tests reported by individuals with HIV in an interview survey conducted in 16 states (n=16,394, interviewed 1995-2002) were compared with the dates of HIV diagnosis reported to HAIRS. The percentage of agreement for the year of diagnosis and the weighed kappa (k) with 95% confidence intervals (CIs) was calculated. Results. Self-reported year of diagnosis agreed with the year of diagnosis in HARS for 56% of date pairs (k=0.69; 95% CI 0.68, 0.70); 30% reported an earlier diagnosis year. Agreement differed by sex, age, race, exposure, and reason or place of testing (p<.01). Lower agreement was found when the self-reported diagnostic test was anonymous (k=0.57; 95% CI 0.52, 0.62) compared with confidential tests (k=0.66; 95% CI 0.64, 0.68). Lower agreement was also found for cases first reported with AIDS (k=0.58; 95% CI 0.55, 0.62) compared with cases first reported with HIV not AIDS (k=0.71; 95% CI 0.70, 0.73) as well as for participants interviewed three years or more after their HARS diagnosis date (k=0.55; 95% CI 0.52, .57) compared with those interviewed within one year (k=0.62; 95% CI 0.61, 0.63). More than 20% of participants in almost all groups, however, reported earlier diagnosis years than those recorded in HARS. Conclusion. As many as 30% of HIV diagnoses may have occurred earlier than recorded in HARS. Additional studies need to determine mechanisms to adequately capture diagnosis dates in HARS.