Monitoring for treatment failure in patients on first-line antiretroviral treatment in resource-constrained settings

Effects of National Adoption of Treat-All Guidelines on Pre-Antiretroviral Therapy (ART) CD4 Testing and Viral Load Monitoring After ART initiation: A Regression Discontinuity Analysis

BACKGROUND

The World Health Organization's Treat-All guidance recommends CD4 testing before initiating antiretroviral therapy (ART), and routine viral load (VL) monitoring (over CD4 monitoring) for patients on ART.

METHODS

We used regression discontinuity analyses to estimate changes in CD4 testing and VL monitoring among 547 837 ART-naive patients enrolling in human immunodeficiency virus (HIV) care during 2006-2018 at 225 clinics in 26 countries where Treat-All policies were adopted. We examined CD4 testing within 12 months before and VL monitoring 6 months after ART initiation among adults (≥20 years), adolescents (10-19 years), and children (0-9 years) in low/lower-middle-income countries (L/LMICs) and high/upper-middle-income countries (H/UMICs).

RESULTS

Treat-All adoption led to an immediate decrease in pre-ART CD4 testing among adults in L/LMICs, from 57.0% to 48.1% (-8.9 percentage points [pp]; 95% CI: -11.0, -6.8), and a small increase in H/UMICs, from 90.1% to 91.7% (+1.6pp; 95% CI: 0.2, 3.0), with no changes among adolescents or children; decreases in pre-ART CD4 testing accelerated after Treat-All adoption in L/LMICs. In L/LMICs, VL monitoring after ART initiation was low among all patients in L/LMICs before Treat-All; while there was no immediate change at Treat-All adoption, VL monitoring trends significantly increased afterwards. VL monitoring increased among adults immediately after Treat-All adoption, from 58.2% to 61.1% (+2.9pp; 95% CI: 0.5, 5.4), with no significant changes among adolescents/children.

CONCLUSIONS

While on-ART VL monitoring has improved in L/LMICs, Treat-All adoption has accelerated and disparately worsened suboptimal pre-ART CD4 monitoring, which may compromise care outcomes for individuals with advanced HIV.

Risk factors for delayed viral suppression on first-line antiretroviral therapy among persons living with HIV in Haiti, 2013-2017

Studies of viral suppression on first-line antiretroviral therapy (ART) in persons living with human immunodeficiency virus (PLHIV) in Haiti are limited, particularly among PLHIV outside of the Ouest department, where the capital Port-au-Prince is located. This study described the prevalence and risk factors for delayed viral suppression among PLHIV in all geographic departments of Haiti between 2013 and 2017. Individuals who received viral load testing 3 to 12 months after ART initiation were included. Data on demographics and clinical care were obtained from the Haitian Active Longitudinal Tracking of HIV database. Multivariable logistic regression was performed to predict delayed viral suppression, defined as a viral load ≥1000 HIV-1 RNA copies/mL after at least 3 months on ART. Viral load test results were available for 3,368 PLHIV newly-initiated on ART. Prevalence of delayed viral suppression was 40%, which is slightly higher than previous estimates in Haiti. In the multivariable analysis, delayed viral suppression was significantly associated with younger age, receiving of care in the Ouest department, treatment with lamivudine (3TC), zidovudine (AZT), and nevirapine (NVP) combined ART regimen, and CD4 counts below 200 cells/mm³. In conclusion, this study was the first to describe and compare differences in delayed viral suppression among PLHIV by geographic department in Haiti. We identified populations to whom public health interventions, such as more frequent viral load testing, drug resistance testing, and ART adherence counseling should be targeted.

Integrating community pharmacy into community based anti-retroviral therapy program: A pilot implementation in Abuja, Nigeria

BACKGROUND

The landscape of Human Immunodeficiency Virus (HIV) epidemic control is shifting with the United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 benchmarks for epidemic control. Community-based Antiretroviral Therapy (CART) models have improved treatment uptake and demonstrated good clinical outcomes. We assessed the feasibility of integrating community pharmacy as a task shift structure for differentiated community ART in Abuja-Nigeria.

METHODS

Stable patients on first line ART regimens from public health facilities were referred to community pharmacies in different locations within the Federal Capital Territory, Abuja for prescription refills and treatment maintenance. Bio-demographic and clinical data were collected from February 25, 2016 to May 31st, 2017 and descriptive statistics analysis applied. The outcomes of measure were prescription refill and patient retention in care at the community pharmacy.

RESULTS

Almost 10% of stable patients on treatment were successfully devolved from eight health facilities to ten community pharmacies. Median age of the participants was 35 years [interquartile range (IQR); 30, 41] with married women in the majority. Prescription refill was 100% and almost all the participants (99.3%) were retained in care after they were devolved to the community pharmacies. Only one participant was lost-to-follow-up as a result of death.

CONCLUSION

Excellent prescription refill and high retention in care with very low loss-to-follow-up were associated with the community pharmacy model. The use of community pharmacy for community ART is feasible in Nigeria. We recommend the scale up of the model in all the 36 states of Nigeria.

Interferon-γ-Inducible Protein 10 (IP-10) as a Screening Tool to Optimize Human Immunodeficiency Virus RNA Monitoring in Resource-Limited Settings

BACKGROUND

Achieving effective antiretroviral treatment (ART) monitoring is a key determinant to ensure viral suppression and reach the UNAIDS 90-90-90 targets. The gold standard for detecting virological failure is plasma human immunodeficiency virus (HIV) RNA (viral load [VL]) testing; however, its availability is very limited in low-income countries due to cost and operational constraints.

