Tenofovir is used commonly in HIV treatment and prevention settings, but factors that correlate with tenofovir exposure in real-world setting are unknown.
Intensive pharmacokinetic (PK) studies of tenofovir in a large, diverse cohort of HIV-infected women over 24-hours at steady-state were performed and factors that influenced exposure (assessed by areas-under-the-time-concentration curves, AUCs) identified
HIV-infected women (n=101) on tenofovir-based therapy underwent intensive 24-hour PK sampling. Data on race/ethnicity, age, exogenous steroid use, menstrual cycle phase, concomitant medications, recreational drugs and/or tobacco, hepatic and renal function, weight and body mass index (BMI) were collected. Multivariable models using forward stepwise selection identified factors associated with effects on AUC. Glomerular filtration rates (GFR) prior to starting tenofovir were estimated by the CKD-EPI equation using both creatinine and cystatin-C measures
The median (range) of tenofovir AUCs was 3350 (1031–13,911) ng x h/mL. Higher AUCs were associated with concomitant ritonavir use (1.33-fold increase, p 0.002), increasing age (1.21-fold increase per decade, p=0.0007) and decreasing BMI (1.04-fold increase per 10% decrease in BMI). When GFR was calculated using cystatin-C measures, mild renal insufficiency prior to tenofovir initiation was associated with higher subsequent exposure (1.35-fold increase when pre-tenofovir GFR <70mL/min, p=0.0075).
Concomitant ritonavir use, increasing age, decreasing BMI and lower GFR prior to tenofovir initiation as estimated by cystatin C were all associated with elevated tenofovir exposure in a diverse cohort of HIV-infected women. Clinicians treating HIV-infected women should be aware of common clinical conditions that affect tenofovir exposure when prescribing this medication.
Tenofovir; pharmacokinetics; HIV-infected women; diverse populations; GFR; cystatin C
The measurement of antiretroviral concentrations in hair is emerging as an important technology to objectively quantify adherence to combination antiretroviral therapy. Hair levels of antiretrovirals are the strongest independent predictor of virologic success in large prospective cohorts of HIV-infected patients and surpass self-report in predicting outcomes. Hair is easy to collect and store, but validated methods to analyze antiretroviral levels in hair using liquid chromatography tandem mass spectrometry (LC-MS/MS) are expensive. We report here on the development of a thin-layer chromatography (TLC) assay for the semiquantitative analysis of nevirapine in hair. TLC assay results from 11 samples were consistent with results using LC-MS/MS [Spearman correlation coefficient 0.99 (95% CI 0.95–0.996)]. This simple, low-cost method of analyzing nevirapine concentrations in hair may provide a novel monitoring tool for antiretroviral adherence in resource-limited settings and merits further study in clinical settings.
Stark racial/ethnic disparities in health outcomes exist among those living with HIV in the United States. One of three primary goals of the National HIV/AIDS Strategy is to reduce HIV-related disparities and health inequities.
Using data from HIV-infected women participating in the Women’s Interagency HIV Study from April 2006 to March 2011, we measured virologic failure (HIV RNA >200 copies/mL) following suppression (HIV RNA <80 copies/mL) on HAART. We identified predictors of virologic failure using discrete-time survival analysis and calculated racial/ethnic-specific population attributable fractions (PAFs).
Of 887 eligible women, 408 (46%) experienced virologic failure during the study period. Hispanic and White women had significantly lower hazards of virologic failure than African-American women (Hispanic hazard ratio, HR=0.8, 95% confidence interval [0.6, 0.9]; White HR=0.7 [0.5, 0.9]). The population attributable fraction of virologic failure associated with low income was higher in Hispanic (aHR=2.2 [0.7, 6.5], PAF=49%) and African-American women (aHR=1.8 [1.1, 3.2], PAF=38%) than among White women (aHR=1.4 [0.6, 3.4], PAF=16%). Lack of health insurance compared to public health insurance was associated with virologic failure only among Hispanic (aHR=2.0 [0.9, 4.6], PAF=22%) and White women (aHR=1.9 [0.7, 5.1], PAF=13%). By contrast, depressive symptoms were associated with virologic failure only among African-American women (aHR=1.6 [1.2, 2.2], PAF=17%).
In this population of treated HIV-infected women, virologic failure was common, and correlates of virologic failure varied by race/ethnicity. Strategies to reduce disparities in HIV treatment outcomes by race/ethnicity should address racial/ethnic-specific barriers including depression and low income to sustain virologic suppression.
disparities; race/ethnicity; virologic failure; HAART; HIV; women
Tenofovir disoproxil fumarate is a widely used antiretroviral for HIV infection that has been associated with an increased risk of chronic kidney disease (CKD). Our objective was to derive a scoring system to predict 5-year risk of developing CKD in HIV-infected individuals and to estimate difference in risk associated with tenofovir use.
We evaluated time to first occurrence of CKD (estimated glomerular filtration rate <60 ml/min per 1.73 m2) in 21 590 HIV-infected men from the Veterans Health Administration initiating antiretroviral therapy from 1997 to 2010.
