Prevented perinatal HIV infections in the era of antiretroviral prophylaxis and treatment, United States, 1994-2020

OBJECTIVE

The primary aim of this serial cross-sectional analysis is to estimate the total number of prevented perinatal HIV transmissions from the time of the initial recommendation for perinatal zidovudine (ZDV) prophylaxis in 1994 through 2020 in the US.

METHODS

The estimated number of prevented transmissions was calculated as annual differences between expected and observed numbers of perinatal HIV transmissions. Annual expected number of transmissions was estimated by multiplying the annual number of births to women with HIV by 0.2255 (22.55%), i.e., the transmission rate of the control group in the ACTG Protocol 076 trial. We used published point estimates or, if only ranges were given, the midpoints of those ranges as the best estimates of the annual numbers of births to women with HIV and infants with perinatal HIV. When data were not available, we linearly interpolated or extrapolated the available data to obtain estimated numbers for each year.

RESULTS

Between 1978 and 2020, the approximate number of live births to women with HIV was 191 267 (95% confidence interval [CI] 190 392-192 110) and for infants with diagnosed perinatal HIV, it was 21 379 (95% CI 21 088-21 695). Since 1994, the annual number of infants born with HIV decreased from 1263 (95% CI 1194-1333) to 33 in 2019 (95% CI 22-45) and 36 in 2020 (95% CI 25-48), corresponding to a 97% reduction. Cumulatively, an estimated total of 22 732 (95% CI 21 340-24 462) perinatal HIV infections were prevented from 1994 through to 2020.

CONCLUSION

The elimination of perinatal HIV transmission-accompanied by the cumulative number of prevented cases exceeding that of perinatal HIV infections-is a major public health achievement in the US.

Evaluation of Serial Testing After Exposure to COVID-19 in Early Care and Education Facilities, Illinois, March-May 2022

OBJECTIVE

To understand SARS-CoV-2 transmission in early care and education (ECE) settings, we implemented a Test to Stay (TTS) strategy, which allowed children and staff who were close contacts to COVID-19 to remain in person if they agreed to test twice after exposure. We describe SARS-CoV-2 transmission, testing preferences, and the number of in-person days saved among participating ECE facilities.

METHODS

From March 21 through May 27, 2022, 32 ECE facilities in Illinois implemented TTS. Unvaccinated children and staff who were not up to date with COVID-19 vaccination could participate if exposed to COVID-19. Participants received 2 tests within 7 days after exposure and were given the option to test at home or at the ECE facility.

RESULTS

During the study period, 331 TTS participants were exposed to index cases (defined as people attending the ECE facility with a positive SARS-CoV-2 test result during the infectious period); 14 participants tested positive, resulting in a secondary attack rate of 4.2%. No tertiary cases (defined as a person with a positive SARS-CoV-2 test result within 10 days after exposure to a secondary case) occurred in the ECE facilities. Most participants (366 of 383; 95.6%) chose to test at home. Remaining in-person after an exposure to COVID-19 saved approximately 1915 in-person days among children and staff and approximately 1870 parent workdays.

CONCLUSION

SARS-CoV-2 transmission rates were low in ECE facilities during the study period. Serial testing after COVID-19 exposure among children and staff at ECE facilities is a valuable strategy to allow children to remain in person and parents to avoid missing workdays.

Effectiveness of an Interactive, Highly Tailored "Video Doctor" Intervention to Suppress Viral Load and Retain Patients With HIV in Clinical Care: A Randomized Clinical Trial

BACKGROUND

To determine whether Positive Health Check, a highly tailored video doctor intervention, can improve viral suppression and retention in care.

SETTING

Four clinics that deliver HIV primary care.

METHODS

A hybrid type 1 effectiveness-implementation randomized trial design was used to test study hypotheses. Participants (N = 799) who were not virally suppressed, were new to care, or had fallen out of care were randomly assigned to receive Positive Health Check or the standard of care alone. The primary endpoint was viral load suppression, and the secondary endpoint was retention in care, both assessed at 12 months, using an intention-to-treat approach. A priori subgroup analyses based on sex assigned at birth and race were examined as well.

