Qian An

Estimation of HIV Incidence in the United States

CONTEXT Incidence of human immunodeficiency virus (HIV) in the United States has not been directly measured. New assays that differentiate recent vs long-standing HIV infections allow improved estimation of HIV incidence. OBJECTIVE To estimate HIV incidence in the United States. DESIGN, SETTING, AND PATIENTS Remnant diagnostic serum specimens from patients 13 years or older and newly diagnosed with HIV during 2006 in 22 states were tested with the BED HIV-1 capture enzyme immunoassay to classify infections as recent or long-standing. Information on HIV cases was reported to the Centers for Disease Control and Prevention through June 2007. Incidence of HIV in the 22 states during 2006 was estimated using a statistical approach with adjustment for testing frequency and extrapolated to the United States. Results were corroborated with back-calculation of HIV incidence for 1977-2006 based on HIV diagnoses from 40 states and AIDS incidence from 50 states and the District of Columbia. MAIN OUTCOME MEASURE Estimated HIV incidence. RESULTS An estimated 39,400 persons were diagnosed with HIV in 2006 in the 22 states. Of 6864 diagnostic specimens tested using the BED assay, 2133 (31%) were classified as recent infections. Based on extrapolations from these data, the estimated number of new infections for the United States in 2006 was 56,300 (95% confidence interval [CI], 48,200-64,500); the estimated incidence rate was 22.8 per 100,000 population (95% CI, 19.5-26.1). Forty-five percent of infections were among black individuals and 53% among men who have sex with men. The back-calculation (n = 1.230 million HIV/AIDS cases reported by the end of 2006) yielded an estimate of 55,400 (95% CI, 50,000-60,800) new infections per year for 2003-2006 and indicated that HIV incidence increased in the mid-1990s, then slightly declined after 1999 and has been stable thereafter. CONCLUSIONS This study provides the first direct estimates of HIV incidence in the United States using laboratory technologies previously implemented only in clinic-based settings. New HIV infections in the United States remain concentrated among men who have sex with men and among black individuals.

Estimated HIV Incidence in the United States, 2006–2009

Background The estimated number of new HIV infections in the United States reflects the leading edge of the epidemic. Previously, CDC estimated HIV incidence in the United States in 2006 as 56,300 (95% CI: 48,200–64,500). We updated the 2006 estimate and calculated incidence for 2007–2009 using improved methodology. Methodology We estimated incidence using incidence surveillance data from 16 states and 2 cities and a modification of our previously described stratified extrapolation method based on a sample survey approach with multiple imputation, stratification, and extrapolation to account for missing data and heterogeneity of HIV testing behavior among population groups. Principal Findings Estimated HIV incidence among persons aged 13 years and older was 48,600 (95% CI: 42,400–54,700) in 2006, 56,000 (95% CI: 49,100–62,900) in 2007, 47,800 (95% CI: 41,800–53,800) in 2008 and 48,100 (95% CI: 42,200–54,000) in 2009. From 2006 to 2009 incidence did not change significantly overall or among specific race/ethnicity or risk groups. However, there was a 21% (95% CI:1.9%–39.8%; p = 0.017) increase in incidence for people aged 13–29 years, driven by a 34% (95% CI: 8.4%–60.4%) increase in young men who have sex with men (MSM). There was a 48% increase among young black/African American MSM (12.3%–83.0%; p<0.001). Among people aged 13–29, only MSM experienced significant increases in incidence, and among 13–29 year-old MSM, incidence increased significantly among young, black/African American MSM. In 2009, MSM accounted for 61% of new infections, heterosexual contact 27%, injection drug use (IDU) 9%, and MSM/IDU 3%. Conclusions/Significance Overall, HIV incidence in the United States was relatively stable 2006–2009; however, among young MSM, particularly black/African American MSM, incidence increased. HIV continues to be a major public health burden, disproportionately affecting several populations in the United States, especially MSM and racial and ethnic minorities. Expanded, improved, and targeted prevention is necessary to reduce HIV incidence.

Estimating the lifetime risk of a diagnosis of the HIV infection in 33 states, 2004-2005.

Purpose:We estimated lifetime risk and age-conditional risk of being diagnosed with HIV in 33 states with name-based HIV reporting. Methods:We used vital statistics data on general and HIV-specific mortality, census data, and HIV surveillance data to calculate cross-sectional, period-specific (2004-2005), and age-specific probabilities of an HIV diagnosis. The probabilities were applied to a hypothetical cohort of 10 million live births, and estimates were derived for the lifetime risk, from birth, of being diagnosed with HIV. Results:The estimated lifetime risk of being diagnosed with HIV was 1.87% for males (95% confidence limit: 1.86 to 1.89) or 1 in 53 males and 0.71% for females (95% confidence limit: 0.70-0.72) or 1 in 141 females. Blacks and Hispanics experienced higher estimated lifetime risk of HIV than whites: 6.23% or 1 in 16 for blacks, 2.88% or 1 in 35 for Hispanics, 0.96% or 1 in 104 for white males; 3.29% or 1 in 30 for blacks, 0.88% or 1 in 114 for Hispanics, and 0.17% or 1 in 588 for white females. The highest risk of HIV diagnosis was observed among people in their 30s. Conclusions:These estimates may help to communicate the risk of HIV infection to affected communities, increase public awareness, and promote early detection and prevention efforts for HIV.

