Research Article: Comparing Measures of Late HIV Diagnosis in Washington State

Date Published: November 15, 2012

Publisher: Hindawi Publishing Corporation

Author(s): Laura Saganic, Jason Carr, Rosa Solorio, Maria Courogen, Tom Jaenicke, Ann Duerr.


As more US HIV surveillance programs routinely use late HIV diagnosis to monitor and characterize HIV testing patterns, there is an increasing need to standardize how late HIV diagnosis is measured. In this study, we compared two measures of late HIV diagnosis, one based on time between HIV and AIDS, the other based on initial CD4+ results. Using data from Washington’s HIV/AIDS Reporting System, we used multivariate logistic regression to identify predictors of late HIV diagnosis. We also conducted tests for trend to determine whether the proportion of cases diagnosed late has changed over time. Both measures lead us to similar conclusions about late HIV diagnosis, suggesting that being male, older, foreign-born, or heterosexual increase the likelihood of late HIV diagnosis. Our findings reaffirm the validity of a time-based definition of late HIV diagnosis, while at the same time demonstrating the potential value of a lab-based measure.

Partial Text

Approximately one in five people living with HIV in the United States is unaware of their HIV status [1]. Research suggests that many of these individuals—at least a quarter of a million people—regularly receive health care services, yet they are not tested for HIV [2]. These missed opportunities are costly, preventing early detection of HIV infection and prolonging the HIV epidemic within our nation [3]. The National HIV/AIDS Strategy includes a goal to reduce HIV infections by increasing the proportion of infected individuals who know their status, from an estimated 79% to 90% by 2015 [4]. Accomplishing this goal will require a substantial increase in HIV testing. Moreover, prevention programs will need better ways to identify and characterize people who are at risk for HIV but who are not routinely tested for HIV.

We used surveillance data from Washington state’s core HIV/AIDS reporting system (eHARS). This data system contains information about all individuals who have received a confidential diagnosis of HIV or AIDS while residing in Washington. The state also maintains a comprehensive laboratory reporting system which can be linked to eHARS and which contains all reported CD4+ T-cell test results associated with each HIV/AIDS case.

Among the 5,639 new HIV cases in Washington state between 2000 and 2009, 91% had adequate data to calculate a time-based measure of late HIV diagnosis (Table 1). All but one of the cases with incomplete data were diagnosed in 2009, which was too recent to determine whether an AIDS diagnosis took place during the 12-month follow-up period. Over the same time period, 71% of new cases had documentation of a valid CD4+ T-cell test result within 90 days of HIV diagnosis. While the proportion of cases without a CD4+ T-cell laboratory result was relatively high (29%), it appeared to decrease over time, from 35% in 2000 to only 17% in 2009. Regardless of measure, cases with complete data generally resembled those with missing or incomplete data. There were no statistical differences by gender or race/ethnicity. However, we did observe small but statistically significant differences with respect to age at HIV diagnosis, mode of HIV exposure, and county of residence (lab-based measure only).

As our state’s HIV epidemic nears the end of its third decade, the proportion of new HIV cases which are diagnosed late remains unacceptably high. Although CDC recommendations for the expansion of HIV testing have been in place for more than five years, a substantial proportion of new cases is still being detected late in the course of their HIV illness, after the point at which treatment should have been initiated. Statewide, declines in late HIV diagnosis over the past ten years appear to be minimal. Indeed, our findings support the notion that targeted HIV testing efforts, which depend heavily on patient and provider perceptions of HIV risk, cannot by themselves reduce the number of HIV-infected people who are infected but unaware of their status [3, 23]. Many of the characteristics we observed to be associated with late HIV diagnosis, such as being heterosexual, or residing in a rural area, are not traditionally considered strong indicators of HIV risk. Therefore, HIV testing efforts need to be broadened to include people who are at elevated risk for HIV but who are, for a variety of reasons, not getting tested.