METHODS

HIV-1-infected adults on first-line ART attending routine visits at the Manhiça District Hospital, Mozambique, were previously evaluated for virologic failure. Plasma levels of interferon-γ-inducible protein 10 (IP-10) were quantified by enzyme-linked immunosorbent assay. Logistic regression was used to build an IP-10-based model able to identify individuals with VL >150 copies/mL. From the 316 individuals analyzed, 253 (80%) were used for model training and 63 (20%) for validation. Receiver operating characteristic curves were employed to evaluate model prediction.

RESULTS

From the individuals included in the training set, 34% had detectable VL. Mean age was 41 years, 70% were females, and median time on ART was 3.4 years. IP-10 levels were significantly higher in subjects with detectable VL (108.2 pg/mL) as compared to those with undetectable VL (38.0 pg/mL) (P < .0001, U test). IP-10 univariate model demonstrated high classification performance (area under the curve = 0.85 [95% confidence interval {CI}, .80-.90]). Using a cutoff value of IP-10 ≥44.2 pg/mL, the model identified detectable VL with 91.9% sensitivity (95% CI, 83.9%-96.7%) and 59.9% specificity (95% CI, 52.0%-67.4%), values confirmed in the validation set.

CONCLUSIONS

IP-10 is an accurate biomarker to screen individuals on ART for detectable viremia. Further studies should evaluate the benefits of IP-10 as a triage approach to monitor ART in resource-limited settings.

Assessment of WHO criteria for identifying ART treatment failure in Vietnam from 2007 to 2011

Objective

We evaluated the sensitivity and specificity of the WHO immunological criteria for detecting antiretroviral therapy (ART) treatment failure in a cohort of Vietnamese patients. We conducted a stratified analysis to determine the effects of BMI, peer support, adherence to antiretroviral (ARV) drugs, age, and gender on the sensitivity and specificity of the WHO criteria.

Methods

We conducted a retrospective cohort study of 605 HIV-infected patients using data previously collected from a cluster randomized control trial study. We compared the sensitivity and specificity of CD4⁺ counts to the gold standard of virologic testing as a diagnostic test for ART failure at different time points of 12, 18, and 24 months.

Results

The sensitivity [95% confidence interval (CI)] of the WHO immunological criteria based on a viral load ≥ 1000 copies/mL was 12% (5%-23%), 14% (2%-43%), and 12.5% (2%-38%) at 12, 18, and 24 months, respectively. In the same order, the specificity was 93% (90%-96%), 98% (96%-99%), and 98% (96%-100%). The positive predictive values (PPV) at 12, 18, and 24 months were 22% (9%-40%), 20% (3%-56%), and 29% (4%-71%); the negative predictive values (NPV) at the same time points were 87% (84%-90%), 97% (95%-98%), and 96% (93%-98%). The stratified analysis revealed similar sensitivities and specificities.

Conclusion

The sensitivity of the WHO immunological criteria is poor, but the specificity is high. Although testing costs may increase, we recommend that Vietnam and other similar settings adopt viral load testing as the principal method for determining ART failure.

Viral load monitoring and antiretroviral treatment outcomes in a pediatric HIV cohort in Ghana

Background

HIV-infected children in sub-Saharan Africa may be at a high risk of staying on a failing first-line regimen and developing drug-resistance HIV variants due to lack of routine viral load monitoring. We investigated whether cumulative viral load, measured as viremia copy-years (VCY) could predict morbidity in a setting where viral load is not routinely monitored.

Methods

This was a single-center prospective observational longitudinal study of HIV-infected children initiating antiretroviral therapy (ART) at the Pediatric HIV/AIDS Care program at Korle-Bu Teaching Hospital in Accra, Ghana. The main outcome was morbidity measured as frequency of hospitalizations, opportunistic infections, and outpatient sick visits. The main explanatory variable was viral load measured as VCY.

Results

The study included 140 children who initiated ART between September 2009 and May 2013 and had at least 2 viral load measurements. There were 184 hospitalizations, with pneumonia being the most common cause (22.8 %). A total of 102 opportunistic infections was documented, with tuberculosis being the most common opportunistic infection (68 %). A total of 823 outpatient sick visits was documented, with upper respiratory infections (14.2 %) being the most common cause. Forty-four percent of our study participants had >4 log₁₀ VCY. Children in this sub-cohort had a higher frequency of sick visits compared with those with <4 log₁₀ VCY (p = 0.03). Only 6.5 % of children with >4 log₁₀ VCY had been identified as treatment failure using WHO clinical and immunological treatment failure criteria.

Conclusions

High level of cumulative viral load may translate to virological failure and subsequent increased all-cause morbidity. Our finding of potential utility of VCY in pediatrics warrants further investigations. VCY may be a good alternate to routine viral load measurement as its determination may be less frequent and could be personalized to save cost.

Superior virologic and treatment outcomes when viral load is measured at 3 months compared to 6 months on antiretroviral therapy

Introduction

Routine viral load (VL) monitoring is utilized to assess antiretroviral therapy (ART) adherence and virologic failure, and it is currently scaled-up in many resource-constrained settings. The first routine VL is recommended as late as six months after ART initiation for early detection of sub-optimal adherence. We aimed to assess the optimal timing of first VL measurement after initiation of ART.

