Background

The U.S. National HIV/AIDS Strategy targets for 2015 include increasing access to care and improving health outcomes for persons living with HIV in the United States (PLWH-US).

Objective

To demonstrate the utility of the NA-ACCORD (North American AIDS Cohort Collaboration on Research and Design) for monitoring trends in the HIV epidemic in the United States and to present trends in HIV treatment and related health outcomes.

Design

Trends from annual cross-sectional analyses comparing patients from pooled, multicenter, prospective, clinical HIV cohort studies with PLWH-US, as reported to national surveillance systems in 40 states.

Setting

U.S. HIV outpatient clinics.

Patients

HIV-infected adults with 1 or more HIV RNA plasma viral load (HIV VL) or CD4 T-lymphocyte (CD4) cell count measured in any calendar year from 1 January 2000 to 31 December 2008.

Measurements

Annual rates of antiretroviral therapy use, HIV VL, and CD4 cell count at death.

Results

45 529 HIV-infected persons received care in an NA-ACCORD–participating U.S. clinical cohort from 2000 to 2008. In 2008, the 26 030 NA-ACCORD participants in care and the 655 966 PLWH-US had qualitatively similar demographic characteristics. From 2000 to 2008, the proportion of participants prescribed highly active antiretroviral therapy increased by 9 percentage points to 83% (P < 0.001), whereas the proportion with suppressed HIV VL (≤2.7 log10 copies/mL) increased by 26 percentage points to 72% (P < 0.001). Median CD4 cell count at death more than tripled to 0.209 × 109 cells/L (P < 0.001).

Limitation

The usual limitations of observational data apply.

Conclusion

The NA-ACCORD is the largest cohort of HIV-infected adults in clinical care in the United States that is demographically similar to PLWH-US in 2008. From 2000 to 2008, increases were observed in the percentage of prescribed HAART, the percentage who achieved a suppressed HIV VL, and the median CD4 cell count at death.

Primary Funding Source

National Institutes of Health, Centers for Disease Control and Prevention, Canadian Institutes of Health Research, Canadian HIV Trials Network, and the government of British Columbia, Canada.

Background

The generalizability of antiretroviral therapy (ART) clinical trial efficacy findings to routine care settings is not well studied. We compared the relative effectiveness of initial ART regimens estimated in AIDS Clinical Trial Group (ACTG) randomized controlled trials with that among patients receiving ART at Antiretroviral Therapy Cohort Collaboration (ART-CC) study sites.

Methods

Treatment-naive HIV-infected patients initiating identical ART regimens in ACTG trials (A5095 and A5142) and at 15 ART-CC cohort study sites were included. Virological failure (HIV-1 RNA >200 copies/ml) at 24- and 48-weeks, incident AIDS-defining events and mortality were measured according to study design (ART-CC cohort vs. ACTG trial) and stratified by 3rd drug [Abacavir (ABC), Efavirenz (EFV), and Lopinavir/r (LPV/r)]. We used logistic regression to estimate and compare odds ratios for virological failure between different regimens and study designs, and used Cox models to estimate and compare hazard ratios for AIDS and death.

Results

Compared with patients receiving ABC, those receiving EFV had roughly half the odds of 24-week virologic failure (>200 copies/mL) in both ACTG 5095 (OR=0.53, 95% CI 0.36–0.79) and ART-CC (0.46, 0.37–0.57). Virologic superiority of EFV (vs. ABC) appeared comparable in ART-CC and ACTG 5095 (ratio of ORs 0.86, 95% CI 0.54–1.35). Odds ratios for 48-week virologic failure, comparing EFV with LPV/r, were also comparable in ACTG 5142 and ART-CC (ratio of ORs 0.87, 0.45–1.69).

Conclusions

Between ART regimen virologic efficacy of 3rd drugs ABC, EFV, and LPV/r observed in the ACTG 5095 and 5142 trials appear generalizable to the routine care setting of ART-CC clinical cohorts.

Viremia copy-years predicted all-cause mortality independent of traditional, cross-sectional viral load measures and time-updated CD4+ T-lymphocyte count in antiretroviral therapy-treated patients suggesting cumulative human immunodeficiency virus replication causes harm independent of its effect on the degree of immunodeficiency.

Background. Cross-sectional plasma human immunodeficiency virus (HIV) viral load (VL) measures have proven invaluable for clinical and research purposes. However, cross-sectional VL measures fail to capture cumulative plasma HIV burden longitudinally. We evaluated the cumulative effect of exposure to HIV replication on mortality following initiation of combination antiretroviral therapy (ART).

Methods. We included treatment-naive HIV-infected patients starting ART from 2000 to 2008 at 8 Center for AIDS Research Network of Integrated Clinical Systems sites. Viremia copy-years, a time-varying measure of cumulative plasma HIV exposure, were determined for each patient using the area under the VL curve. Multivariable Cox models were used to evaluate the independent association of viremia copy-years for all-cause mortality.

