Differences in CD4 cell counts at seroconversion and decline among 5739 HIV-1-infected individuals with well-estimated dates of seroconversion

Mapping age- and sex-specific HIV prevalence in adults in sub-Saharan Africa, 2000-2018

BACKGROUND

Human immunodeficiency virus and acquired immune deficiency syndrome (HIV/AIDS) is still among the leading causes of disease burden and mortality in sub-Saharan Africa (SSA), and the world is not on track to meet targets set for ending the epidemic by the Joint United Nations Programme on HIV/AIDS (UNAIDS) and the United Nations Sustainable Development Goals (SDGs). Precise HIV burden information is critical for effective geographic and epidemiological targeting of prevention and treatment interventions. Age- and sex-specific HIV prevalence estimates are widely available at the national level, and region-wide local estimates were recently published for adults overall. We add further dimensionality to previous analyses by estimating HIV prevalence at local scales, stratified into sex-specific 5-year age groups for adults ages 15-59 years across SSA.

METHODS

We analyzed data from 91 seroprevalence surveys and sentinel surveillance among antenatal care clinic (ANC) attendees using model-based geostatistical methods to produce estimates of HIV prevalence across 43 countries in SSA, from years 2000 to 2018, at a 5 × 5-km resolution and presented among second administrative level (typically districts or counties) units.

RESULTS

We found substantial variation in HIV prevalence across localities, ages, and sexes that have been masked in earlier analyses. Within-country variation in prevalence in 2018 was a median 3.5 times greater across ages and sexes, compared to for all adults combined. We note large within-district prevalence differences between age groups: for men, 50% of districts displayed at least a 14-fold difference between age groups with the highest and lowest prevalence, and at least a 9-fold difference for women. Prevalence trends also varied over time; between 2000 and 2018, 70% of all districts saw a reduction in prevalence greater than five percentage points in at least one sex and age group. Meanwhile, over 30% of all districts saw at least a five percentage point prevalence increase in one or more sex and age group.

CONCLUSIONS

As the HIV epidemic persists and evolves in SSA, geographic and demographic shifts in prevention and treatment efforts are necessary. These estimates offer epidemiologically informative detail to better guide more targeted interventions, vital for combating HIV in SSA.

Re-assessing the late HIV diagnosis surveillance definition in the era of increased and frequent testing

OBJECTIVES

Late HIV diagnosis (CD4 <350 cells/mm³ ) is a key public health metric. In an era of more frequent testing, the likelihood of HIV diagnosis occurring during seroconversion, when CD4 counts may dip below 350, is greater. We applied a correction, considering markers of recent infection, and re-assessed 1-year mortality following late diagnosis.

METHODS

We used national epidemiological and laboratory surveillance data from all people diagnosed with HIV in England, Wales, and Northern Ireland (EW&NI). Those with a baseline CD4 <350 were reclassified as 'not late' if they had evidence of recent infection (recency test and/or negative test within 24 months). A correction factor (CF) was the number reclassified divided by the number with a CD4 <350.

RESULTS

Of the 32 227 people diagnosed with HIV in EW&NI between 2011 and 2019 with a baseline CD4 (81% of total), 46% had a CD4 <350 (uncorrected late diagnosis rate): 34% of gay and bisexual men (GBM), 65% of heterosexual men, and 56% of heterosexual women. Accounting for recency test and/or prior negative tests gave a 'corrected' late diagnosis rate of 39% and corresponding CF of 14%. The CF increased from 10% to 18% during 2011-2015, then plateaued, and was larger among GBM (25%) than heterosexual men and women (6% and 7%, respectively). One-year mortality among people diagnosed late was 329 per 10 000 after reclassification (an increase from 288/10 000).

CONCLUSIONS

The case-surveillance definition of late diagnosis increasingly overestimates late presentation, the extent of which differs by key populations. Adjustment of late diagnosis is recommended, particularly for frequent testers such as GBM.

CRF07_BC is associated with slow HIV disease progression in Chinese patients

HIV subtypes convey important epidemiological information and possibly influence the rate of disease progression. In this study, HIV disease progression in patients infected with CRF01_AE, CRF07_BC, and subtype B was compared in the largest HIV molecular epidemiology study ever done in China. A national data set of HIV pol sequences was assembled by pooling sequences from public databases and the Beijing HIV laboratory network. Logistic regression was used to assess factors associated with the risk of AIDS at diagnosis ([AIDSAD], defined as a CD4 count < 200 cells/µL) in patients with HIV subtype B, CRF01_AE, and CRF07_BC. Of the 20,663 sequences, 9,156 (44.3%) were CRF01_AE. CRF07_BC was responsible for 28.3% of infections, followed by B (13.9%). In multivariable analysis, the risk of AIDSAD differed significantly according to HIV subtype (OR for CRF07_BC vs. B: 0.46, 95% CI 0.39─0.53), age (OR for ≥ 65 years vs. < 18 years: 4.3 95% CI 1.81─11.8), and transmission risk groups (OR for men who have sex with men vs. heterosexuals: 0.67 95% CI 0.6─0.75). These findings suggest that HIV diversity in China is constantly evolving and gaining in complexity. CRF07_BC is less pathogenic than subtype B, while CRF01_AE is as pathogenic as B.

Transmitted HIV-1 is more virulent in heterosexual individuals than men-who-have-sex-with-men

Transmission bottlenecks introduce selection pressures on HIV-1 that vary with the mode of transmission. Recent studies on small cohorts have suggested that stronger selection pressures lead to fitter transmitted/founder (T/F) strains. Manifestations of this selection bias at the population level have remained elusive. Here, we analysed early CD4 cell count measurements reported from ∼340,000 infected heterosexual individuals (HET) and men-who-have-sex-with-men (MSM), across geographies, ethnicities and calendar years. The reduction in CD4 counts early in infection is reflective of the virulence of T/F strains. MSM and HET use predominant modes of transmission, namely, anal and penile-vaginal, with among the largest differences in the selection pressures at transmission across modes. Further, in most geographies, the groups show little inter-mixing, allowing for the differential selection bias to be sustained and amplified. We found that the early reduction in CD4 counts was consistently greater in HET than MSM (P<0.05). To account for inherent variations in baseline CD4 counts, we constructed a metric to quantify the extent of progression to AIDS as the ratio of the reduction in measured CD4 counts from baseline and the reduction associated with AIDS. We found that this progression corresponding to the early CD4 measurements was ∼68% for MSM and ∼87% for HET on average (P<10⁻⁴; Cohen’s d, d_s = 0.36), reflecting the more severe disease caused by T/F strains in HET than MSM at the population level. Interestingly, the set-point viral load was not different between the groups (d_s<0.12), suggesting that MSM were more tolerant and not more resistant to their T/F strains than HET. This difference remained when we controlled for confounding factors using multivariable regression. We concluded that the different selection pressures at transmission have resulted in more virulent T/F strains in HET than MSM. These findings have implications for our understanding of HIV-1 pathogenesis, evolution, and epidemiology.

HIV-1 encounters a key bottleneck at the time of its transmission from one individual to another. This transmission bottleneck can differ between modes of transmission. The stronger this bottleneck is, the more fit the virus has to be to be successfully transmitted. Accordingly, the transmitted/founder (T/F) strains of HIV-1 may have different fitness in risk groups that use different modes of transmission. While studies on small cohorts do support this notion, observations of the manifestations of this differential selection bias at the population level have been lacking. Here, we examined reported early CD4 count measurements from ∼340,000 HET and MSM, across geographies, ethnicities, and calendar years. Early CD4 counts are a measure of the severity of the infection due to T/F strains. HET and MSM transmit predominantly via penile-vaginal and anal modes, respectively, and do not inter-mix significantly. Remarkably, we found that HET consistently had lower early CD4 counts than MSM. This difference could not be attributed to potential confounding factors, such as set-point viral load. The difference thus provided evidence that T/F strains had evolved to be more virulent in HET than MSM at the population level. Intervention strategies may benefit from accounting for this difference between risk groups.

