Poor Obstetric and Infant Outcomes in Human Immunodeficiency Virus-Infected Pregnant Women With Tuberculosis in South Africa: The Tshepiso Study

Background

Before the wide availability of antiretroviral therapy (ART), tuberculosis and human immunodeficiency virus (HIV) disease among pregnant women resulted in poor maternal and neonatal outcomes, including high rates of mother-to-child transmission of both HIV and tuberculosis. We aimed to describe the impact of tuberculosis among HIV-infected mothers on obstetric and infant outcomes in a population with access to ART.

Methods

In this prospective cohort study, we followed up HIV-infected pregnant women with or without tuberculosis disease from January 2011 through January 2014 in Soweto, South Africa. Two controls were enrolled for each case patient, matched by enrollment time, maternal age, gestational age, and planned delivery clinic and followed up for 12 months after delivery.

Results

We recruited 80 case patients and 155 controls, resulting in 224 live-born infants. Infants of mothers with HIV infection and tuberculosis disease had a higher risk of low birth weight (20.8% vs 10.7%; P = .04), prolonged hospitalization at birth (51% vs 16%; P < .001), infant death (68 vs 7 deaths per 1000 births; P < .001), and tuberculosis disease (12% vs 0%; P < .001) despite appropriate maternal therapy and infant tuberculosis preventive therapy. HIV transmission was higher among these infants (4.1% vs 1.3%; P = .20), though this difference was not statistically significant. Obstetric outcomes in coinfected women were also poorer with higher risks of maternal hospitalization (25% vs 11%; P = .005) and preeclampsia (5.5% vs 0.7%; P = .03).

Conclusions

Tuberculosis in HIV coinfected pregnant women remains a significant threat to the health of both mothers and infants. Improving tuberculosis prevention and early diagnosis among pregnant women is critical.

Prevention of TB using rifampicin plus isoniazid reduces nevirapine concentrations in HIV-exposed infants

Background

Newborns of HIV-infected mothers are given daily doses of nevirapine to prevent HIV-1 acquisition. Infants born to mothers with TB should also receive TB preventive therapy. TB preventive regimens include isoniazid for 6 months or rifampicin plus isoniazid for 3 months (RH preventive therapy). The effect of concomitant RH preventive therapy on nevirapine concentrations in infants is unknown.

Patients and methods

Tshepiso was a prospective case-control cohort study of pregnant HIV-infected women with and without TB whose newborn infants received standard doses of nevirapine for HIV prophylaxis. Infants born to mothers with TB also received RH preventive therapy. Infant plasma nevirapine concentrations were measured at 1 and 6 weeks. The effects of RH preventive therapy on nevirapine disposition were investigated in a population pharmacokinetic model.

Results

Of 164 infants undergoing pharmacokinetic sampling, 46 received RH preventive therapy. After adjusting for weight using allometric scaling, the model estimated a 33% reduction in nevirapine trough concentrations with RH preventive therapy compared with TB-unexposed infants not receiving concomitant rifampicin and a 30% decline in trough concentrations in a typical infant between day 7 and 35 post-partum.

Conclusions

Rifampicin-based TB preventative treatment reduces nevirapine concentrations significantly in HIV-exposed infants. Although the nevirapine exposures required to prevent HIV acquisition in breastfeeding infants are undefined, given the potential risks associated with underdosing nevirapine in this setting, it is prudent to avoid rifampicin-based preventive therapy in HIV-exposed children receiving prophylactic nevirapine.

Treatment Failure, Drug Resistance, and CD4 T-Cell Count Decline Among Postpartum Women on Antiretroviral Therapy in South Africa

BACKGROUND

We assessed HIV RNA suppression, resistance, and CD4 T-cell count 12 months postpartum among pregnant women retained in care in an observational cohort study.

METHODS

We prospectively followed two groups of HIV-infected pregnant women--with or without tuberculosis--recruited from prenatal clinics in South Africa. Women who received antiretroviral therapy during pregnancy and reported being on therapy 12 months postpartum were included. Serum samples from women with HIV viremia 12 months postpartum were tested for drug resistance.

RESULTS

Of 103 women in the study, median age and CD4 T-cell count at enrollment were 29 years [interquartile range (IQR): 26-32] and 317 cells per cubic millimeter (IQR: 218-385), respectively; 43 (42%) had tuberculosis at baseline. During pregnancy, 87% of the women achieved an HIV RNA <400 copies per milliliter compared with 71% at 12 months postpartum (P < 0.001). Factors independently associated with an HIV RNA <400 copies per milliliter at 12 months were age ≥ 30 years, detectable plasma efavirenz concentration, and HIV RNA <400 copies per milliliter while pregnant; there was a trend toward both a detectable viral load and peripartum depression. HIV drug resistance results were available from 25 women, and 12 (48%) had major drug resistance mutations. CD4 T-cell count declined a median of 13 cells per cubic millimeter (IQR: -66 to 140) from delivery to 12 months in women with viremia at 12 months.

CONCLUSIONS

Success with maintaining virologic control declined postpartum among HIV-infected women who remained in care and on antiretroviral therapy, and CD4 T-cell count decline and drug resistance were common.

Pharmacokinetics of efavirenz and treatment of HIV-1 among pregnant women with and without tuberculosis coinfection

BACKGROUND

Pregnancy and tuberculosis treatment or prophylaxis can affect efavirenz pharmacokinetics, maternal human immunodeficiency virus type 1 (HIV-1) treatment outcomes, and mother-to-child transmission (MTCT) risk.

METHODS

We evaluated a prospective cohort of pregnant, HIV-infected women with and without tuberculosis in Soweto, South Africa. Pharmacokinetic sampling was performed at gestation week 37 and during the postpartum period. Efavirenz trough concentrations (Cmin) were predicted using population pharmacokinetic models. HIV-viral load was measured at delivery for mothers and at 6 weeks of age for infants.

RESULTS

Ninety-seven women participated; 44 had tuberculosis. Median efavirenz Cmin during pregnancy was 1.35 µg/mL (interquartile range [IQR], 0.90-2.07 µg/mL; 27% had an efavirenz Cmin of < 1 µg/mL), compared with a median postpartum value of 2.00 µg/mL (IQR, 1.40-3.59 µg/mL; 13% had an efavirenz Cmin of < 1 µg/mL). A total of 72% of pregnant women with extensive CYP2B6 genotypes had an efavirenz Cmin of <1 µg/mL. Rifampin did not reduce the efavirenz Cmin. Isoniazid (for prophylaxis or treatment), though, reduced the rate of efavirenz clearance. At delivery, median durations of ART were 13 weeks (IQR, 9-18 weeks) and 21 weeks (IQR, 13-64 weeks) for women with and those without tuberculosis, respectively; 55% and 83%, respectively, had a viral load of <20 copies/mL (P = .021). There was 1 case of MTCT.

CONCLUSIONS

Pregnancy increased the risk of low efavirenz concentrations, but MTCT was rare. A detectable HIV-viral load at delivery was more common among pregnant women with tuberculosis, in whom ART was generally initiated later.