Comparative predictive power of serum vs plasma proteomic signatures in feto-maternal medicine

BACKGROUND

Blood proteins are frequently measured in serum or plasma, because they provide a wealth of information. Differences in the ex vivo processing of serum and plasma raise concerns that proteomic health and disease signatures derived from serum or plasma differ in content and quality. However, little is known about their respective power to predict feto-maternal health outcomes. Predictive power is a sentinel characteristic to determine the clinical use of biosignatures.

OBJECTIVE

This study aimed to compare the power of serum and plasma proteomic signatures to predict a physiological pregnancy outcome.

STUDY DESIGN

Paired serum and plasma samples from 73 women were obtained from biorepositories of a multinational prospective cohort study on pregnancy outcomes. Gestational age at the time of sampling was the predicted outcome, because the proteomic signatures have been validated for such a prediction. Multivariate and cross-validated models were independently derived for serum and plasma proteins.

RESULTS

A total of 1116 proteins were measured in 88 paired samples from 73 women with a highly multiplexed platform using proximity extension technology (Olink Proteomics Inc, Watertown, MA). The plasma proteomic signature showed a higher predictive power (R=0.64; confidence interval, 0.42-0.79; P=3.5×10^-6) than the serum signature (R=0.45; confidence interval, 0.18-0.66; P=2.2×10^-3). The serum signature was validated in plasma with a similar predictive power (R=0.58; confidence interval, 0.34-0.75; P=4.8×10^-5), whereas the plasma signature was validated in serum with reduced predictive power (R=0.53; confidence interval, 0.27-0.72; P=2.6×10^-4). Signature proteins largely overlapped in the serum and plasma, but the strength of association with gestational age was weaker for serum proteins.

CONCLUSION

Findings suggest that serum proteomics are less informative than plasma proteomics. They are compatible with the view that the partial ex-vivo degradation and modification of serum proteins during sample processing are an underlying reason. The rationale for collecting and analyzing serum and plasma samples should be carefully considered when deriving proteomic biosignatures to ascertain that specimens of the highest scientific and clinical yield are processed. Findings suggest that plasma is the preferred matrix.

Association of mid-trimester maternal angiogenic biomarkers with small-for-gestational-age infants in an urban Zambian cohort: a nested case-control study

Objective

To investigate whether angiogenic biomarker concentrations differ between women who deliver small‐for‐gestational‐age (SGA) infants (<10th centile birth weight for gestational age) compared with controls, because identifying SGA risk early could improve outcomes.

Methods

This case‐control study compared serum concentrations of angiogenic biomarkers before 24 weeks of pregnancy from 62 women who delivered SGA infants (cases) and 62 control women from an urban Zambian cohort. Odds of delivering an SGA infant were calculated using conditional logistic regression.

Results

Placental growth factor (PlGF), soluble fms‐like tyrosine kinase (sFLT‐1) and soluble endoglin (sEng) in controls were 37.74 pg/mL (interquartile range [IQR] 23.12–63.15), 2525.18 pg/mL (IQR 1502.21–4265.54) and 2408.18 pg/mL (IQR 1854.87–3017.94), respectively. SGA cases had higher PlGF (40.50 pg/mL, IQR 22.81–67.94) and sFLT‐1 (2613.06 pg/mL, IQR 1720.58–3722.50), and lower sEng (2038.06 pg/mL, IQR 1445.25–3372.26). Participants with sEng concentration below and concomitant sFLT‐1 concentration above their respective thresholds (n = 40) had five‐fold higher odds of SGA (adjusted odds ratio 4.77, 95% confidence interval 1.61–14.1; P = 0.005).

Conclusion

Biomarker concentrations were similar between cases and controls. Participants with concomitant low sEng and high sFLT‐1 had the highest odds of SGA, suggesting that a combination of biomarkers may better for predicting SGA than single biomarkers.

Prediction of SGA risk using the interaction of multiple angiogenic biomarkers may perform better than using a single angiogenic biomarker concentration before 24 weeks gestation.

Maternal HIV, antiretroviral timing, and spontaneous preterm birth in an urban Zambian cohort: the role of local and systemic inflammation

OBJECTIVE

To assess plasma and vaginal inflammation in three antenatal groups (HIV-uninfected women, HIV-infected women entering care on preconceptional ART, and HIV-infected women not on preconceptional ART) and whether these measures are associated with spontaneous preterm birth (sPTB).

