When to start antiretroviral therapy in children aged 2-5 years: a collaborative causal modelling analysis of cohort studies from southern Africa

Early Initiation of Antiretroviral Therapy is Protective Against Seizures in Children With HIV in Zambia: A Prospective Case-Control Study

BACKGROUND

Seizures are relatively common among children with HIV in low- and middle-income countries and are associated with significant morbidity and mortality. Early treatment with antiretroviral therapy (ART) may reduce this risk by decreasing rates of central nervous system infections and HIV encephalopathy.

METHODS

We conducted a prospective, unmatched case-control study. We enrolled children with new-onset seizure from University Teaching Hospital in Lusaka, Zambia and 2 regional hospitals in rural Zambia. Controls were children with HIV and no history of seizures. Recruitment took place from 2016 to 2019. Early treatment was defined as initiation of ART before 12 months of age, at a CD4 percentage >15% in children aged 12-60 months or a CD4 count >350 cells/mm 3 for children aged 60 months or older. Logistic regression models were used to evaluate the association between potential risk factors and seizures.

RESULTS

We identified 73 children with new-onset seizure and compared them with 254 control children with HIV but no seizures. Early treatment with ART was associated with a significant reduction in the odds of seizures [odds ratio (OR) 0.04, 95% confidence interval: 0.02 to 0.09; P < 0.001]. Having an undetectable viral load at the time of enrollment was strongly protective against seizures (OR 0.03, P < 0.001), whereas history of World Health Organization Stage 4 disease (OR 2.2, P = 0.05) or CD4 count <200 cells/mm 3 (OR 3.6, P < 0.001) increased risk of seizures.

CONCLUSIONS

Early initiation of ART and successful viral suppression would likely reduce much of the excess seizure burden in children with HIV.

Factors Associated with Treatment Outcomes Among Children and Adolescents Living with HIV Receiving Antiretroviral Therapy in Central Kenya

Expanded access to HIV treatment services has improved outcomes for children and adolescents living with HIV in Kenya. Minimal data are available on these outcomes. We describe temporal trends in outcomes for children and adolescents initiating antiretroviral therapy (ART) from 2004 to 2014 at sites supported by Centre for Health Solutions—Kenya, in central Kenya. We retrospectively analyzed data from children 0–9 years of age (n = 3,519) and adolescents 10–19 years of age (n = 1,663) living with HIV, who newly initiated ART at 47 health facilities in central Kenya. Year cohorts were analyzed from the Comprehensive Patient Application Database (CPAD) and International Quality Care (IQCare) electronic medical databases, including temporal trends in outcomes and associated factors using multivariable competing risk regression analysis. There were more girls (2,453 [52.7%]) than boys, with most enrolled at World Health Organization (WHO) stage II (1,813 [37.7%]) or III disease (1,694 [35.1%]). Most of the children and adolescents (4,431 [96.4%]) did not have tuberculosis (TB) symptoms. Cumulative lost to follow-up (LTFU) incidence at 6, 12, 24, and 36 months were 5.0%, 9.9%, 22.9%, and 33.1%, respectively. Cumulative mortality incidence at 6, 12, 24, and 36 months were 0.7%, 1.0%, 1.2%, and 1.5%, respectively. The incidence of LTFU was higher among female children and adolescents, those initiated on tenofovir-based regimens, and those with presumptive TB symptoms. Mortality risk was higher among those with WHO stage III or IV disease, and children and adolescents on TB treatment or who had presumptive TB. Enrollment occurred at a young age and pediatric-friendly ART regimens were initiated at earlier WHO stages implying effective early infant diagnosis and treatment for all strategies, resulting in improved treatment outcomes. The higher retention rates in recent years as well as the lower retention after many years of follow-up underscore the importance of implementing longitudinal follow-up strategies targeting this population.

CD4 Trends With Evolving Treatment Initiation Policies Among Children Living With HIV in Zambézia Province, Mozambique, 2012-2018

BACKGROUND

Historically, antiretroviral therapy (ART) initiation was based on CD4 criteria, but this has been replaced with "Test and Start" wherein all people living with HIV are offered ART. We describe the baseline immunologic status among children relative to evolving ART policies in Mozambique.

METHODS

This retrospective evaluation was performed using routinely collected data. Children living with HIV (CL aged 5-14 years) with CD4 data in the period of 2012-2018 were included. ART initiation "policy periods" corresponded to implementation of evolving guidelines: in period 1 (2012-2016), ART was recommended for CD4 <350 cells/mm3; during period 2 (2016-2017), the CD4 threshold increased to <500 cells/mm3; Test and Start was implemented in period 3 (2017-2018). We described temporal trends in the proportion of children with severe immunodeficiency (CD4 <200 cells/mm3) at enrollment and at ART initiation. Multivariable regression models were used to estimate associations with severe immunodeficiency.

