Markers associated with persisting low-level viraemia under antiretroviral therapy in HIV-1 infection

Risk factors and clinical prediction models for low-level viremia in people living with HIV receiving antiretroviral therapy: an 11-year retrospective study

Objective

This study explores the risk factors for low-level viremia (LLV) occurrence after ART and develops a risk prediction model.

Method

Clinical data and laboratory indicators of people living with HIV (PLWH) at Hangzhou Xixi Hospital from 5 April 2011 to 29 December 2022 were collected. LASSO Cox regression and multivariate Cox regression analysis were performed to identify laboratory indicators and establish a nomogram for predicting LLV occurrence. The nomogram's discrimination and calibration were assessed via ROC curve and calibration plots. The concordance index (C-index) and decision curve analysis (DCA) were used to evaluate its effectiveness.

Result

Predictive factors, namely, age, ART delay time, white blood cell (WBC) count, baseline CD4+ T-cell count (baseline CD4), baseline viral load (baseline VL), and total bilirubin (TBIL), were incorporated into the nomogram to develop a risk prediction model. The optimal model (which includes 6 variables) had an AUC for LLV after 1-year, 3-year, and 5-year of listing of 0.68 (95% CI, 0.61-0.69), 0.69 (95% CI, 0.65-0.70), and 0.70 (95% CI, 0.66-0.71), respectively. The calibration curve showed high consistency between predicted and actual observations. The C-index and DCA indicated superior prediction performance of the nomogram. There was a significant difference in CD4 levels between LLV and non-LLV groups during the follow-up time. The dynamic SCR, ALT, TG and BG levels and occurrence of complications differed significantly between the high- and low-risk groups.

Conclusion

A simple-to-use nomogram containing 6 routinely detected variables was developed for predicting LLV occurrence in PLWH after ART.

Factors Associated with Low-Level Viremia in People Living with HIV in the Italian Antiviral Response Cohort Analysis Cohort: A Case-Control Study

Despite effective antiretroviral therapies (ARTs), a subset of people living with HIV (PLWH) still experience low-level viremia (LLV, i.e., 50-1,000 copies/mL). The present study compared PLWH experiencing LLV with those maintaining virological suppression (VS) and explored the potential impact of preexisting drug resistance and other factors on LLV. We conducted a retrospective, 1:1 matched case-control study within a cohort of drug-experienced VS subjects from the Italian Antiviral Response Cohort Analysis database, followed in the period 2009-2019. Cases were individuals experiencing LLV, while controls were those who maintained VS. Matching was for calendar year of first ART regimen. Preexisting drug resistance was calculated as cumulative genotypic susceptibility score (GSS) according to regimen administered at the observational period start. To explore the effect of cumulative GSS, treated as a binary variable (≥2 and <2) and other factors on LLV, we performed a logistic regression analysis. Within a main population of 3,455 PLWH, 337 cases were selected. Cases were comparable to the controls for both gender and age. However, cases showed that they had experienced a longer time since HIV diagnosis, a higher number of drugs previously administered, lower baseline CD4+ T cell count and a higher zenith viral load (VL). By multivariate analysis, we found that higher zenith VL [adjusted odds ratio (aOR) (95% confidence interval [CI]) 1.30 (1.14-1.48)], a cumulative usage of both PI [aOR (95% CI): 2.03 (1.19-3.48)] and InSTI [aOR (95% CI): 2.23 (1.47-3.38)] and a cumulative GSS <2 [aOR (95% CI) 0.67 (0.46-0.98)], were associated with a higher risk in developing LLV. In current high-efficacy ART era, in drug-experienced PLWH, the predictors of increased risk of LLV were the presence of preexisting drug resistance, higher zenith VL, and previous PI, and InSTI exposure.

Prevalence and predictors of persistent low-level HIV viraemia: a retrospective cohort study among people receiving dolutegravir-based antiretroviral therapy in Southern Nigeria

Background

Persistent low-level viraemia (PLLV) is a risk factor for virologic failure among people receiving antiretroviral therapy (ART).

Objectives

We assessed the prevalence and predictors of PLLV among individuals receiving Dolutegravir-based ART in southern Nigeria.