DESIGN

Case--control study nested within a pregnancy cohort in Lusaka, Zambia.

METHODS

We analyzed 11 pro-inflammatory and two anti-inflammatory markers in 207 women with paired plasma and vaginal specimens collected between 16 and 20 gestational weeks. Among 51 HIV-infected women, we repeated the assays in 24-34-week samples. We used confirmatory factor analysis to create inflammation scores and compared them among the three groups.

RESULTS

At baseline, HIV-infected women not on ART had higher vaginal pro-inflammatory scores than HIV-uninfected women [mean 0.37 (95% CI -0.06 to 0.80) vs. -0.02 (-0.32 to 0.27), P = 0.02]. In repeat testing, women not on preconceptional ART had an increase in vaginal inflammation between the baseline and 24-34-week visits compared with those continuing preconceptional ART [mean 0.62 (95% CI -0.80 to 4.20) vs. -0.07 (-2.78 to 2.11), P = 0.04]. In multivariate analyses, baseline vaginal inflammation predicted sPTB (aOR 1.5; 95% CI 1.0-2.3; P = 0.02). Plasma inflammation did not differ by HIV or ART exposure and was not associated with sPTB.

CONCLUSION

Women not receiving ART at entry into pregnancy care had more vaginal inflammation than women entering on treatment. They also experienced an increase in vaginal inflammation between the two sampling timepoints, possibly as a consequence of ART initiation. Vaginal (but not systemic) inflammation was associated with sPTB and offers a potential mechanistic insight into this important adverse birth outcome.

Effects of Depot Medroxyprogesterone Acetate, Copper Intrauterine Devices, and Levonorgestrel Implants on Early HIV Disease Progression

Limited data exist on the effects of contraceptives on HIV disease progression. We studied the association between intramuscular injectable depot medroxyprogesterone acetate (DMPA-IM), the copper intrauterine device (IUD), and the levonorgestrel (LNG) implant on markers of HIV disease progression at the time of HIV detection and 3 months postdetection and time from detection to CD4 count <350 cells/mm³. Among women initiating antiretroviral therapy (ART), we studied the effect of contraceptive group on time from ART initiation to viral load (VL) <40 copies/mL. We included women 16-35 years randomized to DMPA-IM, copper IUD, or LNG implant with incident HIV infection during the Evidence for Contraceptive Options and HIV Outcomes (ECHO) trial (n = 382). We analyzed HIV VL and CD4 cell count according to participants' randomized method and also conducted a "continuous use" analysis that excluded follow-up time after method discontinuation. We used adjusted linear models to compare mean VL and CD4 cell levels by contraceptive group up to the time of ART initiation. We compared time from HIV detection to CD4 count <350 cells/mm³ and, following ART initiation, time to viral suppression (VL <40 copies/mL) using Cox proportional hazards models. At HIV detection, women allocated to DMPA-IM had lower VL relative to copper IUD (-0.28 log₁₀ copies/mL; 95% confidence interval [CI]: -0.55 to -0.01) and LNG implant (-0.27, CI: -0.55 to 0.02) and higher mean CD4 than copper IUD users by 66 cells/mm³ (CI: 11-121). In continuous use analyses women allocated to DMPA-IM progressed to CD4 < 350 cells/mm³ slower than copper IUD users (hazard ratio [HR] = 0.6, CI: 0.3-1.1), whereas copper IUD users progressed faster than LNG implant users (HR = 1.8, CI: 1.0-3.3). Time to viral suppression was faster for DMPA-IM than copper IUD (HR = 1.5, CI: 1.0-2.3) and LNG implant 1.4 (CI: 0.9-2.2) users. We found no evidence of more rapid early HIV disease progression among women using DMPA-IM than among women using copper IUD or LNG implant. Our finding of more rapid progression among copper IUD compared with DMPA-IM users should be interpreted cautiously.