Methods

This was a retrospective, cohort analysis of routine monitoring data of adults enrolled at three primary care clinics in Khayelitsha, Cape Town, between January 2002 and March 2009. Primary outcomes were virologic failure and switch to second-line ART comparing patients in whom first VL done was at three months (VL3M) and six months (VL6M) after ART initiation. Adjusted hazard ratios (aHR) were estimated using Cox proportional hazard models.

Results

In total, 6264 patients were included for the time to virologic failure and 6269 for the time to switch to second-line ART analysis. Patients in the VL3M group had a 22% risk reduction of virologic failure (aHR 0.78, 95% CI 0.64–0.95; p=0.016) and a 27% risk reduction of switch to second-line ART (aHR 0.73, 95% CI 0.58–0.92; p=0.008) when compared to patients in the VL6M group. For each additional month of delay of the first VL measurement (up to nine months), the risk of virologic failure increased by 9% (aHR 1.09, 95% CI 1.02–1.15; p=0.008) and switch to second-line ART by 13% (aHR 1.13, 95% CI 1.05–1.21; p<0.001).

Conclusions

A first VL at three months rather than six months with targeted adherence interventions for patients with high VL may improve long-term virologic suppression and reduce switches to costly second-line ART. ART programmes should consider the first VL measurement at three months after ART initiation.

On the front line of HIV virological monitoring: barriers and facilitators from a provider perspective in resource-limited settings

Scale-up of viral load (VL) monitoring for HIV-infected patients on antiretroviral therapy (ART) is a priority in many resource-limited settings, and ART providers are critical to effective program implementation. We explored provider-perceived barriers and facilitators of VL monitoring. We interviewed all providers (n = 17) engaged in a public health evaluation of dried blood spots for VL monitoring at five ART clinics in Malawi. All ART clinics were housed within district hospitals. We grouped themes at patient, provider, facility, system, and policy levels. Providers emphasized their desire for improved ART monitoring strategies, and frustration in response to restrictive policies for determining which patients were eligible to receive VL monitoring. Although many providers pled for expansion of monitoring to include all persons on ART, regardless of time on ART, the most salient provider-perceived barrier to VL monitoring implementation was the pressure of work associated with monitoring activities. The work burden was exacerbated by inefficient data management systems, highlighting a critical interaction between provider-, facility-, and system-level factors. Lack of integration between laboratory and clinical systems complicated the process for alerting providers when results were available, and these communication gaps were intensified by poor facility connectivity. Centralized second-line ART distribution was also noted as a barrier: providers reported that the time and expenses required for patients to collect second-line ART frequently obstructed referral. However, provider empowerment emerged as an unexpected facilitator of VL monitoring. For many providers, this was the first time they used an objective marker of ART response to guide clinical management. Providers' knowledge of a patient's virological status increased confidence in adherence counseling and clinical decision-making. Results from our study provide unique insight into provider perceptions of VL monitoring and indicate the importance of policies responsive to individual and environmental challenges of VL monitoring program implementation. Findings may inform scale-up by helping policy-makers identify strategies to improve feasibility and sustainability of VL monitoring.

Trends and Determinants of Antiretroviral Therapy Patient Monitoring Practices in Kenya and Uganda

Introduction

Patients receiving antiretroviral therapy (ART) require routine monitoring to track response to treatment and assess for treatment failure. This study aims to identify gaps in monitoring practices in Kenya and Uganda.

Methods

We conducted a systematic retrospective chart review of adults who initiated ART between 2007 and 2012. We assessed the availability of baseline measurements (CD4 count, weight, and WHO stage) and ongoing CD4 and weight monitoring according to national guidelines in place at the time. Mixed-effects logistic regression models were used to analyze facility and patient factors associated with meeting monitoring guidelines.

Results

From 2007 to 2012, at least 88% of patients per year in Uganda had a recorded weight at initiation, while in Kenya there was a notable increase from 69% to 90%. Patients with a documented baseline CD4 count increased from 69% to about 80% in both countries. In 2012, 83% and 86% of established patients received the recommended quarterly weight monitoring in Kenya and Uganda, respectively, while semiannual CD4 monitoring was less common (49% in Kenya and 38% in Uganda). Initiating at a more advanced WHO stage was associated with a lower odds of baseline CD4 testing. On-site CD4 analysis capacity was associated with increased odds of CD4 testing at baseline and in the future.

Discussion

Substantial gaps were noted in ongoing CD4 monitoring of patients on ART. Although guidelines have since changed, limited laboratory capacity is likely to remain a significant issue in monitoring patients on ART, with important implications for ensuring quality care.

Printed Flexible Plastic Microchip for Viral Load Measurement through Quantitative Detection of Viruses in Plasma and Saliva

We report a biosensing platform for viral load measurement through electrical sensing of viruses on a flexible plastic microchip with printed electrodes. Point-of-care (POC) viral load measurement is of paramount importance with significant impact on a broad range of applications, including infectious disease diagnostics and treatment monitoring specifically in resource-constrained settings. Here, we present a broadly applicable and inexpensive biosensing technology for accurate quantification of bioagents, including viruses in biological samples, such as plasma and artificial saliva, at clinically relevant concentrations. Our microchip fabrication is simple and mass-producible as we print microelectrodes on flexible plastic substrates using conductive inks. We evaluated the microchip technology by detecting and quantifying multiple Human Immunodeficiency Virus (HIV) subtypes (A, B, C, D, E, G, and panel), Epstein-Barr Virus (EBV), and Kaposi's Sarcoma-associated Herpes Virus (KSHV) in a fingerprick volume (50 µL) of PBS, plasma, and artificial saliva samples for a broad range of virus concentrations between 10(2) copies/mL and 10(7) copies/mL. We have also evaluated the microchip platform with discarded, de-identified HIV-infected patient samples by comparing our microchip viral load measurement results with reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) as the gold standard method using Bland-Altman Analysis.