We developed a point-based score using multivariable Cox regression models. Median follow-up was 6.3 years, during which 2059 CKD events occurred.
Dominant contributors to the CKD risk score were traditional kidney risk factors (age, glucose, SBP, hypertension, triglycerides, proteinuria); CD4+ cell count was also a component, but not HIV RNA. The overall 5-year event rate was 7.7% in tenofovir users and 3.8% in nonusers [overall adjusted hazard ratio 2.0, 95% confidence interval (CI) 1.8–2.2]. There was a progressive increase in 5-year CKD risk, ranging from less than 1% (zero points) to 16% (≥9 points) in nonusers of tenofovir, and from 1.4 to 21.4% among tenofovir users. The estimated number-needed-to-harm (NNH) for tenofovir use ranged from 108 for those with zero points to 20 for persons with at least nine points. Among tenofovir users with at least 1 year exposure, NNH ranged from 68 (zero points) to five (≥9 points).
The CKD risk score can be used to predict an HIV-infected individual’s absolute risk of developing CKD over 5 years and may facilitate clinical decision-making around tenofovir use.
chronic kidney disease; HIV; risk score; tenofovir
As efforts intensify to eliminate perinatal HIV transmission, understanding kinetics of maternal-to-child transfer of antiretrovirals during pregnancy and breastfeeding is critical. Antiretroviral levels in plasma, cord blood and breastmilk reflect exposure over short intervals. Hair concentrations reflect cumulative exposure and can uniquely quantify in-utero transfer of maternal medications to infants. We measured plasma and hair antiretroviral levels in HIV-infected Ugandan mothers and their infants at delivery and during breastfeeding to assess transfer.
HIV-infected pregnant women were randomized to lopinavir/ritonavir- or efavirenz-based therapy in a larger trial (PROMOTE). At 0, 8 and 12 weeks postpartum, plasma antiretroviral levels were measured in 117 mother-infant pairs; hair levels were assayed at 12 weeks. Ratios and correlations of infant:maternal concentrations were calculated.
By 12 weeks, 90.4% of mothers reported exclusive breastfeeding. Hair and plasma levels over time suggest moderate (47%) to extensive (87%) in-utero transfer of lopinavir and ritonavir, respectively, but negligible transfer of either via breastfeeding. Moderate transfer of efavirenz occurs during pregnancy and breastfeeding (40% cumulative; 15% during breastfeeding). Despite differences in exposure, no infant seroconversions or correlations between infant hair/plasma antiretroviral levels and adverse effects were observed.
Using a unique approach combining hair and plasma data, we found that different antiretrovirals had distinct kinetics of mother-to-infant transfer. Efavirenz transfers during both pregnancy and breastfeeding, whereas lopinavir and ritonavir transfer only in-utero. Further study of the degree and timing of maternal-to-child transfer by antiretroviral will help optimize strategies that protect infants and minimize toxicities during periods of risk.
Tenofovir has been associated with renal tubular injury. Biomarkers that signal early tubular dysfunction are needed because creatinine rise lags behind tenofovir-associated kidney dysfunction. We examined several urinary biomarkers to determine if rises accompanying tenofovir initiation preceded creatinine changes.
Three urinary biomarkers of tubular impairment- neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl- β -D-glucosaminidase (NAG), and β-2-microglobulin (β2MG)-were measured across three time points (one pre-tenofovir visit and two post tenofovir visits) in one hundred and thirty two HIV-positive women from the Women's Interagency HIV Study (WIHS). Women initiating HAART containing tenofovir were propensity score matched to women initiating HAART without tenofovir and women not on HAART.
There were no differences between groups for NGAL or NAG but β2MG was 19 times more likely to be elevated among tenofovir users at the 2nd post tenofovir visit compared to non-TDF users at the pre-tenofovir visit (p<0.01). History of proteinuria was associated with elevated NGAL (p <0.01). Factors associated with elevated NAG were GFR<60 ml/min, history of proteinuria, hepatitis C (p<0.01 for all) and diabetes mellitus (p=0.05). Factors associated with increased odds of elevated β2MG were HIV RNA>100,000 copies/ml, hepatitis C, boosted protease inhibitor (PI) use, and GFR<60 ml/min (p≤0.01 for all).
β2MG levels are elevated in women on tenofovir indicating probable early renal dysfunction. Biomarker elevation is additionally associated with baseline chronic kidney disease, uncontrolled viremia, and boosted PI use. Future studies are needed to explore urinary biomarker thresholds in identifying treated HIV-infected individuals at risk for renal dysfunction.
Tenofovir; urinary biomarkers; HIV infected women
Pre-exposure prophylaxis (PrEP) trials using tenofovir-based regimens have demonstrated that high levels of adherence are required to evaluate efficacy; the incorporation of objective biomarkers of adherence in trial design has been essential to interpretation, given the inaccuracy of self-report. Antiretroviral measurements in scalp hair have been useful as a marker of long-term exposure in the HIV treatment setting, and hair samples are relatively easy and inexpensive to collect, transport, and store for analysis. To evaluate the relationship between dose and tenofovir concentrations in hair, we examined the dose proportionality of tenofovir in hair in healthy, HIV-uninfected adults.