RESULTS

There were no statistically significant differences between Positive Health Check (N = 397) and standard of care (N = 402) for either endpoint. However, statistically significant group differences were identified from a priori subgroup analyses. Male participants receiving Positive Health Check were more likely to achieve suppression at 12 months than male participants receiving standard of care adjusted risk ratio [aRR] [95% confidence interval (CI)] = 1.14 (1.00 to 1.29), P = 0.046}. For retention in care, there was a statistically significant lower risk for a 6-month visit gap in the Positive Health Check arm for the youngest participants, 18-29 years old [aRR (95% CI) = 0.55 (0.33 to 0.92), P = 0.024] and the oldest participants, 60-81 years old [aRR (95% CI) = 0.49 (0.30 to 0.81), P = 0.006].

CONCLUSIONS

Positive Health Check may help male participants with HIV achieve viral suppression, and younger and older patients consistently attend HIV care.

REGISTRY NAME

Positive Health Check Evaluation Trial. Trial ID: 1U18PS004967-01. URL: https://clinicaltrials.gov/ct2/show/NCT03292913.

Age- and Race/Ethnicity-Specific Sex Partner Correlates of Condomless Sex in an Online Sample of Hispanic/Latino, Black/African-American, and White Men Who Have Sex with Men

We sought to identify and compare correlates of condomless receptive anal intercourse with HIV-positive or unknown status partners (CRAI) for younger (< 25 years) and older (≥ 25 years) Hispanic/Latino, black/African-American, and white men who have sex with men (MSM). Baseline data from the Evaluation of Rapid HIV Self-Testing among MSM Project (eSTAMP), a randomized controlled trial with MSM (n = 2665, analytical sample size = 2421), were used. Potential correlates included participants' sociodemographic characteristics and HIV status as well as the characteristics of participants' partners. Younger Hispanic/Latino and black men were most likely to report having older sex partners (≥ 50% of partners being at least 5 years older), and having older partners was a significant correlate of CRAI among younger Hispanic/Latino and white men. Regardless of race/ethnicity, not knowing one's HIV status was a significant correlate of CRAI among younger men, whereas having a black sex partner was a significant correlate among older men. HIV prevention initiatives could address these and other correlates specific to race/ethnicity groups to target their prevention resources and messaging.

Effect of Internet-Distributed HIV Self-tests on HIV Diagnosis and Behavioral Outcomes in Men Who Have Sex With Men: A Randomized Clinical Trial

IMPORTANCE

Undiagnosed HIV infection results in delayed access to treatment and increased transmission. Self-tests for HIV may increase awareness of infection among men who have sex with men (MSM).

OBJECTIVE

To evaluate the effect of providing HIV self-tests on frequency of testing, diagnoses of HIV infection, and sexual risk behaviors.

DESIGN, SETTING, AND PARTICIPANTS

This 12-month longitudinal, 2-group randomized clinical trial recruited MSM through online banner advertisements from March through August 2015. Those recruited were at least 18 years of age, reported engaging in anal sex with men in the past year, never tested positive for HIV, and were US residents with mailing addresses. Participants completed quarterly online surveys. Telephone call notes and laboratory test results were included in the analysis, which was completed from August 2017 through December 2018.

INTERVENTIONS

All participants had access to online web-based HIV testing resources and telephone counseling on request. Participants were randomized in a 1:1 ratio to the control group or a self-testing (ST) group, which received 4 HIV self-tests after completing the baseline survey with the option to replenish self-tests after completing quarterly surveys. At study completion, all participants were offered 2 self-tests and 1 dried blood spot collection kit.

MAIN OUTCOMES AND MEASURES

Primary outcomes were HIV testing frequency (tested ≥3 times during the trial) and number of newly identified HIV infections among participants in both groups and social network members who used the study HIV self-tests. Secondary outcomes included sex behaviors (eg, anal sex, serosorting).

RESULTS

Of 2665 participants, the mean (SD) age was 30 (9.6) years, 1540 (57.8%) were white, and 443 (16.6%) had never tested for HIV before enrollment. Retention rates at each time point were more than 54%, and 1991 (74.7%) participants initiated 1 or more follow-up surveys. More ST participants reported testing 3 or more times during the trial than control participants (777 of 1014 [76.6%] vs 215 of 977 [22.0%]; P < .01). The cumulative number of newly identified infections during the trial was twice as high in the ST participants as the control participants (25 of 1325 [1.9%] vs 11 of 1340 [0.8%]; P = .02), with the largest difference in HIV infections identified in the first 3 months (12 of 1325 [0.9%] vs 2 of 1340 [0.1%]; P < .01). The ST participants reported 34 newly identified infections among social network members who used the self-tests.