HIV-1 variability and viral load technique could lead to false positive HIV-1 detection and to erroneous viral quantification in infected specimens

OBJECTIVES

Viral load (VL) testing is used for early HIV diagnosis in infants (EID) and for detecting early therapeutic failure events, but can be affected by HIV genetic variability. Dried blood samples (DBS) increase VL access and EID in remote settings and when low blood volume is available.

METHODS

This study compares VL values using Siemens VERSANT HIV-1 RNA 1.0 kPCR assay (kPCR) and Roche CAP/CTM Quantitative test v2.0 (CAP/CTM v2.0) in 176 DBS carrying different HIV-1 variants collected from 69 Equatoguinean mothers and their infants with known HIV-1 status (71 infected, 105 uninfected).

RESULTS

CAP/CTM v2.0 provided false positive VLs in 11 (10.5%) cases. VL differences above 0.5 log10 were observed in 42/49 (87.5%) DBS, and were above 1 log10 in 18 cases. CAP/CTM v2.0 quantified all the 41 specimens with previously inferred HIV-1 variant by phylogenetic analysis (68.3% recombinants) whereas kPCR only identified 90.2% of them, and was unable to detect 14.3% of 21 CRF02_AG viruses. CAP/CTM v2.0 showed higher sensitivity than kPCR (95.8% vs. 70.1%), quantifying a higher rate of viruses in infected DBS from subjects under antiretroviral exposure at sampling time compared to kPCR (94.7% vs. 96.2%, p-value<0.001). kPCR showed maximum specificity (100%) whereas for CAP/CTM v2.0 was 89.5%.

CONCLUSIONS

VL assays should increase their sensitivity and specificity to avoid overestimated HIV-1 quantifications, which could be interpreted as virological failure events, or false negative diagnostic results due to genetic variability. We recommend using the same VL technique for each patient during antiretroviral therapy monitoring.

CD4 criteria improves the sensitivity of a clinical algorithm developed to identify viral failure in HIV-positive patients on antiretroviral therapy

INTRODUCTION

Several studies from resource-limited settings have demonstrated that clinical and immunologic criteria are poor predictors of virologic failure, confirming the need for viral load monitoring or at least an algorithm to target viral load testing. We used data from an electronic patient management system to develop an algorithm to identify patients at risk of viral failure using a combination of accessible and inexpensive markers.

METHODS

We analyzed data from HIV-positive adults initiated on antiretroviral therapy (ART) in Johannesburg, South Africa, between April 2004 and February 2010. Viral failure was defined as ≥ 2 consecutive HIV-RNA viral loads >400 copies/ml following suppression ≤ 400 copies/ml. We used Cox-proportional hazards models to calculate hazard ratios (HR) and 95% confidence intervals (CI). Weights for each predictor associated with virologic failure were created as the sum of the natural logarithm of the adjusted HR and dichotomized with the optimal cut-off at the point with the highest sensitivity and specificity (i.e. ≤ 4 vs. >4). We assessed the diagnostic accuracy of predictor scores cut-offs, with and without CD4 criteria (CD4 <100 cells/mm(3); CD4 < baseline; >30% drop in CD4), by calculating the proportion with the outcome and the observed sensitivity, specificity, positive and negative predictive value of the predictor score compared to the gold standard of virologic failure.

RESULTS

We matched 919 patients with virologic failure (1:3) to 2756 patients without. Our predictor score included variables at ART initiation (i.e. gender, age, CD4 count <100 cells/mm(3), WHO stage III/IV and albumin) and laboratory and clinical follow-up data (drop in haemoglobin, mean cell volume (MCV) <100 fl, CD4 count <200 cells/mm(3), new or recurrent WHO stage III/IV condition, diagnosis of new condition or symptom and regimen change). Overall, 51.4% had a score 51.4% had a score ≥ 4 and 48.6% had a score <4. A predictor score including CD4 criteria performed better than a score without CD4 criteria and better than WHO clinico-immunological criteria or WHO clinical staging to predict virologic failure (sensitivity 57.1% vs. 40.9%, 25.2% and 20.9%, respectively).

CONCLUSIONS

Predictor scores or risk categories, with CD4 criteria, could be used to identify patients at risk of virologic failure in resource-limited settings so that these patients may be targeted for focused interventions to improve HIV treatment outcomes.

Measures of viral load using Abbott RealTime HIV-1 Assay on venous and fingerstick dried blood spots from provider-collected specimens in Malawian District Hospitals

BACKGROUND

Viral suppression is a key indicator of antiretroviral therapy (ART) response among HIV-infected patients. Dried blood spots (DBS) are an appealing alternative to conventional plasma-based virologic testing, improving access to monitoring in resource-limited settings. However, validity of DBS obtained from fingerstick in field settings remains unknown.