The Zambian Preterm Birth Prevention Study (ZAPPS): Cohort characteristics at enrollment

Background:Sub-Saharan Africa bears a disproportionate burden of preterm birth and other adverse outcomes. A better understanding of the demographic, clinical, and biologic underpinnings of these adverse outcomes is urgently needed to plan interventions and inform new discovery.  Methods:The Zambian Preterm Birth Prevention Study (ZAPPS) is a prospective observational cohort established at the Women and Newborn Hospital (WNH) in Lusaka, Zambia. We recruit pregnant women from district health centers and the WNH and offer ultrasound examination to determine eligibility. Participants receive routine obstetrical care, lab testing, midtrimester cervical length measurement, and serial fetal growth monitoring. At delivery, we assess gestational age, birthweight, vital status, and sex and assign a delivery phenotype. We collect blood, urine, and vaginal swab specimens at scheduled visits and store them in an on-site biorepository. In September 2017, enrollment of the ZAPPS Phase 1 – the subject of this report – was completed. Phase 2 – which is limited to HIV-uninfected women – reopened in January 2018.  Results:Between August 2015 and September 2017, we screened 1784 women, of whom 1450 (81.2%) met inclusion criteria and were enrolled. The median age at enrollment was 27 years (IQR 23–32) and thee median gestational age was 16 weeks (IQR 13–18). Among parous women (N=866; 64%), 21% (N=182) reported a prior miscarriage, 49% (N=424) reported a prior preterm birth, and 13% (N=116) reported a prior stillbirth. The HIV seroprevalence was 24%. Discussion:We have established a large cohort of pregnant women and newborns at the WHN to characterize the determinants of adverse birth outcomes in Lusaka, Zambia. Our overarching goal is to elucidate biological mechanisms in an effort to identify new strategies for early detection and prevention of adverse outcomes. We hope that findings from this cohort will help guide future studies, clinical care, and policy.

Age at antiretroviral therapy initiation predicts immune recovery, death, and loss to follow-up among HIV-infected adults in urban Zambia

We analyzed the association of age at antiretroviral therapy (ART) initiation with CD4(+) T cell count recovery, death, and loss to follow-up (LTFU) among HIV-infected adults in Zambia. We compared baseline characteristics of patients by sex and age at ART initiation [categorized as 16-29 years, 30-39 years, 40-49 years, 50-59 years, and 60 years and older]. We used the medication possession ratio to assess adherence and analysis of covariance to measure the adjusted change in CD4(+) T cell count during ART. Using Cox proportional hazard regression, we examined the association of age with death and LTFU. In a secondary analysis, we repeated models with age as a continuous variable. Among 92,130 HIV-infected adults who initiated ART, the median age was 34 years and 6,281 (6.8%) were aged ≥50 years. Compared with 16-29 year olds, 40-49 year olds (-46 cells/mm(3)), 50-59 year olds (-53 cells/mm(3)), and 60+ year olds (-60 cells/mm(3)) had reduced CD4(+) T cell gains during ART. The adjusted hazard ratio (AHR) for death was increased for individuals aged ≥40 years (AHR 1.25 for 40-49 year olds, 1.56 for 50-59 year olds, and 2.97 for 60+ year olds). Adherence and retention in care were poorest among 16-29 year olds but similar in other groups. As a continuous variable, a 5-year increase in age predicted reduced CD4(+) T cell count recovery and increased risk of death. Increased age at ART initiation was associated with poorer clinical outcomes, while age <30 years was associated with a higher likelihood of being lost to follow-up. HIV treatment guidelines should consider age-specific recommendations.

Short communication: Late refills during the first year of antiretroviral therapy predict mortality and program failure among HIV-infected adults in urban Zambia

We evaluated the association of the number of late antiretroviral therapy (ART) refills with patient outcomes in a large public-sector human immunodeficiency virus treatment program in Lusaka, Zambia. Using pharmacy data routinely collected during 2004-2010, we calculated the number of late refills during the initial year of ART. We used multivariable Cox proportional hazard regression to examine the association between the number of late refills and death or program failure (i.e., death, loss to follow-up, or program withdrawal) >12 months after ART initiation, with and without stratification by the medication possession ratio (MPR) during the initial year of ART. Of 53,015 adults who received ART for ≥12 months (median follow-up duration, 86.1 months; interquartile range, 53.2-128.2 months), 26,847 (50.6%) had 0 late refills, 16,762 (31.6%) had 1, 6,505 (12.3%) had 2, and 2,901 (5.5%) had ≥3. Kaplan-Meier analysis revealed that ≥3 late refills was associated with a greater mortality risk than 1 and 2 late refills (p<0.001, by the log-rank test). The mortality risk was greater for patients with 2 late refills [adjusted hazard ratio (HR), 1.17; 95% confidence interval (CI), 0.99-1.38] or ≥3 late refills (adjusted HR, 1.51; 95% CI, 1.23-1.87), compared with that for patients with 0-1 late refills. Program failure was associated with ≥2 late refills. An MPR of <80% was associated with similar increases in mortality risk across late-refill strata. Monitoring late refills during the initial period of ART may help resource- and time-constrained clinics identify patients at risk for program failure.