RESULTS

The cohort included 1815 children with CD4 data at enrollment and 1922 at ART initiation. The proportion of children with severe immunodeficiency decreased over time: 20% at enrollment into care in period 1 vs. 16% in period 3 (P = 0.113) and 21% at ART initiation in period 1 vs. 15% in period 3 (P = 0.004). Children initiating ART in period 3 had lower odds of severe immunodeficiency at ART initiation compared with those in period 1 [adjusted odds ratio (aOR) = 0.67; 95% CI: 0.51 to 0.88]. Older age was associated with severe immunodeficiency at enrollment (aOR = 1.13; 95% CI: 1.06 to 1.20) and at ART initiation (aOR = 1.14; 95% CI: 1.08 to 1.21).

CONCLUSIONS

The proportion of children with severe immunodeficiency at ART initiation decreased alongside more inclusive ART initiation guidelines. Earlier treatment of children living with HIV is imperative.

Age-specific mortality rate ratios in adolescents and youth aged 10-24 years living with perinatally versus nonperinatally acquired HIV

OBJECTIVE

To measure mortality incidence rates and incidence rate ratios (IRR) in adolescents and youth living with perinatally acquired HIV (YPHIV) compared with those living with nonperinatally acquired HIV (YNPHIV), by region, by sex, and during the ages of 10-14, 15-19, and 20-24 years in IeDEA.

DESIGN AND METHODS

All those with a confirmed HIV diagnosis, antiretroviral therapy (ART)-naive at enrollment, and who have post-ART follow-up while aged 10-24 years between 2004 and 2016 were included. We estimated post-ART mortality incidence rates and 95% confidence intervals (95% CI) per 100 person-years for YPHIV (enrolled into care <10 years of age) and YNPHIV (enrolled ≥10 years and <25 years). We estimate mortality IRRs in a negative binomial regression model, adjusted for sex, region time-varying age, CD4+ cell count at ART initiation (<350 cells/μl, ≥350 cells/μl, unknown), and time on ART (<12 and ≥12 months).

RESULTS

Overall, 104 846 adolescents and youth were included: 21 340 (20%) YPHIV (50% women) and 83 506 YNPHIV (80% women). Overall mortality incidence ratios were higher among YNPHIV (incidence ratio: 2.3/100 person-years; 95% CI: 2.2-2.4) compared with YPHIV (incidence ratio: 0.7/100 person-years; 95% CI: 0.7-0.8). Among adolescents aged 10-19 years, mortality was lower among YPHIV compared with YNPHIV (all IRRs <1, ranging from 0.26, 95% CI: 0.13-0.49 in 10-14-year-old boys in the Asia-Pacific to 0.51, 95% CI: 0.30-0.87 in 15-19-year-old boys in West Africa).

CONCLUSION

We report substantial amount of deaths occurring during adolescence. Mortality was significantly higher among YNPHIV compared to YPHIV. Specific interventions including HIV testing and early engagement in care are urgently needed to improve survival among YNPHIV.

A scoping review of studies using observational data to optimise dynamic treatment regimens

BACKGROUND

Dynamic treatment regimens (DTRs) formalise the multi-stage and dynamic decision problems that clinicians often face when treating chronic or progressive medical conditions. Compared to randomised controlled trials, using observational data to optimise DTRs may allow a wider range of treatments to be evaluated at a lower cost. This review aimed to provide an overview of how DTRs are optimised with observational data in practice.

METHODS

Using the PubMed database, a scoping review of studies in which DTRs were optimised using observational data was performed in October 2020. Data extracted from eligible articles included target medical condition, source and type of data, statistical methods, and translational relevance of the included studies.

RESULTS

From 209 PubMed abstracts, 37 full-text articles were identified, and a further 26 were screened from the reference lists, totalling 63 articles for inclusion in a narrative data synthesis. Observational DTR models are a recent development and their application has been concentrated in a few medical areas, primarily HIV/AIDS (27, 43%), followed by cancer (8, 13%), and diabetes (6, 10%). There was substantial variation in the scope, intent, complexity, and quality between the included studies. Statistical methods that were used included inverse-probability weighting (26, 41%), the parametric G-formula (16, 25%), Q-learning (10, 16%), G-estimation (4, 6%), targeted maximum likelihood/minimum loss-based estimation (4, 6%), regret regression (3, 5%), and other less common approaches (10, 16%). Notably, studies that were primarily intended to address real-world clinical questions (18, 29%) tended to use inverse-probability weighting and the parametric G-formula, relatively well-established methods, along with a large amount of data. Studies focused on methodological developments (45, 71%) tended to be more complicated and included a demonstrative real-world application only.

