Effect of immediate initiation of antiretroviral treatment on the risk of acquired HIV drug resistance

Prevalence of viral load suppression and acquired drug resistance among people living with HIV in Nepal: a nationally representative surveillance study

OBJECTIVES

This is the first nationally representative study to estimate the prevalence of viral load (VL) suppression and acquired HIV drug resistance (ADR) among people living with HIV (PLHIV) in Nepal.

METHODS

A cross-sectional study recruited 1418 PLHIV from 20 ART centres in Nepal, using a two-stage cluster design. Participants were eligible if they were HIV-positive individuals on ART for 9-15 months or at least 48 months. Plasma specimens were collected and tested for the quantification of HIV-1 RNA. Specimens with a VL ≥1000 copies/mL were further processed for sequencing of PR and RT genes of HIV-1. The sequences were then analysed to detect mutations causing HIV drug resistance.

RESULTS

The prevalence of ADR was 3.7% (95% confidence interval [CI]: 1.8-7.6) and 3.0% (95% CI: 1.8-5.2) among PLHIV who received ART for 9-15 months and 48 months or more, respectively. The prevalence of VL suppression was 95.3% (95% CI: 91.7-97.4) among those on ART for 9-15 months, and 96.5% (95% CI: 94.7-97.7) among those on ART for at least 48 months. The prevalence of any detectable acquired resistance to antiretroviral drugs was 80.7% (95% CI: 58.6-92.5) among those on ART for 9-15 months with VL ≥1000 copies/mL and 81.6% (95% CI: 55.4-94.0) among those on ART for at least 48 months with VL ≥1000 copies/mL.

CONCLUSION

This study suggests that improved accessibility to VL monitoring and timely assessment of drug resistance in routine HIV programs are crucial in Nepal to ensure access to HIV treatment for all in need.

Health economics modeling of antiretroviral interventions amongst HIV serodiscordant couples

Antiretroviral treatment (ART) and pre-exposure prophylaxis (PrEP) for HIV-serodiscordant couples, effectively reduce mortality, transmission events and influence quality of life at the expense of increased costs. We aimed to evaluate health economics of antiretroviral-based strategies for HIV-serodiscordant couples in the China context. A deterministic model of HIV evolution and transmission within a cohort of serodiscordant couples was parameterized using the real-world database of Zhoukou city and published literature. We evaluated the mid-ART (a historical strategy, initiating ART with CD4 < 500 cells/mm³), early-ART (the current strategy, offering ART regardless of CD4 cell counts) and a hypothetical strategy (early-ART combined short-term daily PrEP) versus the late-ART (the baseline strategy, initiating ART with CD4 < 350 cells/mm³) offered by 2008 national guidelines. We estimated the incremental cost-effectiveness ratios (ICER) and incremental cost-utility ratios (ICUR) from a societal perspective, derived by clinical benefits and HIV-caused life quality respectively, and portrayed their changes over a 0-30 year's timeframe. The model projections indicated that the antiretroviral-based interventions were more likely to obtain clinical benefits but difficult to improve quality of life, and cumulative ICER and ICUR were generally decreasing without achieving cost-saving. Scale-up access to ART for the HIV-positive among serodiscordant couples was easily fallen within the range of paying for incremental life-years and quality adjusted life years by the societal willingness. The hypothetical strategy had the potential to prevent most seroconversion events within marriages but required enormous upfront costs, thus it took a long time to reach established thresholds. The current strategy of early-ART is the most cost-effective. Clarifying the obstacles of high cost of PrEP and improving life quality for HIV-serodiscordant couples have emerged as an urgent requisition.

Virological Failure and Acquired Genotypic Resistance Associated With Contemporary Antiretroviral Treatment Regimens

Background

There are few descriptions of virologic failure (VF) and acquired drug resistance (HIVDR) in large cohorts initiating contemporary antiretroviral therapy (ART).

Methods

We studied all persons with HIV (PWH) in a California clinic population initiating ART between 2010 and 2017. VF was defined as not attaining virologic suppression, discontinuing ART, or virologic rebound prompting change in ART.

Results

During the study, 2315 PWH began ART. Six companion drugs were used in 93.3% of regimens: efavirenz, elvitegravir/c, dolutegravir, darunavir/r, rilpivirine, and raltegravir. During a median follow-up of 36 months, 214 (9.2%) PWH experienced VF (2.8 per 100 person-years) and 62 (2.7%) experienced HIVDR (0.8 per 100 person-years). In multivariable analyses, younger age, lower CD4 count, higher virus load, and atazanavir/r were associated with increased VF risk; lower CD4 count, higher virus load, and nevirapine were associated with increased HIVDR risk. Compared with efavirenz, dolutegravir, raltegravir, and darunavir were associated with reduced HIVDR risk. Risks of VF and HIVDR were not significantly associated with ART initiation year. Of the 62 PWH with HIVDR, 42 received an non-nucleoside RT inhibitor (NNRTI), 15 an integrase-strand transfer inhibitor (INSTI), and 5 a protease inhibitor (PI). Among those with HIVDR on an NNRTI or first-generation INSTI, 59% acquired dual class resistance and 29% developed tenofovir resistance; those receiving a PI or dolutegravir developed just M184V.

