The Impact of Delayed Switch to Second-Line Antiretroviral Therapy on Mortality, Depending on Definition of Failure Time and CD4 Count at Failure

Handling missing data when estimating causal effects with targeted maximum likelihood estimation

Targeted maximum likelihood estimation (TMLE) is increasingly used for doubly robust causal inference, but how missing data should be handled when using TMLE with data-adaptive approaches is unclear. Based on data (1992-1998) from the Victorian Adolescent Health Cohort Study, we conducted a simulation study to evaluate 8 missing-data methods in this context: complete-case analysis, extended TMLE incorporating an outcome-missingness model, the missing covariate missing indicator method, and 5 multiple imputation (MI) approaches using parametric or machine-learning models. We considered 6 scenarios that varied in terms of exposure/outcome generation models (presence of confounder-confounder interactions) and missingness mechanisms (whether outcome influenced missingness in other variables and presence of interaction/nonlinear terms in missingness models). Complete-case analysis and extended TMLE had small biases when outcome did not influence missingness in other variables. Parametric MI without interactions had large bias when exposure/outcome generation models included interactions. Parametric MI including interactions performed best in bias and variance reduction across all settings, except when missingness models included a nonlinear term. When choosing a method for handling missing data in the context of TMLE, researchers must consider the missingness mechanism and, for MI, compatibility with the analysis method. In many settings, a parametric MI approach that incorporates interactions and nonlinearities is expected to perform well.

Clinical Outcomes After Viremia Among People Receiving Dolutegravir vs Efavirenz-Based First-line Antiretroviral Therapy in South Africa

Background

We aimed to compare clinical outcomes after viremia between dolutegravir vs efavirenz-based first-line antiretroviral therapy (ART) as evidence is lacking outside clinical trials in resource-limited settings.

Methods

We conducted a retrospective cohort analysis with routine data from 59 South African clinics. We included people with HIV aged ≥15 years receiving first-line tenofovir disoproxil fumarate, lamivudine, dolutegravir (TLD) or tenofovir disoproxil fumarate, emtricitabine, efavirenz (TEE) and with first viremia (≥50 copies/mL) between June and November 2020. We used multivariable modified Poisson regression models to compare retention in care and viral suppression (<50 copies/mL) after 12 months between participants on TLD vs TEE.

Results

At first viremia, among 9657 participants, 6457 (66.9%) were female, and the median age (interquartile range [IQR]) was 37 (31-44) years; 7598 (78.7%) were receiving TEE and 2059 (21.3%) TLD. Retention in care was slightly higher in the TLD group (84.9%) than TEE (80.8%; adjusted risk ratio [aRR], 1.03; 95% CI, 1.00-1.06). Of 6569 participants retained in care with a 12-month viral load, viral suppression was similar between the TLD (78.9%) and TEE (78.8%) groups (aRR, 1.02; 95% CI, 0.98-1.05). However, 3368 participants changed ART during follow-up: the majority from TEE to first-line TLD (89.1%) or second-line (TLD 3.4%, zidovudine/emtricitabine/lopinavir-ritonavir 2.1%). In a sensitivity analysis among the remaining 3980 participants who did not change ART during follow-up and had a 12-month viral load, viral suppression was higher in the TLD (78.9%) than TEE (74.9%) group (aRR, 1.07; 95% CI, 1.03-1.12).

Conclusions

Among people with viremia on first-line ART, dolutegravir was associated with slightly better retention in care and similar or better viral suppression than efavirenz.

Reasons for antiretroviral switching in Colombia: A retrospective cohort study

INTRODUCTION

Long-term use of antiretroviral therapy (ART) for HIV infection might lead to the necessity of switching regimens. We aimed to analyze the reasons for the ART switch, the time-to-switch of ART, and its associated factors in a Colombian cohort.

METHODS

We conducted a retrospective cohort in 20 HIV clinics, including participants ≥18 years old with confirmed HIV infection who underwent an ART switch from January 2017 to December 2019 with at least 6 months of follow-up. A time-to-event analysis and an exploratory Cox model were performed.