Adherence to antiretroviral therapy during and after pregnancy in low-income, middle-income, and high-income countries: a systematic review and meta-analysis

OBJECTIVE

To estimate antiretroviral therapy (ART) adherence rates during pregnancy and postpartum in high-income, middle-income, and low-income countries.

DESIGN

Systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE, SCI Web of Science, NLM Gateway, and Google scholar databases were searched. We included all studies reporting adherence rates as a primary or secondary outcome among HIV-infected pregnant women. Two independent reviewers extracted data on adherence and study characteristics. A random-effects model was used to pool adherence rates; sensitivity, heterogeneity, and publication bias were assessed.

RESULTS

Of 72 eligible articles, 51 studies involving 20 153 HIV-infected pregnant women were included. Most studies were from United States (n =  14, 27%) followed by Kenya (n = 6, 12%), South Africa (n = 5, 10%), and Zambia (n = 5, 10%). The threshold defining good adherence to ART varied across studies (>80, >90, >95, 100%). A pooled analysis of all studies indicated a pooled estimate of 73.5% [95% confidence interval (CI) 69.3-77.5%] of pregnant women who had adequate (>80%) ART adherence. The pooled proportion of women with adequate adherence levels was higher during the antepartum (75.7%, 95% CI 71.5-79.7%) than during postpartum (53.0%, 95% CI 32.8-72.7%; P = 0.005). Selected reported barriers for nonadherence included physical, economic and emotional stresses, depression (especially postdelivery), alcohol or drug use, and ART dosing frequency or pill burden.

CONCLUSION

Our findings indicate that only 73.5% of pregnant women achieved optimal ART adherence. Reaching adequate ART adherence levels was a challenge in pregnancy, but especially during the postpartum period. Further research to investigate specific barriers and interventions to address them is urgently needed globally.

Hyponatremia, hypochloremia, and hypoalbuminemia predict an increased risk of mortality during the first year of antiretroviral therapy among HIV-infected Zambian and Kenyan women

Early mortality rates after initiating antiretroviral therapy (ART) are high in sub-Saharan Africa. We examined whether serum chemistries at ART initiation predicted mortality among HIV-infected women. From May 2005 to January 2007, we enrolled women initiating ART in a prospective cohort study in Zambia and Kenya. We used Cox proportional hazards models to identify risk factors associated with mortality. Among 661 HIV-infected women, 53 (8%) died during the first year of ART, and tuberculosis was the most common cause of death (32%). Women were more likely to die if they were both hyponatremic (sodium <135 mmol/liter) and hypochloremic (chloride <95 mmol/liter) (37% vs. 6%) or hypoalbuminemic (albumin <34 g/liter, 13% vs. 4%) when initiating ART. A body mass index <18 kg/m(2) [adjusted hazard ratio (aHR) 5.3, 95% confidence interval (CI) 2.6-10.6] and hyponatremia with hypochloremia (aHR 4.5, 95% CI 2.2-9.4) were associated with 1-year mortality after adjusting for country, CD4 cell count, WHO clinical stage, hemoglobin, and albumin. Among women with a CD4 cell count >50 cells/μl, hypoalbuminemia was also a significant predictor of mortality (aHR=3.7, 95% CI 1.4-9.8). Baseline hyponatremia with hypochloremia and hypoalbuminemia predicted mortality in the first year of initiating ART, and these abnormalities might reflect opportunistic infections (e.g., tuberculosis) or advanced HIV disease. Assessment of serum sodium, chloride, and albumin can identify HIV-infected patients at highest risk for mortality who may benefit from more intensive medical management during the first year of ART.

