Optimizing the design of a pharmacokinetic trial to evaluate the dosing scheme of a novel tuberculosis drug in children living with or without HIV

Pharmacokinetic (PK) studies in children are usually small and have ethical constraints due to the medical complexities of drawing blood in this special population. Often, population PK models for the drug(s) of interest are available in adults, and these models can be extended to incorporate the expected deviations seen in children. As a consequence, there is increasing interest in the use of optimal design methodology to design PK sampling schemes in children that maximize information using a small sample size and limited number of sampling times per dosing period. As a case study, we use the novel tuberculosis drug delamanid, and show how applications of optimal design methodology can result in highly efficient and model-robust designs in children for estimating PK parameters using a limited number of sampling measurements. Using developed population PK models based on available data from adults living with and without HIV, and limited data on children without HIV, competing designs for children living with HIV were derived and assessed based on robustness to model uncertainty.

Timing of maternal isoniazid preventive therapy on tuberculosis infection among infants exposed to HIV in low-income and middle-income settings: a secondary analysis of the TB APPRISE trial

BACKGROUND

Infants born to women with HIV in settings with a high tuberculosis burden are at risk of tuberculosis infection and rapid progression to active disease. Maternal isoniazid preventive therapy might mitigate this risk, but optimal timing of therapy remains unclear. The TB APPRISE trial showed that initiation of isoniazid during pregnancy resulted in more frequent adverse pregnancy outcomes than when initiated postpartum. We aimed to determine the proportion of infants testing positive for tuberculosis infection born to mothers who initiated isoniazid therapy antepartum compared with postpartum using two commonly used tests, the test agreement, and predictors of test positivity.

METHODS

TB APPRISE was a randomised, double-blind, placebo-controlled, non-inferiority trial done at 13 study sites across eight countries (Botswana, Haiti, India, South Africa, Tanzania, Thailand, Uganda, and Zimbabwe). Pregnant women with HIV on antiretroviral therapy were randomly assigned to receive immediate isoniazid preventive therapy (28 weeks isoniazid [300 mg daily], then placebo until week 40 after delivery) or deferred treatment (placebo until week 12 after delivery, then isoniazid [300 mg daily] for 28 weeks). Mother-infant pairs were followed up until 48 weeks after delivery. We included all liveborn infants with a tuberculin skin test or interferon-γ release assay (IGRA) at 44 weeks. The outcomes assessed in this secondary analysis were tuberculosis test positivity by study group, test agreement, and predictors of test positivity. This study was registered with ClinicalTrials.gov, NCT01494038.

FINDINGS

Between Aug 19, 2014, and April 4, 2016, 956 mothers were randomly assigned, and 749 mother-child pairs were included in this secondary analysis. Of 749 infants, 694 (93%) received Bacille Calmette-Guérin (BCG) vaccination, 675 (90%) were born to mothers who had completed isoniazid treatment, 20 (3%) were exposed to tuberculosis, seven (1%) became HIV positive, and one (<1%) developed probable tuberculosis. 43 (6%; 95% CI 4-8]) of 732 infants had a positive IGRA test result and 55 (8%; 6-10) of 727 infants had a positive tuberculin skin test result. Test positivity did not differ by study group (p=0·88 for IGRA; p=0·44 for tuberculin skin test). Test agreement was poor (κ=0·107 [95% CI 0·002-0·212]). Infant tuberculin skin test positivity was associated with breastfeeding (adjusted odds ratio 6·63 [95% CI 1·57-27·9]), BCG vaccination (4·97 [1·50-16·43]), and maternal tuberculin skin test positivity at delivery (3·28 [1·70-6·33]); IGRA positivity was associated with female sex (2·09 [1·06-4·14]).

INTERPRETATION

Deferral of maternal isoniazid preventive therapy to early postpartum had no effect on infant tuberculosis acquisition in our trial population, regardless of the diagnostic test used; however, tuberculosis test agreement is poor during infancy.

FUNDING

US National Institutes of Health.

Predictors of TB disease in HIV-exposed children from Southern Africa

BACKGROUND: P1041 was a randomised, placebo-controlled isoniazid prophylaxis trial in South Africa. We studied predictors for TB in HIV-exposed children participating in the P1041 trial.METHODS: We included data from entry until Week 108. Predictors considered were type of housing, overcrowding, age, sex, ethnicity, tobacco exposure, weight-for-age percentile Z-score (WAZ), CD4%, viral load (VL), antiretroviral therapy (ART) and number of household smokers.RESULTS: Of 543 HIV-positive (HIV+) and 808 HIV-exposed uninfected (HEU) infants at entry, median age was 96 days (interquartile range: 92-105). Of 1,351 caregivers, 125 (9%) had a smoking history, and 62/1,351 reported current smoking. In 594/1,351 (44%) households, there was at least one smoker. Smoking caregivers consumed 1-5 cigarettes daily. In the HIV+ cohort, significant baseline TB predictors after adjusting covariates were as follows: WAZ (adjusted hazard ratio [aHR] 0.76, P = 0.002) and log10 HIV RNA copies/ml (aHR 1.50, P = 0.009). Higher CD4% (aHR 0.88, P = 0.002) and ART (aHR 0.50, P = 0.006) were protective. In the HEU cohort, smoking exposure was associated with reduced TB-free survival on univariate analysis, but not after adjustment in the multivariate model.CONCLUSION: Low WAZ and high VL were strong predictors of TB disease or death. Rising CD4 percentage and being on ART were protective in the HIV+ cohort.

Effect of pregnancy versus postpartum maternal isoniazid preventive therapy on infant growth in HIV-exposed uninfected infants: a post-hoc analysis of the TB APPRISE trial

Background

Isoniazid preventive therapy (IPT) initiation during pregnancy was associated with increased incidence of adverse pregnancy outcomes in the TB APPRISE trial. Effects of in utero IPT exposure on infant growth are unknown.

Methods

This post-hoc analysis used data from the TB APPRISE trial, a multicentre, double-blind, placebo-controlled trial, which randomised women to 28-week IPT starting in pregnancy (pregnancy-IPT) or postpartum week 12 (postpartum-IPT) in eight countries with high tuberculosis prevalence. Participants were enrolled between August 2014 and April 2016. Based on modified intent-to-treat analyses, we analysed only live-born babies who had at least one follow-up after birth and compared time to infant growth faltering between arms to 12 weeks and 48 weeks postpartum in overall and sex-stratified multivariable Cox proportional hazards regression. Factors adjusted in the final models include sex of infant, mother's baseline BMI, age in years, ART regimen, viral load, CD4 count, education, and household food insecurity.

Results

Among 898 HIV-exposed uninfected (HEU) infants, 447 (49.8%) were females. Infants in pregnancy-IPT had a 1.47-fold higher risk of becoming underweight by 12 weeks (aHR 1.47 [95% CI: 1.06, 2.03]) than infants in the postpartum-IPT; increased risk persisted to 48 weeks postpartum (aHR 1.34 [95% CI: 1.01, 1.78]). Maternal IPT timing was not associated with stunting or wasting. In sex-stratified analyses, male infants in the pregnancy-IPT arm experienced an increased risk of low birth weight (LBW) (aRR 2.04 [95% CI: 1.16, 3.68), preterm birth (aRR 1.81 [95% CI: 1.04, 3.21]) and becoming underweight by 12 weeks (aHR 2.02 [95% CI: 1.29, 3.18]) and 48 weeks (aHR 1.82 [95% CI: 1.23, 2.69]). Maternal IPT timing did not influence growth in female infants.