Racial/Ethnic Disparities in HIV Diagnoses Among Persons Aged 50 Years and Older in 37 US States, 2005–2008

OBJECTIVES We examined racial/ethnic disparities in HIV diagnosis rates for persons aged 50 years and older. METHODS We analyzed surveillance data from the Centers for Disease Control and Prevention regarding HIV diagnoses during 2005 through 2008 in 37 states. Average annual rates of diagnoses were calculated for persons aged 50 years and older and compared with rates for persons aged 13 to 49 years. RESULTS The average annual rate of diagnosis (per 100,000 persons) for older persons was 9.8. Rates among older Blacks (49.2) and Hispanics/Latinos (19.5) were 12.6 and 5.0 times, respectively, the rate among older Whites (3.9); rates among younger Blacks (102.5) and Hispanics/Latinos (39.0) were 7.7 and 2.9 times, respectively, the rate among younger Whites (13.3). Older persons were more likely than younger persons to receive a late HIV diagnosis (prevalence ratio=1.5, P<.001). CONCLUSIONS Racial/ethnic disparities in HIV diagnosis rates are greater among persons aged 50 years and older than among younger persons. The greater HIV diagnosis rates in Blacks and later diagnosis among older persons of all races/ethnicities indicate a need to increase their awareness of risk factors for HIV infection.

Association Between Community Socioeconomic Position and HIV Diagnosis Rate Among Adults and Adolescents in the United States, 2005 to 2009

OBJECTIVES We examined the association between socioeconomic position (SEP) and HIV diagnosis rates in the United States and whether racial/ethnic disparities in diagnosis rates persist after control for SEP. METHODS We used cases of HIV infection among persons aged 13 years and older, diagnosed 2005 through 2009 in 37 states and reported to national HIV surveillance through June 2010, and US Census data, to examine associations between county-level SEP measures and 5-year average annual HIV diagnosis rates overall and among race/ethnicity-sex groups. RESULTS The HIV diagnosis rate was significantly higher for individuals in the low-SEP tertile than for those in the high-SEP tertile (rate ratios for low- vs high-SEP tertiles range = 1.68-3.38) except for White males and Hispanic females. The SEP disparities were larger for minorities than for Whites. Racial disparities persisted after we controlled for SEP, urbanicity, and percentage of population aged 20 to 50 years, and were high in the low-SEP tertile for males and in low- and high-SEP tertiles for females. CONCLUSIONS Findings support continued prioritization of HIV testing, prevention, and treatment to persons in economically deprived areas, and Blacks of all SEP levels.

Racial Disparity in U.S. Diagnoses of Acquired Immune Deficiency Syndrome, 2000–2009

BACKGROUND Increased attention has been focused on health disparities among racial/ethnic groups in the U.S. PURPOSE To assess the extent of progress toward meeting the targets of Healthy People 2010 objectives and eliminating disparities. METHODS All diagnoses of AIDS during 2000-2009 among people aged ≥ 13 years in the 50 states and District of Columbia, reported to national HIV surveillance through June 2010, together with census population data were used in this analysis (conducted in March 2011). This study assesses the trend in racial/ethnic disparities in rates of AIDS diagnoses both between particular groups using rate difference (RD) and rate ratio (RR) and across the entire range of racial/ethnic subgroups using three summary measures of disparity: between-group variance (BGV); Theil index (TI); and mean log deviation (MLD). RESULTS The overall racial/ethnic disparity, black-white disparity, and Hispanic-white disparity in rates of AIDS diagnoses decreased for those aged 25-64 years from 2000 to 2009. The black-white and Hispanic-white disparity in rates of AIDS diagnoses also decreased among men aged ≥ 65 years; however, the black-white disparity increased among young men aged 13-24 years (BGV: p<0.001, black-white RD: p<0.01) from 2000 to 2009. CONCLUSIONS Findings indicate overall decreases in racial/ethnic disparities in AIDS diagnoses except in young men, particularly young black men aged 13-24 years where the burden of AIDS is increasing. HIV testing, prevention, treatment and policy-making should be a priority for this group.

The Epidemiology of Human Immunodeficiency Virus Infection and Care among Adult and Adolescent Females in the United States, 2008-2012