Results. Among 2027 patients contributing 6579 person-years of follow-up, the median viremia copy-years was 5.3 log10 copy × y/mL (interquartile range: 4.9–6.3 log10 copy × y/mL), and 85 patients (4.2%) died. When evaluated separately, viremia copy-years (hazard ratio [HR] = 1.81 per log10 copy × y/mL; 95% confidence interval [CI], 1.51–2.18 per log10 copy × y/mL), 24-week VL (1.74 per log10 copies/mL; 95% CI, 1.48–2.04 per log10 copies/mL), and most recent VL (HR = 1.89 per log10 copies/mL; 95% CI: 1.63–2.20 per log10 copies/mL) were associated with increased mortality. When simultaneously evaluating VL measures and controlling for other covariates, viremia copy-years increased mortality risk (HR = 1.44 per log10 copy × y/mL; 95% CI, 1.07–1.94 per log10 copy × y/mL), whereas no cross-sectional VL measure was independently associated with mortality.

Conclusions. Viremia copy-years predicted all-cause mortality independent of traditional, cross-sectional VL measures and time-updated CD4+ T-lymphocyte count in ART-treated patients, suggesting cumulative HIV replication causes harm independent of its effect on the degree of immunodeficiency.

Background. Screening for tuberculosis prior to highly active antiretroviral therapy (HAART) initiation is not routinely performed in low-incidence settings. Identifying factors associated with developing tuberculosis after HAART initiation could focus screening efforts.

Methods. Sixteen cohorts in the United States and Canada contributed data on persons infected with human immunodeficiency virus (HIV) who initiated HAART December 1995–August 2009. Parametric survival models identified factors associated with tuberculosis occurrence.

Results. Of 37845 persons in the study, 145 were diagnosed with tuberculosis after HAART initiation. Tuberculosis risk was highest in the first 3 months of HAART (20 cases; 215 cases per 100000 person-years; 95% confidence interval [CI]: 131–333 per 100000 person-years). In a multivariate Weibull proportional hazards model, baseline CD4+ lymphocyte count <200, black race, other nonwhite race, Hispanic ethnicity, and history of injection drug use were independently associated with tuberculosis risk. In addition, in a piece-wise Weibull model, increased baseline HIV-1 RNA was associated with increased tuberculosis risk in the first 3 months; male sex tended to be associated with increased risk.

Conclusions. Screening for active tuberculosis prior to HAART initiation should be targeted to persons with baseline CD4 <200 lymphocytes/mm3 or increased HIV-1 RNA, persons of nonwhite race or Hispanic ethnicity, history of injection drug use, and possibly male sex.

Determination of the prevalence of accumulated antiretroviral drug resistance among persons infected with human immunodeficiency virus (HIV) is complicated by the lack of routine measurement in clinical care. By using data from 8 clinic-based cohorts from the North American AIDS Cohort Collaboration on Research and Design, drug-resistance mutations from those with genotype tests were determined and scored using the Genotypic Resistance Interpretation Algorithm developed at Stanford University. For each year from 2000 through 2005, the prevalence was calculated using data from the tested subset, assumptions that incorporated clinical knowledge, and multiple imputation methods to yield a complete data set. A total of 9,289 patients contributed data to the analysis; 3,959 had at least 1 viral load above 1,000 copies/mL, of whom 2,962 (75%) had undergone at least 1 genotype test. Using these methods, the authors estimated that the prevalence of accumulated resistance to 2 or more antiretroviral drug classes had increased from 14% in 2000 to 17% in 2005 (P < 0.001). In contrast, the prevalence of resistance in the tested subset declined from 57% to 36% for 2 or more classes. The authors’ use of clinical knowledge and multiple imputation methods revealed trends in HIV drug resistance among patients in care that were markedly different from those observed using only data from patients who had undergone genotype tests.

Among new patients entering HIV care from 1999 to 2009 in a North Carolina observational clinical cohort, Latinos initiated HIV care at lower CD4 cell counts and were more likely to have several specific AIDS-defining clinical conditions, compared with non-Latinos.

(See the Editorial Commentary by Rio on pages 488–489.)

Background. Late diagnosis of human immunodeficiency virus (HIV) infection remains common despite advances in therapy and prognosis. The southeastern United States is a rapidly growing Latino settlement area where ethnic disparities may contribute to late presentation to care.

Methods. We assessed demographic and clinical factors between racial/ethnic groups at the time of HIV care initiation in the University of North Carolina Center for AIDS Research Clinical Cohort. We identified independent predictors of late presentation, defined as a CD4+ T lymphocyte (CD4) count <350 cells/mm3 or an AIDS-defining event (ADE), using log-linear binomial regression.