A phase I, crossover pharmacokinetic study was performed in 24 HIV-negative adults receiving directly-observed oral tenofovir tablets administered 2, 4, and 7 doses/week for 6 weeks, with a ≥3-week break between periods. Small samples of hair were collected after each six-week period and analyzed for tenofovir concentrations. Geometric-mean-ratios compared levels between each pair of dosing conditions. Intensive plasma pharmacokinetic studies were performed during the daily-dosing period to calculate areas-under-the-time-concentration curves (AUCs).
Over 90% of doses were observed per protocol. Median tenofovir concentrations in hair increased monotonically with dose. A log-linear relationship was seen between dose and hair levels, with an estimated 76% (95% CI 60–93%) increase in hair level per 2-fold dose increase. Tenofovir plasma AUCs modestly predicted drug concentrations in hair.
This study found a strong linear relationship between frequency of dosing and tenofovir levels in scalp hair. The analysis of quantitative drug levels in hair has the potential to improve adherence measurement in the PrEP field and may be helpful in determining exposure thresholds for protection and explaining failures in PrEP trials. Hair measures for adherence monitoring may also facilitate adherence measurement in real-world settings and merit further investigation in upcoming PrEP implementation studies and programs.
A recommendation by San Francisco General Hospital in January 2010 to initiate antiretroviral therapy in all human immunodeficiency virus (HIV)–infected patients led to a rapid increase in HIV RNA suppression among patients with a CD4 cell count of >500 cells/μL after clinic enrollment.
Background. On 1 January 2010, a large, publicly funded clinic in San Francisco announced a “universal ART” approach to initiate antiretroviral therapy (ART) in all human immunodeficiency virus (HIV)-infected persons. The effect of changing guidance on real-world patient outcomes has not been evaluated.
Methods. We evaluated untreated adult patients (defined as going >90 days without ART use) visiting clinic from 2001 to 2011. The cumulative incidence of HIV RNA suppression (viral load, <500 copies/mL), stratified by CD4 cell count at entry and calendar dates representing guideline issuance, were estimated using a competing risk framework. A multivariate Poisson-based model identified factors associated with HIV RNA suppression 6 months after clinic entry.
Results. Of 2245 adults, 87% were male, and the median age was 39 years (interquartile range, 33–45 years). In 534 patients entering clinic with a CD4 cell count of >500 cells/µL, the 1-year incidence of HIV RNA suppression was 10.1% (95% confidence interval [CI], 6.6%–14.6%) before 4 April 2005; 9.1% (95% CI, 3.6%–17.4%) from 4 April 2005 to 1 December 2007; 14.1% (95% CI, 7.5%–22.8%) from 1 December 2007 to the universal ART recommendation and 52.8% (95% CI, 38.2%–65.4%) after. After adjustment, the SFGH policy was associated with a 6-fold increase in the probability of HIV RNA suppression 6 months after clinic entry.
Conclusions. Recommendations to initiate ART in all HIV-infected patients increased the rate of HIV RNA suppression for patients enrolling in care with a CD4 cell count of >500 cells/µL and may foreshadow national trends given the March 2012 revision of national treatment guidelines to favor ART initiation for persons with CD4 cell counts of >500 cells/µL.
Background. Efavirenz exhibits marked interindividual variability in plasma levels and toxicities. Prior pharmacogenetic studies usually measure exposure via single plasma levels, examine limited numbers of polymorphisms, and rarely model multiple contributors. We analyzed numerous genetic and nongenetic factors impacting short-term and long-term exposure in a large heterogeneous population of human immunodeficiency virus (HIV)–infected women.
Methods. We performed 24-hour intensive pharmacokinetic studies in 111 women receiving efavirenz under actual-use conditions and calculated the area-under-the-concentration-time curve (AUC) to assess short-term exposure; the efavirenz concentration in hair was measured to estimate long-term exposure. A total of 182 single-nucleotide polymorphisms (SNPs) and 45 haplotypes in 9 genes were analyzed in relationship to exposure by use of multivariate models that included a number of nongenetic factors.
Results. Efavirenz AUCs increased 1.26-fold per doubling of the alanine aminotransferase level and 1.23-fold with orange and/or orange juice consumption. Individuals with the CYP2B6 516TT genotype displayed 3.5-fold increases in AUCs and 3.2-fold increases in hair concentrations, compared with individuals with the TG/GG genotype. Another SNP in CYP2B6 (983TT) and a p-glycoprotein haplotype affected AUCs without substantially altering long-term exposure.
Conclusions. This comprehensive pharmacogenomics study showed that individuals with the CYP2B6 516TT genotype displayed >3-fold increases in both short-term and long-term efavirenz exposure, signifying durable effects. Pharmacogenetic testing combined with monitoring of hair levels may improve efavirenz outcomes and reduce toxicities.
Our goal in this study was to examine how Vitamin C interacts with antiretroviral therapy in individuals with HIV. We specifically evaluated how Vitamin C impacts highly active antiretroviral therapy (HAART) adherence and HAART effectiveness as adjudicated by HIV viral loads and CD4 cell counts. Women served as their own controls, comparing periods of Vitamin C usage with periods of non-usage.