OBJECTIVE We sought to determine epidemiological patterns in diagnoses of human immunodeficiency virus (HIV) infection and prevalence among females by age, race/ethnicity and transmission category, and essential steps in the continuum of HIV care. METHODS Using data from the National HIV Surveillance System, we estimated the number of females aged 13 years or older diagnosed with HIV infection in 2008 through 2012 and living with HIV at the end of 2011 in the United States. We determined percentages of females linked to care, retained in care, and virally suppressed in 18 jurisdictions with complete reporting of CD4 and viral load test results. RESULTS From 2008 to 2012, the estimated rate of HIV diagnoses among females decreased from 9.3 to 6.9 per 100,000 (-7.1% per year; 95% confidence interval [CI], -7.9, -6.3). In 2012, the diagnosis rate was highest among Blacks/African Americans (35.7), followed by Hispanics or Latinos (6.4), and Native Hawaiian Other Pacific Islander (5.1), and lowest among Whites (1.8). Most females diagnosed in 2012 were linked to care within 3 months of diagnosis (82.5%). About one-half (52.4%) of females living with HIV in 2011 received ongoing care in 2011 and 44.3% had a suppressed viral load. Viral suppression was lower among American Indian/Alaska Native (29.7%) and Black/African American (41.6%) compared with White females (46.5%). The percentage in care and with viral suppression was lower among younger compared with older females. CONCLUSION HIV diagnoses continue to decrease among females; however, disparities exist in HIV burden and viral suppression. Improvements in care and treatment outcomes are needed for all women with particular emphasis on younger women.

Comparison of Rates of Death Having any Death-Certificate Mention of Heart, Kidney, or Liver Disease Among Persons Diagnosed with HIV Infection with those in the General US Population, 2009-2011

Objective : Compare age-adjusted rates of death due to liver, kidney, and heart diseases during 2009-2011 among US residents diagnosed with HIV infection with those in the general population. Methods : Numerators were numbers of records of multiple-cause mortality data from the national vital statistics system with an ICD-10 code for the disease of interest (any mention, not necessarily the underlying cause), divided into those 1) with and 2) without an additional code for HIV infection. Denominators were 1) estimates of persons living with diagnosed HIV infection from national HIV surveillance system data and 2) general population estimates from the US Census Bureau. We compared age-adjusted rates overall (unstratified by sex, race/ethnicity, or region of residence) and stratified by demographic group. Results : Overall, compared with the general population, persons diagnosed with HIV infection had higher age-adjusted rates of death reported with hepatitis B (rate ratio [RR]=42.6; 95% CI: 34.7-50.7), hepatitis C (RR=19.4; 95% CI: 18.1-20.8), liver disease excluding hepatitis B or C (RR=2.1; 95% CI: 1.8-2.3), kidney disease (RR=2.4; 95% CI: 2.2-2.6), and cardiomyopathy (RR=1.9; 95% CI: 1.6-2.3), but lower rates of death reported with ischemic heart disease (RR=0.6; 95% CI: 0.6-0.7) and heart failure (RR=0.8; 95% CI: 0.6-0.9). However, the differences in rates of death reported with the heart diseases were insignificant in some demographic groups. Conclusion : Persons with HIV infection have a higher risk of death with liver and kidney diseases reported as causes than the general population.

HIV Testing Experience Before HIV Diagnosis Among Men Who Have Sex with Men — 21 Jurisdictions, United States, 2007–2013

Gay, bisexual, and other men who have sex with men (MSM) continue to be the population most affected by human immunodeficiency virus (HIV) in the United States. In 2014, 81% of diagnoses of HIV infection were among adult and adolescent males, and among these, 83% of infections were attributable to male-to-male sexual contact (1). Since 2006, CDC has recommended HIV testing at least annually for sexually active MSM to foster early detection of HIV infection and prevent HIV transmission (2,3). Several initiatives and strategies during the past decade have aimed to expand HIV testing among MSM to increase early diagnosis and treatment and reduce transmission. To better understand HIV testing patterns among MSM with diagnosed HIV infection, CDC analyzed data for 2007-2013 from jurisdictions conducting HIV incidence surveillance as part of CDCs National HIV Surveillance System (NHSS). Findings from this analysis suggest that increasing percentages of MSM have had a negative HIV test during the 12 months before diagnosis (48% in 2007, 56% in 2013, among those with a known date of previous negative HIV test), indicating a trend toward increased HIV testing and earlier HIV diagnosis among persons most at risk for HIV.

A Bayesian hierarchical model with novel prior specifications for estimating HIV testing rates

Human immunodeficiency virus (HIV) infection is a severe infectious disease actively spreading globally, and acquired immunodeficiency syndrome (AIDS) is an advanced stage of HIV infection. The HIV testing rate, that is, the probability that an AIDS-free HIV infected person seeks a test for HIV during a particular time interval, given no previous positive test has been obtained prior to the start of the time, is an important parameter for public health. In this paper, we propose a Bayesian hierarchical model with two levels of hierarchy to estimate the HIV testing rate using annual AIDS and AIDS-free HIV diagnoses data. At level one, we model the latent number of HIV infections for each year using a Poisson distribution with the intensity parameter representing the HIV incidence rate. At level two, the annual numbers of AIDS and AIDS-free HIV diagnosed cases and all undiagnosed cases stratified by the HIV infections at different years are modeled using a multinomial distribution with parameters including the HIV testing rate. We propose a new class of priors for the HIV incidence rate and HIV testing rate taking into account the temporal dependence of these parameters to improve the estimation accuracy. We develop an efficient posterior computation algorithm based on the adaptive rejection metropolis sampling technique. We demonstrate our model using simulation studies and the analysis of the national HIV surveillance data in the USA.