Interpretation

Maternal IPT during pregnancy was associated with an increased risk of LBW, preterm birth, and becoming underweight among HEU infants, particularly male infants. These data add to prior TB APPRISE data, suggesting that IPT during pregnancy impacts infant growth, which could inform management, and warrants further examination of mechanisms.

Funding

The TB APPRISE study Supported by the National Institutes of Health (NIH) (award numbers, UM1AI068632 [IMPAACT LOC], UM1AI068616 [IMPAACT SDMC], and UM1AI106716 [IMPAACT LC]) through the National Institute of Allergy and Infectious Diseases, with cofunding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (contract number, HHSN275201800001I) and the National Institute of Mental Health.

Prevalence of neurotoxicity symptoms among postpartum women on isoniazid preventive therapy and efavirenz-based treatment for HIV: an exploratory objective of the IMPAACT P1078 randomized trial

BACKGROUND

This exploratory analysis investigates the prevalence and risk factors of neurocognitive toxicity in postpartum women on HIV treatment in response to a concern of an Isoniazid Preventive Therapy (IPT)/Efavirenz interaction.

TRIAL DESIGN

Pregnant women on HIV treatment from countries with high TB prevalence were randomized in IMPAACT P1078 to 28 weeks of IPT started either during pregnancy or at 12 weeks postpartum. Partway through study implementation, the Patient Health Questionnaire 9, the cognitive complaint questionnaire, and the Pittsburg Sleep Quality Index were added to evaluate depression, cognitive function, and sleep quality at postpartum weeks. Screening for peripheral neuropathy was conducted throughout the study.

METHODS

We summarized percentages of women with depression symptoms, cognitive dysfunction, poor sleep quality and peripheral neuropathy and assessed the association of 11 baseline risk factors of neurotoxicity using logistic regression, adjusted for gestational age stratum.

RESULTS

Of 956 women enrolled, 749 (78%) had at least one neurocognitive evaluation. During the postpartum period, the percentage of women reporting at least mild depression symptoms, cognitive complaint and poor sleep quality peaked at 13%, 8% and 10%, respectively, at 12 weeks, and the percentage of women reporting peripheral neuropathy peaked at 13% at 24 weeks. There was no evidence of study arm differences in odds of all four neurotoxic symptoms.

CONCLUSIONS

Timing of IPT initiation and EFV use were not associated with symptoms of neurotoxicity. Further study is advised to formally assess risk factors of neurotoxicity.

Acylcarnitines and Genetic Variation in Fat Oxidation Genes in HIV-infected, Antiretroviral-treated Children With and Without Myopathy

BACKGROUND

Mitochondrial toxicity resulting in myopathy and lactic acidosis has been described in antiretroviral (ARV)-exposed patients. We hypothesized that myopathy in HIV-infected, ARV-treated children would be associated with metabolic (acylcarnitines) and genetic (variants in metabolic genes) markers of dysfunctional fatty acid oxidation (FAO).

METHODS

Acylcarnitine profiles (ACP) were analyzed for 74 HIV-infected children on nucleoside reverse transcriptase inhibitor (NRTI)-containing ARV. Thirty-seven participants with ≥2 creatine kinase measurements >500 IU (n = 18) or evidence of echocardiographic cardiomyopathy (n = 19) were matched with 37 participants without myopathy. Single nucleotide polymorphisms (SNPs) in FAO genes were also evaluated.

RESULTS

Abnormal ACP was 73% (95% CI: 56%-86%) and 62% (95% CI: 45%-78%) in the myopathic and nonmyopathic groups, respectively. No significant association was found between myopathy and having an abnormal ACP (OR = 2.10, P = 0.22). In univariate analysis, a 1-year increase in NRTI use was associated with a 20% increase in odds of at least 1 ACP abnormality [OR (95% CI) = 1.20 (1.03-1.41); P = 0.02), and a 1-year increase in protease inhibitor use was associated with 28% increase in the odds of having at least 1 ACP abnormality [OR (95% CI) = 1.28 (1.07-1.52); P = 0.006). Three SNPs, all in the gene for the carnitine transporter ( SLC22A5 ), were associated with the cardiomyopathy phenotype.

CONCLUSION

FAO appears to be altered in HIV-infected children with and without myopathy, but abnormal FAO does not fully explain myopathy in ARV-exposed children. Further study of SLC22A5 variation in ARV-exposed people is warranted carnitine transporter dysfunction-related cardiomyopathy may be treatable.

Using a Composite Maternal-Infant Outcome Measure in Tuberculosis-Prevention Studies Among Pregnant Women

BACKGROUND

Tuberculosis (TB-)-preventive therapy (TPT) among pregnant women reduces risk of TB in mothers and infants, but timing of initiation should consider potential adverse effects. We propose an analytical approach to evaluate the risk-benefit of interventions.

METHODS

A novel outcome measure that prioritizes maternal and infant events was developed with a 2-stage Delphi survey, where a panel of stakeholders assigned scores from 0 (best) to 100 (worst) based on perceived desirability. Using data from TB APPRISE, a trial among pregnant women living with human immunodeficiency virus (WLWH) that randomized the timing of initiation of isoniazid, antepartum versus postpartum, was evaluated.

RESULTS

The composite outcome scoring/ranking system categorized mother-infant paired outcomes into 8 groups assigned identical median scores by stakeholders. Maternal/infant TB and nonsevere adverse pregnancy outcomes were assigned similar scores. Mean (SD) composite outcome scores were 43.7 (33.0) and 41.2 (33.7) in the antepartum and postpartum TPT initiation arms, respectively. However, a modifying effect of baseline antiretroviral regimen was detected (P = .049). When women received nevirapine, composite scores were higher (worse outcomes) in the antepartum versus postpartum arms (adjusted difference, 14.3; 95% confidence interval [CI], 2.4-26.2; P = .02), whereas when women received efavirenz there was no difference by timing of TPT (adjusted difference, .62; 95% CI, -3.2-6.2; P = .53).

CONCLUSIONS

For TPT, when used by otherwise healthy persons, preventing adverse events is paramount from the perspective of stakeholders. Among pregnant WLWH in high-TB-burden regions, it is important to consider the antepartum antiretroviral regimen taken when deciding when to initiate TPT. Clinical Trials Registration. NCT01494038 (IMPAACT P1078).

Pharmacokinetics and Safety of Three Months of Weekly Rifapentine and Isoniazid for Tuberculosis Prevention in Pregnant Women

Background

Pregnancy increases the risk of tuberculosis and its complications. A 3-month regimen of weekly isoniazid and rifapentine (3HP) is safe and effective for tuberculosis prevention in adults and children, including those with HIV, but 3HP has not been evaluated in pregnancy.