RESULTS

796 participants switched ART during the study period. The leading cause of ART switch was drug intolerance (n = 449; 56.4%) with a median time-to-switch of 12.2 months. The longest median time-to-switch was due to regimen simplification (42.4 months). People ≥50 years old (HR = 0.6; 95% CI (0.5-0.7) and CDC stage 3 at diagnosis (HR = 0.8; 95% CI (0.6-0.9) had less hazard for switching ART over time.

CONCLUSIONS

In this Colombian cohort, drug intolerance was the main cause of the ART switch, and the time-to-switch is shorter than reports from other countries. In Colombia, it is crucial to apply current recommendations for ART initiation to choose regimens with a better tolerability profile.

Application of targeted maximum likelihood estimation in public health and epidemiological studies: a systematic review

PURPOSE

The targeted maximum likelihood estimation (TMLE) statistical data analysis framework integrates machine learning, statistical theory, and statistical inference to provide a least biased, efficient, and robust strategy for estimation and inference of a variety of statistical and causal parameters. We describe and evaluate the epidemiological applications that have benefited from recent methodological developments.

METHODS

We conducted a systematic literature review in PubMed for articles that applied any form of TMLE in observational studies. We summarized the epidemiological discipline, geographical location, expertize of the authors, and TMLE methods over time. We used the Roadmap of Targeted Learning and Causal Inference to extract key methodological aspects of the publications. We showcase the contributions to the literature of these TMLE results.

RESULTS

Of the 89 publications included, 33% originated from the University of California at Berkeley, where the framework was first developed by Professor Mark van der Laan. By 2022, 59% of the publications originated from outside the United States and explored up to seven different epidemiological disciplines in 2021-2022. Double-robustness, bias reduction, and model misspecification were the main motivations that drew researchers toward the TMLE framework. Through time, a wide variety of methodological, tutorial, and software-specific articles were cited, owing to the constant growth of methodological developments around TMLE.

CONCLUSIONS

There is a clear dissemination trend of the TMLE framework to various epidemiological disciplines and to increasing numbers of geographical areas. The availability of R packages, publication of tutorial papers, and involvement of methodological experts in applied publications have contributed to an exponential increase in the number of studies that understood the benefits and adoption of TMLE.

Incidence of switching to second-line antiretroviral therapy and its predictors among children on antiretroviral therapy at general hospitals, Northern Ethiopia: A survival analysis

BACKGROUND

With expanding access to pediatric antiretroviral therapy, several patients in the developing world were switched to the second-line regimen, and some require third-line medications. A delay in a second-line switch is associated with an increased risk of mortality and other undesired therapeutic outcomes, drives up program costs, and challenges the pediatric antiretroviral therapy service. Nevertheless, there remain limited and often conflicting estimates on second-line antiretroviral therapy use during childhood, especially in resource-limited settings like Ethiopia. Thus, this study intended to determine the incidence and predictors of switching to second-line antiretroviral therapy among children.

METHODS

A retrospective cohort study was conducted by reviewing records of 424 randomly selected children on first-line antiretroviral therapy from January 2014 to December 2018 at public hospitals in the Central and Southern Zones of Tigray, Northern Ethiopia. Data were collected using extraction tool; entered into Epi-data; cleaned, and analyzed by STATA version-14. Kaplan-Meier curve, log-rank test, and life table were used for data description and adjusted hazard ratios and p-value for analysis by Cox proportional hazard regression. Variables at a P-value of ≤0.20 in the bi-variable analysis were taken to multivariable analysis. Finally, statistical significance was declared at a P-value of ≤0.05.