Intrapartum tenofovir and emtricitabine reduces low-concentration drug resistance selected by single-dose nevirapine for perinatal HIV prevention

A single dose of tenofovir/emtricitabine (TDF/FTC) during labor significantly reduces peripartum nevirapine-associated viral drug resistance when measured by consensus HIV sequencing. It is unknown whether this effect extends to HIV subpopulations of <25-50%. We conducted a randomized trial of single-dose TDF/FTC added to peripartum nevirapine to reduce drug resistance associated with nonnucleoside reverse transcriptase inhibitors (NNRTIs). To detect mutations for NNRTIs comprising > or = 2% of the viral population, we used an oligonucleotide ligation assay (OLA) at codons 103, 106, 181, and 190 of HIV reverse transcriptase. To assess development of drug resistance mutations to our study intervention, OLA was also performed at codons 65 and 184. Among the 328 women included in the 2-week analysis, those receiving TDF/FTC were less likely to have NNRTI resistance by OLA (RR = 0.40, 95% CI = 0.21-0.77). A similar trend was observed among the 315 women included in the 6-week analysis (RR = 0.45, 95% CI = 0.31-0.66). Only two (1%) specimens had detectable K65R by OLA. Both were at 6 weeks postpartum; one was detected in the intervention arm and one in the control arm (p = 0.96). M184V was not detected. The ability of single-dose TDF/FTC to protect against peripartum NVP-induced NNRTI resistance extends to minority populations. This efficacy is achieved without significant selection of TDF- or FTC-resistant viruses.

Management of cryotherapy-ineligible women in a "screen-and-treat" cervical cancer prevention program targeting HIV-infected women in Zambia: lessons from the field

OBJECTIVE

We demonstrate the feasibility of implementing a referral and management system for cryotherapy-ineligible women in a "screen-and-treat" cervical cancer prevention program targeting HIV-infected women in Zambia.

METHODS

We established criteria for patient referral, developed a training program for loop electrosurgical excision procedure (LEEP) providers, and adapted LEEP to a resource-constrained setting.

RESULTS

We successfully trained 15 nurses to perform visual inspection with acetic acid (VIA) followed by immediate cryotherapy. Women with positive tests but ineligible for cryotherapy were referred for further evaluation. We trained four Zambian physicians to evaluate referrals, perform punch biopsy, LEEP, and manage intra-operative and post-operative complications. From January 2006 through October 2007, a total of 8823 women (41.5% HIV seropositive) were evaluated by nurses in outlying prevention clinics; of these, 1477 (16.7%) were referred for physician evaluation based on established criteria. Of the 875 (59.2% of 1147 referred) that presented for evaluation, 748 (8.4% of total screened) underwent histologic evaluation in the form of punch biopsy or LEEP. Complications associated with LEEP included anesthesia reaction (n=2) which spontaneously resolved, intra-operative (n=12) and post-operative (n=2) bleeding managed by local measures, and post-operative infection (n=12) managed with antibiotics.

CONCLUSION

With adaptations for a resource-constrained environment, we have demonstrated that performing LEEP is feasible and safe, with low rates of complications that can be managed locally. It is important to establish referral and management systems using LEEP-based excisional evaluation for women with cryotherapy-ineligible lesions in VIA-based "screen-and-treat" protocols nested within HIV-care programs in resource-constrained settings.

Simple adherence assessments to predict virologic failure among HIV-infected adults with discordant immunologic and clinical responses to antiretroviral therapy

We evaluated the association between two antiretroviral therapy (ART) adherence measurements--the medication possession ratio (MPR) and patient self-report--and detectable HIV viremia in the setting of rapid service scale-up in Lusaka, Zambia. Drug adherence and outcomes were assessed in a subset of patients suspected of treatment failure based on discordant clinical and immunologic responses to ART. A total of 913 patients were included in this analysis, with a median time of 744 days (Q1, Q3: 511, 919 days) from ART initiation to viral load (VL) measurement. On aggregate over the period of follow-up, 531 (58%) had optimal adherence (MPR > or =95%), 306 (34%) had suboptimal adherence (MPR 80-94%), and 76 (8%) had poor adherence (MPR <80%). Of the 913 patients, 238 (26%) had VL > or =400 copies/ml when tested. When compared to individuals with optimal adherence, there was increasing risk for virologic failure in those with suboptimal adherence [adjusted relative risk (ARR): 1.3; 95% confidence interval (CI): 1.0, 1.6] and those with poor adherence (ARR: 1.7; 95% CI: 1.3, 2.4) based on MPR. During the antiretroviral treatment course, 676 patients (74%) reported no missed doses. The proportion of patients with virologic failure did not differ significantly among those reporting any missed dose from those reporting perfect adherence (26% vs. 26%, p = 0.97). Among patients with suspected treatment failure, a lower MPR was associated with higher rates of detectable viremia. However, the suboptimal sensitivity and specificity of MPR limit its utility as a sole predictor of virologic failure.