Methods

IMPAACT 2001 was a phase I/II trial evaluating the pharmacokinetics and safety of 3HP among pregnant women with indications for tuberculosis preventative therapy in Haiti, Kenya, Malawi, Thailand, and Zimbabwe (NCT02651259). Isoniazid and rifapentine were provided at standard doses (900 mg/week). Pharmacokinetic sampling was performed with the first (second/third trimester) and twelfth (third trimester/postpartum) doses. Nonlinear mixed-effects models were used to estimate drug population pharmacokinetics.

Results

Of 50 participants, 20 had HIV and were taking efavirenz-based antiretroviral therapy. Among women without HIV, clearance of rifapentine was 28% lower during pregnancy than postpartum (1.20 vs 1.53 L/hour, P < .001), with area under the concentration-time curve (AUC_SS) of 786 and 673 mg × hour/L, respectively. In pregnant women with HIV, clearance was 30% higher than women without HIV (P < .001), resulting in lower AUC_ss (522 mg × hour/L); clearance did not change significantly between pregnancy and postpartum. Pregnancy did not impact isoniazid pharmacokinetics. There were no drug-related serious adverse events, treatment discontinuations, or tuberculosis cases in women or infants.

Conclusions

3HP does not require dose adjustment in pregnancy. Rifapentine clearance is higher among women with HIV, but all women achieved exposures of rifapentine and isoniazid associated with successful tuberculosis prevention. The data support proceeding with larger safety-focused studies of 3HP in pregnancy.

Clinical Trials Registration

ClinicalTrials.gov, NCT02651259.

Pharmacometrics meets statistics-A synergy for modern drug development

Modern drug development problems are very complex and require integration of various scientific fields. Traditionally, statistical methods have been the primary tool for design and analysis of clinical trials. Increasingly, pharmacometric approaches using physiology-based drug and disease models are applied in this context. In this paper, we show that statistics and pharmacometrics have more in common than what keeps them apart, and collectively, the synergy from these two quantitative disciplines can provide greater advances in clinical research and development, resulting in novel and more effective medicines to patients with medical need.

Plasma biomarker factors associated with neurodevelopmental outcomes in children with perinatal HIV infection and controlled viremia

OBJECTIVE

We examined relationships between plasma biomarkers and neurodevelopment in children from sub-Saharan Africa with perinatal HIV (PHIV) with controlled viremia on antiretroviral therapy (ART).

DESIGN

Longitudinal retrospective cohort study of children with controlled blood HIV replication.

METHODS

Children (N = 213; 57% girls) started ART at less than 3 years of age, had neurodevelopmental assessments (cognition, attention/impulsivity, motor proficiency, global executive functions) at 5-11 years, and achieved controlled viremia (HIV-1 RNA <400 copies/ml for ≥9 months before initial assessment). Twenty-three plasma biomarkers were measured at onset of controlled viremia, week 0 (first neurodevelopmental assessment), and week 48 (second neurodevelopmental assessment). Factor analysis was conducted at each time point. Multivariable linear regressions assessed associations between factors and neurodevelopmental scores.

RESULTS

Median age at week 0 was 7.0 years. Eighteen biomarkers loaded on six factors: a (L-10, IFNγ, IFNα2, IL-1β, IL-6, IP-10, TNFα); B (sCD163, sICAM-1, sVCAM-1, CRP); C (sE-selectin, sP-selectin); D [MIP-1β, vascular endothelial growth factor (VEGF)-A]; E (sCD14, CRP); and F (CX3CL1, MCP-1). Higher factor B scores were consistently associated with worse cognition and attention/impulsivity, and higher factor D scores with better attention/impulsivity.

CONCLUSION

These results suggest a detrimental effect of increased endothelial cell activation (sICAM-1, sVCAM-1) and monocyte/macrophage scavenger function (sCD163) and a beneficial effect of increased CCR5 ligand and HIV entry blocker MIP-1β and angiogenesis stimulant-VEGF concentrations on the neurodevelopment of children with PHIV. The model that emerges is of vascular inflammation leading to neurodevelopmental deficits. The role of persistent HIV replication in the central nervous system also needs to be further explored.

Individual and Composite Adverse Pregnancy Outcomes in a Randomized Trial on Isoniazid Preventative Therapy Among Women Living With Human Immunodeficiency Virus

BACKGROUND

International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) P1078, a randomized noninferiority study designed to compare the safety of starting isoniazid preventive therapy (IPT) in women living with human immunodeficiency virus (HIV) either during pregnancy or after delivery, showed that IPT during pregnancy increased the risk of composite adverse pregnancy outcomes, but not individual outcomes. Many known factors are associated with adverse pregnancy outcomes: these factors' associations and effect modifications with IPT and pregnancy outcomes were examined.

METHODS

Pregnant women living with HIV from 8 countries with tuberculosis incidences >60/100 000 were randomly assigned to initiate 28 weeks of IPT either during pregnancy or at 12 weeks after delivery. Using univariable and multivariable logistic regression and adjusting for factors associated with pregnancy outcomes, composite and individual adverse pregnancy outcome measures were analyzed.

RESULTS

This secondary analysis included 925 mother-infant pairs. All mothers were receiving antiretrovirals. The adjusted odds of fetal demise, preterm delivery (PTD), low birth weight (LBW), or a congenital anomaly (composite outcome 1) were 1.63 times higher among women on immediate compared to deferred IPT (95% confidence interval [CI], 1.15-2.31). The odds of fetal demise, PTD, LBW, or neonatal death within 28 days (composite outcome 2) were 1.62 times higher among women on immediate IPT (95% CI, 1.14-2.30). The odds of early neonatal death within 7 days, fetal demise, PTD, or LBW (composite outcome 3) were 1.74 times higher among women on immediate IPT (95% CI, 1.22-2.49).

CONCLUSIONS

We confirmed higher risks of adverse pregnancy outcomes associated with the initiation of IPT during pregnancy, after adjusting for known risk factors for adverse pregnancy outcomes.

Pharmacokinetics and Drug-Drug Interactions of Isoniazid and Efavirenz in Pregnant Women Living With HIV in High TB Incidence Settings: Importance of Genotyping

The World Health Organization guidelines recommend that individuals living with HIV receive ≥ 6 months of isoniazid preventive therapy, including pregnant women. Yet, plasma isoniazid exposure during pregnancy, in the antiretroviral therapy era, has not been well-described. We investigated pregnancy-induced and pharmacogenetic-associated pharmacokinetic changes and drug-drug interactions between isoniazid and efavirenz in pregnant women. Eight hundred forty-seven women received isoniazid for 28 weeks, either during pregnancy or at 12 weeks postpartum, and 786 women received efavirenz. After adjusting for NAT2 and CYP2B6 genotype and weight, pregnancy increased isoniazid and efavirenz clearance by 26% and 15%, respectively. Isoniazid decreased efavirenz clearance by 7% in CYP2B6 normal metabolizers and 13% in slow and intermediate metabolizers. Overall, both isoniazid and efavirenz exposures were reduced during pregnancy, but the main determinants of drug concentration were NAT2 and CYP2B6 genotypes, which resulted in a five-fold difference for both drugs between rapid and slow metabolizers.