CONCLUSIONS

As chronic and progressive conditions become more common, the need will grow for personalised treatments and methods to estimate the effects of DTRs. Observational DTR studies will be necessary, but so far their use to inform clinical practice has been limited. Focusing on simple DTRs, collecting large and rich clinical datasets, and fostering tight partnerships between content experts and data analysts may result in more clinically relevant observational DTR studies.

Better Outcomes Among HIV-Infected Rwandan Children 18-60 Months of Age After the Implementation of "Treat All"

Background:

In 2012, Rwanda introduced a Treat All approach for HIV-infected children younger than 5 years. We compared antiretroviral therapy (ART) initiation, outcomes, and retention, before and after this change.

Methods:

We conducted a retrospective study of children enrolled into care between June 2009 and December 2011 [Before Treat All (BTA) cohort] and between July 2012 and April 2015 [Treat All (TA) cohort].

Setting:

Medical records of a nationally representative sample were abstracted for all eligible aged 18–60 months from 100 Rwandan public health facilities.

Results:

We abstracted 374 medical records: 227 in the BTA and 147 in the TA cohorts. Mean (SD) age at enrollment was [3 years (1.1)]. Among BTA, 59% initiated ART within 1 year, vs. 89% in the TA cohort. Median time to ART initiation was 68 days (interquartile range 14–494) for BTA and 9 days (interquartile range 0–28) for TA (P < 0.0001), with 9 (5%) undergoing same-day initiation in BTA compared with 50 (37%) in TA (P < 0.0001). Before ART initiation, 59% in the BTA reported at least one health condition compared with 35% in the TA cohort (P < 0.0001). Although overall loss to follow-up was similar between cohorts (BTA: 13%, TA: 8%, P = 0.18), loss to follow-up before ART was significantly higher in the BTA (8%) compared with the TA cohort (2%) (P = 0.02).

Conclusions:

Nearly 90% of Rwandan children started on ART within 1 year of enrollment, most within 1 month, with greater than 90% retention after implementation of TA. TA was also associated with fewer morbidities.

Simulation Modeling and Metamodeling to Inform National and International HIV Policies for Children and Adolescents

Objective and Approach:

Computer-based simulation models serve an important purpose in informing HIV care for children and adolescents. We review current model-based approaches to informing pediatric and adolescent HIV estimates and guidelines.

Findings:

Clinical disease simulation models and epidemiologic models are used to inform global and regional estimates of numbers of children and adolescents living with HIV and in need of antiretroviral therapy, to develop normative guidelines addressing strategies for diagnosis and treatment of HIV in children, and to forecast future need for pediatric and adolescent antiretroviral therapy formulations and commodities. To improve current model-generated estimates and policy recommendations, better country-level and regional-level data are needed about children living with HIV, as are improved data about survival and treatment outcomes for children with perinatal HIV infection as they age into adolescence and adulthood. In addition, novel metamodeling and value of information methods are being developed to improve the transparency of model methods and results, as well as to allow users to more easily tailor model-based analyses to their own settings.

Conclusions:

Substantial progress has been made in using models to estimate the size of the pediatric and adolescent HIV epidemic, to inform the development of guidelines for children and adolescents affected by HIV, and to support targeted implementation of policy recommendations to maximize impact. Ongoing work will address key limitations and further improve these model-based projections.

Using longitudinal targeted maximum likelihood estimation in complex settings with dynamic interventions

Longitudinal targeted maximum likelihood estimation (LTMLE) has very rarely been used to estimate dynamic treatment effects in the context of time-dependent confounding affected by prior treatment when faced with long follow-up times, multiple time-varying confounders, and complex associational relationships simultaneously. Reasons for this include the potential computational burden, technical challenges, restricted modeling options for long follow-up times, and limited practical guidance in the literature. However, LTMLE has desirable asymptotic properties, ie, it is doubly robust, and can yield valid inference when used in conjunction with machine learning. It also has the advantage of easy-to-calculate analytic standard errors in contrast to the g-formula, which requires bootstrapping. We use a topical and sophisticated question from HIV treatment research to show that LTMLE can be used successfully in complex realistic settings, and we compare results to competing estimators. Our example illustrates the following practical challenges common to many epidemiological studies: (1) long follow-up time (30 months); (2) gradually declining sample size; (3) limited support for some intervention rules of interest; (4) a high-dimensional set of potential adjustment variables, increasing both the need and the challenge of integrating appropriate machine learning methods; and (5) consideration of collider bias. Our analyses, as well as simulations, shed new light on the application of LTMLE in complex and realistic settings: We show that (1) LTMLE can yield stable and good estimates, even when confronted with small samples and limited modeling options; (2) machine learning utilized with a small set of simple learners (if more complex ones cannot be fitted) can outperform a single, complex model, which is tailored to incorporate prior clinical knowledge; and (3) performance can vary considerably depending on interventions and their support in the data, and therefore critical quality checks should accompany every LTMLE analysis. We provide guidance for the practical application of LTMLE.