Conclusions

Despite the frequent use of contemporary ART regimens, VF and HIVDR continue to occur. Further efforts are required to improve long-term ART virological responses to prevent the consequences of ongoing HIV-1 replication including virus transmission and HIVDR.

Parametric g-formula implementations for causal survival analyses

The g-formula can be used to estimate the survival curve under a sustained treatment strategy. Two available estimators of the g-formula are noniterative conditional expectation and iterative conditional expectation. We propose a version of the iterative conditional expectation estimator and describe its procedures for deterministic and random treatment strategies. Also, because little is known about the comparative performance of noniterative and iterative conditional expectation estimators, we explore their relative efficiency via simulation studies. Our simulations show that, in the absence of model misspecification and unmeasured confounding, our proposed iterative conditional expectation estimator and the noniterative conditional expectation estimator are similarly efficient, and that both are at least as efficient as the classical iterative conditional expectation estimator. We describe an application of both noniterative and iterative conditional expectation to answer "when to start" treatment questions using data from the HIV-CAUSAL Collaboration.

Human Immunodeficiency Virus Drug Resistance: 2018 Recommendations of the International Antiviral Society-USA Panel

Background

Contemporary antiretroviral therapies (ART) and management strategies have diminished both human immunodeficiency virus (HIV) treatment failure and the acquired resistance to drugs in resource-rich regions, but transmission of drug-resistant viruses has not similarly decreased. In low- and middle-income regions, ART roll-out has improved outcomes, but has resulted in increasing acquired and transmitted resistances. Our objective was to review resistance to ART drugs and methods to detect it, and to provide updated recommendations for testing and monitoring for drug resistance in HIV-infected individuals.

Methods

A volunteer panel of experts appointed by the International Antiviral (formerly AIDS) Society–USA reviewed relevant peer-reviewed data that were published or presented at scientific conferences. Recommendations were rated according to the strength of the recommendation and quality of the evidence, and reached by full panel consensus.

Results

Resistance testing remains a cornerstone of ART. It is recommended in newly-diagnosed individuals and in patients in whom ART has failed. Testing for transmitted integrase strand-transfer inhibitor resistance is currently not recommended, but this may change as more resistance emerges with widespread use. Sanger-based and next-generation sequencing approaches are each suited for genotypic testing. Testing for minority variants harboring drug resistance may only be considered if treatments depend on a first-generation nonnucleoside analogue reverse transcriptase inhibitor. Different HIV-1 subtypes do not need special considerations regarding resistance testing.

Conclusions

Testing for HIV drug resistance in drug-naive individuals and in patients in whom antiretroviral drugs are failing, and the appreciation of the role of testing, are crucial to the prevention and management of failure of ART.

Refining the Association Between Body Mass Index and Atrial Fibrillation: G-Formula and Restricted Mean Survival Times

Background

Previous studies assessing the association between body mass index (BMI) and atrial fibrillation (AF) did not account for time‐varying covariates, which may be affected by previous BMI. We illustrate how the g‐formula can account for time‐varying confounding.

Methods and Results

We included 4392 participants from the Framingham Heart Study who were AF free at ages 45 to 55 years, and followed them for up to 20 years. We estimated hazard ratios (HRs) comparing time‐varying nonobese versus obese with Cox models. We used the g‐formula to compare nonobese versus obese and 10% annual decrease in BMI (until normal weight is reached) versus natural course. We estimated HRs and differences in restricted mean survival times, the mean difference in time alive and AF free. We adjusted for sex, age, and time‐varying risk factors. Cox models indicated that nonobese participants had a decreased rate of AF versus obese participants (HR, 0.83; 95% CI, 0.72–0.97). G‐formula analyses comparing everyone had they been nonobese versus obese yielded stronger associations (HR, 0.73; 95% CI, 0.58–0.91). The restricted mean survival time was 19.22 years had everyone been nonobese and 19.03 years had everyone been obese (difference, 2.25 months; 95% CI, −0.66 to 5.16). When assessing a 10% annual decrease in BMI, the association was weaker (HR 0.96; 95% CI, 0.86–1.08).

Conclusions

Decreased BMI was associated with a lower rate of AF after accounting for time‐varying covariates that depend on previous exposure using the g‐formula, which Cox models cannot accommodate. Absolute measures like the restricted mean survival time difference offer context to relative measures of association.

Why Everyone (Almost) with HIV Needs to Be on Treatment: A Review of the Critical Data

Since 2014, a consensus of landmark studies has justified starting antiretroviral therapy (ART) regardless of CD4 count. The evidence for immediate and universal ART is strong, clearly showing individual and population-level benefits, and is supported by all major guidelines groups. Altogether, improvements in ART and recognition of its clinical and epidemiologic benefits justify near-universal ART, preferably as soon after the diagnosis of human immunodeficiency virus (HIV) as possible. Case-based discussions provide a framework to explore the evidence behind the current recommendation for ART for all HIV-positive persons and specific scenarios are discussed in which ART initiation may be delayed.