Applying a Risk-benefit Analysis to Outcomes in Tuberculosis Clinical Trials

Although it is common to analyze efficacy and safety separately in clinical trials, this could yield a misleading study conclusion if an increase in efficacy is accompanied by a decrease in safety. A risk-benefit analysis is a systematic approach to examine safety and efficacy jointly. Both the "rank-based" and "partial-credit" methods described in this paper allow researchers to create a single, composite outcome incorporating efficacy, safety, and other factors. The first approach compares the distribution of rankings between arms. In the second approach, a score can be assigned to each outcome category, considering its severity and comparing the mean or median scores of arms. The methods were applied to the A5279/Brief Rifapentine-Isoniazid Efficacy for TB Prevention study, and design considerations for future clinical trials are discussed, including the challenge of arriving at a consensus on rankings/scorings. If well designed, a risk-benefit analysis may allow for a superiority comparison and, therefore, avoid setting a noninferiority margin. Clinical Trials Registration. NCT01404312 (A5279).

Viral hepatitis B and C in HIV-exposed South African infants

Background

Whilst much attention is given to eliminating HIV mother-to-child transmission (MTCT), little has been done to ensure the same for hepatitis B virus (HBV) transmission. The introduction of HBV immunization at six weeks of age has reduced HBV horizontal transmission in South Africa. However, in order to eliminate HBV MTCT, further interventions are needed. The risk of hepatitis C virus (HCV) MTCT in HIV-infected (HIV+) African women is not yet well described. This study aimed to determine the rate of HBV and HCV vertical transmission in HIV-exposed infants in South Africa.

Methods

Serum samples from infants enrolled in an isoniazid prevention study (P1041) were screened for HBV and HCV serology markers; screening was performed on samples collected at approximately 60 weeks of age of the infants. HBV DNA was quantified in HBsAg positive samples and HBV strains characterized through gene sequencing. All HCV antibody samples with inconclusive results underwent molecular testing.

Results

Three of 821 infants were positive for both HBsAg and HBV DNA. All HBV strains belonged to HBV sub-genotype A1. The rtM204I mutation associated with lamivudine resistance was identified in one infant, a second infant harboured the double A1762T/G1764A BCP mutation. Phylogenetic analysis showed clustering between mother and infant viral genomic sequences. Twenty-one of 821 HIV-exposed infants tested had inconclusive HCV antibody results, none were HCV PCR positive.

Conclusions

This study suggests that HBV vertical transmission is likely to be occurring in HIV-exposed infants in South Africa.. A more robust strategy of HBV prevention, including birth dose vaccination, is required to eradicate HBV MTCT. HCV infection was not detected.

A framework for considering the risk-benefit trade-off in designing noninferiority trials using composite outcome approaches

When a new treatment regimen is expected to have comparable or slightly worse efficacy to that of the control regimen but has benefits in other domains such as safety and tolerability, a noninferiority (NI) trial may be appropriate but is fraught with difficulty in justifying an acceptable NI margin that is based on both clinical and statistical input. To overcome this, we propose to utilize composite risk-benefit outcomes that combine elements from domains of importance (eg, efficacy, safety, and tolerability). The composite outcome itself may be analyzed using a superiority framework, or it can be used as a tool at the design stage of a NI trial for selecting an NI margin for efficacy that balances changes in risks and benefits. In the latter case, the choice of NI margin may be based on a novel quantity called the maximum allowable decrease in efficacy (MADE), defined as the marginal difference in efficacy between arms that would yield a null treatment effect for the composite outcome given an assumed distribution for the composite outcome. We observe that MADE: (1) is larger when the safety improvement for the experimental arm is larger, (2) depends on the association between the efficacy and safety outcomes, and (3) depends on the control arm efficacy rate. We use a numerical example for power comparisons between a superiority test for the composite outcome vs a noninferiority test for efficacy using the MADE as the NI margin, and apply the methods to a TB treatment trial.

Effects of Pregnancy and Isoniazid Preventive Therapy on M. tuberculosis Interferon Gamma Response Assays in Women with HIV

BACKGROUND

Pregnancy is accompanied by immune suppression. We hypothesized that M. tuberculosis-specific inflammatory responses used to identify latent tuberculosis infection (LTBI) lose positivity during pregnancy. We also hypothesized that isoniazid preventive therapy (IPT) may revert LTBI diagnoses because of its sterilizing activity.

METHODS

944 women with HIV participating in a randomized, double-blind, placebo-controlled study comparing 28 weeks of IPT antepartum versus postpartum, were tested by QuantiFERON-gold-in-tube (QGIT) antepartum and by QGIT and tuberculin skin test (TST) at delivery and postpartum. Serial QGIT positivity was assessed by logistic regression using generalized estimating equations.

RESULTS

From entry to delivery, 68 (24%) of 284 QGIT-positive women (24%) reverted to QGIT-negative or indeterminate. Of these, 42 (62%) recovered QGIT positivity postpartum. The loss of QGIT positivity during pregnancy was explained by decreased IFNγ production in response to TB antigen and/or mitogen. At delivery, QGIT identified 205 and TST 113 women with LTBI. Corresponding numbers postpartum were 229 and 122 women. QGIT and TST kappa agreement coefficients were 0.4 and 0.5, respectively. Among QGIT-positive women antepartum or at delivery, 34 (12%) reverted to QGIT-negative after IPT. There were no differences between women who initiated IPT antepartum or postpartum.

CONCLUSIONS

Decreased IFNγ responses in pregnancy reduced QGIT positivity, suggesting that this test cannot reliably rule out LTBI during pregnancy. TST was less affected by pregnancy, but had lower positivity compared to QGIT at all time points. IPT was associated with loss of QGIT positivity, the potential clinical consequences of which need to be investigated.

1387. Women Living with HIV (WLWH) Lose IFNγ Responses Diagnostic of Latent TB Infection (LTBI) during Pregnancy and after INH Prophylactic Treatment (IPT)

Background

TB is the most common opportunistic infection in PLWH. IPT is recommended for PLWH in endemic areas and for those with LTBI diagnosed by Quantiferon gold-in-tube (QGIT) or tuberculin skin test (TST) in other areas. We report on the performance of QGIT and TST in pregnant WLWH who received IPT antepartum (AP) or postpartum (PP).

Methods

WLWH participating in IMPAACT P1078, a randomized, double-blind, placebo-controlled study comparing 28 weeks of IPT AP vs. PP, were tested by QGIT at entry (14–34 weeks gestation) and by QGIT and TST at delivery (L&D) and 44 weeks PP. Serial QGIT positivity was assessed by logistic regression using generalized estimating equations.