Design

This retrospective cohort study used routine program data from electronic medical records of persons receiving Dolutegravir-based first-line ART in 154 PEPFAR/USAID-supported health facilities in Akwa Ibom and Cross Rivers states, Nigeria.

Methods

Clients on first-line Dolutegravir-based ART ⩾6 months, who had a viral load result in the 12 months preceding October 2021 (baseline), and a second viral load result by September 2022 were included. Persons with low-level viraemia (LLV) (viral load 51-999 copies/ml) received additional adherence support. The outcome analysed was PLLV (two consecutive LLV results). Indices were summarized using descriptive statistics, and predictors of PLLV were determined using multivariate logistic regression.

Results

In total, 141,208 persons on ART were included, of which 63.3% (n = 89,944) were females. The median age was 36 [29-44] years, median ART duration was 19 [11-42] months. At the end of the study, 10.5% (14,759/141,208) had initial LLV, 90.1% (13,304/14,759) of which attained undetectable viral load (⩽50 copies/ml), and 1.1% (163/14,759) transitioned to virologic failure (⩾1000 copies/ml) by the end of the study. PLLV prevalence was 0.9% (1292/141,208). Increasing ART duration [adjusted odds ratio (aOR) = 1.0; 95% confidence interval (CI): 1.005-1.008; p < 0.001] and viral suppression (<1000 copies/ml) before initial LLV (aOR = 1.7; 95% CI: 1.50-2.00; p < 0.001) were positively associated with PLLV, while receipt of tuberculosis preventive therapy reduced the likelihood of PLLV (aOR = 0.3; 95% CI: 0.10-0.94; p = 0.039).

Conclusion

PLLV was uncommon among individuals receiving dolutegravir-based ART and was associated with longer ART duration, prior viral suppression, and non-receipt of tuberculosis preventive therapy. This strengthens recommendations for continuous adherence support and comprehensive health services with ART, to prevent treatment failure.

Influencing factors and adverse outcomes of different virologic rebound states in antiretroviral treated HIV/AIDS patients

Antiretroviral therapy (ART) aims to inhibit HIV replication, decrease CD4 T cell loss, and immune function recovery in order to reduce the morbidity and mortality associated with the infection. Treatment should also, improve quality of life and control HIV spread. However, incomplete viral suppression still occurs during ART. Viral suppression and virological failure (VF) thresholds vary between studies in terms of virological rebound (VR) states using different detection thresholds. Further understanding of influencing factors and adverse outcomes in various VR states should provide important guidance for HIV treatment.

HIV-1 Drug Resistance Profiles of Low-Level Viremia Patients and Factors Associated With the Treatment Effect of ART-Treated Patients: A Cross-Sectional Study in Jiangsu, China

Objectives

Evaluating the drug resistance (DR) profiles of LLV patients and the influencing factors of treatment effects in Jiangsu Province.

Method

The Pol gene (Reverse transcriptase and protease) was amplified and sequenced to identify the genotypes and DR profiles among LLV patients in 2021. Questionnaire survey was conducted among HIV/AIDS patients to investigate the potential influence factors of treatment effects.

Results

242 Pol genes were amplified from 345 specimens, and ten genotypes were detected. The DR rate was 40.5%, with 66, 86, and 14 being resistant to NRTIs, NNRTIs, and PIs, respectively. Patients treated with the 2NRTIs+PIs regimen were detected with more DR; and drug resistance was less detected in married or cohabiting patients than unmarried patients. Non-smokers were less likely to develop LLV at follow-up than smokers; patients with stage II clinical stage at diagnosis and using 2NRTIs+PIs regimen were also more likely to develop LLV at follow-up.

Conclusion

Drug resistance profiles in LLV patients are severe and differ in treatment regimens and marital statuses. Meanwhile, smoking history, clinical stage, and treatment regimen may influence the therapeutic effect. It is necessary to include LLV people in the free drug resistance testing program.

Low-level viremia and virologic failure among people living with HIV who received maintenance therapy with co-formulated bictegravir, emtricitabine and tenofovir alafenamide versus dolutegravir-based regimens

BACKGROUND

Real-world experience with low-level viremia (LLV) and its impact remain less reported among people living with HIV (PLWH) who receive antiretroviral therapy (ART) containing second-generation integrase strand transferase inhibitors (INSTIs), including dolutegravir and bictegravir.