RESULTS AND CONCLUSION

Analysis was conducted on 424 charts with a total person-time observation of 11686.1 child-months and an incidence switch rate of 5.6 (95%CI: 4.36-7.09) per 1000 child-month-observations. Being orphan [AHR = 2.36; 95%CI: 1.10-5.07], suboptimal adherence [AHR = 2.10; 95% CI: 1.12-3.92], drug toxicity [AHR = 7.05; 95% CI: 3.61-13.75], advanced latest clinical stage [AHR = 2.75; 95%CI: 1.05-7.15], and tuberculosis co-infection at baseline [AHR = 3.08; 95%CI: 1.26-7.51] were significantly associated with switch to second-line antiretroviral therapy regimen. Moreover, a long duration of follow-up [AHR = 0.75; 95% CI: 0.71-0.81] was associated with decreased risk of switching. Hence, it is better to prioritize strengthening the focused evaluation of tuberculosis co-infection and treatment failure with continuous adherence monitoring. Further research is also needed to evaluate the effect of drug resistance.

Virologic status and pattern of drug resistance mutation among ART-experienced HIV-infected patients in Butuo County, China

OBJECTIVES

To assess the virological outcomes, prevalence of HIV drug resistance mutation (DRM), and correlates in Butuo County.

METHODS

We conducted a cross-sectional study. Virological failure (VF) was defined as HIV-1 RNA ≥1000 copies/mL and on antiretroviral therapy (ART) for ≥6 months. Genotypic drug resistance was performed among VF cases. Correlates of DRM were identified using multivariate logistic regression.

RESULTS

The overall virological suppression rate was 85.3%; DRM was detected in 42.6% (517/1215) VF cases and 6.2% of the sample patients. A total of 90.9% of patients were infected with HIV-1 CRF07_BC subtype. The prevalence of DRM to nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI) were 46.0% and 96.9%, respectively. The most prevalent mutation for NRTI was M184V (84.5%). Lamivudine (3TC), emtricitabine (FTC), and abacavir (ABC) had the highest resistance rates. For NNRTI, K103N (60.7%), nevirapine (NVP), and efavirenz (EFV) had the highest resistance rates and cross resistance to rilpivirine (RPV), doravirine (DOR), and etravirine (ETR). Ritonavir boosted lopinavir (LPV/r) resistance rate was extremely low. The occurrence of DRM was associated with age at ART ≤18 years, baseline CD4 count ≤200 cells/mL, NVP-based regimen, and ART duration >3 years.

CONCLUSION

A relatively high proportion of VF and broad DRM for NRTI and NNRTI were observed, causing high-level resistance to first-line NRTI, NNRTI, and next generation NNRTI. Our findings necessitate the implementation of scaling up virological monitoring, adherence support, and timely switching to an LPV/r-containing regimen when patients with VF to reduce the occurrence of DRM.

Detection of HIV Virologic Failure and Switch to Second-Line Therapy: A Systematic Review and Meta-analysis of Data From Sub-Saharan Africa

Background

The late recognition of virologic failure (VF) places persons with HIV in Sub-Saharan Africa at risk for HIV transmission, disease progression, and death. We conducted a systematic review and meta-analysis to determine if the recognition and response to VF in the region has improved.

Methods

We searched for studies reporting CD4 count at confirmed VF or at switch to second-line antiretroviral therapy (ART). Using a random-effects metaregression model, we analyzed temporal trends in CD4 count at VF-or at second-line ART switch-over time. We also explored temporal trends in delay between VF and switch to second-line ART.

Results

We identified 26 studies enrolling patients with VF and 10 enrolling patients at second-line ART switch. For studies that enrolled patients at VF, pooled mean CD4 cell count at failure was 187 cells/mm3 (95% CI, 111 to 263). There was no significant change in CD4 count at confirmed failure over time (+4 cells/year; 95% CI, -7 to 15). Among studies that enrolled patients at second-line switch, the pooled mean CD4 count was 108 cells/mm3 (95% CI, 63 to 154). CD4 count at switch increased slightly over time (+10 CD4 cells/year; 95% CI, 2 to 19). During the same period, the mean delay between confirmation of VF and switch was 530 days, with no significant decline over time (-14 days/year; 95% CI, -58 to 52).