Results

Among 944 women with study entry mean (SD) of 29 (6) years of age, 521 (245) CD4+ cells/µL, on ART, including 63% with undetectable HIV plasma RNA, 284/944 (30%) were QGIT+ AP, 215/862 (25%) at L&D and 246/764 (32%) PP (P < 0.001), while 127 (15%) were TST+ at L&D and 126 (17%) PP. QGIT was more likely positive than TST at L&D (Odds ratio = 4.3; 95% CI = 2.8–6.8) and PP (6.4; 3.9–10.7; P < 0.001). QGIT and TST agreement coefficients (95% CI) were 0.4 (0.3–0.5) at L&D and 0.5 (0.4–0.5) PP. Among women QGIT+ AP, 59 (24%) reverted to QGIT- or indeterminate at L&D. However, 37 (63%) reverters recovered QGIT+ results PP, suggesting transient suppression of IFNg responses during pregnancy. Responses to the mitogen-positive QGIT kit control were absent in 60 (7%) women AP, 116 (16%) at L&D, but only 3 (0.4%) PP (P < 0.01), supporting the notion of transient immune suppression during pregnancy. Among women QGIT- AP, 33 (7%) converted to QGIT+ PP. Among AP QGIT+ women, 24 (11%) reverted to QGIT- PP after finishing IPT. None of the results differed between treatment arms (P ≥ 0.13).

Conclusion

In WLWH on ART, the loss of IFNγ responses to TB antigen and mitogen in pregnancy decreased the diagnostic value of QGIT. TST was similar at L&D and PP but was less sensitive than QGIT. QGIT conversions likely resulted from a combination of PP immune reconstitution and new TB infections. QGIT reversions might represent a change in TB-specific immunity in response to IPT. Reversions have been reported in adults without HIV after treatment of active TB. The clinical significance of QGIT reversions in PLWH needs further investigation.

Disclosures

All authors: No reported disclosures.

Isoniazid Preventive Therapy in HIV-Infected Pregnant and Postpartum Women

BACKGROUND

The safety, efficacy, and appropriate timing of isoniazid therapy to prevent tuberculosis in pregnant women with human immunodeficiency virus (HIV) infection who are receiving antiretroviral therapy are unknown.

METHODS

In this multicenter, double-blind, placebo-controlled, noninferiority trial, we randomly assigned pregnant women with HIV infection to receive isoniazid preventive therapy for 28 weeks, initiated either during pregnancy (immediate group) or at week 12 after delivery (deferred group). Mothers and infants were followed through week 48 after delivery. The primary outcome was a composite of treatment-related maternal adverse events of grade 3 or higher or permanent discontinuation of the trial regimen because of toxic effects. The noninferiority margin was an upper boundary of the 95% confidence interval for the between-group difference in the rate of the primary outcome of less than 5 events per 100 person-years.

RESULTS

A total of 956 women were enrolled. A primary outcome event occurred in 72 of 477 women (15.1%) in the immediate group and in 73 of 479 (15.2%) in the deferred group (incidence rate, 15.03 and 14.93 events per 100 person-years, respectively; rate difference, 0.10; 95% confidence interval [CI], -4.77 to 4.98, which met the criterion for noninferiority). Two women in the immediate group and 4 women in the deferred group died (incidence rate, 0.40 and 0.78 per 100 person-years, respectively; rate difference, -0.39; 95% CI, -1.33 to 0.56); all deaths occurred during the postpartum period, and 4 were from liver failure (2 of the women who died from liver failure had received isoniazid [1 in each group]). Tuberculosis developed in 6 women (3 in each group); the incidence rate was 0.60 per 100 person-years in the immediate group and 0.59 per 100 person-years in the deferred group (rate difference, 0.01; 95% CI, -0.94 to 0.96). There was a higher incidence in the immediate group than in the deferred group of an event included in the composite adverse pregnancy outcome (stillbirth or spontaneous abortion, low birth weight in an infant, preterm delivery, or congenital anomalies in an infant) (23.6% vs. 17.0%; difference, 6.7 percentage points; 95% CI, 0.8 to 11.9).

CONCLUSIONS

The risks associated with initiation of isoniazid preventive therapy during pregnancy appeared to be greater than those associated with initiation of therapy during the postpartum period. (Funded by the National Institutes of Health; IMPAACT P1078 TB APPRISE ClinicalTrials.gov number, NCT01494038.).

Vitamin D status and risk of incident tuberculosis disease: A nested case-control study, systematic review, and individual-participant data meta-analysis

BACKGROUND

Few studies have evaluated the association between preexisting vitamin D deficiency and incident tuberculosis (TB). We assessed the impact of baseline vitamins D levels on TB disease risk.

METHODS AND FINDINGS

We assessed the association between baseline vitamin D and incident TB in a prospective cohort of 6,751 HIV-negative household contacts of TB patients enrolled between September 1, 2009, and August 29, 2012, in Lima, Peru. We screened for TB disease at 2, 6, and 12 months after enrollment. We defined cases as household contacts who developed TB disease at least 15 days after enrollment of the index patient. For each case, we randomly selected four controls from among contacts who did not develop TB disease, matching on gender and year of age. We also conducted a one-stage individual-participant data (IPD) meta-analysis searching PubMed and Embase to identify prospective studies of vitamin D and TB disease until June 8, 2019. We included studies that assessed vitamin D before TB diagnosis. In the primary analysis, we defined vitamin D deficiency as 25-(OH)D < 50 nmol/L, insufficiency as 50-75 nmol/L, and sufficiency as >75nmol/L. We estimated the association between baseline vitamin D status and incident TB using conditional logistic regression in the Lima cohort and generalized linear mixed models in the meta-analysis. We further defined severe vitamin D deficiency as 25-(OH)D < 25 nmol/L and performed stratified analyses by HIV status in the IPD meta-analysis. In the Lima cohort, we analyzed 180 cases and 709 matched controls. The adjusted odds ratio (aOR) for TB risk among participants with baseline vitamin D deficiency compared to sufficient vitamin D was 1.63 (95% CI 0.75-3.52; p = 0.22). We included seven published studies in the meta-analysis and analyzed 3,544 participants. In the pooled analysis, the aOR was 1.48 (95% CI 1.04-2.10; p = 0.03). The aOR for severe vitamin D deficiency was 2.05 (95% CI 0.87-4.87; p trend for decreasing 25-(OH)D levels from sufficient vitamin D to severe deficiency = 0.02). Among 1,576 HIV-positive patients, vitamin D deficiency conferred a 2-fold (aOR 2.18, 95% CI 1.22-3.90; p = 0.01) increased risk of TB, and the aOR for severe vitamin D deficiency compared to sufficient vitamin D was 4.28 (95% CI 0.85-21.45; p = 0.08). Our Lima cohort study is limited by the short duration of follow-up, and the IPD meta-analysis is limited by the number of possible confounding covariates available across all studies.

CONCLUSION

Our findings suggest vitamin D predicts TB disease risk in a dose-dependent manner and that the risk of TB disease is highest among HIV-positive individuals with severe vitamin D deficiency. Randomized control trials are needed to evaluate the possible role of vitamin D supplementation on reducing TB disease risk.

Statistical considerations for pediatric multidrug-resistant tuberculosis efficacy trials

The inclusion of newly licensed or repurposed drugs in regimens to treat children for multidrug-resistant tuberculosis (TB) may lead to treatment that is shorter than traditional regimens and composed only of oral medications. As an all-oral regimen may be more acceptable and have a better safety profile than current regimens, demonstrating non-inferiority may be satisfactory. Demonstrating non-inferior efficacy requires setting a non-inferiority margin and safeguarding study assay sensitivity. Multi-arm, multistage designs may currently not be appropriate in pediatric trials because of the lack of sensitive and specific intermediate outcomes. However, including an arm with an agent to ameliorate toxicity would be efficient. Covariates can be used to stratify randomization, define subgroups, and improve efficiency of analysis. Enriching the sample for the confirmed-TB subgroup to ensure that they are well represented may be important. Primary outcomes using a fixed timepoint from randomization for all study arms will result in variations in post-treatment duration, but may be the best choice. While blinding of site personnel and patients may not be possible when regimens differ substantially in drugs and modes of administration, blinding should be maintained for independent endpoint review groups and other personnel. Type I error and family-wise error rates should be tightly controlled.