Results. During the period 1999–2009, 853 patients initiated HIV care, of whom 11% were Latino, 28% were white, and 61% were black. Median initial CD4 counts were lower for Latino patients (186 cells/mm3) than white patients (292 cells/mm3; P = .006) and black patients (302 cells/mm3; P = .02). Latino persons were more likely to be late presenters than white or black persons (76% vs 58%; P < .001) and accounted for 86%, 75%, and 50% of all presenting cases of active tuberculosis, histoplasmosis, and toxoplasmosis, respectively. Latino ethnicity, older age, male sex, and earlier entry year were independently associated with late presentation (P < .05 for all). In multivariable analyses, Latino persons were 1.29 times more likely to present to care late than white or black persons (95% confidence interval, 1.15–1.45).

Conclusions. Latinos are more likely to initiate HIV care later in the course of illness than are black and white persons and account for a majority of several ADEs. Strategies to improve earlier HIV testing among Latinos in new settlement areas are needed.

Background

Mortality and morbidity from HIV have dramatically decreased in both high- and low-income countries. However, some patients may not benefit from combination antiretroviral therapy (cART) because of inadequate access to HIV care, including attrition after care initiation.

Methodology/Principal Findings

The study population included all HIV-infected patients receiving cART through the Chinese National Free Antiretroviral Treatment Program from 1 January 2003 to 31 December 2010 (n = 106,542). We evaluated retention in HIV care and used multivariable Cox proportional hazard models to identify independent factors predictive of attrition. The cumulative probability of attrition from cART initiation was 9% at 12 months, 13% at 18 months, 16% at 24 months and 24% at 60 months. A number of factors were associated with attrition, including younger age, male gender, and being single or divorced. Patients with higher CD4 cell counts at cART initiation were more likely to drop out of HIV care. The proportion of patients remaining in HIV care increased in more recent calendar years and among patients who initiated modern cART regimens.

Conclusions/Significance

Retention in HIV care is essential for optimizing individual and public health outcomes. Attrition, even the degree observed in our study, can lead to premature morbidity and mortality, and possibly affect further transmission of HIV and HIV resistant drug variants. Effective strategies to promote retention in HIV care programs are needed. In China these strategies may include focusing particularly on younger male patients and those with higher CD4 cell counts at therapy initiation.

Objective

Patient antiretroviral (ARV) therapy knowledge is essential for regimen adherence, successful therapeutic response, and minimization of resistance evolution. Moreover, a complete and accurate patient ARV history is needed to construct efficacious and tolerable future regimens. In this study we assessed the ability of HIV-infected patients receiving care in a university infectious diseases clinic to accurately recall current and past ARVs.

Methods

A convenience sample (n = 205) of UNC HIV Clinical Cohort participants (n = 1840) completed a comprehensive in-person interview. Patients were asked about current and ever ARV use and were provided proprietary and generic ARV names and photographs. Self-reported sensitivity for current and ever ARV use (proportion that correctly identified all recorded ARVs), was calculated using the medical record as the gold standard.

Results

One hundred and eighty-five patients had received ARVs at some point after enrollment in the cohort study (ever users). For current ARV use (n = 138), self-reported sensitivity was 63% (95% CI: 54–71). For ever use (n = 185), sensitivity was 18% (95% CI: 13–24).

Conclusion

Self-reported cumulative ARV use is not accurate. Since HIV-infected patients are prescribed a number of medications over their treatment course, it is necessary to develop new medication reconciliation techniques that are not dependent on patient memory or knowledge in order to improve patient outcomes.

Background

The Cavidi viral load assay and the ultra-sensitive p24 antigen assay (Up24 Ag) have been suggested as more feasible alternatives to PCR-based HIV viral load assays for use in monitoring patients infected with HIV-1 in resource-limited settings.

Objectives

To describe the performance of the Cavidi ExaVir Load™ assay (version 2.0) and two versions of the Up24 antigen assay and to characterize their agreement with the Roche Monitor HIV-1 RNA assay (version 1.5).

Study Design

Observational study using a convenience sample of 342 plasma specimens from 108 patients enrolled in two ACTG clinical trials to evaluate the performance characteristics of the Up24 Ag assay using two different lysis buffers and the Cavidi ExaVir Load™ assay.

Results

In analysis of agreement with the Roche assay, the Cavidi assay demonstrated superiority to the Up24 Ag assays in accuracy and precision, as well as sensitivity, specificity, and positive and negative predictive values for HIV-1 RNA ≥400, ≥1000 and ≥5000 copies/mL. Logistic performance curves indicated that the Cavidi assay was superior to the Up24 assays for viral loads greater than 650 copies/mL.

Conclusions

The results suggest that the Cavidi ExaVir Load assay could be used for monitoring HIV-1 viral load in resource-limited settings.