CONCLUSIONS AND RELEVANCE

Distribution of HIV self-tests provides a worthwhile mechanism to increase awareness of HIV infection and prevent transmission among MSM.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02067039.

Effects of a brief video intervention on treatment initiation and adherence among patients attending human immunodeficiency virus treatment clinics

Background

Persons with human immunodeficiency virus (HIV) who get and keep a suppressed viral load are unlikely to transmit HIV. Simple, practical interventions to help achieve HIV viral suppression that are easy and inexpensive to administer in clinical settings are needed. We evaluated whether a brief video containing HIV-related health messages targeted to all patients in the waiting room improved treatment initiation, medication adherence, and retention in care.

Methods and findings

In a quasi-experimental trial all patients (N = 2,023) attending two HIV clinics from June 2016 to March 2017 were exposed to a theory-based, 29-minute video depicting persons overcoming barriers to starting treatment, taking medication as prescribed, and keeping medical appointments. New prescriptions at index visit, HIV viral load test results, and dates of return visits were collected through review of medical records for all patients during the 10 months that the video was shown. Those data were compared with the same variables collected for all patients (N = 1,979) visiting the clinics during the prior 10 months (August 2015 to May 2016). Among patients exposed to the video, there was an overall 10.4 percentage point increase in patients prescribed treatment (60.3% to 70.7%, p< 0.01). Additionally, there was an overall 6.0 percentage point improvement in viral suppression (56.7% to 62.7%, p< 0.01), however mixed results between sites was observed. There was not a significant change in rates of return visits (77.5% to 78.8%). A study limitation is that, due to the lack of randomization, the findings may be subject to bias and secular trends.

Conclusions

Showing a brief treatment-focused video in HIV clinic waiting rooms can be effective at improving treatment initiation and may help patients achieve viral suppression. This feasible, low resource-reliant video intervention may be appropriate for adoption by other clinics treating persons with HIV.

Trial registration

http://www.ClinicalTrials.gov (NCT03508310).

Pilot Evaluation of the Ability of Men Who Have Sex with Men to Self-Administer Rapid HIV Tests, Prepare Dried Blood Spot Cards, and Interpret Test Results, Atlanta, Georgia, 2013

In the United States, an estimated 67% of new HIV diagnoses are among men who have sex with men (MSM), however 25% of HIV-positive MSM in the 2014 National HIV Behavioral Surveillance Survey were unaware of their infection. HIV self-testing (HIVST) with rapid diagnostic tests (RDTs) may facilitate access to HIV testing. We evaluated the ability of 22 MSM to conduct two HIV RDTs (OraQuick ^® In-Home HIV Test and a home-use prototype of Sure Check ^® HIV 1/2 Assay), interpret sample images of test results, and collect a dried blood spot (DBS) specimen. While some participants did not follow every direction, most participants were able to conduct HIVST and correctly interpret their results. Interpretation of panels of RDT images was especially difficult when the "control" line was missing, and 27% of DBS cards produced were rated as of bad quality. Modifications to the DBS instructions were necessary prior to evaluating the performance of these tests in real-world settings.

EXPERIENCE OF FORCED SEX AND SUBSEQUENT SEXUAL, DRUG, AND MENTAL HEALTH OUTCOMES: AFRICAN AMERICAN AND HISPANIC WOMEN IN THE SOUTHEASTERN UNITED STATES

OBJECTIVES

This cross-sectional study examined African American and Hispanic women's (N = 1,509) self-reports of unwanted forced sex and its association with behavioral and mental health outcomes after the event.

METHODS

Twenty percent of the women had experienced forced sex (1st occurrence at age 15 years or younger for 10%, 1st occurrence at older than 15 years of age for 10%).

RESULTS

Regardless of when forced sex 1st occurred, women were more likely to have engaged in unprotected vaginal and anal sex, to have had multiple unprotected sex partners, to have sexually transmitted infections, to have reported binge drinking and illicit drug use, and to exhibit distress and have received mental health counseling.

CONCLUSIONS

Forced sex may have wide-ranging behavioral and mental health consequences years later.