Conclusions

VF in Africa remains an event recognized late in HIV infection, a problem compounded by ongoing delays between VF and second-line switch.

Patterns and prognosis of holding regimens for people living with HIV in Asian countries

The use of holding regimens for people living with HIV (PLWH) without effective antiretroviral options can have effects on outcomes and future treatment options. We aimed to investigate the use of holding regimens for PLWH in Asian countries. Data from adults enrolled in routine HIV care in IeDEA Asia-Pacific cohorts were included. Individuals were considered to be on holding regimen if they had been on combination antiretroviral therapy for at least 6 months, had two confirmed viral loads (VL) ≥1000 copies/mL, and had remained on the same medications for at least 6 months. Survival time was analyzed using Fine and Gray's competing risk regression. Factors associated with CD4 changes and VL <1000 copies/mL were analyzed using linear regression and logistic regression, respectively. A total of 425 PLWH (72.9% male; 45.2% high-income and 54.8% low-to-middle-income country) met criteria for being on a holding regimen. From high-income countries, 63.0% were on protease inhibitors (PIs); from low-to-middle-income countries, 58.4% were on non-nucleoside reverse transcriptase inhibitors (NNRTIs); overall, 4.5% were on integrase inhibitors. The combination of lamivudine, zidovudine, and efavirenz was the most commonly used single regimen (n = 46, 10.8%), followed by lamivudine, zidovudine, and nevirapine (n = 37, 8.7%). Forty-one PLWH (9.7%) died during follow-up (mortality rate 2.0 per 100 person-years). Age >50 years compared to age 31-40 years (sub-hazard ratio [SHR] 3.29, 95% CI 1.45-7.43, p = 0.004), and VL ≥1000 copies/ml compared to VL <1000 copies/mL (SHR, 2.14, 95% CI 1.08-4.25, p = 0.029) were associated with increased mortality, while higher CD4 counts were protective. In our Asia regional cohort, there was a diversity of holding regimens, and the patterns of PI vs. NNRTI use differed by country income levels. Considering the high mortality rate of PLWH with holding regimen, efforts to extend accessibility to additional antiretroviral options are needed in our region.

Evaluation of Namibia's antiretroviral therapy guidelines' recommendations for switching from first-line to second-line, using predictors of first-line treatment failure: an exploratory study

OBJECTIVES

The objective of this study was to find out the extent to which the antiretroviral therapy (ART) switching guidelines were complied with and to assess whether immediate switching from first- to second-line ART would have been appropriate than attempting to comply with the guidelines.

METHODS

A case-control study. Cases and controls were patients on second- and first-line ART, respectively. Regression analysis was used to identify factors that were associated with switching to second-line ART. Confidence level was 95% and significance at a p-value <0.05.

RESULTS

81 cases and 102 controls were included. VLs at six and 9 months were implemented for 8.2% and 2.7%, respectively. Switching predictors were poor adherence (adjusted Hazard Ratio [aHR] = 20.3 (p = 0.013); a first VL >1000 copies/ml (aHR = 20.2), <0.001); opportunistic infections (aHR = 12.9, p = 0.006); male gender (aHR = 5.2, p = 0.003); and lack of adherence counseling (aHR = 3.8 p = 0.024).

CONCLUSION

AVL >1000 copies/ml was a predictor of switching. New local research is underway, with a large number of patients, to assess whether this finding applies to the dolutegravir-based regimens.

HIV-1 drug resistance in adults and adolescents on protease inhibitor-based antiretroviral treatment in KwaZulu-Natal Province, South Africa

BACKGROUND

In low- and middle-income countries, increasing levels of HIV drug resistance (HIVDR) on second-line protease inhibitor (PI)-based regimens are a cause for concern, given limited drug options for third-line antiretroviral therapy (ART).

OBJECTIVES

We conducted a retrospective analysis of routine HIV-1 genotyping laboratory data from KwaZulu-Natal, in South Africa, to describe the frequency and patterns of HIVDR mutations and their consequent impact on standardized third-line regimens.