Post-migration acquisition of HIV: Estimates from four European countries, 2007 to 2016

BackgroundThe assumption that migrants acquire human immunodeficiency virus (HIV) before migration, particularly those from high prevalence areas, is common.AimWe assessed the place of HIV acquisition of migrants diagnosed in four European countries using surveillance data.MethodsUsing CD4+ T-cell count trajectories modelled to account for seroconversion bias, we estimated infection year of newly HIV-diagnosed migrants residing in the United Kingdom (UK), Belgium, Sweden and Italy with a known arrival year and CD4+ T-cell count at diagnosis. Multivariate analyses identified predictors for post-migration acquisition.ResultsBetween 2007 and 2016, migrants constituted 56% of people newly diagnosed with HIV in the UK, 62% in Belgium, 72% in Sweden and 29% in Italy. Of 23,595 migrants included, 60% were born in Africa and 70% acquired HIV heterosexually. An estimated 9,400 migrants (40%; interquartile range (IQR): 34-59) probably acquired HIV post-migration. This proportion was similar by risk group, sex and region of birth. Time since migration was a strong predictor of post-migration HIV acquisition: 91% (IQR: 87-95) among those arriving 10 or more years prior to diagnosis; 30% (IQR: 21-37) among those 1-5 years prior. Younger age at arrival was a predictor: 15-18 years (81%; IQR: 74-86), 19-25 years (53%; IQR: 45-63), 26-35 years (37%; IQR: 30-46) and 36 years and older (25%; IQR: 21-33).ConclusionsMigrants, regardless of origin, sex and exposure to HIV are at risk of acquiring HIV post-migration to Europe. Alongside accessible HIV testing, prevention activities must target migrant communities.

Asymptomatic Adolescent HIV: Identifying a Role for Universal HIV Screening in the Pediatric Emergency Department

Adolescents account for most undiagnosed HIV infections in the United States. Although the Centers for Disease Control and Prevention (CDC) recommends universal HIV screening for all patients ≥13 years, <10% of adolescents have been tested for HIV. To identify earlier opportunities for adolescent HIV prevention and diagnosis in a region of high HIV prevalence, we sought to describe pediatric emergency department (PED) visits made by a retrospective cohort of adolescents who were later diagnosed with HIV as young adults (<25 years) through an adult emergency department (ED) universal HIV screening program. CD4+ count was used to estimate the time of HIV infection before diagnosis and all PED visits in the 10 years before diagnosis were analyzed. Universal HIV screening in the adult ED diagnosed 193 young adults (median 22 years; 90% men; 29% stage 3); 70% had CD4+ at diagnosis that was used to estimate time of infection (mean 3.8 years). Thirty-eight HIV-infected young adults had a total of 109 PED visits in the 10 years before HIV diagnosis. Sexual history was documented in 12% of PED visits and a sexually transmitted infection test was sent in 6%. Ten HIV-infected young adults had 26 PED visits during the time in which they were likely already infected with HIV, each a potential missed opportunity for earlier diagnosis. HIV-infected and at-risk adolescents are underrecognized in PED visits. Implementation of CDC-recommended universal screening may lead to earlier diagnoses and improve outcomes; the PED may also be critical in identifying adolescents eligible for preexposure prophylaxis.

Lower Broadly Neutralizing Antibody Responses in Female Versus Male HIV-1 Infected Injecting Drug Users

Understanding the factors involved in the development of broadly neutralizing antibody (bNAb) responses in natural infection can guide vaccine design aimed at eliciting protective bNAb responses. Most of the studies to identify and study the development of bNAb responses have been performed in individuals who had become infected via homo- or heterosexual HIV-1 transmission; however, the prevalence and characteristics of bNAb responses in injecting drug users (IDUs) have been underrepresented. We retrospectively studied the prevalence of bNAb responses in HIV-1 infected individuals in the Amsterdam Cohort, including 50 male and 35 female participants who reported injecting drug use as the only risk factor. Our study revealed a significantly lower prevalence of bNAb responses in females compared to males. Gender, transmission route and CD4+ count at set point, but not viral load, were independently associated with the development of bNAb responses in IDUs. To further explore the influences of gender in the setting of IDU, we also looked into the Swiss 4.5k Screen. There we observed lower bNAb responses in female IDUs as well. These results reveal that the emergence of bNAbs may be dependent on multiple factors, including gender. Therefore, the effect of gender on the development of bNAb responses is a factor that should be taken into account when designing vaccine efficacy trials.

Virological remission after antiretroviral therapy interruption in female African HIV seroconverters

INTRODUCTION

There are few data on the frequency of virological remission in African individuals after treatment with antiretroviral therapy (ART) in primary HIV infection (PHI).

METHODS

We studied participants (n = 82) from South Africa and Uganda in Short Pulse Antiretroviral Treatment at HIV-1 Seroconversion, the first trial of treatment interruption in African individuals with PHI randomized to deferred ART or 48 weeks of immediate ART. All were female and infected with non-B HIV subtypes, mainly C. We measured HIV DNA in CD4+ T cells, CD4+ cell count, plasma viral load (pVL), cell-associated HIV RNA and T-cell activation and exhaustion. We explored associations with clinical progression and time to pVL rebound after treatment interruption (n = 22). Data were compared with non-African Short Pulse Antiretroviral Treatment at HIV-1 Seroconversion participants.

RESULTS

Pretherapy pVL and integrated HIV DNA were lower in Africans compared with non-Africans (median 4.16 vs. 4.72 log10 copies/ml and 3.07 vs. 3.61 log10 copies/million CD4+ T cells, respectively; P < 0.001). Pre-ART HIV DNA in Africans was associated with clinical progression (P = 0.001, HR per log10 copies/million CD4+ T cells increase (95% CI) 5.38 (1.95-14.79)) and time to pVL rebound (P = 0.034, HR per log10 copies/ml increase 4.33 (1.12-16.84)). After treatment interruption, Africans experienced longer duration of viral remission than non-Africans (P < 0.001; HR 3.90 (1.75-8.71). Five of 22 African participants (22.7%) maintained VL less than 400 copies/ml over a median of 188 weeks following treatment interruption.

CONCLUSION

We find evidence of greater probability of virological remission following treatment interruption among African participants, although we are unable to differentiate between sex, ethnicity and viral subtype. The finding warrants further investigation.

Determining the likely place of HIV acquisition for migrants in Europe combining subject-specific information and biomarkers data

In most HIV-positive individuals, infection time is only known to lie between the time an individual started being at risk for HIV and diagnosis time. However, a more accurate estimate of infection time is very important in certain cases. For example, one of the objectives of the Advancing Migrant Access to Health Services in Europe (aMASE) study was to determine if HIV-positive migrants, diagnosed in Europe, were infected pre- or post-migration. We propose a method to derive subject-specific estimates of unknown infection times using information from HIV biomarkers' measurements, demographic, clinical, and behavioral data. We assume that CD4 cell count (CD4) and HIV-RNA viral load trends after HIV infection follow a bivariate linear mixed model. Using post-diagnosis CD4 and viral load measurements and applying the Bayes' rule, we derived the posterior distribution of the HIV infection time, whereas the prior distribution was informed by AIDS status at diagnosis and behavioral data. Parameters of the CD4-viral load and time-to-AIDS models were estimated using data from a large study of individuals with known HIV infection times (CASCADE). Simulations showed substantial predictive ability (e.g. 84% of the infections were correctly classified as pre- or post-migration). Application to the aMASE study (n = 2009) showed that 47% of African migrants and 67% to 72% of migrants from other regions were most likely infected post-migration. Applying a Bayesian method based on bivariate modeling of CD4 and viral load, and subject-specific information, we found that the majority of HIV-positive migrants in aMASE were most likely infected after their migration to Europe.

Barriers and facilitators to HIV testing in people age 50 and above: a systematic review

Approximately 13% of people living with HIV in the UK are unaware of their infection. New diagnoses among people ≥50 years is increasing. Unique factors may be associated with testing in this group. This systematic review aims to identify patient and clinician-related barriers/facilitators to HIV testing in people aged ≥50 years. A systematic electronic search was conducted. Papers were assessed for eligibility and data from eligible studies were extracted. Barriers/facilitators were grouped, and the number of times they were reported was noted. Because of considerable heterogeneity, a narrative approach has been undertaken to synthesise data. In total, 17 studies were included. Main barriers to testing were low perceived risk and clinicians' preconceptions about older people. Main facilitators were regular use of healthcare services or being offered/encouraged to test by a healthcare provider. Although being encouraged to test was a common facilitator, clinicians' preconceptions about older people was the biggest barrier. This shows a divide between clinicians' preconceptions and patients' expectations, which may impact on testing rates. This review is an important first step in identifying potential barriers/facilitators for further study or to be addressed in the design of future interventions.

Joint estimation of CD4+ cell progression and survival in untreated individuals with HIV-1 infection

OBJECTIVE

We compiled the largest dataset of seroconverter cohorts to date from 25 countries across Africa, North America, Europe, and Southeast/East (SE/E) Asia to simultaneously estimate transition rates between CD4 cell stages and death, in antiretroviral therapy (ART)-naive HIV-1-infected individuals.