Determinants and Experiences of Repeat Pregnancy among HIV-Positive Kenyan Women--A Mixed-Methods Analysis

OBJECTIVE

To identify factors associated with repeat pregnancy subsequent to an index pregnancy among women living with HIV (WLWH) in western Kenya who were enrolled in a 24-month phase-II clinical trial of triple-ART prophylaxis for prevention of mother-to-child transmission, and to contextualize social and cultural influences on WLWH's reproductive decision making.

METHODS

A mixed-methods approach was used to examine repeat pregnancy within a 24 month period after birth. Counselor-administered questionnaires were collected from 500 WLWH. Forty women (22 with a repeat pregnancy; 18 with no repeat pregnancy) were purposively selected for a qualitative interview (QI). Simple and multiple logistic regression analyses were performed for quantitative data. Thematic coding and saliency analysis were undertaken for qualitative data.

RESULTS

Eighty-eight (17.6%) women had a repeat pregnancy. Median maternal age was 23 years (range 15-43 years) and median gestational age at enrollment was 34 weeks. In multiple logistic regression analyses, living in the same compound with a husband (adjusted odds ratio (AOR): 2.33; 95% confidence interval (CI): 1.14, 4.75) was associated with increased odds of repeat pregnancy (p ≤ 0.05). Being in the 30-43 age group (AOR: 0.25; 95% CI: 0.07, 0.87), having talked to a partner about family planning (FP) use (AOR: 0.53; 95% CI: 0.29, 0.98), and prior usage of FP (AOR: 0.45; 95% CI: 0.25, 0.82) were associated with a decrease in odds of repeat pregnancy. QI findings centered on concerns about modern contraception methods (side effects and views that they 'ruined the womb') and a desire to have the right number of children. Religious leaders, family, and the broader community were viewed as reinforcing cultural expectations for married women to have children. Repeat pregnancy was commonly attributed to contraception failure or to lack of knowledge about post-delivery fertility.

CONCLUSIONS

In addition to cultural context, reproductive health programs for WLWH may need to address issues related to living circumstances and the possibility that reproductive-decision making may extend beyond the woman and her partner.

Exclusive breastfeeding among women taking HAART for PMTCT of HIV-1 in the Kisumu Breastfeeding Study

Background

One of the most effective ways to promote the prevention of mother-to-child transmission (PMTCT) of HIV-1 in resource-limited settings is to encourage HIV-positive mothers to practice exclusive breastfeeding (EBF) for the first 6 months post-partum while they receive antiretroviral therapy (ARV). Although EBF reduces mortality in this context, its practice has been low. We studied the rate of adherence to EBF and assessed associated maternal and infant characteristics using data from a phase II PMTCT clinical trial conducted in Western Kenya which included a counseling intervention to encourage EBF by all participants.

Methods

We analyzed data from the Kisumu Breastfeeding Study (KiBS), conducted between July 2003 and February 2009. This study enrolled a total of 522 HIV-1 infected pregnant women. Data on breastfeeding were available for 480 mother-infant pairs. Infant feeding and general nutrition counseling began at 35 weeks gestation and continued throughout the 6 month post-partum intervention period, following World Health Organization (WHO) infant feeding guidelines. Data on infant feeding were collected during routine clinic visits and home visits using food frequency questionnaires and dietary recall methods. Participants were instructed to exclusively breastfeed until initiation of weaning at 5.5 months post-partum. We used Kaplan-Meier methods to estimate the rates of EBF at 5.25 months post-partum, stratified by maternal and infant characteristics measured at enrollment, delivery, and 2 weeks post-partum.

Results

The estimated EBF rate at 5.25 months post-partum was 80.4%. Only 3% of women introduced other foods (most commonly water with or without glucose, cow’s milk, formula, and fruit) by 2 months; this percentage increased to 5% of women by 4 months. Women who had ≥3 previous births (p < 0.01) and who were not living with the infant’s father (p = 0.04) were more likely to exclusively breastfeed. Mixed feeding was more common for male infants than for female infants (p = 0.04).

Conclusion

Exclusive breastfeeding was common in this clinical trial, which emphasized EBF as a best practice until infants reached 5.5 months of age. Counseling initiated prior to delivery and continued during the post-partum period provided a consistent message reinforcing the benefits of EBF. The findings from this study suggest high adherence to EBF in resource limited settings can be achieved by a comprehensive counseling intervention that encourages EBF.