An intra-individual, cross-sectional comparative study ‘nested’ in the WIHS observational cohort study
Women in the Women’s Interagency HIV Study (WIHS).
Adherence, CD4 count and Viral load.
Our study population was drawn from 2,813 HIV+ participants who contributed 44,588 visits in WIHS from October, 1994 to April, 2009. Among them, there were 1,122 Vitamin C users with 4,954 total visits where use was reported. In the multivariate model adjusting for age, education, race, income, drug use, Vitamin C use order and depression score, there was a 44% increase in the odds of >=95% HAART adherence among participants during their period of Vitamin C use compared to when they were not using Vitamin C (OR=1.44; 95% CI=1.1–1.9; P-value=0.0179). There was an association with Vitamin C usage and CD4 counts on viral loads.
Vitamin C usage appears to be associated with improved adherence. Future Vitamin C studies should target specific HAART drugs, and prospective clinical outcomes.
Swaziland has made great progress towards its goal of malaria elimination by 2015. However, malaria importation from neighbouring high-endemic Mozambique through Swaziland’s eastern border remains a major factor that could prevent elimination from being achieved. In order to reach elimination, Swaziland must rapidly identify and treat imported malaria cases before onward transmission occurs.
A nationwide formative assessment was conducted over eight weeks to determine if the imported cases of malaria identified by the Swaziland National Malaria Control Programme could be linked to broader social networks and to explore methods to access these networks.
Using a structured format, interviews were carried out with malaria surveillance agents (6), health providers (10), previously identified imported malaria cases (19) and people belonging to the networks identified through these interviews (25). Most imported malaria cases were Mozambicans (63%, 12/19) making a living in Swaziland and sustaining their families in Mozambique. The majority of imported cases (73%, 14/19) were labourers and self-employed contractors who travelled frequently to Mozambique to visit their families and conduct business. Social networks of imported cases with similar travel patterns were identified through these interviews. Nearly all imported cases (89%, 17/19) were willing to share contact information to enable network members to be interviewed. Interviews of network members and key informants revealed common congregation points, such as the urban market places in Manzini and Malkerns, as well as certain bus stations, where people with similar travel patterns and malaria risk behaviours could be located and tested for malaria.
This study demonstrated that imported cases of malaria belonged to networks of people with similar travel patterns. This study may provide novel methods for screening high-risk groups of travellers using both snowball sampling and time-location sampling of networks to identify and treat additional malaria cases. Implementation of a proactive screening programme of importation networks may help Swaziland halt transmission and achieve malaria elimination by 2015.
Malaria; Elimination; Importation; Swaziland; Active case detection; Social networks
Early identification and management of treatment failure on highly active antiretroviral therapy (HAART) is crucial in maintaining a sustained response to therapy in HIV infection. However, HIV viral load and resistance testing, and second-line HAART regimens, are unaffordable to many patients in India, leaving them with limited treatment options. Predictors and reasons for antiretroviral switching, therefore, are likely to differ in settings of varying resources. A one-year, observational study of patients receiving antiretroviral therapy was conducted in a private, non-profit hospital in Bangalore. This paper examines the predictors and consequences of antiretroviral treatment switching in this setting and explores reasons for switching in a subset of patients. Data on demographics, drug regimens, adherence, and physical and psychosocial outcomes were collected quarterly. Tests of viral load and CD4 cell counts were performed every six months. One third of the patients switched therapy during the study period. Baseline predictors of switching included lower CD4 cell counts and more physical symptoms. Contrary to studies in other settings, a high viral load did not predict treatment switching, and only a minority of those experiencing drug failure were switched to second-line regimens. Both groups (switchers and non-switchers) improved significantly over time with respect to CD4 counts and showed a reduction in physical and depressive symptoms and psychological well-being, and any differences between the groups were no longer significant at the end of the study, once we controlled for baseline levels. Clinical, policy and research implications of these findings are discussed within the context of resource-limited settings.
HIV/AIDS; antiretroviral therapy; HAART; treatment switch; India
Although early initiation of antiretroviral therapy in HIV-infected patients after a diagnosis of Pneumocystis pneumonia increased after ACTG 5164 (7.4%–50.0%), a subsequent implementation and dissemination initiative optimized uptake of early antiretroviral therapy as clinically routine (50.0%–80.3%).
Background. Diffusion, dissemination, and implementation of scientific evidence into routine clinical practice is not well understood. The Adult AIDS Clinical Trials Group (ACTG) Protocol 5164 showed that early antiretroviral therapy (ART; ie, within 14 days) after diagnosis of an opportunistic infection improved clinical outcomes, compared with later initiation. Subsequently, the San Francisco General Hospital (SFGH) HIV/AIDS Service performed the SFGH 5164 Initiative to disseminate and implement the findings of ACTG 5164.