Emulating a trial of joint dynamic strategies: An application to monitoring and treatment of HIV-positive individuals

Decisions about when to start or switch a therapy often depend on the frequency with which individuals are monitored or tested. For example, the optimal time to switch antiretroviral therapy depends on the frequency with which HIV-positive individuals have HIV RNA measured. This paper describes an approach to use observational data for the comparison of joint monitoring and treatment strategies and applies the method to a clinically relevant question in HIV research: when can monitoring frequency be decreased and when should individuals switch from a first-line treatment regimen to a new regimen? We outline the target trial that would compare the dynamic strategies of interest and then describe how to emulate it using data from HIV-positive individuals included in the HIV-CAUSAL Collaboration and the Centers for AIDS Research Network of Integrated Clinical Systems. When, as in our example, few individuals follow the dynamic strategies of interest over long periods of follow-up, we describe how to leverage an additional assumption: no direct effect of monitoring on the outcome of interest. We compare our results with and without the "no direct effect" assumption. We found little differences on survival and AIDS-free survival between strategies where monitoring frequency was decreased at a CD4 threshold of 350 cells/μl compared with 500 cells/μl and where treatment was switched at an HIV-RNA threshold of 1000 copies/ml compared with 200 copies/ml. The "no direct effect" assumption resulted in efficiency improvements for the risk difference estimates ranging from an 7- to 53-fold increase in the effective sample size.

HIV drug resistance in sub-Saharan Africa: public health questions and the potential role of real-world data and mathematical modelling

The prevalence of pretreatment resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs) is >10% in many low-income countries. As a consequence, several sub-Saharan African countries have implemented, or are considering the introduction of, non-NNRTI-based first-line antiretroviral therapy (ART) for treatment-naïve and treatment-experienced patients. This is occurring at a time when ART programmes are expanding, in response to the World Health Organization guidelines, which recommend ART initiation regardless of CD4 cell count. Both those developments raise important questions regarding their potential impact on HIV drug resistance and the impact of HIV drug resistance on clinical outcomes. Those issues are particularly relevant to sub-Saharan Africa, where standardised ART regimens are used and where viral load monitoring and resistance testing are often not done routinely. It is therefore essential to forecast the impact of the implementation of universal ART, and the introduction of drugs such as dolutegravir to first-line regimens, on HIV drug resistance in order to inform future policies and to help ensure sustainable positive long-term outcomes. We discuss important public health considerations regarding HIV drug resistance, and describe how mathematical modelling, combined with real-world data from the four African Regions of the International epidemiology Databases to Evaluate AIDS consortium, could provide an early warning system for HIV drug resistance in sub-Saharan Africa.

AIDS Therapy Evaluation in the Netherlands (ATHENA) national observational HIV cohort: cohort profile

PURPOSE

In 1998, the AIDS Therapy Evaluation in the Netherlands (ATHENA) national observational HIV cohort was established to demonstrate the lifesaving effectiveness of triple combination antiretroviral therapy, including HIV-protease inhibitors, that had recently been made available for clinical use. Subsequently, the HIV Monitoring Foundation was established by the Dutch Ministry of Health, Welfare and Sport to continue ATHENA as an open cohort in order to continue the registration and monitoring of all HIV-positive people as an integral part of HIV care in all 26 HIV treatment centres in the Netherlands.

PARTICIPANTS

To date, a total of 25 036 participants have been enrolled in the cohort, with 263 600 person-years of follow-up. As of 1 January 2017, 19 035 HIV-1-positive participants were known to be in care: 18 824 adults (81% men and 19% women) and 211 children (47% boys and 53% girls). The remaining 6001 participants had either died (46%), were lost to care (29%) or had moved abroad (25%).

FINDINGS TO DATE

Today, with over 20 years of follow-up, the ATHENA cohort has provided extensive knowledge on HIV treatment, comorbidities and coinfections and created insight into the transmission dynamics of the HIV epidemic.

FUTURE PLANS

ATHENA continues to enrol and monitor HIV positive people entering HIV care in the Netherlands. Future research will continue to provide tangible input into HIV care and prevention policies in the Netherlands and internationally.

HIV drug resistance in low-income and middle-income countries

After 15 years of global scale-up of antiretroviral therapy (ART), rising prevalence of HIV drug resistance in many low-income and middle-income countries (LMICs) poses a growing threat to the HIV response, with the potential to drive an increase in mortality, HIV incidence, and costs. To achieve UNAIDS global targets, enhanced strategies are needed to improve quality of ART services and durability of available ART regimens, and to curb resistance. These strategies include roll out of drugs with greater efficacy and higher genetic barriers to resistance than those that are currently widely used, universal access to and improved effectiveness of viral load monitoring, patient-centred care delivery models, and reliable drug supply chains, in conjunction with frameworks for resistance monitoring and prevention. In this Review, we assess contemporary data on HIV drug resistance in LMICs and their implications for the HIV response, highlighting the potential impact and resistance risks of novel ART strategies and knowledge gaps.