Abstract

Predictors of study retention and scheduled visit attendance in the University of North Carolina Center for AIDS Research (UNC CFAR) prospective clinical cohort of HIV-infected patients enrolled between 1 January 2001 and 1 January 2008 are reported. At study entry, 1636 participants were 32% female, 58% were African-American, 49% had not received HIV care elsewhere, 71% were receiving or initiated combination antiretroviral therapy, and 26% were diagnosed with AIDS, with median (quartiles) age of 40 (34; 47) years, distance to clinic of 45 (21; 70) miles, HIV-1 RNA of 1396 (200; 26,750) copies/ml, and CD4 of 374 (182; 602) cells/mm3. Participants contributed a median of 7 (4; 13) scheduled visits and 2.25 (1.0; 3.9) years alive under follow-up. During 6134 person-years of follow-up, 414 participants dropped out and 145 died. Accounting for differences in death by participant characteristics, the 6-year cumulative probability of retention was 67% [95% confidence limits (CL): 65, 70%], with 6.75 (95% CL: 6.13, 7.43) drop outs per 100 person-years. In a multivariable Cox proportional hazards model, retention was higher among participants who were insured, had not received HIV care elsewhere, had controlled HIV viremia, and were living in nonurban areas or proximate to the clinic. In a multivariable modified Poisson regression model that accounted for differences in drop out and death by participant characteristics, visit attendance was higher among older, AIDS-diagnosed, immune compromised, and cART-initiated participants. The UNC CFAR clinical cohort has ample enrollment with retention and visit attendance modestly influenced by factors such as disease severity.

Objective

To determine the impact of age and initial HAART regimen class on virologic and immunologic response within 24 months after initiation.

Design

Pooled analysis of data from 19 prospective cohort studies in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD).

Methods

Twelve thousand, one hundred and ninety-six antiretroviral-naive adults who initiated HAART between 1998 and 2008 using a boosted protease inhibitor-based regimen or a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen were included in our study. Discrete time-to-event models estimated adjusted hazard odds ratios (aHOR) and 95% confidence intervals (CIs) for suppressed viral load (≤500 copies/ml) and, separately, at least 100 cells/μl increase in CD4 cell count. Truncated, stabilized inverse probability weights accounted for selection biases from discontinuation of initial regimen class.

Results

Among 12 196 eligible participants (mean age = 42 years), 50% changed regimen classes after initiation (57 and 48% of whom initiated protease inhibitor and NNRTI-based regimens, respectively). Mean CD4 cell count at initiation was similar by age. Virologic response to treatment was less likely in those initiating using a boosted protease inhibitor [aHOR = 0.77 (0.73, 0.82)], regardless of age. Immunologic response decreased with increasing age [18–<30: ref; 30–<40: aHOR 0.92 (0.85, 1.00); 40–<50: aHOR = 0.85 (0.78, 0.92); 50–<60: aHOR = 0.82 (0.74, 0.90); ≥60: aHOR=0.74 (0.65, 0.85)], regardless of initial regimen.

Conclusion

We found no evidence of an interaction between age and initial anti-retroviral regimen on virologic or immunologic response to HAART; however, decreased immunologic response with increasing age may have implications for age-specific when-to-start guidelines.

This observational cohort study by Andrew Edmonds and colleagues reports that treatment with highly active antiretroviral therapy (HAART) markedly improves the survival of HIV-infected children in Kinshasa, DRC, a resource-deprived setting.

Background

The effect of highly active antiretroviral therapy (HAART) on the survival of HIV-infected children has not been well quantified. Because most pediatric HIV occurs in low- and middle-income countries, our objective was to provide a first estimate of this effect among children living in a resource-deprived setting.

Methods and Findings

Observational data from HAART-naïve children enrolled into an HIV care and treatment program in Kinshasa, Democratic Republic of the Congo, between December 2004 and May 2010 were analyzed. We used marginal structural models to estimate the effect of HAART on survival while accounting for time-dependent confounders affected by exposure. At the start of follow-up, the median age of the 790 children was 5.9 y, 528 (66.8%) had advanced or severe immunodeficiency, and 405 (51.3%) were in HIV clinical stage 3 or 4. The children were observed for a median of 31.2 mo and contributed a total of 2,089.8 person-years. Eighty children (10.1%) died, 619 (78.4%) initiated HAART, six (0.8%) transferred to a different care provider, and 76 (9.6%) were lost to follow-up. The mortality rate was 3.2 deaths per 100 person-years (95% confidence interval [CI] 2.4–4.2) during receipt of HAART and 6.0 deaths per 100 person-years (95% CI 4.1–8.6) during receipt of primary HIV care only. The mortality hazard ratio comparing HAART with no HAART from a marginal structural model was 0.25 (95% CI 0.06–0.95).

Conclusions

HAART reduced the hazard of mortality in HIV-infected children in Kinshasa by 75%, an estimate that is similar in magnitude but with lower precision than the reported effect of HAART on survival among children in the United States.

Please see later in the article for the Editors' Summary

Editors' Summary

Background

In 2009, an estimated 2.5 million children were living with HIV, the majority of whom (2.3 million) were in sub-Saharan Africa. Most (90%) of these children acquired HIV from their HIV-infected mothers during pregnancy, birth, or breastfeeding, highlighting the importance of giving effective drugs for the prevention of mother to child transmission. As such interventions are still not widely accessible or available in most resource-limited countries, where the burden of HIV is highest, every day an estimated 1,000 children were newly infected with HIV in 2009, but only 360,000 children were receiving highly active antiretroviral therapy (HAART).