METHODS

This was a cross-sectional analysis of all HIV-1 genotypic resistance tests conducted by the National Health Laboratory Service in KwaZulu-Natal, South Africa (Jan 2015 - Dec 2016), for adults and adolescents (age ≥10 years) on second-line PI-based ART with virological failure. We assigned a third-line regimen to each record, based on a national treatment algorithm and calculated the genotypic susceptibility score (GSS) for that regimen.

RESULTS

Of 348 samples analyzed, 287 (83%) had at least one drug resistance mutation (DRM) and 114 (33%) had at least one major PI DRM. Major PI resistance was associated with longer duration on second-line ART (aOR per 6-months, 1.11, 95% CI 1.04-1.19) and older age (aOR 1.03, 95% CI 1.01-1.05). Of 112 patients requiring third-line ART, 12 (11%) had a GSS of <2 for the algorithm-assigned third-line regimen.

CONCLUSIONS

One in three people failing second-line ART had significant PI DRMs. A subgroup of these individuals had extensive HIVDR, where the predicted activity of third-line ART was suboptimal, highlighting the need for continuous evaluation of outcomes on third-line regimens and close monitoring for emergent HIV-1 integrase-inhibitor resistance.

Who's slipping through the cracks? A comprehensive individual, clinical and health system characterization of people with virological failure on first-line HIV treatment in Uganda and South Africa

OBJECTIVES

HIV virological failure remains a major threat to programme success in sub-Saharan Africa. While HIV drug resistance (HIVDR) and inadequate adherence are the main drivers of virological failure, the individual, clinical and health system characteristics that lead to poor outcomes are not well understood. The objective of this paper is to identify those characteristics among people failing first-line antiretroviral therapy (ART).

METHODS

We enrolled a cohort of adults in HIV care experiencing virological failure on first-line ART at five sites and used standard statistical methods to characterize them with a focus on three domains: individual/demographic, clinical, and health system, and compared each by country of enrolment.

RESULTS

Of 840 participants, 51% were women, the median duration on ART was 3.2 years [interquartile range (IQR) 1.1, 6.4 years] and the median CD4 cell count prior to failure was 281 cells/µL (IQR 121, 457 cells/µL). More than half of participants [53%; 95% confidence interval (CI) 49-56%] stated that they had > 90% adherence and 75% (95% CI 72-77%) took their ART on time all or most of the time. Conversely, the vast majority (90%; 95% CI 86-92%) with a completed genotypic drug resistance test had any HIV drug resistance. This population had high health system use, reporting a median of 3 (IQR 2.6) health care visits and a median of 1 (IQR 1.1) hospitalization in the preceding 6 months.

CONCLUSIONS

Patients failing first-line ART in sub-Saharan Africa generally report high rates of adherence to ART, have extremely high rates of HIV drug resistance and utilize significant health care resources. Health systems interventions to promptly detect and manage treatment failure will be a prerequisite to establishing control of the HIV epidemic.

Improved detection and management of advanced HIV disease through a community adult TB-contact tracing intervention with same-day provision of the WHO-recommended package of care including ART initiation in a rural district of Mozambique

INTRODUCTION

AIDS-mortality remains unacceptably high in sub-Saharan Africa, largely driven by advanced HIV disease (AHD). We nested a study in an existing tuberculosis (TB) contact-tracing intervention (Xpatial-TB). The aim was to assess the burden of AHD among high-risk people living with HIV (PLHIV) identified and to evaluate the provision of the WHO-recommended package of care to this population.

METHODS

All PLHIV ≥14 years old identified between June and December 2018 in Manhiça District by Xpatial-TB were offered to participate in the study if ART naïve or had suboptimal ART adherence. Consenting individuals were screened for AHD. Patients with AHD (CD4 < 200 cells/μL or WHO stage 3 or 4) were offered a package of interventions in a single visit, including testing for cryptococcal antigen (CrAg) and TB-lipoarabinomannan (TB-LAM), prophylaxis and treatment for opportunistic infections, adherence support or accelerated ART initiation. We collected information on follow-up visits carried out under routine programmatic conditions for six months.