Attitudes toward family planning among HIV-positive pregnant women enrolled in a prevention of mother-to-child transmission study in Kisumu, Kenya

Background

Preventing unintended pregnancies among HIV-positive women through family planning (FP) reduces pregnancy-related morbidity and mortality, decreases the number of pediatric HIV infections, and has also proven to be a cost-effective way to prevent mother-to-child HIV transmission. A key element of a comprehensive HIV prevention agenda, aimed at avoiding unintended pregnancies, is recognizing the attitudes towards FP among HIV-positive women and their spouse or partner. In this study, we analyze FP attitudes among HIV-infected pregnant women enrolled in a PMTCT clinical trial in Western Kenya.

Methods and Findings

Baseline data were collected on 522 HIV-positive pregnant women using structured questionnaires. Associations between demographic variables and the future intention to use FP were examined using Fisher's exact tests and permutation tests. Most participants (87%) indicated that they intended to use FP. However, only 8% indicated condoms as a preferred FP method, and 59% of current pregnancies were unintended. Factors associated with positive intentions to use FP were: marital status (p = 0.04), having talked to their spouse or partner about FP (p<0.001), perceived spouse or partner approval of FP (p<0.001), previous use of a FP method (p = 0.006), attitude toward the current pregnancy (p = 0.02), disclosure of a sexually transmitted infection (STI) diagnosis (p = 0.03) and ethnic group (p = 0.03).

Conclusion

A significant gap exists between future FP intentions and current FP practices. Support and approval by the spouse or partner are key elements of FP intentions. Counseling services should be offered to both members of a couple to increase FP use, especially given the high number of unplanned pregnancies among HIV-positive women. Condoms should be promoted as part of a dual use method for HIV and STI prevention and for contraception. Integration of individual and couple FP services into routine HIV care, treatment and support services is needed in order to avoid unintended pregnancies and to prevent mother-to-child HIV transmission.

Newly identified HIV infections in correctional facilities, United States, 2007

We used Centers for Disease Control and Prevention HIV Counseling and Testing System data from 2007 to determine the percentage and characteristics of persons newly identified as HIV-positive in US correctional facilities. The newly identified HIV positivity was 0.7%, and 30% of detainees newly identified with HIV were categorized as having low-risk heterosexual contact or no acknowledged risk. Correctional facilities should provide detainees with routine opt-out HIV testing, unless the prevalence of previously undiagnosed HIV infection has been documented to be less than 0.1%.

Sexual risk behaviors among African-American and Hispanic women in five counties in the Southeastern United States: 2008-2009

PURPOSE

We examined sexual risk behaviors and unrecognized HIV infection among heterosexually active African-American and Hispanic women.

METHODS

Women not previously diagnosed with HIV infection were recruited in rural counties in North Carolina (African American) and Alabama (African American), and an urban county in southern Florida (Hispanic) using multiple methods. They completed a computer-administered questionnaire and were tested for HIV infection.

RESULTS

Between October 2008 and September 2009, 1,527 women (1,013 African American and 514 Hispanic) enrolled in the study. Median age was 35 years (range, 18-59), 33% were married or living as married, 50% had an annual household income of $12,000 or less, and 56% were employed full or part time. Two women (0.13%) tested positive for HIV. In the past 12 months, 19% had been diagnosed with a sexually transmitted infection (other than HIV), 87% engaged in unprotected vaginal intercourse (UVI), and 26% engaged in unprotected anal intercourse (UAI). In multivariate analysis, UAI was significantly (p < .05) more likely among those who reported ever being pregnant, binge drinking in the past 30 days, ever exchanging sex for things needed or wanted, engaging in UVI, or being of Hispanic ethnicity. UAI was also more likely to occur with partners with whom women had a current or past relationship as opposed to casual partners.

CONCLUSION

A high percentage of our sample of heterosexually active women of color had recently engaged in sexual risk behaviors, particularly UAI. More research is needed to elucidate the interpersonal dynamics that may promote this high-risk behavior. Educational messages that explicitly address the risks of heterosexual anal intercourse need to be developed for heterosexually active women and their male partners.

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.