DESIGN

A hidden Markov model incorporating a misclassification matrix was used to represent natural short-term fluctuations and measurement errors in CD4 cell counts. Covariates were included to estimate the transition rates and survival probabilities for each subgroup.

RESULTS

The median follow-up time for 16 373 eligible individuals was 4.1 years (interquartile range 1.7-7.1), and the mean age at seroconversion was 31.1 years (SD 8.8). A total of 14 525 individuals had recorded CD4 cell counts pre-ART, 1885 died, and 6947 initiated ART. Median (interquartile range) survival for men aged 20 years at seroconversion was 13.0 (12.4-13.4), 11.6 (10.9-12.3), and 8.3 years (7.9-8.9) in Europe/North America, Africa, and SE/E Asia, respectively. Mortality rates increase with age (hazard ratio 2.22, 95% confidence interval 1.84-2.67 for >45 years compared with <25 years) and vary by region (hazard ratio 2.68, 1.75-4.12 for Africa and 1.88, 1.50-2.35 for Asia compared with Europe/North America). CD4 cell decline was significantly faster in Asian cohorts compared with Europe/North America (hazard ratio 1.45, 1.36-1.54).

CONCLUSION

Mortality and CD4 cell progression rates exhibited regional and age-specific differences, with decreased survival in African and SE/E Asian cohorts compared with Europe/North America and in older age groups. This extensive dataset reveals heterogeneities between regions and ages, which should be incorporated into future HIV models.

Sex disparities in outcomes among adults on long-term antiretroviral treatment in northern Nigeria

BACKGROUND

There are conflicting reports of sex differences in HIV treatment outcomes in Africa. We investigated sex disparities in treatment outcomes for adults on first line antiretroviral treatment (ART) in Nigeria.

METHODS

We compared clinical and immunologic responses to ART between HIV-infected men (n=205) and women (n=140) enrolled in an ART program between June 2004 and December 2007, with follow-up through June 2014. We employed Kaplan-Meier estimates to examine differences in time to immunologic failure and loss to follow-up (LTFU), and generalized estimating equations to assess changes in CD4+ count by sex.

RESULTS

Men had lower baseline mean CD4+ count compared to women (327.6 cells/µL vs 413.4, respectively, p<0.01). Women had significantly higher rates of increase in CD4+ count than men, even after adjusting for confounders, p<0.0001. There was no significant difference in LTFU by sex: LTFU rate was 2.47/1000 person-months (95% CI 1.6-3.9) in the first five years for men vs 1.98/1000 person-months (95% CI (1.3-3.0) for women. There was no difference in time to LTFU by sex over the study period.

CONCLUSIONS

Women achieved better long-term immune response to ART at baseline and during treatment, but had similar rates of long-term retention in care to men. Targeted efforts are needed to improve immune outcomes in men in our setting.

Increase in CD4+ T-Cell Count at the Time of HIV Diagnosis and Antiretroviral Treatment Initiation Among Persons With HIV in New York City

BACKGROUND

 Trends in CD4+ T-cell count at human immunodeficiency virus (HIV) infection diagnosis and antiretroviral therapy (ART) initiation can be characterized using laboratory tests from surveillance.

METHODS

 We used CD4+ T-cell counts and viral loads from New York City for persons who received a diagnosis of HIV infection during 2006-2012.

RESULTS

 From 2006 to 2012, the median CD4+ T-cell count increased from 325 to 379 cells/µL at diagnosis and from 178 to 360 cells/μL at ART initiation. CD4+ T-cell counts were consistently lower in women, blacks, Hispanics, persons who inject drugs, and heterosexuals.

DISCUSSION

 Increases in CD4+ T-cell count at diagnosis and ART initiation suggest that the time from HIV infection to ART initiation has been reduced substantially in New York City.

Inferring HIV incidence from case surveillance with CD4+ cell counts

BACKGROUND

In some countries, HIV surveillance is based on case-reporting of newly diagnosed infections. We present a new back-projection method for estimating HIV-incidence trends using individuals' CD4 cell counts at diagnosis.

METHODS

On the basis of a review of CD4 cell count distributions among HIV-uninfected people, CD4 cell count following primary infection, and rates of CD4 cell count decline over time among people with HIV, we simulate the expected distribution in time between infection and diagnosis. Applying this to all diagnosed individuals provides a distribution of likely infection times and estimates for population incidence, level of undiagnosed HIV, and the average time from infection to diagnosis each year. We applied this method to the national HIV case surveillance data of Australia for 1983-2013.

RESULTS

The estimated number of new HIV infections in Australia in 2013 was 912 (95% uncertainty bound 835-1002). We estimate that 2280 (95% uncertainty bound 1900-2830) people were living with undiagnosed HIV at the end of 2013, corresponding to approximately 9.4% (95% uncertainty bound 7.8-10.1%) of all people living with HIV. With increases in the average CD4 count at diagnosis, the inferred HIV testing rate has been increasing over time and the estimated mean and median times between infection and diagnosis have decreased substantially. However, the estimated mean time between infection and diagnosis is considerably greater than the median, indicating that some people remain undiagnosed for long periods. Differences were found between cases attributable to male homosexual exposure versus other cases.

CONCLUSION

This methodology provides a novel way of estimating population incidence by combining diagnosis dates and CD4 cell counts at diagnosis.

Delineating the third age: joint models of older people's quality of life and attrition in Britain 2002-2010

OBJECTIVES

In the public mind, later life is being transformed by the emerging possibility of a flourishing third age with sustained quality of life. We draw trajectories of life quality measured using CASP-19 over eight years. We refine these trajectories by jointly modelling attrition, since older people tend to leave longitudinal studies (attrite) not at random.

METHODS

Growth curve models are applied to the English Longitudinal Study of Ageing waves 1 to 5. Then joint model is estimated where attrition is considered. Extensive predictors are entered including demographic attributes, social and economic status, health conditions, and behaviours.

RESULTS

Strong non-linear age trajectory of life quality is revealed by the growth curve models where the peak is achieved in the late 60s. Then the joint model uncovers the peak somewhat later in time, and also reveals secular improvement in life quality experienced by recent cohorts. Sharp estimates for many predictors of higher levels of life quality are also found.

CONCLUSION

For the first time, the trajectories of life quality in the third age are drawn and improvement across cohorts is demonstrated. The contributions are estimated for predictors amenable to intervention such as social capital. This can help in policy discussion on improving the lives of older people in the third age.

An overview of the HIV epidemic among men who have sex with men in the United Kingdom, 1999-2013

We describe epidemiological trends in HIV among men who have sex with men (MSM) in the United Kingdom (UK) to inform prevention strategies. National HIV surveillance data were analysed for trends. Multivariable analyses identified predictors of late diagnosis (<350 copies/µL) and mortality. Between 1999 and 2013, 37,560 MSM (≥15 years) were diagnosed with HIV in the UK. New diagnoses rose annually from 1,440 in 1999 to 3,250 in 2013. The majority of MSM were of white ethnicity (85%) and UK-born (68%). Median CD4 count increased steadily from 350 cells/µL to 463 cells/µL. HIV testing in England increased from 10,900 tests in 1999 to 102,600 in 2013. One-year death rates after diagnosis declined among late presenters (4.7% to 1.9%). Despite declining late diagnosis (50% to 31%), the number of men diagnosed late annually has remained high since 2004. Older age (≥50 years), and living outside London were predictors of late presentation; older age and late presentation were predictors of one-year mortality. Increases in new diagnoses reflect increased testing and ongoing transmission. Over 900 men present late each year and mortality in this group remains high and preventable. Appropriate prevention and testing strategies require strengthening to reduce HIV transmission and late diagnosis.

Time from human immunodeficiency virus seroconversion to reaching CD4+ cell count thresholds <200, <350, and <500 Cells/mm³: assessment of need following changes in treatment guidelines

BACKGROUND

Recent updates of human immunodeficiency virus (HIV) treatment guidelines have raised the CD4+ cell count thresholds for antiretroviral therapy initiation from 350 to 500 cells/mm(3) in the United States and from 200 to 350 cells/mm³ in mid- and low-income countries. Robust data of time from HIV seroconversion to CD4+ cell counts of 200, 350, and 500 cells/mm³ are lacking but are needed to inform health care planners of the likely impact and cost effectiveness of these and possible future changes in CD4+ cell count initiation threshold.