OBJECTIVES

Investigate feasibility and accuracy of DBS vs plasma collected by healthcare workers in real-world settings of remote hospitals in Malawi. Compare venous DBS to fingerstick DBS for identifying treatment failure.

STUDY DESIGN

We recruited patients from ART clinics at two district hospitals in Malawi, collecting plasma, venous DBS (vDBS), and fingerstick DBS (fsDBS) cards for the first 149 patients, and vDBS and fsDBS only for the subsequent 398 patients. Specimens were tested using Abbott RealTime HIV-1 Assay (lower detection limit 40 copies/ml (plasma) and 550 copies/ml (DBS)).

RESULTS

21/149 (14.1%) had detectable viremia (>1.6 log copies/ml), 13 of which were detectable for plasma, vDBS, and fsDBS. Linear regression demonstrated high correlation for plasma vs. DBS (vDBS: β=1.19, R(2)=0.93 (p<0.0001); fsDBS β=1.20, R(2)=0.90 (p<0.0001)) and vDBS vs. fsDBS (β=0.88, R(2)=0.73, (p<0.0001)). Mean difference between plasma and vDBS was 1.1 log copies/ml [SD: 0.27] and plasma and fsDBS 1.1 log copies/ml [SD: 0.31]. At 5000 copies/ml, sensitivity was 100%, and specificity was 98.6% and 97.8% for vDBS and fsDBS, respectively, compared to plasma.

CONCLUSIONS

DBS from venipuncture and fingerstick perform well at the failure threshold of 5000 copies/ml. Fingerstick specimen source may improve access to virologic treatment monitoring in resource-limited settings given task-shifting in high-volume, low-resource facilities.

Simplified clinical prediction scores to target viral load testing in adults with suspected first line treatment failure in Phnom Penh, Cambodia

Background

For settings with limited laboratory capacity, 2013 World Health Organization (WHO) guidelines recommend targeted HIV-1 viral load (VL) testing to identify virological failure. We previously developed and validated a clinical prediction score (CPS) for targeted VL testing, relying on clinical, adherence and laboratory data. While outperforming the WHO failure criteria, it required substantial calculation and review of all previous laboratory tests. In response, we developed four simplified, less error-prone and broadly applicable CPS versions that can be done ‘on the spot’.

Methodology/Principal

Findings From May 2010 to June 2011, we validated the original CPS in a non-governmental hospital in Phnom Penh, Cambodia applying the CPS to adults on first-line treatment >1 year. Virological failure was defined as a single VL >1000 copies/ml. The four CPSs included CPS1 with ‘current CD4 count’ instead of %-decline-from-peak CD4; CPS2 with hemoglobin measurements removed; CPS3 having ‘decrease in CD4 count below baseline value’ removed; CPS4 was purely clinical. Score development relied on the Spiegelhalter/Knill-Jones method. Variables independently associated with virological failure with a likelihood ratio ≥1.5 or ≤0.67 were retained. CPS performance was evaluated based on the area-under-the-ROC-curve (AUROC) and 95% confidence intervals (CI). The CPSs were validated in an independent dataset. A total of 1490 individuals (56.6% female, median age: 38 years (interquartile range (IQR 33–44)); median baseline CD4 count: 94 cells/µL (IQR 28–205), median time on antiretroviral therapy 3.6 years (IQR 2.1–5.1)), were included. Forty-five 45 (3.0%) individuals had virological failure. CPS1 yielded an AUROC of 0.69 (95% CI: 0.62–0.75) in validation, CPS2 an AUROC of 0.68 (95% CI: 0.62–0.74), and CPS3, an AUROC of 0.67 (95% CI: 0.61–0.73). The purely clinical CPS4 performed poorly (AUROC-0.59; 95% CI: 0.53–0.65).

Conclusions

Simplified CPSs retained acceptable accuracy as long as current CD4 count testing was included. Ease of field application and field accuracy remains to be defined.

Pooled HIV-1 viral load testing using dried blood spots to reduce the cost of monitoring antiretroviral treatment in a resource-limited setting

Rollout of routine HIV-1 viral load monitoring is hampered by high costs and logistical difficulties associated with sample collection and transport. New strategies are needed to overcome these constraints. Dried blood spots from finger pricks have been shown to be more practical than the use of plasma specimens, and pooling strategies using plasma specimens have been demonstrated to be an efficient method to reduce costs. This study found that combination of finger-prick dried blood spots and a pooling strategy is a feasible and efficient option to reduce costs, while maintaining accuracy in the context of a district hospital in Malawi.

Validation of a clinical prediction score to target viral load testing in adults with suspected first-line treatment failure in resource-constrained settings

BACKGROUND

Although routine viral load (VL) monitoring currently is too costly for poor countries, clinical failure criteria perform poorly. We previously developed an algorithm combining a clinical predictor score (CPS) with targeted VL testing in a Cambodian patient population (derivation population). We now prospectively validate the algorithm in the same clinical setting (validation population), assess its operational performance, and explore its cost-saving potential.

METHODS

We performed a cross-sectional study in a tertiary hospital in Phnom Penh, Cambodia, applying the CPS in adults on first-line antiretroviral treatment for at least 1 year. Treatment failure was defined as a VL >1000 copies per milliliter. The area under the receiver-operating characteristic (AUROC) curve of the CPS to detect treatment failure in the current study population (validation population) was compared with the AUROC of the CPS obtained in the patient population where the CPS was derived from in 2008 in the same study setting (derivation population). Costs related to VL testing and second-line regimens with the different testing strategies were compared.