METHODS

Virally suppressed PLWH who had achieved plasma HIV RNA load (PVL) <50 copies/mL for ≥6 months and were switched to either dolutegravir- or bictegravir-based ART were included in this retrospective cohort study. The incidence rates of developing LLV events (PVL, 50-199 copies/mL) and virologic failure (VF) (PVL ≥1000 copies/mL) were compared between the dolutegravir and bictegravir cohorts.

RESULTS

A total of 623 and 862 PLWH switched to dolutegravir-based and bictegravir-based ART, respectively, were included. The incidence rates of developing LLV were 6.2 per 100 person-years of follow-up (PYFU) in the bictegravir cohort and 3.8 per 100 PYFU in the dolutegravir cohort (incidence rate ratio [IRR], 1.63; 95% confidence interval [CI], 0.90-2.95, p=0.08), while the rates of VF were 0.69 per 100 PYFU and 0.95 per 100 PYFU, respectively, in the bictegravir and dolutegravir cohort (IRR, 0.72; 95% CI, 0.12-3.39, p=0.34). Presence of LLV events was not associated with subsequent VF in multivariate analysis. Secondary analysis also demonstrated that resistance-associated mutations (RAMs) to nucleoside reverse-transcriptase inhibitors before switch were not associated with adverse virologic outcomes in either cohort.

CONCLUSIONS

Among virally suppressed PLWH, the incidences of developing LLV or VF were similar after switch to dolutegravir- or bictegravir-based ART. Preexisting RAMs to nucleoside reverse-transcriptase inhibitors or the LLV events were not associated with subsequent VF.

Factors associated with low-level viraemia in people with HIV starting antiretroviral therapy: A Swedish observational study

Objective

Low-level viraemia (LLV) occurs in some people with HIV (PWH) receiving antiretroviral therapy (ART) and has been linked to inferior treatment outcomes. We investigated factors associated with LLV in a nationwide cohort of Swedish PWH starting ART.

Methods

Participants were identified from the InfCareHIV register, with the following inclusion criteria: ART initiation 2006–2017, age >15 years, ≥4 viral load (VL) results available and no documented treatment interruptions or virologic failure (≥2 consecutive VL ≥200 copies/ml) during follow-up. Starting from 6 months after ART initiation, participants were followed for 24 months and categorised as viral suppression (VS; VL <50 copies/ml) or LLV (≥2 consecutive VL 50–199 copies/ml). We analysed the association between the following factors and LLV using multivariable logistic regression: sex, age, pre-ART VL and CD4 count, ART regimen, country of birth, HIV-1 subtype and transmission category.

Results

Among 3383 participants, 3132 (92.6%) had VS and 251 (7.4%) had LLV. In univariable analyses, factors associated with LLV were male sex, higher age, lower pre-ART CD4 count, higher pre-ART VL and ART regimen. After adjustment, the following factors were associated with LLV (adjusted odds ratio; 95% confidence interval): male sex (1.6; 1.1–2.3), higher pre-ART VL (2.7; 2.2–3.3), pre-ART CD4 count <200 cells/μl (1.6; 1.2–2.2), protease inhibitor (PI)-based regimen (1.5; 1.1–2.1), non-standard ART (2.4; 1.0–5.5) and injecting drug use (2.0; 1.1–3.7).

Conclusion

Among Swedish PWH, LLV during ART was associated with markers of HIV disease severity before starting ART, male sex, injecting drug use and use of PI-based or non-standard ART regimens.

Persistent low-level viraemia in antiretroviral treatment-experienced patients is not linked to viral resistance or inadequate drug concentrations

OBJECTIVES

To assess genotypic sensitivity scores (GSSs), plasma antiretroviral concentrations (PACs) and immunovirological outcomes at Week 96 (W96) in patients with persistent low-level viraemia (LLV).

METHODS

On 1 January 2017, we analysed data from patients on three-drug regimens with persistent LLV defined as at least two consecutive plasma viral loads (pVLs) between 21 and 200 copies/mL (including one pVL of ≥50 copies/mL), at the Pitié-Salpêtrière Hospital. Outcomes were: GSS, PACs and HIV-DNA load at study entry; and virological status and proportion of patients with resistance-associated mutations (RAMs) at W96.