Source case identification in HIV-exposed infants and tuberculosis diagnosis in an isoniazid prevention study

BACKGROUND

Identifying source cases of children exposed to tuberculosis (TB) is challenging. We examined the time-point of obtaining contact information of TB source cases in human immunodeficiency virus (HIV) infected and HIV-exposed uninfected (HEU) children in a randomised, placebo-controlled trial of pre-exposure to isoniazid prophylaxis.

METHODS

A total of 543 HIV-infected and 808 HEU infants without TB exposure aged 3-4 months were enrolled between 2004 and 2008. At 3-monthly follow-up, infants were evaluated for TB and care givers were asked about new TB exposure.

RESULTS

In total, 128 cases of TB disease and 40 deaths were recorded among 19% (105/543) of the HIV-infected and 8% (63/808) of the HEU children; 229 TB contact occasions were reported in 205/1351 (15%) children, of which 83% (189/229) were in the household. Of the 189 household contacts, 108 (53%) underwent microbiological evaluations; 81% (87/108) were positive. HIV-infected and HEU infants had similar frequencies of TB contact: in 48% of infants with definite TB, 58% with probable TB and 43% with possible TB. Of 128 children diagnosed with TB, a TB contact was identified for 59. Of these, 29/59 (49%) were identified at or after the child's TB diagnosis.

CONCLUSION

TB source cases are often identified at or after a child's TB diagnosis. More effort is required for earlier detection.

Totality of outcomes: A different paradigm in assessing interventions for treatment of tuberculosis

Conventional analytic methods used for tuberculosis (TB) outcomes research use standardized outcomes definitions and assess safety and efficacy separately. These methods are subject to important limitations. Conventionally utilized outcome definitions fail to capture important aspects of patients' treatment experience and obscure meaningful differences between patients. Assessing safety and efficacy separately fails to yield an objective risk–benefit comparison to guide clinical practice. We propose to address these issues through an analytic approach based on prioritized outcomes. This approach enables a more comprehensive and integrated assessment of TB interventions. It simultaneously considers a “totality of outcomes”, including clinical benefit, adverse events, and quality of life. These composite outcomes are ranked terms of overall desirability and compared using statistical methods for ordinal outcomes. Here we discuss the application of this approach to TB research, the considerations involved with prioritizing TB treatment outcomes, and the statistical methods involved in comparing prioritized outcomes.

Toward Earlier Inclusion of Pregnant and Postpartum Women in Tuberculosis Drug Trials: Consensus Statements From an International Expert Panel

Tuberculosis is a major cause of morbidity and mortality in women of childbearing age (15-44 years). Despite increased tuberculosis risk during pregnancy, optimal clinical treatment remains unclear: safety, tolerability, and pharmacokinetic data for many tuberculosis drugs are lacking, and trials of promising new tuberculosis drugs exclude pregnant women. To advance inclusion of pregnant and postpartum women in tuberculosis drug trials, the US National Institutes of Health convened an international expert panel. Discussions generated consensus statements (>75% agreement among panelists) identifying high-priority research areas during pregnancy, including: (1) preventing progression of latent tuberculosis infection, especially in women coinfected with human immunodeficiency virus; (2) evaluating new agents/regimens for treatment of multidrug-resistant tuberculosis; and (3) evaluating safety, tolerability and pharmacokinetics of tuberculosis drugs already in use during pregnancy and postpartum. Incorporating pregnant women into clinical trials would extend evidence-based tuberculosis prevention and treatment standards to this special population.

Low Vitamin-D Levels Combined with PKP3-SIGIRR-TMEM16J Host Variants Is Associated with Tuberculosis and Death in HIV-Infected and -Exposed Infants

Background

This study examined the associations of 25-hydroxyvitamin D and specific host genetic variants that affect vitamin D levels or its effects on immune function, with the risk of TB or mortality in children.

Methods

A case-cohort sample of 466 South African infants enrolled in P1041 trial (NCT00080119) underwent 25-hydroxyvitamin D testing by chemiluminescent immunoassay. Single nucleotide polymorphisms (SNPs) that alter the effect of vitamin D [e.g. vitamin D receptor (VDR)], vitamin D levels [e.g. vitamin D binding protein (VDBP)], or toll like receptor (TLR) expression (SIGIRR including adjacent genes PKP3 and TMEM16J) were identified by real-time PCR. Outcomes were time to TB, and to the composite of TB or death by 192 weeks of follow-up. Effect modification between vitamin D status and SNPs for outcomes was assessed.

Findings

Median age at 25-hydroxyvitamin D determination was 8 months; 11% were breastfed, 51% were HIV-infected and 26% had low 25-hydroxyvitamin D (<32ng/mL). By 192 weeks, 138 incident TB cases (43 definite/probable, and 95 possible) and 26 deaths occurred. Adjusting for HIV status and potential confounders, low 25-hydroxyvitamin D was associated with any TB (adjusted hazard ratio [aHR] 1.76, 95% CI 1.01–3.05; p = 0.046) and any TB or death (aHR 1.76, 95% CI 1.03–3.00; p = 0.038). Children with low 25-hydroxyvitamin D and TMEM 16J rs7111432-AA or PKP3 rs10902158-GG were at increased risk for probable/definite TB or death (aHR 8.12 and 4.83, p<0.05) and any TB or death (aHR 4.78 and 3.26, p<0.005) respectively; SNPs in VDBP, VDR, and vitamin D precursor or hydroxylation genes were not. There was significant interaction between low 25-hydroxyvitamin D and, TMEM 16J rs7111432-AA (p = 0.04) and PKP3 rs10902158-GG (p = 0.02) SNPs.

Conclusions

Two novel SNPs, thought to be associated with innate immunity, in combination with low vitamin D levels were identified as increasing a young child’s risk of developing TB disease or death. Identifying high-risk children and providing targeted interventions such as vitamin D supplementation may be beneficial.

Trial Registration

ClinicalTrials.gov NCT00080119

Social ecological predictors of longitudinal HIV treatment adherence in youth with perinatally acquired HIV

OBJECTIVE

To apply a social ecological model to explore the psychosocial factors prospectively associated with longitudinal adherence to antiretroviral treatment in youth perinatally infected with HIV.

METHODS

Randomly selected youth, age 8 to <19 years old, completed cognitive testing and psychosocial questionnaires at baseline as part of a multisite protocol (N = 138). A validated caregiver-report measure of adherence was completed at baseline and 24 and 48 weeks after baseline.

RESULTS

In multivariate analysis, youth awareness of HIV status, caregiver not fully responsible for medications, low caregiver well-being, adolescent perceptions of poor caregiver-youth relations, caregiver perceptions of low social support, and African American ethnicity were associated with nonadherence over 48 weeks.