METHODS

Using Concerted Action on Seroconversion to AIDS and Death in Europe data from individuals with well-estimated dates of HIV seroconversion, we fitted mixed models on the square root of CD4+ cell counts measured before combined antiretroviral therapy (cART) initiation. Restricting analyses to adults (age >16 years), we predicted time between seroconversion and CD4+ cell count <200, <350, and <500 cells/mm³ as well as CD4+ cell count distribution and proportions reaching these thresholds at 1, 2, and 5 years after seroconversion.

RESULTS

Median (interquartile range [IQR]) follow-up for the 18495 eligible individuals from seroconversion while cART-free was 3.7 years (1.5, 7). Most of the subjects were male (78%), had a median age at seroconversion of 30 years (IQR, 25-37 years), and were infected through sex between men (55%). Estimated median times (95% confidence interval [CI]) from seroconversion to CD4+ cell count <500, <350, and <200 cells/mm(3) were 1.19 (95% CI, 1.12-1.26), 4.19 (95% CI, 4.09-4.28), and 7.93 (95% CI, 7.76-8.09) years, respectively. Almost half of infected individuals would require treatment within 1 year of seroconversion for guidelines recommending its initiation at 500 cells/mm³, compared with 26% and 9% for guidelines recommending initiation at 350 and 200 cells/mm³, respectively.

CONCLUSIONS

These data suggest substantial increases in the number of individuals who require treatment and call for early HIV testing.

The contribution of viral genotype to plasma viral set-point in HIV infection

Disease progression in HIV-infected individuals varies greatly, and while the environmental and host factors influencing this variation have been widely investigated, the viral contribution to variation in set-point viral load, a predictor of disease progression, is less clear. Previous studies, using transmission-pairs and analysis of phylogenetic signal in small numbers of individuals, have produced a wide range of viral genetic effect estimates. Here we present a novel application of a population-scale method based in quantitative genetics to estimate the viral genetic effect on set-point viral load in the UK subtype B HIV-1 epidemic, based on a very large data set. Analyzing the initial viral load and associated pol sequence, both taken before anti-retroviral therapy, of 8,483 patients, we estimate the proportion of variance in viral load explained by viral genetic effects to be 5.7% (CI 2.8-8.6%). We also estimated the change in viral load over time due to selection on the virus and environmental effects to be a decline of 0.05 log10 copies/mL/year, in contrast to recent studies which suggested a reported small increase in viral load over the last 20 years might be due to evolutionary changes in the virus. Our results suggest that in the UK epidemic, subtype B has a small but significant viral genetic effect on viral load. By allowing the analysis of large sample sizes, we expect our approach to be applicable to the estimation of the genetic contribution to traits in many organisms.

Frequency and correlates of late presentation for HIV infection in France: older adults are a risk group - results from the ANRS-VESPA2 Study, France

Correlates of late presentation (LP) for HIV infection in Metropolitan France and French overseas departments (FODs) were assessed among HIV-infected patients recently diagnosed, using data from a large cross-sectional survey, representative of the French HIV-infected population, conducted in 2011. LP was defined as presentation with either clinical AIDS events within the calendar year of diagnosis or CD4 < 350/mm(3) and presentation with advanced disease (PAD) was defined as presentation with either clinical AIDS events or CD4 < 200/mm(3). Correlates of LP/PAD were assessed through logistic modelling, separately in Metropolitan France and FODs. In Metropolitan France, 47.7% of participants were late presenters and 29.3% presented with advanced disease. LP was more frequent among male and female migrants from sub-Saharan Africa (SSA; 58.5% and 56.4%) and non-African heterosexual males (61.8%) than among men who have sex with men (34.8%). In FODs, 53.2% of participants were late presenters and 36.8% presented with an advanced disease. LP was more frequent among men than women (60.6% vs. 45.3%) and among those with a lower level of education (56.6% vs. 47.5%). A consistent positive association was found in adjusted analyses between LP/PAD and increasing age at diagnosis among all subpopulations, in both settings. In Metropolitan France, among men who have sex with men, those self-declaring as bisexual were at higher risk of LP/PAD; among non-African heterosexual males and females, religiosity was associated with increased risk of LP/PAD; and among SSA migrants, those diagnosed within the year following their arrival in France were at higher risk of LP/PAD. Older age at diagnosis is a major risk factor for LP/PAD independently of any other socio-demographic characteristics. Promotion of HIV testing should be renewed to target each subgroup at risk while paying a particular attention to middle-aged or older adults whose attitudes and beliefs towards HIV/AIDS might prevent them from seeking testing.

Slow immunological progression in HIV-1 CRF07_BC-infected injecting drug users

Human immunodeficiency virus type 1 (HIV-1) circulating recombinant form (CRF) 07_BC has caused serious HIV-1 epidemics among injecting drug users (IDUs) in East Asia. Little is known about the characteristics of the virus and its impact on disease progression among the infected individuals. In this study, we compared immunological progression between 423 IDUs infected with CRF07_BC and 194 men who have sex with men (MSM) with primary subtype B infection, and a representative full-length CRF07_BC molecular clone, pCRF07_BC, was constructed to characterize the virus. We found that IDUs infected with CRF07_BC had significantly slower immunological progression in the Cox proportional hazards model (hazard ratio: 0.30; 95% confidence interval: 0.13–0.69; P=0.004). The constructed recombinant CRF07_BC viruses had a reduced processing of the Gag/Gag-Pol polyproteins, a decreased incorporation of Vpr in the virus particle, tethering of virus particles on the plasma membrane and decreased virus growth kinetics. These phenotypes are related to the unique 7-amino acid deletion in the p6 of CRF07_BC, since complementation of the 7-amino acid in pCRF07_BC could improve the defective phenotypes. In summary, compared with MSM infected with HIV-1 subtype B, IDUs infected with CRF07_BC had slower immunological progression, which is likely correlated with interference of virus particle maturation by the 7-amino acid deletion in p6.

The effects of age on associations between markers of HIV progression and markers of metabolic function including albumin, haemoglobin and lipid concentrations

OBJECTIVES

We investigated whether age modified associations between markers of HIV progression, CD4 T lymphocyte count and HIV RNA viral load (VL), and the following markers of metabolic function: albumin, haemoglobin, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC).

METHODS

A retrospective analysis of data from the United Kingdom Collaborative HIV Cohort was carried out. Analyses were limited to antiretroviral-naïve subjects to focus on the impact of HIV disease itself. A total of 16670 subjects were included in the analysis. Multilevel linear regression models assessed associations between CD4 count/VL and each of the outcomes. Statistical tests for interactions assessed whether associations differed among age groups.

RESULTS

After adjustment for gender and ethnicity, there was evidence that lower CD4 count and higher VL were associated with lower TC, LDL-C, haemoglobin and albumin concentrations but higher triglyceride concentrations. Age modified associations between CD4 count and albumin (P < 0.001) and haemoglobin (P = 0.001), but not between CD4 count and HDL-C, LDL-C and TC, or VL and any outcome. Among participants aged < 30, 30-50 and > 50 years, a 50 cells/μL lower CD4 count correlated with a 2.4 [95% confidence interval (CI) 1.7-3.0], 3.6 (95% CI 3.2-4.0) and 5.1 (95% CI 4.0-6.1) g/L lower haemoglobin concentration and a 0.09 (95% CI 0.07-0.11), 0.12 (95% CI 0.11-0.13) and 0.16 (95% CI 0.13-0.19) g/L lower albumin concentration, respectively.

CONCLUSIONS

We present evidence that age modifies associations between CD4 count and plasma albumin and haemoglobin levels. A given reduction in CD4 count was associated with a greater reduction in haemoglobin and albumin concentrations among older people living with HIV. These findings increase our understanding of how the metabolic impact of HIV is influenced by age.

A new method to assign country of HIV infection among heterosexuals born abroad and diagnosed with HIV

OBJECTIVE

To apply a new method to ascertain likely place of HIV infection among persons born abroad and diagnosed with HIV in the United Kingdom (UK).

DESIGN

Analyses of heterosexual adults born abroad, diagnosed with HIV in the UK between 2004 and 2010, and reported to the national HIV diagnoses database.

METHODS

Year of infection was ascertained by applying an estimated rate of CD4 cell count decline between an individual's CD4 cell count at diagnosis and estimates of CD4-cell count at infection. A person was classified as having probably acquired HIV while living in the UK if estimated year of infection was later than reported year of arrival in the UK.