RESULTS

Fifty-seven patients were included, with median age of 52.6 years (IQR 45.2-57.9), last CD4 count of 658 cells/mm3 (IQR 462-909) and total ART duration of 10.2 years (IQR 5.7-15.2). LLV duration was 14.0 months (IQR 5.5-22.3). GSS was 3 in 46/57 (81%) patients and PACs were adequate in 53/57 (93%) patients. Median total HIV-DNA was 2.65 log10 copies/106 cells (IQR 2.44-2.86). During follow-up, 26/57 (46%) had experienced ART modifications. At W96, 38/57 (67%) patients remained with LLV, 15/60 (26%) had achieved confirmed pVL of <20 copies/mL and 4/57 (7%) had virological failure. The four virological failures were due to three ART interruptions and one incomplete adherence (selection of Y181C RAM). No factors (patient characteristics at study entry, GSS, PACs, total HIV-DNA load and ART modification) were associated with W96 viral outcome, except for time from HIV diagnosis and the LLV duration at study entry.

CONCLUSIONS

A substantial number of patients harbouring LLV had no resistance to ART and adequate PACs. Two-thirds of these patients remained with this LLV status.

Time to Viral Rebound After Interruption of Modern Antiretroviral Therapies

BACKGROUND

Development of HIV remission strategies requires precise information on time to HIV rebound after treatment interruption, but there is uncertainty regarding whether modern ART regimens and timing of ART initiation may impact this outcome.

METHODS

ACTG A5345 enrolled individuals who initiated ART during chronic or early HIV infection and on suppressive ART for ≥2 years. Participants underwent carefully monitored antiretroviral interruption. ART was restarted upon two successive viral loads ≥1,000 copies/mL. We compared participants of A5345 with participants of 6 historic ACTG treatment interruption studies.

RESULTS

Thirty-three chronic-treated and 12 early-treated participants interrupted ART with evaluable time to viral rebound. Median time to viral rebound ≥1000 HIV RNA copies/mL was 22 days. Acute retroviral rebound syndrome was diagnosed in 9% of chronic-treated and none of early-treated individuals. All participants of the historic studies were on older protease inhibitor-based regimens while 97% of A5345 participants were on integrase inhibitor-based ART. There were no differences in the timing of viral rebound comparing A5345 versus historic studies. In a combined analysis, a higher percentage of early-treated participants remained off ART at post-treatment interruption week 12 (chronic vs early: 2% vs 9%, P=0.0496). One chronic-treated and one early-treated A5345 participant remained off ART for >24 weeks. All participants re-suppressed after ART re-initiation.

CONCLUSIONS

Early ART initiation, using either older or newer ART regimens, was associated with a significant delay in the time to HIV rebound after ART interruption, lowering the barrier for HIV remission.

Associations Between Plasma Human Immunodeficiency Virus (HIV) Ribonucleic Acid Levels and Incidence of Invasive Cancer in People With HIV After Initiation of Combination Antiretroviral Therapy

Background

Human immunodeficiency virus (HIV) viremia could be involved in the increased risk of cancer in people with HIV (PWH) receiving combination antiretroviral therapy (cART). We analyzed the association between plasma HIV ribonucleic acid levels in PWH starting cART and incident invasive cancer using the Swedish cohort InfCare HIV linked with national registers.

Methods

Adults starting cART in 1996–2017 were included if they had ≥1 viral load (VL) measurement before receiving any antiretroviral agent (pre-ART VL) and ≥2 VLs ≥6 months after start of cART. Viremia during cART was analyzed both as viremia-copy-years and categorized as suppression (<50 copies/mL), low-level viremia ([LLV] 50–999 copies/mL), and nonsuppression (≥1000 copies/mL). The main outcome was a composite of invasive malignancies with increased incidence among PWH. We fitted proportional subhazard models (including sex, age, pre-ART CD4 count, and injection drug use) for both pre-ART VL and viremia during cART.