CONCLUSIONS

Interventions focusing on caregivers and their interactions with the individual youth and extrafamilial system should be prioritized for prevention and treatment efforts to address nonadherence during the transition into adolescents.

Barriers to medication adherence in HIV-infected children and youth based on self- and caregiver report

OBJECTIVE

Nonadherence to antiretroviral therapy among children/youth with HIV often is associated with disease progression. This study examined the agreement between child and caregiver perceptions of barriers to adherence and factors associated with these barriers.

METHODS

Children/youth with perinatally acquired HIV and their parents/caregivers (n = 120 dyads) completed a questionnaire about 19 potential barriers to adherence to the child's antiretroviral therapy regimen. Agreement between the 2 reports was measured via the kappa statistic. Factors associated with the barriers were assessed by using multiple logistic regression.

RESULTS

Of the 120 children, 55% were African American, 54% were boys, and the average age was 12.8 years. The most frequently reported barrier by either the caregiver or youth was "forgot." There were varying degrees of agreement between child and caregiver on the following barriers: "forgot," "taste," "child was away from home," "child refused," and "child felt good." Children who knew their HIV status were more likely to report logistical barriers, such as scheduling issues. Children with a biological parent as their caregiver were more likely to report regimen or fear of disclosure as a barrier.

CONCLUSIONS

Lack of agreement was observed for more than half of the studied barriers, indicating discrepancies between children's and caregivers' perceptions of factors that influence medication-taking. The findings suggest a need for interventions that involve both child and caregiver in the tasks of remembering when to administer the child's medications, sustaining adherence, and appropriately transitioning medication responsibility to the youth.

Evaluation of tuberculosis diagnostics in children: 2. Methodological issues for conducting and reporting research evaluations of tuberculosis diagnostics for intrathoracic tuberculosis in children. Consensus from an expert panel

Confirming the diagnosis of childhood tuberculosis is a major challenge. However, research on childhood tuberculosis as it relates to better diagnostics is often neglected because of technical difficulties, such as the slow growth in culture, the difficulty of obtaining specimens, and the diverse and relatively nonspecific clinical presentation of tuberculosis in this age group. Researchers often use individually designed criteria for enrollment, diagnostic classifications, and reference standards, thereby hindering the interpretation and comparability of their findings. The development of standardized research approaches and definitions is therefore needed to strengthen the evaluation of new diagnostics for detection and confirmation of tuberculosis in children. In this article we present consensus statements on methodological issues for conducting research of Tuberculosis diagnostics among children, with a focus on intrathoracic tuberculosis. The statements are complementary to a clinical research case definition presented in an accompanying publication and suggest a phased approach to diagnostics evaluation; entry criteria for enrollment; methods for classification of disease certainty, including the rational use of culture within the case definition; age categories and comorbidities for reporting results; and the need to use standard operating procedures. Special consideration is given to the performance of microbiological culture in children and we also recommend for alternative methodological approaches to report findings in a standardized manner to overcome these limitations are made. This consensus statement is an important step toward ensuring greater rigor and comparability of pediatric tuberculosis diagnostic research, with the aim of realizing the full potential of better tests for children.

Medication adherence in children and adolescents with HIV infection: associations with behavioral impairment

The impact of behavioral functioning on medication adherence in children with perinatally acquired HIV infection is not well-explored, but has important implications for intervention. This report addresses the relationship between behavioral functioning and child self-report or caregiver report of medication adherence among children and adolescents enrolled in Pediatric AIDS Clinical Trials Group Protocol 219C (conducted 2000-2007). A total of 1134 participants, aged 3-17 years, received a behavioral evaluation and adherence assessment. Complete adherence was defined as taking 100% of prescribed antiretroviral medications during three days preceding the study visit. Multivariable logistic regression models were used to evaluate associations between adherence and behavioral functioning, adjusting for potential confounders, including demographic, psychosocial, and health factors. Children demonstrated higher than expected rates of behavioral impairment (≈7% expected with T > 65) in the areas of conduct problems (14%, z = 7.0, p < 0.001), learning problems (22%, z = 12.2, p < 0.001), somatic complaints (22%, z = 12.6, p < 0.001), impulsivity-hyperactivity (20%, z = 11.1, p < 0.001), and hyperactivity (19%, z = 10.6, p < 0.001). Children with behavioral impairment in one or more areas had significantly increased odds of nonadherence [adjusted odds ratio (aOR) = 1.49, p = 0.04]. The odds of nonadherence were significantly higher for those with conduct problems and general hyperactivity (aOR = 2.03, p = 0.005 and aOR = 1.68, p = 0.02, respectively). Psychosocial and health factors, such as recent stressful life events and higher HIV RNA levels, were also associated with nonadherence. Knowledge of behavioral, health, and social influences affecting the child and family should guide the development of appropriate, evidence-based interventions for medication adherence.

Relationships between the use of second-generation antipsychotics and changes in total cholesterol levels in children and adolescents perinatally infected with HIV

PURPOSE: Perinatally HIV-infected children, who are increasingly aging into adolescence and early adulthood, have significant rates of psychiatric co-morbidities, some of which are treated with second-generation antipsychotics (SGAs). SGAs have been associated with elevated total cholesterol (TC) in youth, but no studies have examined this association in perinatally HIV-infected youth. This study examined changes in TC levels of youth with perinatally acquired HIV infection and co-morbid psychiatric conditions treated with SGAs. PATIENTS AND METHODS: Long-term changes in TC levels were examined using data from the US multisite prospective Pediatric AIDS Clinical Trials Group 219C cohort study. The change in TC levels from baseline to 12 months after initiating SGA use was compared between 52 SGA-exposed and 148 matched SGA-unexposed perinatally HIV-infected youth, using generalized estimating equation models adjusting for other covariates. The prevalence and time to incident hypercholesterolemia were also compared between these 2 groups. RESULTS: After adjustment for confounders, 52 youth with prescriptions for SGAs had a larger increase in TC levels than 148 matched youth without antipsychotic prescriptions (mean difference = 9 mg/dL, z = 1.96, df = 1, P = 0.0496). Among youth with TC below 220 mg/dL at baseline, 27% of SGA-exposed youth developed hypercholesterolemia (defined as two consecutive TC measurements ≥220 mg/dL), compared with 13% of SGA-unexposed patients (Fisher's exact test, P = 0.046). CONCLUSIONS: Caution should be used in prescribing SGAs to perinatally HIV-infected youth with psychiatric co-morbidities due to increased risk of hypercholesterolemia. Patients should be monitored, and alternative evidence-based treatments considered when available.