Older age at initiation of antiretroviral therapy predicts low bone mineral density in children with perinatally-infected HIV in Zimbabwe

BACKGROUND

Perinatally-acquired HIV infection commonly causes stunting in children; how this affects bone and muscle development is unclear. We investigated differences in bone and muscle mass and muscle function between children with HIV (CWH) and uninfected children.

SETTING

Cross-sectional study of CWH (6-16 years) receiving antiretroviral therapy (ART) for >6 months and similar aged children testing HIV-negative at primary health clinics in Zimbabwe.

METHODS

From Dual-energy X-ray Absorptiometry (DXA) we calculated total-body less-head (TBLH) Bone Mineral Content (BMC) for lean mass adjusted-for-height (TBLH-BMCLBM) Z-scores, and lumbar spine (LS) Bone Mineral Apparent Density (BMAD) Z-scores.

RESULTS

The 97 CWH were older (mean age 12.7 vs. 10.0 years) and taller (mean height 142 cm vs. 134 cm) than 77 uninfected. However, stunting (height-for-age Z-score ≤ -2) was more prevalent in CWH (35% vs. 5%, p < 0.001). Among CWH, 15% had low LS-BMAD (Z-score ≤ -2) and 13% low TBLH-BMCLBM, vs. 1% and 3% respectively in those uninfected (both p ≤ 0.02). After age, sex, height and puberty adjustment, LS-BMAD was 0.33 SDs (95%CI -0.01, 0.67; p = 0.06) lower in CWH, with no differences by HIV status in TBLH-BMCLBM, lean mass (0.11 [-0.03, 0.24], p = 0.11) or grip strength (0.05 [-0.16, 0.27], p = 0.62). However, age at ART initiation was correlated with both LS-BMAD Z-score (r = -0.33, p = 0.001) and TBLH-BMCLBM Z-score (r = -0.23, p = 0.027); for each year ART initiation was delayed a 0.13 SD reduction in LS-BMAD was seen.

CONCLUSION

Size-adjusted low bone density is common in CWH. Delay in initiating ART adversely affects bone density. Findings support immediate ART initiation at HIV diagnosis.

The contribution of observational studies in supporting the WHO 'treat all' recommendation for HIV/AIDS

In 2015, the World Health Organization (WHO) recommended that all people living with HIV (PLWH) should start antiretroviral therapy (ART) irrespective of clinical or immune status. This recommendation followed almost 20 years of research into the clinical and population-level benefits and risks of starting ART early compared with deferring treatment. This article summarises the ways in which observational data support the work of WHO, including the support provided by the International epidemiology Databases to Evaluate AIDS (IeDEA), taking the example of 'treat all'.

A review of time scale fundamentals in the g-formula and insidious selection bias

PURPOSE OF REVIEW

We review recent examples of data analysis with the g-formula, a powerful tool for analyzing longitudinal data and survival analysis. Specifically, we focus on the common choices of time scale and review inferential issues that may arise.

RECENT FINDINGS

Researchers are increasingly engaged with questions that require time scales subject to left-truncation and right-censoring. The assumptions necessary for allowing right-censoring are well defined in the literature, whereas similar assumptions for left-truncation are not well defined. Policy and biologic considerations sometimes dictate that observational data must be analyzed on time scales that are subject to left-truncation, such as age.

SUMMARY

Further consideration of left-truncation is needed, especially when biologic or policy considerations dictate that age is the relevant time scale of interest. Methodologic development is needed to reduce potential for bias when left-truncation may occur.

Optimal timing of antiretroviral treatment initiation in HIV-positive children and adolescents: a multiregional analysis from Southern Africa, West Africa and Europe

Background

There is limited knowledge about the optimal timing of antiretroviral treatment initiation in older children and adolescents.

Methods

A total of 20 576 antiretroviral treatment (ART)-naïve patients, aged 1-16 years at enrolment, from 19 cohorts in Europe, Southern Africa and West Africa, were included. We compared mortality and growth outcomes for different ART initiation criteria, aligned with previous and recent World Health Organization criteria, for 5 years of follow-up, adjusting for all measured baseline and time-dependent confounders using the g-formula.

Results

Median (1st;3rd percentile) CD4 count at baseline was 676 cells/mm 3 (394; 1037) (children aged ≥ 1 and < 5 years), 373 (172; 630) (≥ 5 and < 10 years) and 238 (88; 425) (≥ 10 and < 16 years). There was a general trend towards lower mortality and better growth with earlier treatment initiation. In children < 10 years old at enrolment, by 5 years of follow-up there was lower mortality and a higher mean height-for-age z-score with immediate ART initiation versus delaying until CD4 count < 350 cells/mm 3 (or CD4% < 15% or weight-for-age z-score < -2) with absolute differences in mortality and height-for-age z-score of 0.3% (95% confidence interval: 0.1%; 0.6%) and -0.08 (-0.09; -0.06) (≥ 1 and < 5 years), and 0.3% (0.04%; 0.5%) and -0.07 (-0.08; -0.05) (≥ 5 and < 10 years). In those aged > 10 years at enrolment we did not find any difference in mortality or growth with immediate ART initiation, with estimated differences of -0.1% (-0.2%; 0.6%) and -0.03 (-0.05; 0.00), respectively. Growth differences in children aged < 10 years persisted for treatment thresholds using higher CD4 values. Regular follow-up led to better height and mortality outcomes.