RESULTS

Of 10 612 heterosexual adults born abroad included in the analyses, 85% (9065) were of black-African ethnicity. We estimate that 33% (26-39%) of persons acquired HIV while living in the UK. This percentage increased from 24% (16-39%) in 2004 to 46% (31-50%) in 2010 (P < 0.01). The estimate of 33% is three times higher than national estimates of HIV acquired in the UK based on clinic reports (11%) (P <  0.01).

CONCLUSION

: Assigning place of HIV infection using routinely available clinical and demographic data and estimated rates of CD4 cell decline is feasible. We report a high and increasing proportion of persons born abroad who appear to have acquired their HIV infection while living in the UK. These findings highlight the need for continued targeted HIV prevention efforts, particularly among black-African communities.

Epidemiological and Immunological Characteristics at the Time of HIV Diagnosis for HIV/AIDS Cohort Registrants Representative of HIV-Infected Populations in Korea

OBJECTIVES

The Korea HIV/AIDS cohort was constructed with 18 hospitals that care for HIV-infected individuals in 2006. We compared the epidemiological and immunological characteristics of the cohort registrants with those of the HIVinfected population at the time of HIV diagnosis.

METHODS

This study was conducted on 5717 people living with HIV/AIDS from 1985 to 2009, of which 789 individuals registered with the Korea HIV/AIDS cohort study. Individuals who had data from initial CD4+ T-cell counts measured within 6 months following HIV diagnosis were selected as study participants to predict the status of disease progression at the time of HIV diagnosis. A total of 2886 patients (50%) were selected from people living with HIV/AIDS, of whom 424 individuals (54%) were cohort registrants. The χ(2) test and Wilcoxon rank sum test were used for analysis.

RESULTS

The distributions of age, marital status, diagnosed regions, reason for HIV testing, and screening site were similar between the HIV-infected population and the cohort registrants. In 1985-2004, the male ratio for the cohort registrants (94.3%) was significantly higher than that measured for the HIV-infected population (89.5%) (p = 0.0339). With regard to transmission route, homosexual contact of cohort registrants (46.6%) was higher than that of the HIV-infected population (40.1%) (p = 0.022) in 2005-2009. No statistical difference in CD4+ T-cell counts at the time of HIV diagnosis was found between the HIVinfected population and cohort registrants (p = 0.2195).

CONCLUSION

The Korea HIV/AIDS cohort registrants represent the HIV-infected population, and the data collected from this cohort could be used as a foundation for national statistics.

Immediate antiviral therapy appears to restrict resting CD4+ cell HIV-1 infection without accelerating the decay of latent infection

HIV type 1 (HIV-1) persists within resting CD4(+) T cells despite antiretroviral therapy (ART). To better understand the kinetics by which resting cell infection (RCI) is established, we developed a mathematical model that accurately predicts (r = 0.65, P = 2.5 × 10(-4)) the initial frequency of RCI measured about 1 year postinfection, based on the time of ART initiation and the dynamic changes in viremia and CD4(+) T cells. In the largest cohort of patients treated during acute seronegative HIV infection (AHI) in whom RCI has been stringently quantified, we found that early ART reduced the generation of latently infected cells. Although RCI declined after the first year of ART in most acutely infected patients, there was a striking absence of decline when initial RCI frequency was less than 0.5 per million. Notably, low-level viremia was observed more frequently as RCI increased. Together these observations suggest that (i) the degree of RCI is directly related to the availability of CD4(+) T cells susceptible to HIV, whether viremia is controlled by the immune response and/or ART; and (ii) that two pools of infected resting CD4(+) T cells exist, namely, less stable cells, observable in patients in whom viremia is not well controlled in early infection, and extremely stable cells that are established despite early ART. These findings reinforce and extend the concept that new approaches will be needed to eradicate HIV infection, and, in particular, highlight the need to target the extremely small but universal, long-lived latent reservoir.

Is the virulence of HIV changing? A meta-analysis of trends in prognostic markers of HIV disease progression and transmission

OBJECTIVE

The potential for changing HIV-1 virulence has significant implications for the AIDS epidemic, including changing HIV transmission rates, rapidity of disease progression, and timing of ART. Published data to date have provided conflicting results.

DESIGN

We conducted a meta-analysis of changes in baseline CD4(+) T-cell counts and set point plasma viral RNA load over time in order to establish whether summary trends are consistent with changing HIV-1 virulence.

METHODS

We searched PubMed for studies of trends in HIV-1 prognostic markers of disease progression and supplemented findings with publications referenced in epidemiological or virulence studies. We identified 12 studies of trends in baseline CD4(+) T-cell counts (21, 052 total individuals), and eight studies of trends in set point viral loads (10 ,785 total individuals), spanning the years 1984-2010. Using random-effects meta-analysis, we estimated summary effect sizes for trends in HIV-1 plasma viral loads and CD4(+) T-cell counts.

RESULTS

Baseline CD4(+) T-cell counts showed a summary trend of decreasing cell counts [effect = -4.93  cells/μl per year, 95% confidence interval (CI) -6.53 to -3.3]. Set point viral loads showed a summary trend of increasing plasma viral RNA loads (effect = 0.013  log(10)  copies/ml per year, 95% CI -0.001 to 0.03). The trend rates decelerated in recent years for both prognostic markers.

CONCLUSION

Our results are consistent with increased virulence of HIV-1 over the course of the epidemic. Extrapolating over the 30 years since the first description of AIDS, this represents a CD4(+) T cells loss of approximately 148  cells/μl and a gain of 0.39  log(10)  copies/ml of viral RNA measured during early infection. These effect sizes would predict increasing rates of disease progression, and need for ART as well as increasing transmission risk.

Late presentation and transmitted drug resistance mutations in new HIV-1 diagnoses in Detroit

OBJECTIVE

To characterize the epidemiology and transmitted drug resistance mutation (TDRM) patterns among individuals with newly diagnosed HIV-1 infection seen at Henry Ford Hospital in Detroit from 2006 to 2008.

METHODS

This was a retrospective analysis of medical records from individuals aged ≥ 18 years with a new diagnosis of HIV-1 infection. Individuals who underwent genotypic resistance testing were included in the study.

RESULTS

One hundred thirty-three individuals were included; 99 (74%) were males, 104 (78%) were African-Americans, and 61 (46%) had a CD4+ count of ≤ 200 cells/μl. The prevalence of TDRM was 17% (23/133). Non-nucleoside reverse transcriptase mutations occurred in 11 (8%), nucleoside reverse transcriptase mutations in 13 (10%), and protease inhibitor mutations in 10 (8%). CD4+ count >350 cells/μl and HIV viral load on presentation were associated with TDRM in the multivariate analysis (p=0.004 and p<0.001 respectively).

CONCLUSIONS

Late diagnosis of HIV-1 and transmitted antiretroviral resistance are relatively common in Detroit. While most newly diagnosed persons were candidates for antiretroviral therapy on presentation, the high prevalence of TDRM has significant implications in the selection of first-line highly active antiretroviral therapy (HAART).

A cost-effectiveness analysis of alternative HIV retesting strategies in sub-saharan Africa

BACKGROUND

Guidelines in sub-Saharan Africa on when HIV-seronegative persons should retest range from never to annually for lower-risk populations and from annually to every 3 months for high-risk populations.

METHODS

We designed a mathematical model to compare the cost-effectiveness of alternative HIV retesting frequencies. Cost of HIV counseling and testing, linkage to care, treatment costs, disease progression, and mortality, and HIV transmission are modeled for three hypothetical cohorts with posited annual HIV incidence of 0.8%, 1.3%, and 4.0%, respectively. The model compared costs, quality-adjusted life-years gained, and secondary infections averted from testing intervals ranging from 3 months to 30 years. Input parameters from sub-Saharan Africa were used and explored in sensitivity analyses.

RESULTS

Accounting for secondary infections averted, the most cost-effective testing frequency was every 7.5 years for 0.8% incidence, every 5 years for 1.3% incidence, and every 2 years for 4.0% incidence. Optimal testing strategies and their relative cost-effectiveness were most sensitive to assumptions about HIV counseling and testing and treatment costs, rates of CD4 decline, rates of HIV transmission, and whether tertiary infections averted were taken into account.

CONCLUSIONS

While higher risk populations merit more frequent HIV testing than low risk populations, regular retesting is beneficial even in low-risk populations. Our data demonstrate benefits of tailoring testing intervals to resource constraints and local HIV incidence rates.