The use of second-generation antipsychotics and the changes in physical growth in children and adolescents with perinatally acquired HIV

Second-generation antipsychotics (SGAs) are increasingly prescribed to treat psychiatric symptoms in pediatric patients infected with HIV. We examined the relationship between prescribed SGAs and physical growth in a cohort of youth with perinatally acquired HIV-1 infection. Pediatric AIDS Clinical Trials Group (PACTG), Protocol 219C (P219C), a multicenter, longitudinal observational study of children and adolescents perinatally exposed to HIV, was conducted from September 2000 until May 2007. The analysis included P219C participants who were perinatally HIV-infected, 3-18 years old, prescribed first SGA for at least 1 month, and had available baseline data prior to starting first SGA. Each participant prescribed an SGA was matched (based on gender, age, Tanner stage, baseline body mass index [BMI] z score) with 1-3 controls without antipsychotic prescriptions. The main outcomes were short-term (approximately 6 months) and long-term (approximately 2 years) changes in BMI z scores from baseline. There were 236 participants in the short-term and 198 in the long-term analysis. In linear regression models, youth with SGA prescriptions had increased BMI z scores relative to youth without antipsychotic prescriptions, for all SGAs (short-term increase = 0.192, p = 0.003; long-term increase = 0.350, p < 0.001), and for risperidone alone (short-term = 0.239, p = 0.002; long-term = 0.360, p = 0.001). Participants receiving both protease inhibitors (PIs) and SGAs showed especially large increases. These findings suggest that growth should be carefully monitored in youth with perinatally acquired HIV who are prescribed SGAs. Future research should investigate the interaction between PIs and SGAs in children and adolescents with perinatally acquired HIV infection.

Assessment of adherence to antiretroviral therapy in perinatally HIV-infected children and youth using self-report measures and pill count

BACKGROUND

Parent/caregiver or child/youth self-report and pill counts are commonly used methods for assessing adherence to antiretroviral therapy among children and youth with HIV. The purpose of this study was to compare these different methods with one another and with viral load.

METHODS

Randomly selected parent/caregiver and child/youth dyads were interviewed using several adherence self-report measures and an announced pill count was performed. Adherence assessment methods were compared with one another and their relative validity was assessed by comparison with the child's viral load close to the time of the interview or pill count, adjusting for primary caregiver, child age, and child disclosure of the diagnosis.

RESULTS

There were 151 evaluable participants. Adherence rate by pill count was >or=90% in 52% of participants, was significantly associated with log(RNA) viral load (p = .032), and had significant agreement with viral load <400 copies/mL. However, pill count data were incomplete for 26% of participants. With similar proportions considered adherent, a variety of self-report adherence assessment methods also were associated with log(RNA) viral load including: "no dose missed within the past 1 month" (p = .054 child/youth interview, p = .004 parent/caregiver interview), and no barrier to adherence identified (p = .085 child/youth interview, p = .015 parent/caregiver interview). Within-rater and inter-rater agreement was high among self-report methods. Three day recall of missed doses was not associated with viral load.

CONCLUSION

Findings demonstrate the validity of adherence assessment strategies that allow the parent/caregiver or child/youth to report on adherence over a longer period of time and to identify adherence barriers. Adherence assessed by announced pill count was robustly associated with viral load, but there was incomplete data for many participants.

The role of cognitive functioning in medication adherence of children and adolescents with HIV infection

OBJECTIVE

To evaluate the relationship between cognitive functioning and medication adherence in children and adolescents with perinatally acquired HIV infection.

METHODS

Children and adolescents, ages 3-18 (N = 1,429), received a cognitive evaluation and adherence assessment. Multiple logistic regression models were used to identify associations between adherence and cognitive status, adjusting for potential confounding factors.

RESULTS

Children's average cognitive performance was within the low-average range; 16% of children were cognitively impaired (MDI/FSIQ <70). Cognitive status was not associated with adherence to full medication regimens; however, children with borderline/low average cognitive functioning (IQ 70-84) had increased odds of nonadherence to the protease inhibitor class of antiretroviral therapy. Recent stressful life events and child health characteristics, such as HIV RNA detectability, were significantly associated with nonadherence.

CONCLUSION

Cognitive status plays a limited role in medication adherence. Child and caregiver psychosocial and health characteristics should inform interventions to support adherence.

Allocation of family responsibility for illness management in pediatric HIV

OBJECTIVE

The purpose of the study is to describe allocation of responsibility for illness management in families of children and adolescents perinatally infected with HIV.

METHODS

A total of 123 youth (ages 8-18) and caregivers completed family responsibility and medication adherence questionnaires as part of a substudy of Pediatric AIDS Clinical Trials Group protocol 219c.

RESULTS

Approximately one-fourth of the youth reported being fully responsible for taking medications. A smaller percentage of caregivers reported full youth responsibility. Older youth and caregivers of older youth reported higher degree of youth responsibility for medication-related tasks, though age was unrelated to adherence. Caregiver report of greater responsibility for medications was associated with better adherence.

CONCLUSIONS

Caregivers are likely to transition responsibility for HIV care to older youth but this transition was not always successful as evidenced by poor medication adherence. Interventions supporting successful transition may improve adherence and subsequently health outcomes in pediatric HIV.

Predictors of adherence to antiretroviral medications in children and adolescents with HIV infection

BACKGROUND

Most evaluations of adherence to antiretroviral therapy in children with HIV infection have focused on validation of adherence measures via their association with virological outcomes. However, few studies have fully explored associations with other factors to guide development of adherence interventions.

METHODS

In this study, we examined the relationship of self-reported medication adherence to health, demographic, and psychosocial characteristics of children and their caregivers, using data from an ongoing multicenter prospective observational study of long-term outcomes of HIV infection conducted by the Pediatric AIDS Clinical Trials Group. Child and caregiver characteristics were evaluated for association with adherence via univariate and multiple logistic regression models.

RESULTS

Of the 2088 children and adolescents, 84% reported complete adherence to antiretroviral therapy medications over the past 3 days. The median viral load was approximately 10 times higher among nonadherent than adherent children, and the strength of this association increased with age. Factors associated with at least marginally significant increases in nonadherence in a multiple logistic regression model included increasing age in years, female gender, detectable HIV viral load, occurrence of recent stressful life events, repeating a grade in school, self-assessment of adherence by the subject, and diagnosis of depression or anxiety. Having an adult other than the biological parent as the primary caregiver, using a buddy system to remember to take antiretroviral therapy medications, higher caregiver education level, previous adherence assessments, and taking antipsychotic medications were each associated with improved adherence. After controlling for these characteristics, there was no significant association of adherence with race, knowledge of HIV status, medication burden, CD4 percentage, or current antiretroviral therapy.

CONCLUSIONS

Rates of self-reported adherence were relatively high and were influenced by multiple child and family characteristics. These findings identify targets for adherence interventions and highlight the importance of evaluating and supporting the family environment to optimize adherence.

Immune reconstitution after receipt of highly active antiretroviral therapy in children with advanced or progressive HIV disease and complete or partial viral load response

We assessed CD4 cell recovery in 175 children with advanced human immunodeficiency virus disease who had received a 4-drug antiretroviral regimen and were categorized as viral load (VL) responders (VLRs), partial VLRs, or non-VLRs. Median CD4 cell counts increased from baseline to week 48, and, among children with maximal follow-up, increases in CD4 cell counts were sustained to week 96 among VLRs and partial VLRs but not among non-VLRs. For VL rebounders still in the study, CD4 cell counts remained increased for 32 weeks after VL rebound. Sustained immunologic benefits can be achieved even with partial VL response in children with advanced disease.