Although HAART improves the survival of adults living with HIV, less is known about the degree to which HAART affects the survival of HIV-infected children—although response to antiretroviral treatment is known to differ across age groups. Furthermore, as the course of HIV disease in children is different from that in adults (partly because of the impact of the virus on the immature thymus, which can lead to high HIV RNA viremia and rapid death), it is inappropriate to extrapolate results from studies of adults to pediatric populations. Therefore, it is imperative that the effect of HAART on survival be quantified specifically in children.

Why Was This Study Done?

Most observational studies of the effects of treatment on child survival have been undertaken in high-income countries, such as Italy and the United States. As most children with HIV live in low-resource areas, where multiple factors, such as delayed presentation to care and a higher incidence of co-occurring conditions, might adversely affect treatment outcomes, there is a specific need for information on the effects of HAART in children with HIV living in low-income countries. Although some investigations have taken place in pediatric cohorts from such countries (for example, Côte d'Ivoire, Haiti, Lesotho, Thailand, and Zambia), the effect of HAART on mortality has not been accurately quantified among children in a resource-deprived setting. Therefore, in this observational clinical cohort study, the researchers investigated the effect of HAART on mortality in HIV-infected children in Kinshasa, in the Democratic Republic of the Congo (DRC).

What Did the Researchers Do and Find?

The researchers analyzed data from 790 children enrolled into an HIV program in Kinshasa, DRC, between December 2004 and May 2010 and used a statistical model (marginal structural models) to adjust for time-dependent confounding factors, such as the fact that HAART is typically initiated in sicker patients, for example, those with lower CD4 cell percentages. Assuming that all children starting HAART received it uninterruptedly throughout follow-up, using this statistical model, the researchers were able to compare the hazard ratio of death had all children initiated HAART to that had no children initiated HAART during follow-up.

In the study, 619 out of the 790 children (78.4%) initiated HAART during follow-up and were followed for a median of 31.2 months, with a median of 30 HIV care visits. Of those who started treatment, 110 (17.8%) switched to an alternative regimen because of an adverse event or treatment failure. During the 2,089.8 accrued person-years of follow-up, 80 children (10.1%) died, giving an overall mortality rate of 3.8 deaths per 100 person-years. The unadjusted mortality rate ratio comparing HAART to no HAART was 0.54. Using a marginal structural model, the researchers estimated that compared to no HAART, HAART reduced the hazard (rate) of mortality during follow-up by 75%.

What Do These Findings Mean?

These findings show that treatment with HAART markedly improved the survival of children infected with HIV in Kinshasa, DRC, and suggest that HAART is as effective in improving the survival of HIV-infected children in a severely resource-deprived country (still recovering from civil war) as in more resource-privileged settings—an important finding given that the vast majority of children receiving HAART live in resource-poor areas. This study provides additional evidence that accelerating rollout of antiretroviral therapy to children with HIV in resource-poor countries is lifesaving and effective. Future research needs to address how effective HAART is in understudied populations in resource-poor countries, such as undernourished children or those with co-infections such as tuberculosis.

Additional Information

Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001044.

The World Health Organization's Web site has more information about the treatment of children living with HIV

Médecins Sans Frontières's Campaign for Access to Essential Medicines Web site has more information on pediatric HAART

Background:

Initiatives to improve early detection and access to HIV services have increased over time. We assessed the immune status of patients at initial presentation for HIV care from 1997-2007 in 13 US and Canadian clinical cohorts.

Methods:

We analyzed data from 44,491 HIV-infected patients enrolled in the North American – AIDS Cohort Collaboration on Research and Design. We identified first presentation for HIV care as the time of first CD4+ T-lymphocyte (CD4) measurement and excluded patients who prior to this date had HIV RNA measurements, evidence of antiretroviral exposure, or a history of AIDS-defining illness. Trends in mean CD4 count (measured as cells/mm3) and 95% confidence intervals ([,]) were determined using linear regression adjusted for age, gender, race/ethnicity, HIV transmission risk and cohort.

Results:

Median age at first presentation for HIV care increased over time (range 40-43 years, p<0.01), while the proportion of patients with injection drug use HIV transmission risk decreased (26% to 14%, p<0.01) and heterosexual transmission risk increased (16% to 23%, p<0.01). Median CD4 at presentation increased from 256 (IQR: 96-455) to 317 (IQR: 135-517) in 1997 to 2007 (p<0.01). The proportion with a CD4 count ≥350 at first presentation also increased from 1997 to 2007 (38% to 46%, p=<0.01). The estimated adjusted mean CD4 count increased at a rate of 6 [5, 7] per year.

Conclusion:

CD4 count at first presentation for HIV care has increased annually over the past 11 years, but has remained <350 cells/mm3, suggesting the urgent need for earlier HIV diagnosis and treatment.