Development and validation of decision rules to guide frequency of monitoring CD4 cell count in HIV-1 infection before starting antiretroviral therapy

Background

Although CD4 cell count monitoring is used to decide when to start antiretroviral therapy in patients with HIV-1 infection, there are no evidence-based recommendations regarding its optimal frequency. It is common practice to monitor every 3 to 6 months, often coupled with viral load monitoring. We developed rules to guide frequency of CD4 cell count monitoring in HIV infection before starting antiretroviral therapy, which we validated retrospectively in patients from the Swiss HIV Cohort Study.

Methodology/Principal Findings

We built up two prediction rules (“Snap-shot rule” for a single sample and “Track-shot rule” for multiple determinations) based on a systematic review of published longitudinal analyses of CD4 cell count trajectories. We applied the rules in 2608 untreated patients to classify their 18 061 CD4 counts as either justifiable or superfluous, according to their prior ≥5% or <5% chance of meeting predetermined thresholds for starting treatment. The percentage of measurements that both rules falsely deemed superfluous never exceeded 5%. Superfluous CD4 determinations represented 4%, 11%, and 39% of all actual determinations for treatment thresholds of 500, 350, and 200×10⁶/L, respectively. The Track-shot rule was only marginally superior to the Snap-shot rule. Both rules lose usefulness for CD4 counts coming near to treatment threshold.

Conclusions/Significance

Frequent CD4 count monitoring of patients with CD4 counts well above the threshold for initiating therapy is unlikely to identify patients who require therapy. It appears sufficient to measure CD4 cell count 1 year after a count >650 for a threshold of 200, >900 for 350, or >1150 for 500×10⁶/L, respectively. When CD4 counts fall below these limits, increased monitoring frequency becomes advisable. These rules offer guidance for efficient CD4 monitoring, particularly in resource-limited settings.

A strong case for viral genetic factors in HIV virulence

HIV infections show great variation in the rate of progression to disease, and the role of viral genetic factors in this variation had remained poorly characterized until recently. Now a series of four studies [1-4] published within a year has filled this important gap and has demonstrated a robust effect of the viral genotype on HIV virulence.

Increased rate of CD4+ T-cell decline and faster time to antiretroviral therapy in HIV-1 subtype CRF01_AE infected seroconverters in Singapore

Background

It remains controversial as to whether HIV-1 subtypes influence disease progression. Singapore offers a unique opportunity to address this issue due to the presence of co-circulating subtypes. We compared subtype CRF01_AE and non-CRF01_AE infected patients, with regards to estimated annual rate of CD4+ T-cell loss and time from estimated data of seroconversion (EDS) to antiretroviral therapy (ART).

Methods

We recruited ART-naive patients with known dates of seroconversion between October 2002 and December 2007 at the Singapore Communicable Disease Centre, the national reference treatment centre. Multilevel mixed-effects models were used to analyse the rate of CD4+ T-cell decline. Time from EDS to ART was analyzed with the Kaplan-Meier survival method and compared with Cox proportional hazards models.

Results

54 patients with previously assigned HIV-1 subtypes (24 CRF01_AE, 17 B, 8 B', 1 CRF33_01B, 3 CRF34_01B and 1 G) were observed for 89 patient-years. Subtype CRF01_AE and non-CRF01_AE infected patients did not differ in age, gender, risk factor, rate of symptomatic seroconversion, baseline CD4+ T-cell count, log₁₀ viral load or haemoglobin concentration. The estimated annual rate of CD4+ T-cell loss was 58 cells/mm³/year (95% CI: 7 to 109; P = 0.027) greater in subtype CRF01_AE infected patients compared to non-CRF01_AE patients, after adjusting for age, baseline CD4+ T-cell count and baseline log₁₀ viral load. The median time from EDS to ART was 1.8 years faster comparing CRF01_AE to non-CRF01_AE infected patient with a 2.5 times (95% CI: 1.2-5.0; P = 0.013) higher hazard for ART initiation, after controlling for age, baseline CD4+ T-cell count and baseline log₁₀ viral load.

Conclusions

Infecting subtype significantly impacted the rate of CD4+ T-cell loss and time to treatment in this cohort. Studies to understand the biological basis for this difference could further our understanding of HIV pathogenesis.

CD4 decline in seroconverter and seroprevalent individuals in the precombination of antiretroviral therapy era

BACKGROUND

Studies based on seroconverters have increased our understanding of HIV disease. It is not clear, however, whether their disease progression differs from that of the general HIV population, given their reasons for presenting for testing.

METHODS

Using linear mixed models we compared CD4 decline rates for a seroconverter (CASCADE) and seroprevalent group (Concorde trial) with time origin being dates of seroconversion and randomization, respectively. Follow-up was censored at the earlier of last alive date and 1 January 1996. Analyses were adjusted for risk group, age and sex. To explore the role of symptomatic seroconversion we further categorized seroconverters into two groups: with and without an HIV test interval below 30 days as proxy.

RESULTS

The 7226 seroconverter and 1746 seroprevalent eligible individuals were mainly men (78 and 85%, respectively) infected through sex between men (52 and 63%) with mean [95% confidence interval (CI)] baseline CD4 cell count of 610 (602, 619) and 492 (479, 505) cells/μl, respectively. There was no evidence that rate of CD4 decline differs between the two groups even after adjusting for potential confounders (P = 0.67). Estimated loss in the year after reaching an arbitrary threshold of 400 cells/μl was 67 (95% CI 65, 69) and 67 (64, 69) cells/μl in the seroconverter and seroprevalent group, respectively. Whereas seroconverters with test interval below 30 days (n = 310) experienced faster decline, there was no difference in rates between other seroconverters and seroprevalent individuals (P = 0.87).

CONCLUSIONS

These data suggest that estimates of HIV progression derived from seroconverters are likely to hold more generally for the HIV-infected population.

Phylogenetic approach reveals that virus genotype largely determines HIV set-point viral load

HIV virulence, i.e. the time of progression to AIDS, varies greatly among patients. As for other rapidly evolving pathogens of humans, it is difficult to know if this variance is controlled by the genotype of the host or that of the virus because the transmission chain is usually unknown. We apply the phylogenetic comparative approach (PCA) to estimate the heritability of a trait from one infection to the next, which indicates the control of the virus genotype over this trait. The idea is to use viral RNA sequences obtained from patients infected by HIV-1 subtype B to build a phylogeny, which approximately reflects the transmission chain. Heritability is measured statistically as the propensity for patients close in the phylogeny to exhibit similar infection trait values. The approach reveals that up to half of the variance in set-point viral load, a trait associated with virulence, can be heritable. Our estimate is significant and robust to noise in the phylogeny. We also check for the consistency of our approach by showing that a trait related to drug resistance is almost entirely heritable. Finally, we show the importance of taking into account the transmission chain when estimating correlations between infection traits. The fact that HIV virulence is, at least partially, heritable from one infection to the next has clinical and epidemiological implications. The difference between earlier studies and ours comes from the quality of our dataset and from the power of the PCA, which can be applied to large datasets and accounts for within-host evolution. The PCA opens new perspectives for approaches linking clinical data and evolutionary biology because it can be extended to study other traits or other infectious diseases.

Some untreated patients infected by HIV die within a couple of years, while others survive more than 25 years. To date, it is still unclear whether this variance in the virulence of the infection is due to the host or to the virus genotype. One of the main difficulties in answering this question is that, as for most human diseases, we tend not to know who infected whom. Here, we solve this problem by adopting a phylogenetic approach, which estimates the heritability of species traits on a phylogeny. In our case, species correspond to infected patients and the trait is an infection trait. The phylogeny is obtained from the HIV RNA sequences isolated in each patient. We find that more than half of the variance observed in the set-point viral load—a trait that predicts virulence—is heritable from one infection to the next. This implies that set-point viral load is strongly controlled by the virus genotype. This application of the phylogenetic comparative approach to infectious diseases yields major results for the deciphering of HIV pathogenesis. Future applications to other traits and/or other pathogens will help us to better understand rapidly evolving diseases of humans.