Nevirapine-associated hepatotoxicity and rash among HIV-infected pregnant women in Kenya

BACKGROUND

Few studies have evaluated the risk of nevirapine (NVP)-associated hepatotoxicity among HIV-infected pregnant women with a CD4 count ≥250 cells/mm(3).

METHODS

We enrolled HIV-infected pregnant Kenyan women who initiated triple antiretroviral therapy (ART) at 34 weeks gestation. We compared the rates of severe hepatotoxicity (grades 3-4 hepatotoxicity) and rash-associated hepatotoxicity (rash with ≥grade 2 hepatotoxicity) with NVP and nelfinavir (NFV), respectively.

RESULTS

We initiated triple ART in 522 pregnant women; severe hepatotoxicity and rash-associated hepatotoxicity occurred in 14 (3%) and 9 (2%) women, respectively. Women who initiated NVP had higher rates of severe hepatotoxicity (5% vs 1%; P = .03) and rash-associated hepatotoxicity (4% vs 0%; P = .003) when compared with NFV. Among women who initiated NVP (n = 254), a baseline CD4 count ≥250 cells/mm(3) was not associated with severe hepatotoxicity (5% vs 3%; P = .52) or rash-associated hepatotoxicity (4% vs 3%; P = .69).

CONCLUSION

Nevirapine use but not CD4 count ≥250 cells/mm(3) was associated with hepatotoxicity.

Triple-antiretroviral prophylaxis to prevent mother-to-child HIV transmission through breastfeeding--the Kisumu Breastfeeding Study, Kenya: a clinical trial

BACKGROUND

Effective strategies are needed for the prevention of mother-to-child HIV transmission (PMTCT) in resource-limited settings. The Kisumu Breastfeeding Study was a single-arm open label trial conducted between July 2003 and February 2009. The overall aim was to investigate whether a maternal triple-antiretroviral regimen that was designed to maximally suppress viral load in late pregnancy and the first 6 mo of lactation was a safe, well-tolerated, and effective PMTCT intervention.

METHODS AND FINDINGS

HIV-infected pregnant women took zidovudine, lamivudine, and either nevirapine or nelfinavir from 34-36 weeks' gestation to 6 mo post partum. Infants received single-dose nevirapine at birth. Women were advised to breastfeed exclusively and wean rapidly just before 6 mo. Using Kaplan-Meier methods we estimated HIV-transmission and death rates from delivery to 24 mo. We compared HIV-transmission rates among subgroups defined by maternal risk factors, including baseline CD4 cell count and viral load. Among 487 live-born, singleton, or first-born infants, cumulative HIV-transmission rates at birth, 6 weeks, and 6, 12, and 24 mo were 2.5%, 4.2%, 5.0%, 5.7%, and 7.0%, respectively. The 24-mo HIV-transmission rates stratified by baseline maternal CD4 cell count <500 and ≥500 cells/mm(3) were 8.4% (95% confidence interval [CI] 5.8%-12.0%) and 4.1% (1.8%-8.8%), respectively (p = 0.06); the corresponding rates stratified by baseline maternal viral load <10,000 and ≥10,000 copies/ml were 3.0% (1.1%-7.8%) and 8.7% (6.1%-12.3%), respectively (p = 0.01). None of the 12 maternal and 51 infant deaths (including two second-born infants) were attributed to antiretrovirals. The cumulative HIV-transmission or death rate at 24 mo was 15.7% (95% CI 12.7%-19.4%).

CONCLUSIONS

This trial shows that a maternal triple-antiretroviral regimen from late pregnancy through 6 months of breastfeeding for PMTCT is safe and feasible in a resource-limited setting. These findings are consistent with those from other trials using maternal triple-antiretroviral regimens during breastfeeding in comparable settings.

Nevirapine-associated hepatotoxicity was not predicted by CD4 count ≥250 cells/μL among women in Zambia, Thailand and Kenya

OBJECTIVE

The aim of the study was to determine risk factors for developing severe hepatotoxicity (grade 3 or 4 hepatotoxicity) and rash-associated hepatotoxicity (rash with ≥ grade 2 hepatotoxicity) among women initiating nevirapine-based antiretroviral therapy (ART).

METHODS

The Non-Nucleoside Reverse Transcriptase Inhibitor Response Study was a prospective cohort study carried out in Zambia, Thailand and Kenya. Between May 2005 and January 2007, we enrolled antiretroviral-naïve HIV-infected women initiating nevirapine-based ART. At enrollment and at weeks 2, 4, 8, 16 and 24, participants had serum alanine transferase (ALT) and aspartate transaminase (AST) measured and were evaluated clinically for hepatitis and rash.