Plasma human immunodeficiency virus type 1 (HIV-1) viral load is a valuable tool for HIV research and clinical care but is often used in a noncumulative manner. The authors developed copy-years viremia as a measure of cumulative plasma HIV-1 viral load exposure among 297 HIV seroconverters from the Multicenter AIDS Cohort Study (1984–1996). Men were followed from seroconversion to incident acquired immunodeficiency syndrome (AIDS), death, or the beginning of the combination antiretroviral therapy era (January 1, 1996); the median duration of follow-up was 4.6 years (interquartile range (IQR), 2.7–6.5). The median viral load and level of copy-years viremia over 2,281 semiannual follow-up assessments were 29,628 copies/mL (IQR, 8,547–80,210) and 63,659 copies × years/mL (IQR, 15,935–180,341). A total of 127 men developed AIDS or died, and 170 survived AIDS-free and were censored on January 1, 1996, or lost to follow-up. Rank correlations between copy-years viremia and other measures of viral load were 0.56–0.87. Each log10 increase in copy-years viremia was associated with a 1.70-fold increased hazard (95% confidence interval: 0.94, 3.07) of AIDS or death, independently of infection duration, age, race, CD4 cell count, set-point, peak viral load, or most recent viral load. Copy-years viremia, a novel measure of cumulative viral burden, may provide prognostic information beyond traditional single measures of viremia.

Background

Amplification based HIV-1 viral load and genotypic resistance assays are expensive, technologically complex and may be difficult to implement in resource limited settings. Inexpensive, simpler assays are urgently needed.

Objectives

To determine the suitability of the ExaVir™ Load and ExaVir™ Drug assays for use in patient monitoring.

Study Design

Specimens from 108 adults were used to compare ExaVir™ Load HIV-1 RT to Amplicor HIV-1 Monitor® HIV-1 RNA, and ExaVir™ Drug phenotype to HIV GenoSure™ genotype.

Results

HIV-1 RT and HIV-1 RNA levels were comparable (Pearson correlation coefficient 0.83). Most (94%) had detectable results in both assays. The mean difference (HIV-1 RT minus HIV-1 RNA) was -0.21 log10 cps/mL equivalents. Relationship between HIV-1 RT and HIV-1 RNA was not affected by RT mutations, CD4 cell count, or efavirenz (EFV) or nevirapine (NVP) use. Phenotypes were generally consistent with genotype findings for EFV, but not for NVP. Most patients (93.9%) with phenotypic EFV resistance had at least one EFV mutation, while 78.0% of patients with phenotypic NVP resistance had at least one NVP mutation. Eleven of 49 samples tested for EFV susceptibility were found resistant (n=2) or with reduced susceptibility (n=9) despite the absence of genotypic resistance. Eleven of 45 samples tested for NVP susceptibility were found resistant (n=9) or with reduced susceptibility (n=2) with no evidence of genotypic mutations.

Conclusions

The ExaVir™ Load assay performed well and may be an alternative to amplification based techniques for HIV-1 RNA quantification. The ExaVir™ Drug assay for phenotypic resistance testing requires further evaluation, especially for NVP.

We assessed CD4 count at initial presentation for HIV care among ≥50-year-olds from 1997-2007 in 13 US and Canadian clinical cohorts and compared to <50-year-olds. 44,491 HIV-infected individuals in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) were included in our study. Trends in mean CD4 count (measured as cells/mm3) and 95% confidence intervals ([,]) were determined using linear regression stratified by age category and adjusted for gender, race/ethnicity, HIV transmission risk and cohort. From 1997-2007, the proportion of individuals presenting for HIV care who were ≥50-years-old increased from 17% to 27% (p-value < 0.01). The median CD4 count among ≥50 year-olds was consistently lower than younger adults. The interaction of age group and calendar year was significant (p-value <0.01) with both age groups experiencing modest annual improvements over time (< 50-year-olds: 5 [4 , 6] cells/mm3; ≥50-year-olds: 7 [5 , 9] cells/mm3), after adjusting for sex, race/ethnicity, HIV transmission risk group and cohort; however, increases in the two groups were similar after 2000. A greater proportion of older individuals had an AIDS-defining diagnosis at, or within three months prior to, first presentation for HIV care compared to younger individuals (13% vs. 10%, respectively). Due to the increasing proportion, consistently lower CD4 counts, and more advanced HIV disease in adults ≥50-year-old at first presentation for HIV care, renewed HIV testing efforts are needed.

Background We aimed to estimate the effect of anti-retroviral therapy (ART) on incident tuberculosis (TB) in a cohort of HIV-infected children.

Methods We analysed data from ART-naïve, TB disease-free children enrolled between December 2004 and April 2008 into an HIV care program in Kinshasa, Democratic Republic of Congo. To estimate the effect of ART on TB incidence while accounting for time-dependent confounders affected by exposure, a Cox proportional hazards marginal structural model was used.