Conclusions

Immediate ART is associated with lower mortality and better growth for up to 5 years in children < 10 years old. Our results on adolescents were inconclusive.

Bootstrap inference when using multiple imputation

Many modern estimators require bootstrapping to calculate confidence intervals because either no analytic standard error is available or the distribution of the parameter of interest is nonsymmetric. It remains however unclear how to obtain valid bootstrap inference when dealing with multiple imputation to address missing data. We present 4 methods that are intuitively appealing, easy to implement, and combine bootstrap estimation with multiple imputation. We show that 3 of the 4 approaches yield valid inference, but that the performance of the methods varies with respect to the number of imputed data sets and the extent of missingness. Simulation studies reveal the behavior of our approaches in finite samples. A topical analysis from HIV treatment research, which determines the optimal timing of antiretroviral treatment initiation in young children, demonstrates the practical implications of the 4 methods in a sophisticated and realistic setting. This analysis suffers from missing data and uses the g-formula for inference, a method for which no standard errors are available.

A qualitative analysis of the barriers to antiretroviral therapy initiation among children 2 to 18 months of age in Swaziland

HIV/AIDS remains one of the leading causes of death among children under 5 years old in Swaziland. Although studies have shown that early initiation of infants and children diagnosed with HIV on antiretroviral therapy (ART) significantly reduces mortality, many children do not initiate ART until the later stages of disease. This study was designed to collect qualitative data from mothers and caregivers of HIV-positive children to identify the barriers to ART initiation. Focus group discussion (FGD) sessions were conducted in siSwati between July and September 2014 among caregivers of aged children 2-18 months in Swaziland who did or did not initiate ART between January 2011 and December 2012 after HIV DNA PCR-positive diagnosis of the infants. Denial, guilt, lack of knowledge, tuberculosis (TB)/HIV co-infection, HIV-related stigma, lack of money, and distance to clinics were reported by the participants as barriers to ART initiation. The findings further revealed that non-initiation on ART was not linked to a negative perception of the treatment. Findings suggest a need to improve sensitivity among healthcare workers as well as education and counselling services that will facilitate the ART initiation process.

Universal antiretroviral therapy for HIV-infected children: a review of the benefits and risks to consider during implementation

Background: The 2016 World Health Organization (WHO) consolidated guidelines on the use of antiretroviral drugs for treating and preventing HIV infection, recommended to start all HIV-infected children on antiretroviral therapy (ART). Here, we explore the possible benefits and risks of implementing universal ART for all HIV-infected children and adolescents and outline some of the key considerations that led to the 2016 revision of WHO guidelines.

Methods: We conducted a review of the published data from 2000 to 2016, to ascertain the clinical and programmatic benefits, as well as the risks of implementing universal ART for all children.

Results and discussion: Universal ART for all children has the potential to increase treatment coverage, which in 2015 was only 51% globally, as well as providing several biological benefits, by preventing: premature death/loss to follow-up, progressive destruction of the immune system, poor growth and pubertal delay, poor neuro-cognitive outcomes and future burden to the health care system with complications of untreated HIV-infection. However, the strategy could be associated with risks, notably development of HIV drug resistance, antiretroviral drug toxicities and increased costs to an already stretched health system.

Conclusion: Overall, our findings suggest that the benefits could outweigh the risks and support universal ART for all HIV-infected children, but recognize that national programmes will need to put measures in place to minimize the risks if they choose to implement the strategy.

Survival of HIV-1 vertically infected children

PURPOSE OF REVIEW

It is 20 years since the start of the combination antiretroviral therapy (cART) era and more than 10 years since cART scale-up began in resource-limited settings. We examined survival of vertically HIV-infected infants and children in the cART era.

RECENT FINDINGS

Good survival has been achieved on cART in all settings with up to 10-fold mortality reductions compared with before cART availability. Although mortality risk remains high in the first few months after cART initiation in young children with severe disease, it drops rapidly thereafter even for those who started with advanced disease, and longer term mortality risk is low. However, suboptimal retention on cART in routine programs threatens good survival outcomes and even on treatment children continue to experience high comorbidity risk; infections remain the major cause of death. Interventions to address infection risk include a cotrimoxazole prophylaxis, isoniazid preventive therapy, routine childhood and influenza immunization, and improving maternal survival.