RESULTS

A total of 2881 adults were identified in the Xpatial TB-contact intervention. Overall, 23% (673/2881) were HIV positive, including 351 TB index (64.2%) and 322 TB contacts (13.8%). Overall, 159/673 PLHIV (24%) were ART naïve or had suboptimal ART adherence, of whom 155 (97%, 124 TB index and 31 TB-contacts) consented to the study and were screened for AHD. Seventy percent of TB index-patients (87/124) and 16% of TB contacts (5/31) had CD4 < 200 cells/µL. Four (13%) of the TB contacts had TB, giving an overall AHD prevalence among TB contacts of 29% (9/31). Serum-CrAg was positive in 4.6% (4/87) of TB-index patients and in zero TB contacts. All ART naïve TB contacts without TB initiated ART within 48 hours of HIV diagnosis. Among TB cases, ART timing was tailored to the presence of TB and cryptococcosis. Six-month mortality was 21% among TB-index cases and zero in TB contacts.

CONCLUSIONS

A TB contact-tracing outreach intervention identified undiagnosed HIV and AHD in TB patients and their contacts, undiagnosed cryptococcosis among TB patients, and resulted in an adequate provision of the WHO-recommended package of care in this rural Mozambican population. Same-day and accelerated ART initiation was feasible and safe in this population including among those with AHD.

High Prevalence of NRTI and NNRTI Drug Resistance Among ART-Experienced, Hospitalized Inpatients

BACKGROUND

Patients hospitalized with advanced HIV have a high mortality risk. We assessed viremia and drug resistance among differentiated care services and explored whether expediting the switching of failing treatments may be justified.

SETTING

Hospitals in the Democratic Republic of (DRC) Congo (HIV hospital) and Kenya (general hospital including HIV care).

METHODS

Viral load (VL) testing and drug resistance (DR) genotyping were conducted for HIV inpatients ≥15 years, on first-line antiretroviral therapy (ART) for ≥6 months, and CD4 ≤350 cells/µL. Dual-class DR was defined as low-, intermediate-, or high-level DR to at least 1 nucleoside reverse transcriptase inhibitor and 1 non-nucleoside reverse transcriptase inhibitor. ART regimens were considered ineffective if dual-class DR was detected at viral failure (VL ≥1000 copies/mL).

RESULTS

Among 305 inpatients, 36.7% (Kenya) and 71.2% (DRC) had VL ≥1000 copies/mL, of which 72.9% and 73.7% had dual-class DR. Among viral failures on tenofovir disoproxil fumarate (TDF)-based regimens, 56.1% had TDF-DR and 29.8% zidovudine (AZT)-DR; on AZT regimens, 71.4% had AZT-DR and 61.9% TDF-DR, respectively. Treatment interruptions (≥48 hours during past 6 months) were reported by 41.7% (Kenya) and 56.7% (DRC). Approximately 56.2% (Kenya) and 47.4% (DRC) on TDF regimens had tenofovir diphosphate concentrations <1250 fmol/punch (suboptimal adherence). Among viral failures with CD4 <100 cells/µL, 76.0% (Kenya) and 84.6% (DRC) were on ineffective regimens.

CONCLUSIONS

Many hospitalized, ART-experienced patients with advanced HIV were on an ineffective first-line regimen. Addressing ART failure promptly should be integrated into advanced disease care packages for this group. Switching to effective second-line medications should be considered after a single high VL on non-nucleoside reverse transcriptase inhibitor-based first-line if CD4 ≤350 cells/µL or, when VL is unavailable, among patients with CD4 ≤100 cells/µL.