Results 364 children contributed 596.0 person-years of follow-up. At baseline, the median age was 6.9 years; 163 (44.8%) were in HIV clinical stage 3 or 4. During follow-up, 242 (66.5%) children initiated ART and 81 (22.3%) developed TB. At TB diagnosis, 41 (50.6%) were receiving ART. The TB incidence rate in those receiving ART was 10.2 per 100 person-years [95% confidence interval (CI) 7.4–13.9] compared with 20.4 per 100 person-years (95% CI 14.6–27.8) in those receiving only primary HIV care. TB incidence decreased with time on ART, from 18.9 per 100 person-years in the first 6 months to 5.3 per 100 person-years after 12 months of ART. The model-estimated TB hazard ratio for ART was 0.51 (95% CI 0.27–0.94).

Conclusions For HIV-infected children in TB-endemic areas, ART reduces the hazard of developing TB by 50%.

Background

Although combination antiretroviral therapy continues to evolve, with potentially more effective options emerging each year, the ability of therapy to prevent multiple regimen failure and mortality in clinical practice remains poorly defined.

Methods

Sixteen cohorts representing over 60 sites contributed data on all individuals who initiated combination antiretroviral therapy. We identified those individuals who experienced virologic failure (defined as a human immunodeficiency virus [HIV] RNA level >1000 copies/mL), received modified therapy, and subsequently had a second episode of virologic failure. Multivariate Cox regression was used to assess factors associated with time to second regimen failure and the time to death after the onset of second regimen failure.

Results

Of the 42,790 individuals who received therapy, 7159 experienced a second virologic failure. The risk of second virologic failure decreased from 1996 (56 cases per 100 person-years) through 2005 (16 cases per 100 person-years; P < .001). The cumulative mortality after onset of second virologic failure was 26% at 5 years and decreased over time. A history of AIDS, a lower CD4+ T cell count, and a higher plasma HIV RNA level were each independently associated with mortality. Similar trends were observed when analysis was limited to the subset of previously treatment-naive patients

Conclusions

Although the rates of multiple regimen failure have decreased dramatically over the past decade, mortality rates for those who have experienced failure of at least 2 regimens have remained high. Plasma HIV RNA levels, CD4+ T cell counts at time of treatment failure, and a history of AIDS remain independent risk factors for death, which emphasizes that these factors remain important targets for those in need of more-aggressive therapeutic interventions.

Background

The optimal time for the initiation of antiretroviral therapy for asymptomatic patients with human immunodeficiency virus (HIV) infection is uncertain.

Methods

We conducted two parallel analyses involving a total of 17,517 asymptomatic patients with HIV infection in the United States and Canada who received medical care during the period from 1996 through 2005. None of the patients had undergone previous antiretroviral therapy. In each group, we stratified the patients according to the CD4+ count (351 to 500 cells per cubic millimeter or >500 cells per cubic millimeter) at the initiation of antiretroviral therapy. In each group, we compared the relative risk of death for patients who initiated therapy when the CD4+ count was above each of the two thresholds of interest (early-therapy group) with that of patients who deferred therapy until the CD4+ count fell below these thresholds (deferred-therapy group).

Results

In the first analysis, which involved 8362 patients, 2084 (25%) initiated therapy at a CD4+ count of 351 to 500 cells per cubic millimeter, and 6278 (75%) deferred therapy. After adjustment for calendar year, cohort of patients, and demographic and clinical characteristics, among patients in the deferred-therapy group there was an increase in the risk of death of 69%, as compared with that in the early-therapy group (relative risk in the deferred-therapy group, 1.69; 95% confidence interval [CI], 1.26 to 2.26; P<0.001). In the second analysis involving 9155 patients, 2220 (24%) initiated therapy at a CD4+ count of more than 500 cells per cubic millimeter and 6935 (76%) deferred therapy. Among patients in the deferred-therapy group, there was an increase in the risk of death of 94% (relative risk, 1.94; 95% CI, 1.37 to 2.79; P<0.001).

Conclusions

The early initiation of antiretroviral therapy before the CD4+ count fell below two prespecified thresholds significantly improved survival, as compared with deferred therapy.

Background

Current measures of the clinical efficacy of antiretroviral therapy (ART) in the treatment of HIV include the change in HIV RNA in the plasma and the gain in CD4 cells.

Methods

We propose new measures for evaluating the efficacy of treatment that is based upon combinations of non-nucleoside and nucleoside reverse transcriptase inhibitors. Our efficacy measures are: the CD4 gain per virion eliminated, the potential of CD4 count restoration and the viral reproduction number (R0). These efficacy measures are based upon a theoretical understanding of the impact of treatment on both viral dynamics and the immune reconstitution. Patient data were obtained from longitudinal HIV clinical cohorts.