Evaluation of a new testing policy for human immunodeficiency virus to improve screening rates

OBJECTIVE

To assess the effect of a change in human immunodeficiency virus (HIV) testing policy on HIV testing rates in an urban maternity clinic population.

METHODS

Since 1995, our institution has provided pretest counseling and voluntary HIV testing to all pregnant women. After the 1999 Institute of Medicine recommendation of HIV testing with patient notification as a routine component of prenatal care, we conducted a prospective study to determine whether this policy would increase our HIV screening rates. The intervention incorporated HIV testing into the routine battery of tests drawn at antenatal care. Not to be tested required active refusal. The intervention group was comprised of all women receiving an initial antenatal visit in one of our eight maternity clinics between August 1, 1999, and July 30, 2000. The control group was comprised of all women presenting for prenatal care in the same clinics during the year before the intervention.

RESULTS

The 3415 women in the intervention group and 3778 controls were similar with respect to most demographic and risk factors. After the intervention, HIV testing increased from 75% to 88% (P <.001). Among all women in both years of the study, women who were in the intervention group, less than 20 years of age, or who had a history of substance abuse, were more likely not to refuse testing.

CONCLUSION

After implementation of a policy of routine HIV testing with active patient refusal, HIV testing rates increased among pregnant women in our large, urban obstetric clinic population.

Zambian women's attitudes toward mass nevirapine therapy to prevent perinatal transmission of HIV

Use of mass nevirapine therapy--universal provision of the drug without HIV testing--for prevention of perinatal HIV in high prevalence settings with extreme resource constraints is a controversial strategy. A quarter of pregnant Zambian women surveyed would prefer to receive nevirapine through a non-testing mass strategy, and most would support mass therapy as a policy if it would make the drug available to a larger proportion of the at-risk population.

Cost-effective use of nevirapine to prevent vertical HIV transmission in sub-Saharan Africa

OBJECTIVE

To assess the cost-effectiveness of alternative strategies of nevirapine (NVP) administration to prevent vertical HIV transmission in sub-Saharan Africa.

DESIGN

A decision-analysis model was constructed to estimate the costs and effects of NVP-based prevention strategies for two separate groups of women: those who qualify for standard therapy by attending a 36-week prenatal visit, and those who do not qualify, owing to preterm delivery or lack of prenatal care.

RESULTS

For women in prenatal care, mass provision of NVP without maternal serodiagnosis was found to yield greater health gains at an acceptable cost, compared with providing targeted therapy to only those women identified as seropositive. However, this conclusion was strongly contingent on several uncertain assumptions, most importantly the probability that a woman who does not know her serostatus will nonetheless adhere to therapy. Among those women who present for delivery without prior enrollment in a prenatal strategy, either late provision of maternal-infant NVP or treatment of only the infant would likely be a cost-effective alternative to the current practice of offering no preventive therapy.

CONCLUSIONS

NVP intervention offers a cost-effective avenue for preventing vertical HIV transmission in sub-Saharan Africa. The optimal choice between mass therapy and targeted therapy cannot be confidently identified without information regarding adherence among women who do not know their serostatus. For women who do not receive NVP prenatally, treatment on presentation for delivery would be cost-effective even in the face of modest clinical efficacy. Clinical assessment of adherence to therapy among women who do not know their status and the field effectiveness of alternative approaches to NVP administration is urgently needed to allow identification of optimal prevention strategies.

An appraisal of screening for maternal type-specific herpes simplex virus antibodies to prevent neonatal herpes

Almost all neonatal herpes simplex virus infections occur as a result of first-episode maternal infection during late pregnancy when delivery occurs before the development of protective maternal antibodies. Screening of pregnant women for the presence of type-specific herpes simplex virus antibodies has therefore been suggested as a means of identifying women vulnerable to herpes simplex virus acquisition and subsequent transmission of herpes simplex virus to their neonates. Couples in whom herpes simplex virus serotype discordance is identified could be counseled regarding sexual behavior modification to avoid maternal herpes simplex virus infection. However, the ramifications of routine screening for herpes simplex virus susceptibility during pregnancy could be profound in terms of costs, prenatal care delivery, and even social duress. The recent US Food and Drug Administration approval of type-specific herpes simplex virus antibody assays for clinical use lends temporal urgency to the need for a critical examination of the relevant data. After we performed such an evaluation and created a decision analysis model to assess the potential cost-effectiveness of herpes simplex virus antibody screening, we concluded that screening for maternal type-specific herpes simplex virus antibodies cannot be recommended to prevent neonatal herpes.