The effect of aging, nutrition, and exercise during HIV infection

Medical advances continue to change the face of human immunodeficiency virus- acquired immunodeficiency syndrome (HIV/AIDS). As life expectancy increases, the number of people living with HIV rises, presenting new challenges for the management of a chronic condition. Aging, nutrition, and physical activity can influence outcomes in other chronic conditions, and emerging data show that each of these factors can impact viral replication and the immune system in HIV. HIV infection results in a decline of the immune system through the depletion of CD4+ T cells. From initial infection, viral replication is a continuous phenomenon. Immunosenescence, a hallmark of aging, results in an increased susceptibility to infections secondary to a delayed immune response, and this phenomenon may be increased in HIV-infected patients. Optimal nutrition is an important adjunct in the clinical care of patients with HIV. Nutritional interventions may improve the quality and span of life and symptom management, support the effectiveness of medications, and improve the patient's resistance to infections and other disease complications by altering immunity. Moderate physical activity can improve many immune parameters, reduce the risk of acute infection, and combat metabolic abnormalities. As people with HIV age, alternative therapies such as nutrition and physical activity may complement medical management.

HIV transmission and high rates of late diagnoses among adults aged 50 years and over

OBJECTIVES

Describe the epidemiology and impact of late diagnosis among older adults living with HIV and estimate age at infection.

METHODS

Comparative national analyses between individuals diagnosed when aged 50 years and over with individuals diagnosed prior to 50 years. Age at infection was estimated using CD4 cell count at diagnosis.

RESULTS

A total of 8255 older adults accessed HIV care in England, Wales and Northern Ireland in 2007, a 3.5-fold increase compared to 2000; with one in 10 individuals newly diagnosed in 2007. When compared with younger adults at diagnosis, older adults were significantly more likely to be men (74 vs. 58%; P < 0.001), infected through sex between men (40 vs. 34%; P < 0.001) and of white ethnicity (60 vs. 38%; P < 0.001). Older heterosexual adults were more likely to be infected within the UK (16 vs. 12%; P < 0.001), with evidence of travel abroad among white heterosexual men. Almost half (48%) of older adults were late presenters vs. a third (33%) of younger adults. Older late presenters were 14 times more likely to die within a year of diagnosis compared with older adults who were not diagnosed late (14 vs. 1%; P < 0.001) and had 2.4 times the risk of dying than younger late presenters. We estimate that nearly half (48%) of older adults diagnosed between 2000 and 2007 acquired their infection at age 50 and over.

CONCLUSION

Our study provides evidence of HIV transmission, high rates of late presentation and an increased risk of short-term mortality among older adults. These findings highlight the need for increased targeted prevention efforts and strategies to increase HIV testing among older adults at risk of HIV.

The effect of transmitted HIV-1 drug resistance on pre-therapy viral load

BACKGROUND

Reduced replication capacity of viruses expressing drug resistant mutations implies that patients with transmitted drug resistance (TDR) could have lower HIV RNA viral load than those infected with wild-type virus.

METHODS

We performed analysis using data from the UK HIV Drug Resistance Database and the UK CHIC study. Eligible patients had a resistance test performed between 1997 and 2007 while naive to antiretroviral therapy, were 16 years or older, and had a viral load and CD4 cell count measurement within 6 months of this test. Models were adjusted for CD4 cell count, viral subtype, ethnicity, risk group, sex, age, calendar year, clinical centre, and viral load assay.

RESULTS

Of a total of 7994 patients included, 709 (9%) had TDR: 604 (85%) had resistance to one drug class only [350 nucleos(t)ide reverse transcriptase inhibitors (NRTIs), 164 non-nucleos(t)ide reverse transcriptase inhibitors (NNRTIs), 90 protease inhibitors (PIs)], 77 (11%) to two classes (42 NRTIs/NNRTIs, 31 NRTIs/PIs, 4 NNRTIs/PIs), and 28 (4%) had resistance to all three classes. The overall mean (SD) viral load at the time of resistance testing was 4.60 (0.82) log(10) copies/ml, and did not differ by class of TDR. However, patients harbouring M184V/I (n = 61) had a significantly lower viral load [adjusted mean difference -0.33 log10 copies/ml (95% CI -0.54 to -0.11), 53% lower (95% CI 22 to 71%), P = 0.002] compared to wild-type virus.

DISCUSSION

Our study provides clear evidence of an in-vivo fitness cost associated with the M184V/I mutation independent of drug effects which select for this mutation. This was not observed for any other mutation, but true effects may have been obscured by reversion of initially resistant viruses to wild-type.

HIV-1 viral subtype differences in the rate of CD4+ T-cell decline among HIV seroincident antiretroviral naive persons in Rakai district, Uganda

BACKGROUND

Data on the effect of HIV-1 viral subtype on CD4 T-cell decline are limited.

METHODS

We assessed the rate of CD4 T-cell decline per year among 312 HIV seroincident persons infected with different HIV-1 subtypes. Rates of CD4 decline by HIV-1 subtype were determined by linear mixed effects models, using an unstructured convariance structure.

RESULTS

A total of 59.6% had D, 15.7% A, 18.9% recombinant viruses (R), and 5.8% multiple subtypes (M). For all subtypes combined, the overall rate of CD4 T-cell decline was -34.5 [95% confidence interval (CI), -47.1, -22.0] cells/ microL per yr, adjusted for age, sex, baseline CD4 counts, and viral load. Compared with subtype A, the adjusted rate of CD4 cell loss was -73.7/microL/yr (95% CI, -113.5, -33.8, P < 0.001) for subtype D, -43.2/microL/yr (95% CI, -90.2, 3.8, P = 0.072) for recombinants, and -63.9/microL/yr (95% CI, -132.3, 4.4, P = 0.067) for infection with multiple HIV subtypes. Square-root transformation of CD4 cell counts did not change the results.

CONCLUSIONS

Infection with subtype D is associated with significantly faster rates of CD4 T-cell loss than subtype A. This may explain the more rapid disease progression for subtype D compared with subtype A.

Decrease of initial CD4+ T-cell counts at the time of diagnosis of HIV infection in Korea; 1988-2006

The aim of the study was to evaluate the trends of initial CD4+ T-cell counts (CD4+) at HIV diagnoses and to identify the factors influencing the annual changes of CD4+ cell counts in Korea during 1988-2006. As a retrospective study, 2613 individuals (>/=15 years at diagnosis, their CD4+ counts were measured within six months) were selected from all 4580 HIV-infected Koreans diagnosed between 1985 and 2006. The mean CD4+ cell counts in all the selected individuals was 312 cells/mm(3), and this value decreased significantly by 20.3 cells/mm(3)/year over the 19 year study period. Men had lower CD4+ cell count than women by 22.7 cells/mm(3), and age at HIV diagnosis had an inverse relationship with CD4+ cell counts of 23.5 cells/mm(3) lower per 10 years advancing age. Cases diagnosed in hospitals showed CD4+ cell count levels 33.9 cells/mm(3) lower than public institutions by 33.9 cells/mm(3). Gender and age seemed to affect trends of CD4+ count; however the institution where cases were diagnosed had the strongest effect on decreasing CD4+ cell counts. The results suggest that HIV diagnoses in recent years are being made in later stages of HIV infection and that it is imperative to develop more efficient programmes for early HIV diagnosis to prevent transmission.

Comparison of early CD4 T-cell count in HIV-1 seroconverters in Côte d'Ivoire and France: the ANRS PRIMO-CI and SEROCO cohorts

OBJECTIVE

We compared CD4+ decline among untreated HIV-1-infected seroconverters living in Côte d'Ivoire (CI) and in France.

METHODS

HIV-1-infected adults were enrolled in the ANRS1220 PRIMO-CI (CI, 1997-2006) and ANRSCO2 SEROCO (France, 1988-1995) cohorts. CD4+ count and percentage declines were estimated from enrollment until 24 months of seroconversion by linear random-effect models adjusted for time since seroconversion, age, gender, cell-associated HIV DNA, HIV RNA, and country.

RESULTS

Overall 521 seroconverters (CI 148, 62% men; France 373, 77% men) were enrolled after a median of 7.6 months since seroconversion. Median follow-up duration was 12.7 months. Median age was 28 years. Median baseline CD4+ count was 472 and 560 cells per cubic millimeter, respectively. Median baseline HIV RNA was 4.4 and 4.0 log10 copies per milliliter and median HIV DNA was 3.0 and 2.8 log10 copies per 10(6) peripheral blood mononuclear cells, respectively. In adjusted models, CD4+ count and percentage at baseline were lower in CI than in France (P < 0.01), and the difference did not vary during follow-up (P = 0.55). Low HIV RNA and low HIV DNA at baseline were associated with higher CD4+ count at baseline.

CONCLUSIONS

CD4+ count and percentage were lower in CI than in France. These differences were already observed during early infection and remained similar after adjustment.