Results

After 32 105 person-years, 3254 of 4931 participants (66%) were classified as suppressed, 438 (9%) were classified as LLV, and 1221 (25%) were classified as nonsuppressed. Neither viremia category nor cumulative viremia during cART had a statistically significant association with cancer. Higher pre-ART VL was associated with cancer (adjusted subhazard ratio, 1.4; 95% confidence interval, 1.0–1.8); this remained statistically significant with viremia during cART in the model. In subanalysis, the association with pre-ART VL was statistically significant for acquired immune deficiency syndrome (AIDS)-defining and infection-related non-AIDS-defining cancer, but not for other malignancies.

Conclusions

In this nationwide cohort, pre-ART VL was an independent predictor of invasive cancer, whereas viremia profile during cART was not associated with cancer incidence.

Differences in HIV Markers between Infected Individuals Treated with Different ART Regimens: Implications for the Persistence of Viral Reservoirs

In adherent individuals, antiretroviral therapy (ART) suppresses HIV replication, restores immune function, and prevents the development of AIDS. However, ART is not curative and has to be followed lifelong. Persistence of viral reservoirs forms the major obstacle to an HIV cure. HIV latent reservoirs persist primarily by cell longevity and proliferation, but replenishment by residual virus replication despite ART has been proposed as another potential mechanism of HIV persistence. It is a matter of debate whether different ART regimens are equally potent in suppressing HIV replication. Here, we summarized the current knowledge on the role of ART regimens in HIV persistence, focusing on differences in residual plasma viremia and other virological markers of the HIV reservoir between infected individuals treated with combination ART composed of different antiretroviral drug classes.

Is HIV-1 viraemia below 20 copies/mL in antiretroviral-treated patients associated with virologic outcome?

BACKGROUND

We aimed to investigate whether very low-level HIV-1 viraemia (VLLV) <20 copies/mL in HIV-1-infected patients on antiretroviral therapy (ART) whose VL was <20 copies/mL, was associated with a subsequent VL > 20 copies/mL.

METHODS

VLLV was defined as VL <20 copies/mL and positive HIV-1-PCR. We compared patients with positive and negative HIV-1-PCRs <20 copies/mL at two time points, T0 and T1, after 21st of January 2016. Factors associated with a VLLV and subsequent VL >20 copies/mL were identified by logistic regression models.

RESULTS

Of 1341 participants at T0, 958 (71.4%) had a negative and 383 patients (28.6%) had positive HIV-RNA PCR signal during VL < 20 copies/mL. The negative relative to the positive signal at T0 was independently associated with dolutegravir (DTG) mono and/or DTG-lamivudine dual therapy (compared to nevirapine), a pre-ART-VL of 1000-9999 copies/mL (compared to ≥100,000 copies/mL), and each additional year of virologic suppression. Having a virolologic outcome at T1 of ≥ 20 copies/mL was independently associated with prior positive signal at T0. (OR = 2.291, 95% CI = 1.457-3.601, p value < .001), a past ART interruption, and a change in ART regimen during follow-up. Each additional year of virologic suppression was independently associated with a lower risk for a subsequent VL ≥ 20 copies/mL.

CONCLUSIONS

A positive HIV-1 RNA PCR <20 copies/mL at T0, was associated with a subsequent VL ≥ 20 copies/mL at T1. This was not a rare phenomenon among patients with VL <20 copies/mL. In most patients with a positive PCR signal, this was not followed by a clinically relevant HIV-1 viraemia, defined as ≥ 200 copies/mL.

Counter-intuitive plasma vitamin D and zinc status in HIV-1-infected adults with persistent low-level viraemia after treatment initiation: a pilot case-control study

