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Should viral load thresholds be lowered?: Revisiting the WHO definition for virologic failure in patients on antiretroviral therapy in resource-limited settings.

ABSTRACT: The World Health Organization (WHO) guidelines on antiretroviral therapy (ART) define treatment failure as 2 consecutive viral loads (VLs) ?1000?copies/mL. There is, however, little evidence supporting 1000 copies as an optimal threshold to define treatment failure. Objective of this study was to assess the correlation of the WHO definition with the presence of drug-resistance mutations in patients who present with 2 consecutive unsuppressed VL in a resource-limited setting.In 10 nurse-led clinics in rural Lesotho children and adults on first-line ART for ?6 months received a first routine VL. Those with plasma VL ?80?copies/mL were enrolled in a prospective study, receiving enhanced adherence counseling (EAC) and a follow-up VL after 3 months. After a second unsuppressed VL genotypic resistance testing was performed. Viruses with major mutations against ?2 drugs of the current regimen were classified as "resistant".A total of 1563 adults and 191 children received a first routine VL. Of the 138 adults and 53 children with unsuppressed VL (?80?copies/mL), 165 (116 adults; 49 children) had a follow-up VL after EAC; 108 (74 adults; 34 children) remained unsuppressed and resistance testing was successful. Ninety of them fulfilled the WHO definition of treatment failure (both VL ?1000?copies/mL); for another 18 both VL were unsuppressed but with <1000?copies/mL. The positive predictive value (PPV) for the WHO failure definition was 81.1% (73/90) for the presence of resistant virus. Among the 18 with VL levels between 80 and 1000?copies/mL, thereby classified as "non-failures", 17 (94.4%) harbored resistant viruses. Lowering the VL threshold from 1000?copies/mL to 80?copies/mL at both determinations had no negative influence on the PPV (83.3%; 90/108).The current WHO-definition misclassifies patients who harbor resistant virus at VL below 1000?c/mL as "nonfailing." Lowering the threshold to VL ?80?copies/mL identifies a significantly higher number of patients with treatment-resistant virus and should be considered.

SUBMITTER: Labhardt ND

PROVIDER: S-EPMC4956783 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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Should viral load thresholds be lowered?: Revisiting the WHO definition for virologic failure in patients on antiretroviral therapy in resource-limited settings.

Labhardt Niklaus D ND Bader Joëlle J Lejone Thabo Ishmael TI Ringera Isaac I Hobbins Michael A MA Fritz Christiane C Ehmer Jochen J Cerutti Bernard B Puga Daniel D Klimkait Thomas T

Medicine 20160701 28

The World Health Organization (WHO) guidelines on antiretroviral therapy (ART) define treatment failure as 2 consecutive viral loads (VLs) ≥1000 copies/mL. There is, however, little evidence supporting 1000 copies as an optimal threshold to define treatment failure. Objective of this study was to assess the correlation of the WHO definition with the presence of drug-resistance mutations in patients who present with 2 consecutive unsuppressed VL in a resource-limited setting.In 10 nurse-led clini ...[more]

PMID: 27428189

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Project description:ObjectiveTo evaluate associations between hair antiretroviral hair concentrations as an objective, cumulative adherence metric, with self-reported adherence and virologic outcomes.DesignAnalysis of cohort A of the ACTG-A5288 study. These patients in resource-limited settings were failing second-line protease inhibitor-based antiretroviral therapy (ART) but were susceptible to at least one nucleoside reverse transcriptase inhibitor (NRTI) and their protease inhibitor, and continued taking their protease inhibitor-based regimen.MethodsAntiretroviral hair concentrations in participants taking two NRTIs with boosted atazanavir (n = 69) or lopinavir (n = 112) were analyzed at weeks 12, 24, 36 and 48 using liquid-chromatography--tandem-mass-spectrometry assays. Participants' self-reported percentage of doses taken in the previous month; virologic failure was confirmed HIV-1 RNA at least 1000 copies/ml at week 24 or 48.ResultsFrom 181 participants with hair samples (61% women, median age: 39 years; CD4+ cell count: 167 cells/μl; HIV-1 RNA: 18 648 copies/ml), 91 (50%) experienced virologic failure at either visit. At 24 weeks, median hair concentrations were 2.95 [interquartile range (IQR) 0.49-4.60] ng/mg for atazanavir, 2.64 (IQR 0.73--7.16) for lopinavir, and 0.44 (IQR 0.11--0.76) for ritonavir. Plasma HIV-1 RNA demonstrated inverse correlations with hair levels (rs -0.46 to -0.74) at weeks 24 and 48. Weaker associations were seen with self-reported adherence (rs -0.03 to -0.24). Decreasing hair concentrations were significantly associated with virologic failure, the hazard ratio (95% CI) for ATV, LPV, and RTV were 0.69 (0.56-0.86), 0.77 (0.68-0.87), and 0.12 (0.06-0.27), respectively.ConclusionProtease inhibitor hair concentrations showed stronger associations with subsequent virologic outcomes than self-reported adherence in this cohort. Hair adherence measures could identify individuals at risk of second-line treatment failure in need of interventions.

