Context: Human immunodeficiency virus infection affects 850,000 to 950,000 persons in the United States, with approximately 40,000 new infections annually. Diagnosis of unsuspected HIV infection could identify those who would benefit from interventions or reduce transmission from those unaware of their status.
Objective: To synthesize the evidence on risks and benefits of screening for HIV infection.
Data Sources: MEDLINE (though June 30, 2004), Cochrane Clinical Trials Registry (2004, Issue 2), reference lists, and experts.
Study Selection: Controlled studies of screening and antiretroviral therapy, counseling, prophylaxis for opportunistic infections, more frequent Papanicolaou smear testing, immunizations, and routine monitoring and follow-up; observational studies on counseling, risk factors, accuracy of antibody testing, work-up, acceptability of screening and uptake of interventions, harms of interventions and screening, and long-term outcomes.
Data Extraction: Using preset criteria, the authors assessed the quality of included studies and abstracted information about settings, patients, interventions, and outcomes.
Data Synthesis: There are no published trials directly linking screening for HIV with clinical outcomes. Approximately 0.3% of U.S. adults have HIV infection, and almost all will progress to AIDS if untreated. Risk factor assessment could identify adults at substantially higher risk, but would miss a significant proportion of infected persons. Screening tests for HIV are extremely accurate. Acceptance rates for screening and use of recommended interventions vary widely. Many persons are currently diagnosed at advanced stages of disease. Highly active antiretroviral treatment (HAART) reduces the risk of clinical progression or death compared to less intense regimens, and can result in sustained improvements in intermediate outcomes. HAART is associated with a significantly greater impact on clinical outcomes than other interventions. Although HAART is associated with significant short-term adverse events, these are usually self-limited and effective alternative regimens can be found. Increased duration of HAART use appears associated with an increased rate of cardiovascular complications over 3–4 years, but background rates of cardiovascular complications appear low. There are insufficient data to estimate the effects of counseling or HAART on transmission rates.
Conclusions: Identification and treatment of unsuspected HIV infection at immunologically advanced stages of disease can result in marked reductions in clinical progression and mortality. Although long-term studies of HAART are not yet available, the estimated three-year benefits of HIV screening appear to greatly outweigh the risks of cardiovascular complications in both low- and high-prevalence settings using conservative estimates of the effectiveness of interventions. The yield from screening in populations with prevalence ≥1% would be substantially higher, however, than the yield from screening in the general population. Data are insufficient to accurately estimate the benefits (reduced clinical progression or spread of disease) from identifying HIV-infected persons at earlier stages of disease, or the effects of screening on the stage at which patients are diagnosed.
Keywords: HIV, HIV infections, HIV seropositivity, mass screening