Determinants of persistent low-level viraemia [PLLV, a viral load (VL) of between 50 and 500 copies/mL] have not been elucidated. In a case-control study, we evaluated the influence of micronutrients on PLLV in a population of 454 HIV-1 adults having initiated antiretroviral therapy (ART) between January 2007 and December 2011. Plasma levels of retinol (vitamin A), 25-OH vitamin D₂ + D₃, vitamin E and zinc were measured at ART initiation in cases (PLLV after 6 months of ART) and in controls (VL <50 copies/mL after 6 months). Cases and controls were matched for the CD4 cell count (±50/mm³) and ethnic origin. Intergroup differences in demographic, biological and treatment parameters and sunshine intensity at ART initiation were adjusted using a propensity score. A receiver operating characteristic (ROC) curve was used to assess intergroup differences in plasma micronutrient levels. Thirty-three of the 454 patients (7.3%) displayed PLLV (median VL: 92 copies/mL). Patients were predominantly male (89%), Caucasian (64%) and CDC stage C (25%). The median age was 38 years, the median initial VL was 5.2 log₁₀ copies/mL and the median CD4 count was 74/mm³. The 22 cases and matched controls were balanced in these respects, and had similar vitamin A/E levels. Two cases (9%) and 9 controls (41%) had a vitamin D level <10.3 ng/mL (p = 0.0015), and 2 cases (9%) and 10 controls (48%) had a zinc level <74.6 μg/dL (p = 0.04). Our results support in vitro studies suggesting that vitamin D favours HIV-1 replication and that HIV-1 is zinc-dependent. Wide-scale, prospective studies are required.

A Single Quantifiable Viral Load Is Predictive of Virological Failure in Human Immunodeficiency Virus (HIV)-Infected Patients on Combination Antiretroviral Therapy: The Austrian HIV Cohort Study

Background.  Viral loads (VLs) detectable at low levels are not uncommon in patients on combination antiretroviral therapy (cART). We investigated whether a single quantifiable VL predicted virological failure (VF). Methods.  We analyzed patients receiving standard regimens with at least 1 VL measurement below the limit of quantification (BLQ) in their treatment history. The first VL measurement after 6 months of unmodified cART served as baseline VL for the subsequent analyses of the time to reach single VL levels of ≥200, ≥400, and ≥1000 copies/mL. Roche TaqMan 2.0 was used to quantify human immunodeficiency virus-1 ribonucleic acid. Factors associated with VF were determined by Cox proportional hazards models. Results.  Of 1614 patients included in the study, 68, 44, and 34 experienced VF ≥200, ≥400, and ≥1000 copies/mL, respectively. In multivariable analyses, compared with patients who were BLQ, a detectable VL ≤ 50 and VL 51-199 copies/mL predicted VF ≥ 200 copies/mL (hazards ratio [HR] = 2.19, 95% confidence interval [CI] = 1.06-4.55 and HR = 4.21, 95% CI = 2.15-8.22, respectively). In those with VL 51-199 copies/mL, a trend for an increased risk of VF ≥400 and VF ≥1000 copies/mL could be found (HR = 2.13, 95% CI = 0.84-5.39 and HR = 2.52, 95% CI = 0.96-6.60, respectively). Conclusions.  These findings support closer monitoring and adherence counseling for patients with a single measurement of quantifiable VL <200 copies/mL.

Factors Associated with Low-Level Viraemia and Virological Failure: Results from the Austrian HIV Cohort Study

Background

In human immunodeficiency virus treatment adequate virological suppression is warranted, nevertheless for some patients it remains a challenge. We investigated factors associated with low-level viraemia (LLV) and virological failure (VF) under combined antiretroviral therapy (cART).

Materials and Methods

We analysed patients receiving standard regimens between 1^st July 2012 and 1^st July 2013 with at least one viral load (VL) measurement below the quantification limit (BLQ) in their treatment history. After a minimum of 6 months of unmodified cART, the next single VL measurement within 6 months was analysed. VF was defined as HIV RNA levels ≥200 copies/mL and all other quantifiable measurements were classified as LLV. Factors associated with LLV and VF compared to BLQ were identified by logistic regression models.

Results

Of 2276 participants, 1972 (86.6%) were BLQ, 222 (9.8%) showed LLV and 82 (3.6%) had VF. A higher risk for LLV and VF was shown in patients with cART interruptions and in patients with boosted PI therapy. The risk for LLV and VF was lower in patients from centres using the Abbott compared to the Roche assay to measure VL. A higher risk for LLV but not for VF was found in patients with a higher VL before cART [for >99.999 copies/mL: aOR (95% CI): 4.19 (2.07–8.49); for 10.000–99.999 copies/mL: aOR (95% CI): 2.52 (1.23–5.19)] and shorter cART duration [for <9 months: aOR (95% CI): 2.59 (1.38–4.86)]. A higher risk for VF but not for LLV was found in younger patients [for <30 years: aOR (95% CI): 2.76 (1.03–7.35); for 30–50 years: aOR (95% CI): 2.70 (1.26–5.79)], people originating from high prevalence countries [aOR (95% CI): 2.20 (1.09–4.42)] and in male injecting drug users [aOR (95% CI): 2.72 (1.38–5.34)].