Human immunodeficiency virus in an aging population, a complication of success

The proportion of human immunodeficiency virus (HIV)-infected patients aged 50 and older has greatly increased since the beginning of the epidemic, particularly since 1996, when combination antiretroviral therapy became available. By 2015, 50% of HIV-infected individuals in the United States are likely to be aged 50 and older. The rate of progression of untreated HIV disease, response to therapy, and complicating effects of comorbidities differ in older and younger patients. Older untreated patients with HIV demonstrate faster rates of CD4(+) cell loss and more rapid progression to acquired immunodeficiency syndrome (AIDS) and death than younger individuals. Synergistic deleterious effects of chronic immune activation on the course of HIV infection with the immune senescence of aging may promote this accelerated course. Despite the increasing prevalence in older patients and cost-effectiveness analyses that favor HIV testing, older patients are less likely to be routinely evaluated for HIV infection. Consequently, when diagnosed, older patients have more-advanced disease than do younger patients and, upon presentation with AIDS-defining conditions, are less likely to receive timely appropriate therapy. The treatment of older HIV-infected patients is complicated by preexisting comorbid conditions, including cardiovascular, hepatic, and metabolic complications, which in turn may be exacerbated by the effects of HIV infection per se, modest immunodeficiency (i.e., at CD4(+) counts >350 cells/microL), and the metabolic and other adverse effects of combination antiretroviral therapy. Nevertheless, older patients derive substantial benefit from combination antiretroviral therapy despite having less of an immunological response than expected given their adherence to therapy and excellent virological responses.

Treatment responses in antiretroviral treatment-naive premenopausal and postmenopausal HIV-1-infected women: an analysis from AIDS Clinical Trials Group Studies

Menopause may affect antiretroviral treatment (ART) response. Immunologic and virologic responses to ART were compared in 220 premenopausal and 47 postmenopausal women enrolled in 2 studies involving ART-naive persons. Changes in CD4 counts or human immunodeficiency virus type 1 RNA levels were similar at 24, 48, and 96 weeks after treatment initiation. ART-naive women should respond to ART regardless of menopausal status.

No evidence of a change in HIV-1 virulence since 1996 in France

OBJECTIVE

We investigated temporal trends in the CD4 cell count and in plasma HIV RNA and total HIV DNA levels measured at the time of primary HIV infection, as proxies for HIV-1 virulence, taking changes in patient characteristics into account.

DESIGN

We studied 903 patients enrolled during primary HIV infection in the French multicenter ANRS PRIMO cohort from 1996 to 2007.

METHODS

Associations between the year of primary HIV infection and the values of the three markers were tested with regression models. The year of primary HIV infection was first introduced as a restricted cubic splines function in a regression model in order to explore the shape of the associations, and then as a continuous/categorical variable. The following confounders were considered in multiple regression analysis: time since infection and age (introduced as restricted cubic spline functions), sex, place of birth (Africa vs. others), symptomatic primary HIV infection, smoking, and virus-related factors (subtype B vs. non-B, and drug resistance mutations).

RESULTS

Multivariate analysis showed no temporal trends in the CD4 cell count (square-root) or in HIV-1 RNA and DNA levels (log10) measured at the time of primary HIV infection. We observed the well described associations between the prognostic markers and the time since infection, sex, symptomatic primary HIV infection, and smoking.

CONCLUSION

The CD4 cell count and HIV RNA and DNA levels measured at the time of primary HIV-1 infection remained stable across 12 consecutive years (1996-2007) in the ANRS PRIMO cohort, suggesting no major change in virulence, after taking into account changes in patient characteristics.

Clinical prognostic value of RNA viral load and CD4 cell counts during untreated HIV-1 infection--a quantitative review

Background

The prognostic value of CD4 counts and RNA viral load for identifying treatment need in HIV-infected individuals depends on (a) variation within and among individuals, and (b) relative risks of clinical progression per unit CD4 or RNA difference.

Methodology/Principal Findings

We reviewed these measurements across (a) 30 studies, and (b) 16 cohorts of untreated seropositive adults. Median within-population interquartile ranges were 74,000 copies/mL for RNA with no significant change during the course of infection; and 330 cells/µL for CD4, with a slight proportional increase over infection. Applying measurement and physiological fluctuations observed on chronically infected patients, we estimate that 45% of population-level variation in RNA, and 25% of variation in CD4, were due to within-patient fluctuations. Comparing a patient with RNA at upper 75^th centile with a patient at median RNA, 5-year relative risks were 1.4 (95% CI 1.2–1.7) for AIDS and 1.5 (1.3–1.9) for death, without change over the course of infection. In contrast, for a patient with CD4 count at the lower 75^th centile, relative risks increased from 1.0 at seroconversion to maxima of 6.3 (4.4–8.9) for AIDS and 5.5 (2.7–10.1) for death by year 6, when the population median had fallen to 300 cells/µL. Below 300 cells/µL, prognostic power did not increase, due to a narrower CD4 range.

Conclusions

Findings support the current WHO recommendation (used with clinical criteria) to start antiretroviral treatment in low-income settings at CD4 thresholds of 200–350 cells/µL, without pre-treatment RNA monitoring – while not precluding earlier treatment based on clinical, socio-demographic or public health criteria.

Increasing clinical virulence in two decades of the Italian HIV epidemic

The recent origin and great evolutionary potential of HIV imply that the virulence of the virus might still be changing, which could greatly affect the future of the pandemic. However, previous studies of time trends of HIV virulence have yielded conflicting results. Here we used an established methodology to assess time trends in the severity (virulence) of untreated HIV infections in a large Italian cohort. We characterized clinical virulence by the decline slope of the CD4 count (n = 1423 patients) and the viral setpoint (n = 785 patients) in untreated patients with sufficient data points. We used linear regression models to detect correlations between the date of diagnosis (ranging 1984-2006) and the virulence markers, controlling for gender, exposure category, age, and CD4 count at entry. The decline slope of the CD4 count and the viral setpoint displayed highly significant correlation with the date of diagnosis pointing in the direction of increasing virulence. A detailed analysis of riskgroups revealed that the epidemics of intravenous drug users started with an apparently less virulent virus, but experienced the strongest trend towards steeper CD4 decline among the major exposure categories. While our study did not allow us to exclude the effect of potential time trends in host factors, our findings are consistent with the hypothesis of increasing HIV virulence. Importantly, the use of an established methodology allowed for a comparison with earlier results, which confirmed that genuine differences exist in the time trends of HIV virulence between different epidemics. We thus conclude that there is not a single global trend of HIV virulence, and results obtained in one epidemic cannot be extrapolated to others. Comparison of discordant patterns between riskgroups and epidemics hints at a converging trend, which might indicate that an optimal level of virulence might exist for the virus.

Is HIV becoming more virulent? Initial CD4 cell counts among HIV seroconverters during the course of the HIV epidemic: 1985-2007

BACKGROUND

Whether human immunodeficiency virus (HIV) seroconverters have been presenting with progressively lower CD4 cell counts over the course of the HIV epidemic is controversial. Additional data on whether HIV might have become more virulent on a population level (measured by post-seroconversion CD4 cell counts) may provide important insights regarding HIV pathogenesis.

METHODS

To determine whether post-seroconversion CD4 cell counts have changed over time, we evaluated 2174 HIV seroconverters as part of a large cohort study during the period 1985-2007. Participants were documented antiretroviral-naive HIV seroconverters who had a CD4 cell count measured within 6 months after receiving a diagnosis of HIV infection. Multiple linear regression models were used to assess trends in initial CD4 cell counts.

RESULTS

The mean initial CD4 cell count decreased during the study period from 632 cells/mm(3) in 1985-1990 to 553 cells/mm(3) in 1991-1995, 493 cells/mm(3) in 1996-2001, and 514 cells/mm(3) in 2002-2007. During those periods, the percentages of seroconverters with an initial CD4 cell count <350 cells/mm(3) were 12%, 21%, 26%, and 25%, respectively. In the multiple linear model, the mean decrease in CD4 cell count from 1985-1990 was 65 cells/mm(3) in 1991-1995 (P < .001)), 107 cells/mm(3) in 1996-2001 (P < .001), and 102 cells/mm(3) in 2002-2007 (P < .001). Similar trends occurred with regard to CD4 cell percentage and total lymphocyte count. Similar decreases in initial CD4 cell counts were observed among African American and white persons during the epidemic.

DISCUSSION

A significant decrease in initial CD4 cell counts among HIV seroconverters in the United States has occurred during the HIV epidemic. These data provide an important clinical correlate to suggestions that HIV may have adapted to the host, resulting in a more virulent infection.