RESULTS

One thousand four hundred ninety individuals {56.6% female, median age 38 years [interquartile range (IQR): 33-44]} were included, with a median baseline CD4 cell count of 94 cells per microliter (IQR: 28-205). Median time on antiretroviral treatment was 3.6 years (IQR: 2.1-5.1), 45 (3.0%) individuals had treatment failure. The AUROC of the CPS in validation was 0.75 (95% confidence interval: 0.67 to 0.83), relative to an AUROC of 0.70 in the derivation population. At the CPS cutoff ≥ 2, VL was indicated for 164 (11%) individuals, preventing inappropriate switching to second line in 143 cases. Twenty-four cases of treatment failure would be missed. When applied in routine care, the AUROC was 0.69 (95% confidence interval: 0.60 to 0.77). Overall 1-year program costs with targeted VL testing were 4-fold reduced.

CONCLUSIONS

The algorithm performed well in validation and has cost-saving potential. Further studies to assess its performance, feasibility, and impact in different settings are warranted.

A Portable, Pressure Driven, Room Temperature Nucleic Acid Extraction and Storage System for Point of Care Molecular Diagnostics

Many new and exciting portable HIV viral load testing technologies are emerging for use in global medicine. While the potential to provide fast, isothermal, and quantitative molecular diagnostic information to clinicians in the field will soon be a reality, many of these technologies lack a robust front end for sample clean up and nucleic acid preparation. Such a technology would enable many different downstream molecular assays. Here, we present a portable system for centrifuge-free room temperature nucleic acid extraction from small volumes of whole blood (70 µL), using only thermally stable reagents compatible with storage and transport in low resource settings. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis of simulated samples demonstrate a lower limit of detection of 1000 copies/ml, with the ability to detect differences in viral load across four orders of magnitude. The system can also be used to store extracted RNA on detachable cartridges for up to one week at ambient temperature, and can be operated using only hand generated air pressure.

[Risk factors associated with virologic failure in HIV- infected patients receiving antiretroviral therapy at a public hospital in Peru]

OBJECTIVE

To describe clinical and biological characteristics of subjects with virologic failure who participated in the sexually transmitted diseases HIV/AIDS National Program from a Peruvian public hospital.

MATERIALS AND METHODS

An exploratory descriptive study was performed with data from subjects older than 18 who started high activity antiretroviral therapy (HAART) between May 2004 and December 2009 and who had a viral load control after 24 weeks of HAART. Virologic failure was defined as a viral load value above 1000 copies/mL on follow up after 24 weeks on HAART.

RESULTS

Of 1478 records of patients on HAART analyzed, the median age was 35 years [IQR, 29-41] and 69.6% were male. Also, virologic failure occurred in 24% and 3.7% died. Of subjects with virologic failure, 9.5% died. On multivariate analysis, age, history of antiretroviral use before starting HAART, change of antiretroviral therapy due to toxicity, opportunistic infections during HAART, level of CD4 + lymphocytes below 100 cells/ml at start of HAART, adherence and clinical stage were independently associated with virologic failure. In the group of patient with no history of antiretroviral use before starting HAART, age, opportunistic infections during HAART were associated with virologic failure.

CONCLUSION

This study identified factors associated with virologic failure. Further studies are needed to evaluate whether the use of these factors can help to identify prospectively patients at high risk of failure, and to design interventions aimed to reduce this risk.

Virological failure and drug resistance during first line anti-retroviral treatment in Indonesia

The virological response and development of drug resistance during first-line anti-retroviral treatment (ART) were studied in Indonesia where the majority of patients infected with HIV have a history of injecting drug use, which is often linked with lower treatment adherence and development of drug-resistance. As many as 575 patients starting ART between September 2007 and March 2010 in Hasan Sadikin Hospital Bandung were followed prospectively. Clinical and laboratory monitoring was performed every 6 months. Plasma samples with HIV-RNA ≥ 400 copies/ml were examined for drug resistance mutations. Most patients were male (72.3%), 59.7% had a history of injecting drug use, and the median CD4+ cells count before start of ART was 35 cells/mm(3) (IQR 10-104). From 438 HIV patients with HIV-RNA measurements, 40 (9.1%) subjects had HIV-RNA ≥ 400 copies/ml after 24 weeks (median follow-up 16 (IQR 8-25) months). Of these failing patients 16 (47%) subjects had drug resistance mutations, predominantly M184V (35.3%), Y181C (23.5%), K103N (11.7%), and TAMs (11.7%). A history of treatment discontinuation ≥ 1 month, reported by 5.3% (23) of patients, was strongly associated with virological failure (adjusted OR 12.64, 95% CI 4.51-35.41); and a history of injecting drug use was not (OR 0.75, 95% CI 0.38-1.46). This is the largest and most systematic evaluation of virological response to first line ART in Indonesia. Patients in this cohort responded well to first line ART, with low rates of virological failure and drug resistance. A history of injecting drug use should not be a reason to withhold ART in this setting.

