The association between HIV pretreatment drug resistance and virological outcomes in children and adults in sub-Saharan Africa: A systematic review and meta-analysis

INTRODUCTION

Pretreatment drug resistance (PDR) could occur in antiretroviral treatment (ART) naïve individuals, those previously exposed to ART, or individuals re-initiating ARV after a long period of interruption. Few studies have shown its association with virological outcomes, although inconsistent. The objective of this review was to provide a synthesis of the association between PDR and virological outcomes (virological failure or suppression).

METHODS

This report is presented following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The method was subdivided into three main phases: record identification, screening, and report inclusion. Record identification consisted of an initial search with search term "HIV pretreatment drug resistance". Another search was done using terms "Pretreatment drug resistance OR pre-treatment drug resistance OR Pretreatment drug resist* OR pre-treatment drug resist* OR pretreatment antiretroviral resistance OR pretreatment medic* OR pretreatment medic* resist*" and a list of all the countries in sub-Saharan Africa. After the electronic search, studies were screened from full list based on their title and abstract and then full articles retrieved and studies were assessed based on set criteria. Inclusion criteria involved observational studies that report the association between PDR and virological failure. Data from trials that reported the association were also included. Published articles like modelling studies and reviews, and studies with data that had been previously included in the review were excluded. The Mantel Haenszel method with odds ratios was used for synthesis (meta-analyses) with the weights of each study which depends on the number of events and totals.

RESULTS

A total of 733 records(studies) were obtained from all database search of which 74 reported on PDR, virological outcomes in sub-Saharan Africa (SSA). Out of the 74 articles, 11 were excluded and 26 did not explicitly report data needed, and 5 did not meet the inclusion criteria. Of the remaining 32 studies, 19 studies that had complete data on the number of participants with PDR and no PDR according to virological failure (VF) were included in the metanalyses. The pooled results from eleven (13) of these studies showed those with PDR had higher odds of virological failure compared to those without PDR OR 3.64[95% CI 2.93, 4.52]. The result was similar when stratified in adults and in children. In six (6) studies that had Virological suppression (VS) as outcome, there was a reduction in the odds of VS in those with PDR compared to those without PDR, OR 0.42 (95% CI 0.30, 0.58).

CONCLUSION

In conclusion, this systematic review indicates that PDR increases the risk of virological failure in sub-Saharan Africa. The risk could be reduced by PDR monitoring for NNRTIs and INSTIs.

Clinical Impact of Pretreatment Human Immunodeficiency Virus Drug Resistance in People Initiating Nonnucleoside Reverse Transcriptase Inhibitor-Containing Antiretroviral Therapy: A Systematic Review and Meta-analysis

BACKGROUND

Increased access to antiretroviral therapy (ART) has resulted in rising levels of pretreatment human immunodeficiency virus drug resistance (PDR). This is the first systematic review and meta-analysis to assess the impact of PDR on treatment outcomes among people initiating nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART, including the combination of efavirenz (EFV), tenofovir (TDF), and lamivudine or emtricitabine (XTC).

METHODS

We systematically reviewed studies and conference proceedings comparing treatment outcomes in populations initiating NNRTI-based ART with and without PDR. We conducted subgroup analyses by regimen: (1) NNRTIs + 2 nucleoside reverse transcriptase inhibitors (NRTIs), (2) EFV + 2 NRTIs, or (3) EFV/TDF/XTC; by population (children vs adults); and by definition of resistance (PDR vs NNRTI PDR).

RESULTS

Among 6197 studies screened, 32 were analyzed (31 441 patients). We found that individuals with PDR initiating NNRTIs across all the subgroups had increased risk of virological failure compared to those without PDR. Risk of acquisition of new resistance mutations and ART switch was also higher in people with PDR.

CONCLUSIONS

This review shows poorer treatment outcomes in the presence of PDR, supporting the World Health Organization's recommendation to avoid using NNRTIs in countries where levels of PDR are high.

The relative contributions of HIV drug resistance, nonadherence and low-level viremia to viremic episodes on antiretroviral therapy in sub-Saharan Africa

INTRODUCTION

To achieve viral suppression among more than 90% of people on antiretroviral therapy (ART), improved understanding is warranted of the modifiable causes of HIV viremic episodes. We assessed the relative contributions of drug-resistance, nonadherence and low-level viremia (LLV) (viral load 50-999 cps/ml) on viremic episodes in sub-Saharan Africa.

METHODS

In a multicountry adult cohort initiating nonnucleoside reverse transcriptase inhibitor-based first-line ART, viremic episodes (viral load ≥1000 cps/ml) were classified as first, viral nonsuppression at 12 months; second, virological rebound at 24 months (after initial viral suppression at 12 months); third, failure to achieve viral resuppression at 24 months (after viremic episode at 12 months). We used adjusted odds ratios from multivariable logistic regression to estimate attributable fractions for each risk factor.

RESULTS

Of 2737 cohort participants, 1935 had data on pretreatment drug resistance (PDR) and at least 1 viral load outcome. Viral nonsuppression episodes [173/1935 (8.9%)] were attributable to nonadherence in 30% (35% in men vs. 24% in women) and to PDR to nonnucleoside reverse transcriptase inhibitors in 10% (15% in women vs. 6% in men). Notably, at contemporary PDR prevalences of 10-25%, PDR would explain 13-30% of viral nonsuppression. Virological rebound episodes [96/1515 (6.3%)] were mostly attributable to LLV (29%) and nonadherence (14%), and only rarely to PDR (1.1%). Failures to achieve viral resuppression [66/81 (81.5%)] were mostly attributable to the presence of acquired drug resistance (34%) and only rarely to nonadherence (2.4%).

CONCLUSION

Effective adherence interventions could substantially reduce viral nonsuppression (especially in men) and virological rebound (especially during LLV), but would have limited effect on improving viral resuppression. Alternative ART regimens could circumvent PDR and acquired resistance.