Results

We found that the CD4 cell gain per virion eliminated ranged from 10-2 to 600 CD4 cells/virion, the potential of CD4 count restoration ranged from 60 to 1520 CD4 cells/μl, and the basic reproduction number was reduced from an average of 5.1 before therapy to an average of 1.2 after one year of therapy. There was substantial heterogeneity in these efficacy measures among patients with detectable viral replication. We found that many patients who achieved viral suppression did not have high CD4 cell recovery profiles. Our efficacy measures also enabled us to identify a subgroup of patients who were not virally suppressed but had the potential to reach a high CD4 count and/or achieve viral suppression if they had been switched to a more potent regimen.

Conclusion

We show that our new efficacy measures are useful for analyzing the long-term treatment efficacy of combination reverse transcriptase inhibitors and argue that achieving a low R0 does not imply achieving viral suppression.

Objectives

Current treatment guidelines recommend immediate modification of antiretroviral therapy in HIV infected individuals with incomplete viral suppression. These recommendations have not been tested in observational studies or large randomized trials. We evaluated the consequences of delayed modification following virologic failure.

Design/Methods

We used prospective data from two clinical cohorts to estimate the effect of time until regimen modification following first regimen failure on all-cause mortality. The impact of regimen type was also assessed. Since the effect of delayed switching can be confounded if subjects with a poor prognosis modify therapy earlier than those with a good prognosis, we used a statistical methodology—marginal structural models—to control for time-dependent confounding.

Results

A total of 982 subjects contributed 3414 person-years of follow up following first regimen failure. Delay until treatment modification was associated with an elevated hazard of all-cause mortality among subjects failing a reverse transcriptase inhibitor-based regimen (hazard ratio per additional three months delay=1.23, 95% CI:1.08, 1.40), but appeared to have a small protective effect among subjects failing a protease inhibitor-based regimen (hazard ratio per additional three months delay=0.93, 95% CI: 0.87, 0.99).

Conclusions

Delay in modification after failure of regimens that do not contain a protease inhibitor is associated with increased mortality. Protease inhibitor-based regimens are less dependent on early versus delayed switching strategies. Efforts should be made to minimize delay until treatment modification in resource poor regions, where the majority of patients are starting reverse transcriptase inhibitor-based regimens and HIV RNA monitoring may not be available.

Background: Smoking tobacco is disproportionably common among HIV-infected patients in the highly active antiretroviral therapy (HAART) era. Methods: An observational cohort study of 300 HIV-positive patients receiving care between 1996 and 2005 examined the effect of smoking on pneumonia risk. Multivariable analyses assessed the association between smoking and pneumonia risk and identified independent predictors of pneumonia during the HAART era. Results: Current smoking was common (67%). Eighty-two patients (27%) experienced 119 pneumonia episodes during 2151 patient-years of follow-up, with 7.2 episodes/100 person-years among smokers and 2.9 episodes/100 person-years among non-smokers (unadjusted incidence rate ratio (IRR): 2.50 (95% CI: 1.58, 4.09). Adjustment for age and HIV RNA level resulted in an IRR of 1.77 (95% CI: 0.98, 3.21). No prior antiretroviral therapy use (P-value <0.001), higher HIV RNA level (P-value = 0.01), lower CD4 count (P-value = 0.01), younger age (P-value = 0.01), and alcohol use (P-value = 0.04) were independent predictors of pneumonia. HAART use decreased pneumonia risk (IRR 0.28, 95% CI: 0.18, 0.44). Conclusions: While HIV-positive smokers had over a 2-fold increase in the rate of pneumonia, the trend did not reach statistical significance in multivariable models. Clinical factors such as HAART, alcohol use and immunological status are important in pneumonia risk.

Background

The association between baseline drug resistance mutations and subsequent increase in viral failure has not been established for HIV-infected children. We evaluated drug resistance mutations at 39 codon sites (21 protease inhibitor (PI) resistant codons and 18 nucleoside reverse transcriptase inhibitor (NRTI) resistant codons) for 92 clinically stable NRTI-experienced, PI-naive HIV-infected children 2 to 17 years of age who were initiating new therapy with ritonavir plus zidovudine (ZDV) and lamivudine or plus stavudine. The association between baseline drug resistance mutations and subsequent viral failure after 12 and 24 weeks of highly active antiretroviral therapy (HAART) was studied.

Results

There were few primary PI associated mutations in this PI-naïve population, but 84% had NRTI mutations – codons 215 (66%), 41 (42%), 67 (37%), 210 (33%) and 70 (32%). None of the specific baseline drug resistance mutations were associated with a higher rate of virologic failure after 12 or 24 weeks of HAART. Median week 12 viral load decreased as the total number of NRTI mutations at baseline increased (P = 0.006). Specifically, a higher level of baseline ZDV resistance mutation was associated with a decrease in viral failure after 12 weeks on a ZDV-containing HAART regimen (P = 0.017).

Conclusion

No increase was seen in the rate of viral failure after HAART associated with the presence of resistance mutations at baseline. This paradoxical result may be due to adherence, replicative capacity, or ZDV hypersusceptibility to the new regimen.