Challenges and opportunities for the implementation of virological testing in resource-limited settings

Though the advantages of routine virological monitoring for patients on anti-retroviral therapy have been established, cost and complexity limit its full implementation. Monitoring is important for diagnosing virological failure early on, before the development of drug resistance mutations, and to trigger early adherence interventions. Simple and cost-effective viral load tests that facilitate simplification and decentralization of testing and strategies, such as the use of dried blood spots and pooled sample testing, which further aid simplification, are becoming available. In addition, replacing immunological monitoring with virological monitoring in non-viremic patients in a phased manner will reduce the costs associated with dual immuno-virological monitoring. Going forward, the simplification of testing paired with price reducing strategies that will allow for healthy competition between multiple manufacturers will enable the implementation of viral load testing in resource-poor settings. It is important that future HIV and AIDS treatment guidelines provide clear recommendations for routine virological monitoring and that governments and donors fund the implementation of accurate and operationally proven testing platforms in a comprehensive manner.

HIV in Africa: Challenges and Directions for the Next Decade

Africa carries a disproportionate burden of the global HIV endemic, accounting for two thirds of the global 33.3 million people living with HIV. While tremendous advances have been made in addressing the HIV epidemic in Africa, considerable challenges remain. Testing for HIV increased by 86% from 2007 to 2009 but more than 75% of people 15-49 years remain unaware of their HIV status. CD4 count at diagnosis tends to be low and linkage to care and treatment is suboptimal. The scale-up of antiretroviral therapy is ongoing but is hampered by the lack of diagnostic capability to monitor response to therapy and a substantial healthcare workforce shortage. Prevention strategies such as male circumcision, pre-exposure prophylaxis, and antiretroviral therapy for prevention have generated great excitement but cost and healthcare infrastructure deficiencies may limit their widespread applicability. Operational research to validate and inform treatment decisions, health care policies, and prevention strategies is sorely needed.

Perspectives on introduction and implementation of new point-of-care diagnostic tests

In recent years, there has been significant investment from both the private and public sectors in the development of diagnostic technologies to meet the need for human immunodeficiency virus (HIV) and tuberculosis testing in low-resource settings. Future investments should ensure that the most appropriate technologies are adopted in settings where they will have a sustainable impact. Achieving these aims requires the involvement of many stakeholders, as their needs, operational constraints, and priorities are often distinct. Here, we discuss these considerations from different perspectives representing those of various stakeholders involved in the development, introduction, and implementation of diagnostic tests. We also discuss some opportunities to address these considerations.

Challenges in implementing HIV laboratory monitoring in resource-constrained settings: how to do more with less

Laboratory monitoring for HIV disease in resource-limited settings has now become one of the key challenges for antiretroviral treatment (ART) access and success, as emphasized by the 2010 revised WHO guidelines for ART in resource-limited settings. Thus, the most common method for initiating ART, and monitoring treatment response in resource-constrained environments is the measurement of CD4 T-cell count. Affordable CD4 T-cell counting has gradually been made possible by using simple, compact and robust, low-cost, new-generation cytometers, operating as single-platform volumetric instruments. Several cost-effective point-of-care CD4 T-cell testing options are also already on the market, in order to improve access to CD4 T-cell monitoring, especially for rural patients, and to reduce loss-to-follow-up of patients. In addition, HIV RNA viral load measurement is becoming increasingly important, mainly for a systematic confirmation of first-line ART failure before switching to second-line treatment to avoid belated as well as premature therapeutic decisions and their potentially negative consequences. Viral load testing should now be considered as the standard of care for therapeutic failure in all resource-limited settings. However, the measurement of HIV viral load remains a centralized marker, carried out in a limited number of reference laboratories. Finally, the costs of second-line ART regimens, rather than the laboratory test costs themselves, currently constitute the primary determinant of the total cost in ART switching. Laboratory monitoring strategies may become more attractive as price negotiations render second-line ART regimens less expensive worldwide.

Development and validation of systems for rational use of viral load testing in adults receiving first-line ART in sub-Saharan Africa

BACKGROUND

World Health Organization (WHO) immunological and clinical criteria for monitoring first-line antiretroviral treatment (ART) offer low accuracy for predicting viral failure. Targeting viral load assays to those at high risk has been recommended and a system to do this has been developed in Cambodia. Systems for use in sub-Saharan African populations were evaluated.

METHODS

A new Ugandan-based scoring system for targeting viral load assays was developed from data from the first 4 years of a Ugandan cohort (N = 559) receiving first-line ART. The accuracy of this, the Cambodian system and the WHO criteria to predict viral failure, through targeting viral load assays, were compared in a separate population of 496 Ugandans.

RESULTS

The new Ugandan scoring system included CD4 cell count, mean cell volume, adherence, and HIV-associated clinical events as predictors of viral failure. In the validation population, the Ugandan system undertook viral load assays in 61 (12.3%) cases offering 20.5% sensitivity and 100% positive predictive value (PPV) to predict viral failure. The Cambodian system undertook viral load assays in 33 (6.7%) cases producing 23.1% sensitivity and 90.0% PPV. WHO criteria recommended viral load assays in 72 (14.5%) cases offering 30.8% sensitivity and 100% PPV.

CONCLUSION

Locally developed algorithms based on clinical and immunological criteria may offer little additional accuracy over WHO criteria for targeting viral load assays. When possible, confirming viral load before switching therapy is recommended. Scoring systems are more flexible than WHO criteria in allowing ART providers to choose the proportion of the population that undergo targeted viral load testing.

Economic evaluation of monitoring virologic responses to antiretroviral therapy in HIV-infected children in resource-limited settings

OBJECTIVE

Antiretroviral therapy (ART) management for HIV-infected children is critical in many resource-constrained countries. We investigated the cost-effectiveness and cost-utility of different frequencies of monitoring plasma viral load among HIV-positive children initiating ART in a resource-limited setting.