Protocol for a randomised feasibility study of Point-Of-care HIV viral load testing to Enhance Re-suppression in South Africa: the POwER study

INTRODUCTION

Access to HIV viral load testing remains difficult for many people on antiretroviral therapy (ART) in low-income and middle-income countries. Weak laboratory and clinic systems often delay the detection and management of viraemia, which can lead to morbidity, drug resistance and HIV transmission. Point-of-care testing could overcome these challenges. We aim to assess whether it is feasible to conduct a randomised trial of point-of-care viral load testing to manage viraemia.

METHODS AND ANALYSIS

We will conduct an open-label, single-site, individually randomised, feasibility study of Point-Of-care HIV viral load testing to Enhance Re-suppression, in Durban, South Africa. We will enrol approximately 100 people living with HIV who are aged ≥18 years, receiving first-line ART but with recent viraemia ≥1000 copies/mL, and randomise them 1:1 to receive point-of-care viral load or standard laboratory viral load monitoring, after 12 weeks. All participants will continue to receive care from public sector healthcare workers following South African HIV management guidelines. Participants with persistent viraemia ≥1000 copies/mL will be considered for switching to second-line ART. We will compare the proportion in each study arm who achieve the primary outcome of viral suppression <50 copies/mL at 24 weeks after enrolment. Additional outcomes include proportions retained in the study, proportions with HIV drug resistance, time to viral load results and time to switching to second-line ART. We will assess implementation of point-of-care viral load testing using process evaluation data, and through interviews and focus groups with healthcare workers.

ETHICS AND DISSEMINATION

University of Oxford Tropical Research Ethics Committee and the Biomedical Research Ethics Committee of the University of KwaZulu-Natal have approved the study. We will present results to stakeholders, and through conferences and open-access, peer-reviewed journals.

TRIAL REGISTRATION NUMBER

PACTR202001785886049.

Increased Mortality With Delayed and Missed Switch to Second-Line Antiretroviral Therapy in South Africa

BACKGROUND

After failure of first-line antiretroviral therapy (ART) in the public sector, delayed or missed second-line ART switch is linked with poor outcomes in patients with advanced HIV.

SETTING

We investigated delayed or missed second-line ART switch after confirmed virologic failure in the largest private sector HIV cohort in Africa.

METHODS

We included HIV-infected adults with confirmed virologic failure after 6 months of nonnucleoside reverse-transcriptase inhibitor-based ART. We estimated the effect of timing of switch on the hazard of death using inverse probability of treatment weighting of marginal structural models. We adjusted for time-dependent confounding of CD4 count, viral load, and visit frequency.

RESULTS

Five thousand seven hundred forty-eight patients (53% female) with confirmed virologic failure met inclusion criteria; the median age was 40 [interquartile range (IQR): 35-47], advanced HIV was present in 48% and the prior duration of nonnucleoside reverse-transcriptase inhibitor-based ART was 1083 days (IQR: 665-1770). Median time to confirmation of virologic failure and to second-line switch was 196 (IQR: 136-316) and 220 days (IQR: 65-542), respectively. Switching to second-line ART after confirmed failure compared with remaining on first-line ART reduced risk of subsequent death [adjusted hazard ratio: 0.47 (95% confidence interval: 0.36 to 0.63)]. Compared with patients who experienced delayed switch, those switched immediately had a lower risk of death, regardless of CD4 cell count.

CONCLUSIONS

Delayed or missed switch to second-line ART after confirmed first-line ART failure is common in the South African private sector and associated with mortality. Novel interventions to minimize switch delay should be tested and not limited to those with advanced disease at treatment failure.

Prevalence of nonsuppressed viral load and associated factors among HIV-positive adults receiving antiretroviral therapy in Eswatini, Lesotho, Malawi, Zambia and Zimbabwe (2015 to 2017): results from population-based nationally representative surveys

INTRODUCTION

The global target for 2020 is that ≥90% of people living with HIV (PLHIV) receiving antiretroviral therapy (ART) will achieve viral load suppression (VLS). We examined VLS and its determinants among adults receiving ART for at least four months.