Project description:BackgroundThe results of international clinical trials that are assessing when to initiate antiretroviral therapy (ART) will not be available for several years.ObjectiveTo inform HIV treatment decisions about the optimal CD4 threshold at which to initiate ART in South Africa while awaiting the results of these trials.DesignCost-effectiveness analysis by using a computer simulation model of HIV disease.Data sourcesPublished data from randomized trials and observational cohorts in South Africa.Target populationHIV-infected patients in South Africa.Time horizon5-year and lifetime.PerspectiveModified societal.InterventionNo treatment, ART initiated at a CD4 count less than 0.250 x 10(9) cells/L, and ART initiated at a CD4 count less than 0.350 x 10(9) cells/L.Outcome measuresMorbidity, mortality, life expectancy, medical costs, and cost-effectiveness.Results of base-case analysisIf 10% to 100% of HIV-infected patients are identified and linked to care, a CD4 count threshold for ART initiation of 0.350 x 10(9) cells/L would reduce severe opportunistic diseases by 22,000 to 221,000 and deaths by 25,000 to 253,000 during the next 5 years compared with ART initiation at 0.250 x 10(9) cells/L; cost increases would range from $142 million (10%) to $1.4 billion (100%). Either ART initiation strategy would increase long-term survival by at least 7.9 years, with a mean per-person life expectancy of 3.8 years with no ART and 12.5 years with an initiation threshold of 0.350 x 10(9) cells/L. Compared with an initiation threshold of 0.250 x 10(9) cells/L, a threshold of 0.350 x 10(9) cells/L has an incremental cost-effectiveness ratio of $1200 per year of life saved.Results of sensitivity analysisInitiating ART at a CD4 count less than 0.350 x 10(9) cells/L would remain cost-effective over the next 5 years even if the probability that the trial would demonstrate the superiority of earlier therapy is as low as 17%.LimitationThis model does not consider the possible benefits of initiating ART at a CD4 count greater than 0.350 x 10(9) cells/L or of reduced HIV transmission.ConclusionEarlier initiation of ART in South Africa will probably reduce morbidity and mortality, improve long-term survival, and be cost-effective. While awaiting trial results, treatment guidelines should be liberalized to allow initiation at CD4 counts less than 0.350 x 10(9) cells/L, earlier than is currently recommended.Primary funding sourceNational Institute of Allergy and Infectious Diseases and the Doris Duke Charitable Foundation.

Project description:BackgroundThe potential impact of pre-exposure chemoprophylaxis (PrEP) on heterosexual transmission of HIV-1 infection in resource-limited settings is uncertain.Methodology/principle findingsA deterministic mathematical model was used to simulate the effects of antiretroviral PrEP on an HIV-1 epidemic in sub-Saharan Africa under different scenarios (optimistic, neutral and pessimistic) both with and without sexual disinhibition. Sensitivity analyses were used to evaluate the effect of uncertainty in input parameters on model output and included calculation of partial rank correlations and standardized rank regressions. In the scenario without sexual disinhibition after PrEP initiation, key parameters influencing infections prevented were effectiveness of PrEP (partial rank correlation coefficient (PRCC) = 0.94), PrEP discontinuation rate (PRCC = -0.94), level of coverage (PRCC = 0.92), and time to achieve target coverage (PRCC = -0.82). In the scenario with sexual disinhibition, PrEP effectiveness and the extent of sexual disinhibition had the greatest impact on prevention. An optimistic scenario of PrEP with 90% effectiveness and 75% coverage of the general population predicted a 74% decline in cumulative HIV-1 infections after 10 years, and a 28.8% decline with PrEP targeted to the highest risk groups (16% of the population). Even with a 100% increase in at-risk behavior from sexual disinhibition, a beneficial effect (23.4%-62.7% decrease in infections) was seen with 90% effective PrEP across a broad range of coverage (25%-75%). Similar disinhibition led to a rise in infections with lower effectiveness of PrEP (< or = 50%).Conclusions/significanceMathematical modeling supports the potential public health benefit of PrEP. Approximately 2.7 to 3.2 million new HIV-1 infections could be averted in southern sub-Saharan Africa over 10 years by targeting PrEP (having 90% effectiveness) to those at highest behavioral risk and by preventing sexual disinhibition. This benefit could be lost, however, by sexual disinhibition and by high PrEP discontinuation, especially with lower PrEP effectiveness (< or = 50%).

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Should viral load thresholds be lowered?: Revisiting the WHO definition for virologic failure in patients on antiretroviral therapy in resource-limited settings.

Publications

Should viral load thresholds be lowered?: Revisiting the WHO definition for virologic failure in patients on antiretroviral therapy in resource-limited settings.

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