Conclusions

For both VF and LLV, factors associated with adherence play a prominent role. Furthermore, performance characteristics of the diagnostic assay used for VL quantification should also be taken into consideration.

Determinants of residual viraemia during combination HIV treatment: Impacts of baseline HIV RNA levels and treatment choice

OBJECTIVES

Effective HIV therapy reflects suppression of plasma HIV RNA levels below assay detection thresholds, although lower levels of "residual viraemia" have also been demonstrated over extended periods of effective antiretroviral treatment. Here we examine the determinants of HIV RNA suppression below the standard assay threshold (40 HIV-1 RNA copies/mL) as well as factors associated with detectable HIV RNA below this reported detection limit.

METHODS

Between 2007 and 2010, 11 575 consecutive viral load (VL) tests were obtained from 1540 patients, including 356 on effective antiretroviral therapy followed since initiation (1996-2001: n = 165; 2002-2009: n = 191). Analyses modelled the probability of an undetectable VL given successful suppression to < 200 copies/mL, and the probability of residual viraemia given an undetectable result.

RESULTS

Detectable HIV RNA amplification was demonstrated in 20% of samples with a VL result < 40 copies/mL. Longitudinal analyses from 356 patients revealed that the likelihood of achieving results < 40 copies/mL was increased with current nonnucleoside reverse transcriptase inhibitor (NNRTI) therapy [odds ratio (OR) 2.0; P < 0.05] and reduced with prior virological rebound (OR 0.5; P < 0.05). In contrast, the presence of detectable HIV RNA < 40 copies/mL was strongly associated with pretreatment HIV RNA levels among those on current protease inhibitor (PI) treatment (OR 1.5 per log10 copies/mL increase; P = 0.02) as well as those on NNRTIs (OR 1.7; P = 0.002).

CONCLUSIONS

While HIV treatment history was associated with plasma HIV RNA levels below the detection limit, residual viraemia results were dominantly determined by pretreatment VL. These findings support the concept of a stable, long-lived reservoir of latently infected cells as a source of residual viraemia despite effective HIV treatment.

Low-level HIV-1 viraemia in patients on HAART: risk factors and management in clinical practice

OBJECTIVES

Characterization of the conditions favouring HIV-1 low-level viraemia (LLV) during treatment is required to guide strategies for prevention and cure.

METHODS

The characteristics and treatments of 171 patients experiencing a confirmed LLV of 50-1000 copies/mL (PLLVs) were compared with those of 146 patients with persistently controlled viraemia. We analysed the risk factors for LLV, the parameters affecting the level of viraemia and the presence of resistance-associated mutations (RAMs). We compared outcomes for PLLVs on fully effective HAART as a function of treatment modifications.

RESULTS

LLV was <500 copies/mL in at least 90% of cases. A higher zenith viral load (VL) (5.27 versus 4.91 log10 copies/mL, OR 2.23; P = 0.0003), a shorter time on continuous HAART (4.3 versus 6.8 years, OR 0.88; P = 0.0003) and previously detected RAMs (43% versus 23%, OR 2.42; P = 0.0033) were independent predictors of LLV. NNRTIs were less frequently used in PLLVs and were associated with more stable treatment. The presence of any RAM during LLV was associated with a lower zenith VL and a higher LLV. In the absence of resistance, virological success was achieved in similar proportions of patients with and without treatment modification.

CONCLUSIONS

Viraemia >500 copies/mL should no longer be considered to be LLV. In patients with a high zenith VL, several years on continuous HAART may be required to decrease the HIV reservoir and prevent LLV. Resistance testing is useful to detect RAMs, leading if necessary to treatment modifications. In the absence of resistance, treatment changes seemed dispensable.