Prevention of mother-to-child transmission of HIV-1

Several recently published randomized trials have demonstrated that a substantial proportion of the mother-to-child transmission of HIV-1 can be prevented by antiretroviral therapy late in gestation and at delivery to mother and infant. The cost implications of these findings are considerable for resource-poor settings. Preliminary data also suggest very low rates of transmission among mothers receiving maximally suppressive combination drug regimens. Prophylactic cesarean delivery has also been shown to reduce transmission in women not receiving antiretroviral agents, and may play a role in selected patients. The avoidance of breast feeding with infant formula supplementation is clearly protective against HIV-1 transmission, but may not improve infant survival in some poorer settings because of associated increases in other infectious diseases and malnutrition.

Prevention of mother-to-child transmission of HIV in Thailand: physicians' attitudes on zidovudine use, pregnancy termination, and willingness to provide care

We administered a survey to Thai physicians, using regular mail, on their attitudes and practices regarding zidovudine (ZDV) use and pregnancy termination in HIV-infected pregnant women. We surveyed their willingness to care for these patients as well. In 1997, 79.5% of 480 respondents reported that they did not routinely use perinatal ZDV prophylaxis. Predictors of failure to use ZDV found to be significant in our logistic regression model included practice outside of Bangkok (odds ratio [OR] = 2.0), belief that ZDV is not cost effective (OR = 2.5), unfamiliarity with AIDS Clinical Trials Group (ACTG) 076 results (OR = 2.5), and failure to screen for HIV routinely (OR = 4.9). Elective abortion for HIV-infected women was advocated by 45.3% of respondents. Factors associated in multivariable analysis with this preference included specialty training in obstetrics/gynecology (OR = 1.8), practice inside Bangkok (OR = 2.0), male gender (OR = 1.9), and treatment of < or =2 HIV-infected patients yearly (OR = 1.8). A significant proportion of respondents described themselves as unwilling to perform pelvic examinations (19.2%), vaginal deliveries (30.7%), or cesarean deliveries (39.5%) on women who were known to be infected with HIV. We conclude that many Thai obstetric providers are reluctant to care for HIV-infected women, do not routinely use perinatal ZDV prophylaxis, and prefer to terminate pregnancies among HIV-infected patients. Physician education concerning the value of HIV screening and antiretroviral therapy in HIV-infected pregnant women is needed urgently in Thailand.

Rapid testing and zidovudine treatment to prevent vertical transmission of human immunodeficiency virus in unregistered parturients: a cost-effectiveness analysis

OBJECTIVE

To assess the potential effectiveness and costs of a program to prevent vertical transmission of human immunodeficiency virus (HIV) in parturients without prenatal care.

METHODS

A decision-analysis model was constructed to compare three management strategies for unregistered women presenting in labor: 1) the current standard of treating no one; 2) HIV testing with a rapid antibody assay, followed by zidovudine treatment according to AIDS Clinical Trial Group Protocol 076 if seropositive; and 3) treating all women without rapid testing. Cost and probability data were obtained from a literature review and local estimates. Sensitivity analyses were performed for pertinent uncertainties.

RESULTS

Under baseline assumptions (5% HIV prevalence, treatment efficacy of an 18% reduction in transmission rate, and lifetime cost of pediatric HIV $103,708), giving no treatment resulted in 1275 infected infants per 100,000 mother-infant pairs. The rapid-test strategy prevented 183 cases of infant HIV infection and resulted in a net savings to the medical system of $57,997 per case averted. The treat-all strategy prevented an additional 46 cases per 100,000 mother-infant pairs, but at a cost of $342,068 per additional case averted. With other estimates at baseline, rapid testing was cost-saving when the HIV prevalence exceeded 0.97%, the treatment efficacy exceeded a 5.8% reduction in the transmission rate, and the lifetime cost of pediatric HIV infection exceeded $33,625.

CONCLUSION

Rapid HIV testing of unregistered parturients followed by zidovudine treatment if seropositive would be cost saving to the medical system.