Methods. We evaluated patients who received a diagnosis of Pneumocystis jirovecii pneumonia (PCP) from 1 January 2001 through 30 March 2011. Survival analyses were used to assess changes in the time to initiation of ART after PCP, and logistic regression was used to evaluate changes in the odds of early ART (ie, within 14 days) because of ACTG 5164 and SFGH 5164 Initiative.
Results. Among 162 patients, the adjusted hazard of ART initiation increased by 3.05 (95% confidence interval [CI], 1.86–5.02) after ACTG 5164 and by 4.89 (95% CI, 2.76–8.67) after the SFGH Initiative, compared with before ACTG 5164. When compared with before ACTG 5164, the proportion of patients who received ART within the 14 days after PCP diagnosis increased from 7.4% to 50.0% (P < .001) after ACTG 5164 and from 50.0% to 83.0% (P = .02) after the SFGH 5164 Initiative.
Conclusions. Diffusion of findings from of a randomized trial changed practice at an academic medical center, but dissemination and implementation efforts were required to establish early ART at acceptable levels. Early ART initiation can be achieved in real-world patient populations.
Sufficient drug exposure is crucial for maintaining durable responses to HIV treatments. However, monitoring drug exposure using single blood samples only provides short-term information and is highly subject to intra-individual pharmacokinetic variation. Drugs can accumulate in hair over a long period of time, so hair drug levels can provide drug exposure information over prolonged periods. We now report on a specific, sensitive and reproducible LC-MS/MS method for measuring nevirapine (NVP), a widely used antiretroviral drug, levels in human hair using even a single short strand of hair. Hair samples are cut into small segments and drug is extracted in methanol/trifluoroacetic acid (v/v, 9:1) shaken at 37°C in a water bath overnight, followed by liquid-liquid extraction under alkaline conditions. The extracted samples are then separated on a BDS-C18 column with mobile phase composed as 50% acetonitrile containing 0.15% acetic acid and 4 mM ammonium acetate with an isocratic elution for a total run time of 3 min. and detected by triple quadrupole electrospray multiple reaction mode at precursor/product ion at 267.0>225.9 m/z. Deuterated nevirapine-d5 was used as internal standard. This method was validated from 0.25 to 100 ng/mg using 2 mg hair samples. The accuracies for spiked NVP hair control samples were 98–106% with coefficients of variation (CV) less than 10%. The CV for incurred hair control samples was less than 7%. The extraction efficiency for incurred control hair samples was estimated at more than 95% by repeated extractions. This method has been successfully applied to analyze more than 1000 hair samples from participants in a large ongoing cohort study of HIV-infected participants. We also showed that nevirapine in human hair can easily be detected in a single short strand of hair. This method will allow us to identify drug non-adherence using even a single strand of hair.
Antiretroviral drug; Nevirapine; Hair; LC-MS/MS; TDM; Adherence
Human immunodeficiency virus (HIV)–infected individuals frequently have consumed garlic, a popular complementary supplement. Researchers rarely have studied garlic’s association with antiretroviral therapies, however, even though that association is very relevant clinically.
To examine associations of supplemental use of garlic with highly active antiretroviral treatment (HAART) adherence level and HAART effectiveness (HIV viral load and CD4+ cell counts) in HIV-infected women.
The research team carried out a self-controlled, longitudinal study nested within the Women’s Interagency HIV Study (WIHS). The team used a paired study design that allowed participants to serve as their own controls. The team first identified all of the study’s visits in which the participant self-reported the use of a garlic supplement since her last visit (index visit). Then for each index visit, the team identified a matching visit (a control visit) using the following criteria: (a) the visit must be one for the same participant in which that participant reported no garlic supplementation; (b) the visit must immediately precede the index visit (less than 1 year apart); and (c) at the time of the control visit, the participant must have been using antiretroviral therapy identical to that used at the time of the index visit.
Participants were persons using garlic supplementation who already were participants in the WIHS.
The research team used a logistic regression model to examine the association between garlic supplementation and HAART adherence level. The team used a mixed linear model to examine the association of garlic supplementation with HIV viral load and CD4+ cell counts.
From October 1994 to April 2009, 390 HIV-infected women in the WIHS made 1112 visits at which they reported using garlic supplements. Seventy-seven HIV-infected women using HAART met the research team’s selection criteria and contributed 99 pairs of visits for the study. Among the women who used garlic supplements, 22% were 50 years and older; 58% were black and non-Hispanic; and 23% had less than a high-school education. Neither use of garlic supplementation nor reasons for using garlic supplements were significantly associated with the HAART adherence level, HIV viral load, or CD4+ cell counts; however, “use garlic as needed,” a potential marker of a disease state, was significantly associated with higher viral load (P = .0003).
Short-term garlic supplementation did not impact HAART adherence level, HIV viral load, and CD4+ cell counts.
In a longitudinal study of outcomes on atazanavir-based therapy in a large cohort of HIV-infected women, hair levels of atazanavir were the strongest independent predictor of virologic suppression. Hair antiretroviral concentrations may serve as a useful tool in HIV care.
Background. Adequate exposure to antiretrovirals is important to maintain durable responses, but methods to assess exposure (eg, querying adherence and single plasma drug level measurements) are limited. Hair concentrations of antiretrovirals can integrate adherence and pharmacokinetics into a single assay.