SUMMARY

Pediatric survival has improved substantially with cART and HIV-infected children are aging into adulthood. It is important to ensure access to diagnosis and early cART, good program retention as well as optimal comorbidity prophylaxis and treatment to achieve the best possible long-term survival and health outcomes for vertically infected children.

Growth and Mortality Outcomes for Different Antiretroviral Therapy Initiation Criteria in Children Ages 1-5 Years: A Causal Modeling Analysis

BACKGROUND

There is limited evidence regarding the optimal timing of initiating antiretroviral therapy (ART) in children. We conducted a causal modeling analysis in children ages 1-5 years from the International Epidemiologic Databases to Evaluate AIDS West/Southern-Africa collaboration to determine growth and mortality differences related to different CD4-based treatment initiation criteria, age groups, and regions.

METHODS

ART-naïve children of ages 12-59 months at enrollment with at least one visit before ART initiation and one follow-up visit were included. We estimated 3-year growth and cumulative mortality from the start of follow-up for different CD4 criteria using g-computation.

RESULTS

About one quarter of the 5,826 included children was from West Africa (24.6%).The median (first; third quartile) CD4% at the first visit was 16% (11%; 23%), the median weight-for-age z-scores and height-for-age z-scores were -1.5 (-2.7; -0.6) and -2.5 (-3.5; -1.5), respectively. Estimated cumulative mortality was higher overall, and growth was slower, when initiating ART at lower CD4 thresholds. After 3 years of follow-up, the estimated mortality difference between starting ART routinely irrespective of CD4 count and starting ART if either CD4 count <750 cells/mm³ or CD4% <25% was 0.2% (95% CI = -0.2%; 0.3%), and the difference in the mean height-for-age z-scores of those who survived was -0.02 (95% CI = -0.04; 0.01). Younger children ages 1-2 and children in West Africa had worse outcomes.

CONCLUSIONS

Our results demonstrate that earlier treatment initiation yields overall better growth and mortality outcomes, although we could not show any differences in outcomes between immediate ART and delaying until CD4 count/% falls below 750/25%.

Outcomes of Infants Starting Antiretroviral Therapy in Southern Africa, 2004-2012

BACKGROUND

There are limited published data on the outcomes of infants starting antiretroviral therapy (ART) in routine care in Southern Africa. This study aimed to examine the baseline characteristics and outcomes of infants initiating ART.

METHODS

We analyzed prospectively collected cohort data from routine ART initiation in infants from 11 cohorts contributing to the International Epidemiologic Database to Evaluate AIDS in Southern Africa. We included ART-naive HIV-infected infants aged <12 months initiating ≥3 antiretroviral drugs between 2004 and 2012. Kaplan-Meier estimates were calculated for mortality, loss to follow-up (LTFU), transfer out, and virological suppression. We used Cox proportional hazard models stratified by cohort to determine baseline characteristics associated with outcomes mortality and virological suppression.

RESULTS

The median (interquartile range) age at ART initiation of 4945 infants was 5.9 months (3.7-8.7) with follow-up of 11.2 months (2.8-20.0). At ART initiation, 77% had WHO clinical stage 3 or 4 disease and 87% were severely immunosuppressed. Three-year mortality probability was 16% and LTFU 29%. Severe immunosuppression, WHO stage 3 or 4, anemia, being severely underweight, and initiation of treatment before 2010 were associated with higher mortality. At 12 months after ART initiation, 17% of infants were severely immunosuppressed and the probability of attaining virological suppression was 56%.

CONCLUSIONS

Most infants initiating ART in Southern Africa had severe disease with high probability of LTFU and mortality on ART. Although the majority of infants remaining in care showed immune recovery and virological suppression, these responses were suboptimal.

Paediatric European Network for Treatment of AIDS (PENTA) guidelines for treatment of paediatric HIV-1 infection 2015: optimizing health in preparation for adult life

The 2015 Paediatric European Network for Treatment of AIDS (PENTA) guidelines provide practical recommendations on the management of HIV‐1 infection in children in Europe and are an update to those published in 2009. Aims of treatment have progressed significantly over the last decade, moving far beyond limitation of short‐term morbidity and mortality to optimizing health status for adult life and minimizing the impact of chronic HIV infection on immune system development and health in general. Additionally, there is a greater need for increased awareness and minimization of long‐term drug toxicity. The main updates to the previous guidelines include: an increase in the number of indications for antiretroviral therapy (ART) at all ages (higher CD4 thresholds for consideration of ART initiation and additional clinical indications), revised guidance on first‐ and second‐line ART recommendations, including more recently available drug classes, expanded guidance on management of coinfections (including tuberculosis, hepatitis B and hepatitis C) and additional emphasis on the needs of adolescents as they approach transition to adult services. There is a new section on the current ART ‘pipeline’ of drug development, a comprehensive summary table of currently recommended ART with dosing recommendations. Differences between PENTA and current US and World Health Organization guidelines are highlighted and explained.