METHODS

We analysed data from the population-based HIV impact assessment (PHIA) surveys in Eswatini, Lesotho, Malawi, Zambia and Zimbabwe (2015 to 2017). PHIA surveys are nationally representative, cross-sectional household surveys. Data collection included structured interviews, home-based HIV testing and laboratory testing. Blood samples from PLHIV were analysed for HIV RNA, CD4 counts and recent exposure to antiretroviral drugs (ARVs). We calculated representative estimates for the prevalence of VLS (viral load <1000 copies/mL), nonsuppressed viral load (NVL; viral load ≥1000 copies/mL), virologic failure (VF; ARVs present and viral load ≥1000 copies/mL), interrupted ART (ARVs absent and viral load ≥1000 copies/mL) and rates of switching to second-line ART (protease inhibitors present) among PLHIV aged 15 to 59 years who participated in the PHIA surveys in Eswatini, Lesotho, Malawi, Zambia and Zimbabwe, initiated ART at least four months before the survey and were receiving ART at the time of the survey (according to self-report or ARV testing). We calculated odds ratios and incidence rate ratios for factors associated with NVL, VF, interrupted ART, and switching to second-line ART.

RESULTS

We included 9200 adults receiving ART of whom 88.8% had VLS and 11.2% had NVL including 8.2% who experienced VF and 3.0% who interrupted ART. Younger age, male sex, less education, suboptimal adherence, receiving nevirapine, HIV non-disclosure, never having married and residing in Zimbabwe, Lesotho or Zambia were associated with higher odds of NVL. Among people with NVL, marriage, female sex, shorter ART duration, higher CD4 count and alcohol use were associated with lower odds for VF and higher odds for interrupted ART. Many people with VF (44.8%) had CD4 counts <200 cells/µL, but few (0.31% per year) switched to second-line ART.

CONCLUSIONS

Countries are approaching global VLS targets for adults. Treatment support, in particular for younger adults, and people with higher CD4 counts, and switching of people to protease inhibitor- or integrase inhibitor-based regimens may further reduce NVL prevalence.

Joint modelling of longitudinal and time-to-event data: an illustration using CD4 count and mortality in a cohort of patients initiated on antiretroviral therapy

Background

Modelling of longitudinal biomarkers and time-to-event data are important to monitor disease progression. However, these two variables are traditionally analyzed separately or time-varying Cox models are used. The former strategy fails to recognize the shared random-effects from the two processes while the latter assumes that longitudinal biomarkers are exogenous covariates, resulting in inefficient or biased estimates for the time-to-event model. Therefore, we used joint modelling for longitudinal and time-to-event data to assess the effect of longitudinal CD4 count on mortality.

Methods

We studied 4014 patients from the Centre for the AIDS Programme of Research in South Africa (CAPRISA) who initiated ART between June 2004 and August 2013. We used proportional hazards regression model to assess the effect of baseline characteristics (excluding CD4 count) on mortality, and linear mixed effect models to evaluate the effect of baseline characteristics on the CD4 count evolution over time. Thereafter, the two analytical approaches were amalgamated to form an advanced joint model for studying the effect of longitudinal CD4 count on mortality. To illustrate the virtues of the joint model, the results from the joint model were compared to those from the time-varying Cox model.

Results

Using joint modelling, we found that lower CD4 count over time was associated with a 1.3-fold increase in the risk of death, (HR: 1.34, 95% CI: 1.27-1.42). Whereas, results from the time-varying Cox model showed lower CD4 count over time was associated with a 1.2-fold increase in the risk of death, (HR: 1.17, 95% CI: 1.12-1.23).

Conclusions

Joint modelling enabled the assessment of the effect of longitudinal CD4 count on mortality while correcting for shared random effects between longitudinal and time-to-event models. In the era of universal test and treat, the evaluation of CD4 count is still crucial for guiding the initiation and discontinuation of opportunistic infections prophylaxis and assessment of late presenting patients. CD4 count can also be used when immunological failure is suspected as we have shown that it is associated with mortality.