Methods. Small hair samples were collected from participants in the Women's Interagency HIV Study (WIHS), a large cohort of human immunodeficiency virus (HIV)-infected (and at-risk noninfected) women. From 2003 through 2008, we analyzed atazanavir hair concentrations longitudinally for women reporting receipt of atazanavir-based therapy. Multivariate random effects logistic regression models for repeated measures were used to estimate the association of hair drug levels with the primary outcome of virologic suppression (HIV RNA level, <80 copies/mL).
Results. 424 WIHS participants (51% African-American, 31% Hispanic) contributed 1443 person-visits to the analysis. After adjusting for age, race, treatment experience, pretreatment viral load, CD4 count and AIDS status, and self-reported adherence, hair levels were the strongest predictor of suppression. Categorized hair antiretroviral levels revealed a monotonic relationship to suppression; women with atazanavir levels in the highest quintile had odds ratios (ORs) of 59.8 (95% confidence ratio, 29.0–123.2) for virologic suppression. Hair atazanavir concentrations were even more strongly associated with resuppression of viral loads in subgroups in which there had been previous lapses in adherence (OR, 210.2 [95% CI, 46.0–961.1]), low hair levels (OR, 132.8 [95% CI, 26.5–666.0]), or detectable viremia (OR, 400.7 [95% CI, 52.3–3069.7]).
Conclusions. Antiretroviral hair levels surpassed any other predictor of virologic outcomes to HIV treatment in a large cohort. Low antiretroviral exposure in hair may trigger interventions prior to failure or herald virologic failure in settings where measurement of viral loads is unavailable. Monitoring hair antiretroviral concentrations may be useful for prolonging regimen durability.
In resource-limited settings, many patients, with no prior PI treatment on a second-line, high genetic barrier, ritonavir boosted protease inhibitor (PI) containing regimen have virologic failure.
We conducted a cross-sectional survey to investigate the aetiology of virologic failure in two public health antiretroviral clinics in South Africa documenting the prevalence of virologic failure (HIV RNA load > 500 copies/ml) and genotypic antiretroviral resistance; and lopinavir hair and plasma concentrations in a nested case-control study.
Ninety three patients treated with a second-line regimen including lopinavir boosted with ritonavir were included, of whom 50 (25 cases, with virologic failure and 25 controls) were included in a nested case control study. Of 93 patients 37(40%) had virological failure, only 2 of which had had major protease inhibitor mutations. The negative predictive values: probability of failure with lopinavir plasma concentration > 1μg/mL or hair concentrations > 3.63ng/mg for virologic failure were 86% and 89%, and positive predictive values of low concentrations 73% and 79%, respectively, whereas all virologic failures with HIV RNA loads above 1000 copies/ml, of patients without protease inhibitor resistance, could be explained by either having a low lopinavir concentration in plasma or hair.
Most patients who fail a LPV/r regimen, in our setting, have poor lopinavir exposure. A threshold plasma lopinavir concentration (indicating recent LPV/r use) and/or hair concentration (indicating longer term lopinavir exposure) are valuable in determining the aetiology of virologic failure and identifying patients in need of adherence counselling or resistance testing.
Lopinavir; medication adherence; resource-limited settings; protease inhibitor resistance mutations; plasma concentration; hair concentration
The extended use of antiretroviral drugs among human immunodeficiency virus (HIV)–seropositive individuals underscores the need for a comprehensive evaluation of therapy-associated clinical symptoms.
Beginning in April 2000, 364 HIV-seronegative and 1256 HIV-seropositive women enrolled in a multicenter cohort study reported clinical symptoms that included abdominal pain, diarrhea, anorexia, nausea and/or vomiting, myalgias, fatigue, fever, body fat redistribution, dizziness, headaches, paresthesias, xerostomia, nephrolithiasis, and rash. We examined the prevalence of symptoms with respect to HIV infection and the use of highly active antiretroviral therapy (HAART), using data-correlation models.
In the 6 months before a study visit, 49% of HIV-seronegative women, 67% of HIV-seropositive women not receiving therapy, and 69% of HIV-seropositive women receiving HAART reported any clinical symptom. The odds ratios (ORs) for reporting any symptom were 1.4 (95% confidence interval [CI], 1.1–1.8) for women who changed HAART regimens and 0.9 (95% CI, 0.7–1.1) for women reporting stable HAART use, compared with those reporting no therapy use. Significant findings (P < .05) for particular symptoms were an increased odds of diarrhea, nausea and/or vomiting, body fat redistribution, myalgias, and paresthesias, when data for women who changed HAART regimens were compared with those for women not receiving therapy. The OR for reporting any symptom was 1.5 (95% CI, 1.2–1.9) for women who switched HAART regimens and 1.6 (95% CI, 1.3–1.9) for women who discontinued HAART, compared with those reporting stable HAART use.
Our findings confirm the high prevalence of clinical symptoms among HIV-seropositive women who changed HAART regimens. The high prevalence of symptoms among HIV-seronegative women and HIV-seropositive women not receiving therapy demonstrates that caution should be used when attributing the occurrence of symptoms entirely to HAART.
