Population-based monitoring of an urban HIV/AIDS epidemic. Magnitude and trends in the District of Columbia.

OBJECTIVE

To assess the extent of the human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) epidemic in the District of Columbia and demonstrate an approach to monitoring HIV infection and projecting AIDS incidence at a community level.

DESIGN

Backcalculation methods to reconstruct HIV incidence from AIDS incidence in subgroups. Results were compared with directly measured HIV seroprevalence in selected sentinel populations: childbearing women, civilian applicants for military service, and hospital patients admitted for conditions unrelated to HIV infection.

RESULTS

Between the start of the epidemic in 1980 and January 1, 1991, one in 57 District of Columbia men aged 20 to 64 years was diagnosed with AIDS. Unlike the plateau projected for the nation, AIDS incidence for the District of Columbia was projected to increase by 34% between 1990 and 1994. Models of HIV infection incidence suggested two broad epidemic waves of approximately equal size. The first occurred in men who have sex with men and peaked during the period from 1982 through 1983. The second began in the mid-1980s in injecting drug users and heterosexuals. We estimated that among District of Columbia residents aged 20 to 64 years, 0.3% of white women, 2.9% of white men, 1.6% of black women, and 4.9% of black men were living with HIV infection as of January 1, 1991. These estimates are broadly consistent with survey data: among black childbearing women in their 20s, HIV prevalence doubled to 2% between the fall of 1989 and the spring of 1991; from military applicant data, we estimated that over 5% of black men born from 1951 through 1967 were HIV-positive; in the sentinel hospital, HIV prevalence rates among male patients aged 25 to 34 years were 11.3% in white men and 16.9% in black men.

CONCLUSION

Backcalculation and surveys yielded quantitatively consistent estimates of HIV prevalence. Many injecting drug users and heterosexuals in the District of Columbia were infected after January 1, 1986. Similar monitoring of the epidemic in other localities is needed to focus efforts to reduce the incidence of HIV transmission.