Temporal trends in mortality and loss to follow-up among children enrolled in Côte d'Ivoire's national antiretroviral therapy program

BACKGROUND

During 2004-2008, >2000 children (<15 years old) initiated antiretroviral therapy (ART) in Côte d'Ivoire. Nationally representative outcomes, temporal trends in outcomes during 2004-2008 and site-level outcome determinants have not been investigated.

METHODS

Incidence rates of death, loss to follow-up (LTFU) and attrition (death or LTFU) were evaluated in a nationally representative, retrospective cohort study among 2,110 children, who initiated ART at 29 facilities in Côte d'Ivoire during 2004-2008.

RESULTS

At ART initiation, 54% were male, 1% was HIV-2-infected and median age was 5.1 years. Median CD4% was 11%, and 61% had weight-for-age Z-score (WAZ) ≤-2. Vaccination completion was documented for 9% of children. Eleven of 29 facilities had an integrated nutrition program. Over 4585 person-years of ART, 237 children died and 427 became LTFU. Twelve-month attrition was 22% overall, but increased from 4% to 34% during 2004-2008, due to increases in 12-month mortality (from 3-11%) and 12-month LTFU (from 2% to 23%). In adjusted analysis, compared with enrollees in 2004, enrollees in 2008 had nearly 4-fold higher mortality and 8-fold higher LTFU. World Health Organization stage III/IV, CD4% <10%, WAZ ≤ 2 and hemoglobin <8 g/dL, were predictive of mortality. Incomplete vaccination was predictive of mortality and LTFU. Facilities with nutrition programs had lower LTFU and mortality rates. Clinics reporting nurse dissatisfaction with working conditions had higher LTFU rates.

CONCLUSION

Investigation of causes of increasing mortality and LTFU is needed. Ensuring earlier ART initiation, vaccination completion, scale-up of site-level nutrition programs and nurse work-environment satisfaction, could improve pediatric ART program outcomes.

Association between age at antiretroviral therapy initiation and 24-month immune response in West-African HIV-infected children

OBJECTIVE

We describe the association between age at antiretroviral therapy (ART) initiation and 24-month CD4 cell response in West African HIV-infected children.

METHODS

All HIV-infected children from the IeDEA paediatric West African cohort, initiating ART, with at least two CD4 cell count measurements, including one at ART initiation (baseline) were included. CD4 cell gain on ART was estimated using a multivariable linear mixed model adjusted for baseline variables: age, CD4 cell count, sex, first-line ART regimen. Kaplan-Meier survival curves and a Cox proportional hazards regression model compared immune recovery for age within 24 months post-ART.

RESULTS

Of the 4808 children initiated on ART, 3014 were enrolled at a median age of 5.6 years; 61.2% were immunodeficient. After 12 months, children at least 4 years at baseline had significantly lower CD4 cell gains compared with children less than 2 years, the reference group (P<0.001). However, by 24 months, we observed higher CD4 cell gain in children who initiated ART between 3 and 4 years compared with those less than 2 years (P<0.001). The 24-month CD4 cell gain was also strongest in immunodeficient children at baseline. Among these children, 75% reached immune recovery: 12-month rates were significantly highest in all those aged 2-5 years at ART initiation compared with those less than 2 years. Beyond 12 months on ART, immune recovery was significantly lower in children initiated more than 5 years (adjusted hazard ratio: 0.69, 95% confidence interval: 0.56-0.86).

CONCLUSION

These results suggest that both the initiation of ART at the earliest age less than 5 years and before any severe immunodeficiency is needed for improving 24-month immune recovery on ART.

Targeted Maximum Likelihood Estimation for Dynamic and Static Longitudinal Marginal Structural Working Models

This paper describes a targeted maximum likelihood estimator (TMLE) for the parameters of longitudinal static and dynamic marginal structural models. We consider a longitudinal data structure consisting of baseline covariates, time-dependent intervention nodes, intermediate time-dependent covariates, and a possibly time-dependent outcome. The intervention nodes at each time point can include a binary treatment as well as a right-censoring indicator. Given a class of dynamic or static interventions, a marginal structural model is used to model the mean of the intervention-specific counterfactual outcome as a function of the intervention, time point, and possibly a subset of baseline covariates. Because the true shape of this function is rarely known, the marginal structural model is used as a working model. The causal quantity of interest is defined as the projection of the true function onto this working model. Iterated conditional expectation double robust estimators for marginal structural model parameters were previously proposed by Robins (2000, 2002) and Bang and Robins (2005). Here we build on this work and present a pooled TMLE for the parameters of marginal structural working models. We compare this pooled estimator to a stratified TMLE (Schnitzer et al. 2014) that is based on estimating the intervention-specific mean separately for each intervention of interest. The performance of the pooled TMLE is compared to the performance of the stratified TMLE and the performance of inverse probability weighted (IPW) estimators using simulations. Concepts are illustrated using an example in which the aim is to estimate the causal effect of delayed switch following immunological failure of first line antiretroviral therapy among HIV-infected patients. Data from the International Epidemiological Databases to Evaluate AIDS, Southern Africa are analyzed to investigate this question using both TML and IPW estimators. Our results demonstrate practical advantages of the pooled TMLE over an IPW estimator for working marginal structural models for survival, as well as cases in which the pooled TMLE is superior to its stratified counterpart.