Our knowledge of pharmacogenetic variability in diverse populations is scarce, especially in sub-Saharan Africa. To bridge this gap in knowledge, we characterised population frequencies of clinically relevant pharmacogenetic traits in two distinct South African population groups. We genotyped 211 tagging single nucleotide polymorphisms (tagSNPs) in 12 genes that influence antiretroviral drug disposition, in 176 South African individuals belonging to two distinct population groups residing in the Western Cape: the Xhosa (n = 109) and Cape Mixed Ancestry (CMA) (n = 67) groups. The minor allele frequencies (MAFs) of eight tagSNPs in six genes (those encoding the ATP binding cassette sub-family B, member 1 [ABCB1], four members of the cytochrome P450 family [CYP2A7P1, CYP2C18, CYP3A4, CYP3A5] and UDP-glucuronosyltransferase 1 [UGT1A1]) were significantly different between the Xhosa and CMA populations (Bonferroni p < 0.05). Twenty-seven haplotypes were inferred in four genes (CYP2C18, CYP3A4, the gene encoding solute carrier family 22 member 6 [SLC22A6] and UGT1A1) between the two South African populations. Characterising the Xhosa and CMA population frequencies of variant alleles important for drug transport and metabolism can help to establish the clinical relevance of pharmacogenetic testing in these populations.
pharmacogenetics; South Africa; Xhosa; Cape Mixed Ancestry; HIV; antiretrovirals
To determine prevalence and predictors of complementary and alternative medicine (CAM) use disclosure to health care providers and whether CAM use disclosure is associated with highly active antiretroviral therapy (HAART) adherence among HIV-infected women, we analyzed longitudinal data collected between October 1994 and March 2002 from HIV-infected CAM-using women enrolled in the Women's Interagency HIV Study. Repeated measures Poisson regression models were constructed to evaluate associations of selected predictors with CAM use disclosure and association between CAM use disclosure and HAART adherence. A total of 1377 HIV-infected women reported CAM use during study follow-up and contributed a total of 4689 CAM-using person visits. The overall prevalence of CAM use disclosure to health care providers was 36% across study visits. Women over 45 years old, with a college education, or with health insurance coverage were more likely to disclose their CAM use to health care providers, whereas women identified as non-Hispanic Black or other ethnicities were less likely to communicate their CAM usage. More health care provider visits, more CAM domains used, and higher health care satisfaction scores had significant relationships with increased levels of CAM use disclosure. Restricting analysis to use of herbal or nonherbal medications only, similar results were obtained. Compared to other CAM domains, mind–body practice had the lowest prevalence of CAM use disclosure. Additionally, CAM use disclosure was significantly associated with higher HAART adherence. From this study, we showed that a high percentage of HIV-infected women did not discuss their CAM use with health care providers. Interventions targeted towards both physicians and patients may enhance communication of CAM use, avoid potential adverse events and drug interactions, and enhance HAART adherence.
Small intensive pharmacokinetic (PK) studies of medications in early-phase trials cannot identify the range of factors that influence drug exposure in heterogeneous populations. We performed PK studies in large numbers of HIV-infected women on nonnucleoside-reverse-transcriptase-inhibitors (NNRTIs) under conditions of actual use to assess patient characteristics that influence exposure and evaluated the relationship between exposure and response.
225 women on NNRTI-based antiretroviral regimens from the Women’s Interagency HIV Study (WIHS) were enrolled into 12 or 24-hour PK studies. Extensive demographic, laboratory and medication covariate data was collected before and during the visit to be used in multivariate models. Total NNRTI drug exposure was estimated by area-under-the-concentration-time curves (AUC).
Hepatic inflammation and renal insufficiency were independently associated with increased nevirapine (NVP) exposure in multivariate analyses; crack cocaine, high fat diets, and amenorrhea were associated with decreased levels (n=106). Higher efavirenz (EFV) exposure was seen with increased transaminase, albumin levels, and orange juice consumption; tenofovir use, increased weight, being African-American and amenorrhea were associated with decreased exposure (n=119). With every 10-fold increase in NVP or EFV exposure, participants were 3.3 and 3.6 times as likely to exhibit virologic suppression, respectively. Patients with higher drug exposure were also more likely to report side effects on therapy.
Our study identifies and quantitates previously unrecognized factors modifying NNRTI exposure in the “real-world” setting. Comprehensive PK studies in representative populations are feasible and may ultimatley lead to dose optimization strategies in patients at risk for failure or adverse events.