DESIGN/METHODS

A stochastic agent-based simulation model was built and directly informed by a cohort of 304 HIV-infected children starting ART in Thailand between 2001 and 2009. The model simulated the expected costs and clinical outcomes over time according to different viral load monitoring frequencies and initiation of second-line therapies when appropriate.

RESULTS

The optimal frequency of viral load monitoring was found to be annual, after a single screening at 6 months. Associated costs of viral load monitoring and appropriate ART would approximately triple current treatment costs. Compared with current conditions, a single screening during the first year of ART led to a 58.4% reduction in the total person-years of virological failure with annual monitoring leading to a 76.6% reduction. The incremental cost per quality adjusted life year gained from the optimal monitoring frequency was estimated as US$ 68,084 when including costs of ART and US$ 7224 without ART costs. The estimated cost attributed to preventing 1 year of virological failure was US$ 3393 with ART costs and US$ 359 without ART costs.

CONCLUSION

Even infrequent viral load monitoring is likely to provide substantial clinical benefit to HIV-infected children on ART. Viral load monitoring can be considered cost-effective in many resource-limited settings. However, the costs associated with second-line therapies could be a barrier to its economic feasibility.

Monitoring of highly active antiretroviral therapy in HIV infection

PURPOSE OF REVIEW

Patients on antiretroviral therapy (ART) in high-income countries have routine laboratory tests to monitor ART efficacy/toxicity. We review studies describing the outcomes and costs of different monitoring approaches, predominantly in low-income countries.

RECENT FINDINGS

CD4 cell counts, HIV RNA viral load and clinical events are frequently discordant; viral load suppression occurs with WHO-defined CD4 failure and, as expected, viral load failure often occurs before CD4 failure. Routine CD4 monitoring provides small but significant mortality/morbidity benefits over clinical monitoring, but, at current prices, is not yet cost-effective in many sub-Saharan African countries. Viral load monitoring is less cost-effective with modelling studies reporting variable results. More research into point-of-care tests, methods for targeting monitoring and thresholds for defining failure is needed. Most laboratory monitoring for toxicity is neither effective nor cost-effective. In terms of models for delivery of care, task-shifting with nurse-led and decentralized care appear as effective as doctor-led or centralized care.

SUMMARY

Recent studies have improved the evidence base for monitoring on ART. Future research to increase cost-effectiveness by better targeting of monitoring and/or evaluating implementation of less costly point-of-care tests will contribute to long-term success of ART while continuing to increase ART coverage.

Drug resistance prevalence in human immunodeficiency virus type 1 infected pediatric populations in Honduras and El Salvador during 1989-2009

BACKGROUND

Emergence of viral resistance is a major obstacle for antiretroviral treatment (ART) effectiveness. Human immunodeficiency virus type-1 (HIV-1) variants and drug-resistance mutations were identified in naive and antiretroviral drug-experienced children with virologic failure, in Honduras and El Salvador.

METHODS

Dried blood spots (DBS) from 80 individuals (54 from Honduras, 26 from El Salvador) infected during their childhood between 1989 and 2009 were collected in 2009. The HIV pol region was amplified and sequenced to identify antiretroviral-resistant mutations according to the 2009 International AIDS Society. The genotypic drug resistance interpretation was performed using the Stanford algorithm. HIV-1 variants were characterized by phylogenetic analysis and subtyping tools.

RESULTS

HIV-1 protease and reverse transcription sequences were obtained from DBS specimens in 71 and 66 patients, respectively, of the 80 patients. All children were native Central Americans carrying subtype B, with a mean age of 9 years, most were male (65%), perinatally infected (96%), with moderate/severe AIDS symptoms (70%), and receiving first line ART at the time of sequencing (65%). Diagnostic delay was frequently observed. Infected children from Honduras presented longer ART experience and clinical outcomes, and more frequent severe symptoms. Resistant variants infected 1 of 11 naive children from El Salvador but none of the perinatally infected naive children from Honduras. Resistance was higher among ART-exposed individuals in both countries and similar for protease inhibitors (16%), nucleoside reverse transcription inhibitors (44%-52%), and nonnucleoside reverse-transcription inhibitors (66.7%). One in 10 pretreated children in each country was infected with resistant viruses to the 3 drug families.

CONCLUSIONS

Our data support the need for continued surveillance of resistance patterns using DBS at national levels among naive and pretreated children to optimize the ART regimens.

Outcomes of Universal Access to Antiretroviral Therapy (ART) in Georgia

Since 2004, Georgia achieved universal access to free antiretroviral therapy (ART). A retrospective cohort study was conducted to evaluate the outcomes of Georgia's ART program. The study included adult patients enrolled in the ART program from 2004 through 2009. Of 752 patients, 76% were men, 60% were injection drug users (IDU), 59% had a history of an AIDS-defining illness, and 53% were coinfected with hepatitis C. The median baseline CD4 cell count was 141 cells/mm(3). During followup, 152 (20%) patients died, with the majority of deaths occurring within 12 months of ART initiation. Mortality was associated with advanced immunodeficiency or the presence of incurable disease at baseline. Among patients remaining on treatment, the median CD4 gain was 216 cell/mm(3) and 86% of patients had viral load <400 copies/ml at the last clinical visit. The Georgia ART program has been successful in treating injection drug users infected with HIV.