Neurologic complications of pediatric human immunodeficiency virus: implications for clinical practice and management challenges in the African setting

Approximately 3.4 million children worldwide are affected with human immunodeficiency virus (HIV)/AIDS with more than 90% of them residing in sub-Saharan Africa, according to the World Health Organization. A significant proportion of the children eligible for treatment with antiretroviral therapy are not currently receiving it. Neurologic manifestations of HIV are common in both adults and children. There is a large spectrum of neurologic conditions that may be caused by the virus; however, early invasion of the central nervous system by the virus, affecting the developing fetal and infant brain, is believed to result in the most common primary HIV-related central nervous system complication, HIV encephalopathy. This article summarizes the spectrum of neuro-HIV in children, focuses on the neurocognitive and behavioral sequelae, reviews the effects of treatment on the primary neurologic effects of the disease, and discusses the specific challenges of identifying and managing these problems in resource-limited contexts, such as those found on the African continent.

Optimization of antiretroviral therapy in HIV-infected children under 3 years of age: a systematic review

BACKGROUND

Treatment of young HIV-infected children is challenging because of rapid disease progression, high viral loads and few drug options. This review was undertaken to update evidence on the management of young HIV-infected children and to inform the development of the 2013 WHO guidelines for antiretroviral therapy (ART) in low and middle-income countries.

DESIGN

A systematic review and meta-analysis.

METHODS

We identified and critically assessed randomized controlled trials that evaluated treatment strategies in perinatally HIV-infected infants and young children (aged <3 years).

RESULTS

Eight studies were included. Antiretroviral therapy (ART) initiation in asymptomatic infants led to 74% reduction in mortality or disease progression [hazard ratio 0.36, 95% confidence interval (CI) 0.18-0.74, P = 0.0002]. Regardless of previous exposure to prevention of mother to child transmission (PMTCT), treatment failure at 24 weeks was more likely in children starting nevirapine-based than in those starting lopinavir/ritonavir (lopinavir/r)-based ART (hazard ratio 1.79, 95% CI 1.33-2.41, P = 0.0001). Infants starting lopinavir/r-based ART and substituting lopinavir/r with nevirapine once virologic suppression was achieved were less likely to experience viral load more than 50 copies/ml (hazard ratio 0.62, 95% CI 0.41-0.92, P = 0.02) but more likely to have confirmed virologic failure (>1000 copies/ml) than those remaining on lopinavir/r (hazard ratio 10.19, 95% CI 2.36-43.94, P = 0.002). Children receiving induction-maintenance ART (four-drug NNRTI-based regimen for 36 weeks followed by three-drug ART) showed better short-term immunologic and virologic responses, but no long-term benefits. The only trial comparing continuous ART from infancy with interrupted ART beyond infancy was terminated early because the duration of treatment interruption was less than 3 months in most infants.

CONCLUSION

ART initiation in asymptomatic infants reduces morbidity and mortality. Lopinavir/r-based first-line ART is superior to nevirapine-based regimens in young children, regardless of PMTCT exposure, but lopinavir/r use is challenging. Substituting lopinavir/r with nevirapine following virologic suppression may be feasible where viral load testing is available. Considering current evidence, induction-maintenance and treatment interruption strategies are not recommended. This review contributed to the evidence base for the 2013 WHO guidelines on antiretroviral therapy, which recommend that all children below 3 years start lopinavir/r-based ART and that lopinavir/r can be substituted with nevirapine once sustained virologic suppression is achieved.

Antiretroviral treatment in HIV-infected infants and young children: novel issues raised by the Mississippi baby

The recent case report of an HIV-infected child in Mississippi with viral control post-antiretroviral therapy (ART) interruption has sparked interest in the possibility of 'functional cure' in infants if they initiate ART very soon after birth. The 'Mississippi baby' also raises many new questions around the clinical care of HIV-infected infants and young children, including when treatment should be initiated, why treatment should be initiated, what treatment should be initiated, and how to identify infants early enough to treat them adequately. Here, we review research conducted before the report of the 'Mississippi baby' highlighting the important new issues that now need to be taken into consideration.