HIV; antiretrovirals; nevirapine; efavirenz; pharmacokinetics; drug exposure; women
Our objective was to describe the association that childcare burden, household composition, and health care utilization have with adherence to highly active antiretroviral therapy (HAART) among women in the United States. The primary outcome was 95% or more adherence to HAART evaluated at 10,916 semiannual visits between October 1998 and March 2006 among 1419 HIV-infected participants enrolled in the Women's Interagency HIV Study. HAART adherence levels of 95% or more were reported at 76% of the semiannual visits. At only 4% of the person-visits did women report either quite a bit or extreme difficulty in caring for child; at 52% of the person-visits women reported at least one child 18 years of age or older living in the household. We found a one-unit increase in the difficulty in caring for children (childcare burden was assessed on a 5-point scale: not difficult  to extremely difficult ) was associated with a 6% decreased odds of 95% or more HAART adherence (adjusted odds ratio [OR] = 0.94; p = 0.07). Each additional child 18 years of age or less living in the household was associated with an 8% decreased odds of 95% or more adherence (adjusted OR = 0.92, p = 0.03). Both the number and type of adult living in the household, as well as health care utilization were not associated with HAART adherence. Greater child care burden and number of children 18 years old or younger living in household were both inversely associated with HAART adherence. Assessing patients' difficulties in caring for children and household composition are important factors to consider when addressing adherence to HAART.
Antiretroviral (ARV) therapies fail when behavioral or biologic factors lead to inadequate medication exposure. Currently available methods to assess ARV exposure are limited. Levels of ARVs in hair reflect plasma concentrations over weeks to months and may provide a novel method for predicting therapeutic responses.
The Women's Interagency HIV Study, a prospective cohort of HIV-infected women, provided the basis for developing and assessing methods to measure commonly-prescribed protease inhibitors (PIs) - lopinavir (LPV) and atazanavir (ATV) - in small hair samples. We examined the association between hair PI levels and initial virologic responses to therapy in multivariate logistic regression models.
ARV concentrations in hair were strongly and independently associated with treatment response for 224 women starting a new PI-based regimen. For participants initiating LPV/RTV, the odds ratio (OR) for virologic suppression was 39.8 (95%CI 2.8–564) for those with LPV hair levels in the top tertile (>1.9ng/mg) compared to the bottom (≤0.41ng/mg) when controlling for self-reported adherence, age, race, starting viral load and CD4, and prior PI experience. For women starting ATV, the adjusted OR for virologic success was 7.7 (95%CI 2.0-29.7) for those with hair concentrations in the top tertile (>3.4ng/mg) compared to the lowest (≤1.2ng/mg).
PI levels in small hair samples were the strongest independent predictor of virologic success in a diverse group of HIV-infected adults. This noninvasive method for determining ARV exposure may have particular relevance for the epidemic in resource-poor settings due to the ease of collecting and storing hair.
Hair levels; therapeutic drug monitoring; antiretroviral exposure; virologic response; protease inhibitors; atazanavir; lopinavir; WIHS cohort
Our objective was to describe the association that childcare burden, household composition, and health care utilization have with adherence to highly active antiretroviral therapy (HAART) among women in the United States. The primary outcome was 95% or more adherence to HAART evaluated at 10,916 semiannual visits between October 1998 and March 2006 among 1419 HIV-infected participants enrolled in the Women’s Interagency HIV Study. HAART adherence levels of 95% or more were reported at 76% of the semiannual visits. At only 4% of the person-visits did women report either quite a bit or extreme difficulty in caring for child; at 52% of the person-visits women reported at least one child 18 years of age or older living in the household. We found a one-unit increase in the difficulty in caring for children (childcare burden was assessed on a 5-point scale: not difficult  to extremely difficult ) was associated with a 6% decreased odds of 95% or more HAART adherence (adjusted odds ratio [OR]=0.94; p=0.07). Each additional child 18 years of age or less living in the household was associated with an 8% decreased odds of 95% or more adherence (adjusted OR=0.92, p=0.03). Both the number and type of adult living in the household, as well as health care utilization were not associated with HAART adherence. Greater child care burden and number of children 18 years old or younger living in household were both inversely associated with HAART adherence. Assessing patients’ difficulties in caring for children and household composition are important factors to consider when addressing adherence to HAART.
A highly sensitive and selective method using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) was developed and validated for the measurement of three antiretroviral agents, efavirenz, lopinavir and ritonavir, in human hair. Hair samples from adherent HIV-infected patients on antiretroviral therapies were cut into about 1 mm length segments and drugs were extracted by first shaking the samples with methanol in a 37°C water bath overnight (>14 h), followed by methyl tert-butyl ether/ethyl acetate (1:1) extraction under weak alkaline conditions. The extracted lopinavir and ritonavir were separated by reversed-phase chromatography and detected by tandem mass spectrometry in electrospray positive ionization mode with multiple reaction monitoring (MRM), while efavirenz was monitored in negative ionization MRM mode. This method was validated from 0.01 to 4.0 ng/mg hair for ritonavir and 0.05–20 ng/mg hair for lopinavir and efavirenz by using 2 mg of a human hair sample. The interday and intraday assay precision (coefficients of variation, CV) for spiked quality control (QC) samples at low, medium and high concentrations were within 15% and accuracy ranged from 89% to 110%. Assay reproducibility was also demonstrated by analysis of incurred hair QC samples (CV <14%). No significant matrix ionization suppression was observed. This developed method allowed for the monitoring of these target medications in the hair samples of HIV-infected women on antiretroviral therapy in an observational study using small amounts of hair.