RESULTS

Nevirapine-based ART was initiated in 820 women and baseline ALT or AST results were abnormal (≥ grade 1) in 113 (14%) women. After initiating nevirapine-based ART, severe hepatotoxicity occurred in 41 (5%) women and rash-associated hepatotoxicity occurred in 27 (3%) women. In a multivariate logistic regression model, severe hepatotoxicity and rash-associated hepatotoxicity were both associated with baseline abnormal (≥ grade 1) ALT or AST results, but not with a baseline CD4 cell count ≥250 cells/μL. Three participants (0.4%) died with symptoms suggestive of fatal hepatotoxicity; all three women had baseline CD4 count <100 cells/μL and were receiving anti-tuberculosis therapy.

CONCLUSION

Among women taking nevirapine-based ART, severe hepatotoxicity and rash-associated hepatotoxicity were predicted by abnormal baseline ALT or AST results, but not by a CD4 count ≥250 cells/μL. In resource-limited settings where transaminase testing is available, testing should focus on early time-points and on women with abnormal baseline ALT or AST results.

Effectiveness of non-nucleoside reverse-transcriptase inhibitor-based antiretroviral therapy in women previously exposed to a single intrapartum dose of nevirapine: a multi-country, prospective cohort study

BACKGROUND

Intrapartum and neonatal single-dose nevirapine (NVP) reduces the risk of mother-to-child HIV transmission but also induces viral resistance to non-nucleoside reverse transcriptase inhibitor (NNRTI) drugs. This drug resistance largely fades over time. We hypothesized that women with a prior single-dose NVP exposure would have no more than a 10% higher cumulative prevalence of failure of their NNRTI-containing antiretroviral therapy (ART) over the first 48 wk of therapy than would women without a prior exposure.

METHODS AND FINDINGS

We enrolled 355 NVP-exposed and 523 NVP-unexposed women at two sites in Zambia, one site in Kenya, and two sites in Thailand into a prospective, non-inferiority cohort study and followed them for 48 wk on ART. Those who died, discontinued NNRTI-containing ART, or had a plasma viral load >or=400 copies/ml at either the 24 wk or 48 wk study visits and confirmed on repeat testing were characterized as having failed therapy. Overall, 114 of 355 NVP-exposed women (32.1%) and 132 of 523 NVP-unexposed women (25.2%) met criteria for treatment failure. The difference in failure rates between the exposure groups was 6.9% (95% confidence interval [CI] 0.8%-13.0%). The failure rates of women stratified by our predefined exposure interval categories were as follows: 47 of 116 women in whom less than 6 mo elapsed between exposure and starting ART failed therapy (40%; p<0.001 compared to unexposed women); 25 of 67 women in whom 7-12 mo elapsed between exposure and starting ART failed therapy (37%; p = 0.04 compared to unexposed women); and 42 of 172 women in whom more than 12 mo elapsed between exposure and starting ART failed therapy (24%; p = 0.82 compared to unexposed women). Locally weighted regression analysis also indicated a clear inverse relationship between virologic failure and the exposure interval.

CONCLUSIONS

Prior exposure to single-dose NVP was associated with an increased risk of treatment failure; however, this risk seems largely confined to women with a more recent exposure. Women requiring ART within 12 mo of NVP exposure should not be prescribed an NNRTI-containing regimen as first-line therapy.

HIV transmission in a state prison system, 1988-2005

INTRODUCTION

HIV prevalence among state prison inmates in the United States is more than five times higher than among nonincarcerated persons, but HIV transmission within U.S. prisons is sparsely documented. We investigated 88 HIV seroconversions reported from 1988-2005 among male Georgia prison inmates.

METHODS

We analyzed medical and administrative data to describe seroconverters' HIV testing histories and performed a case-crossover analysis of their risks before and after HIV diagnosis. We sequenced the gag, env, and pol genes of seroconverters' HIV strains to identify genetically-related HIV transmission clusters and antiretroviral resistance. We combined risk, genetic, and administrative data to describe prison HIV transmission networks.

RESULTS

Forty-one (47%) seroconverters were diagnosed with HIV from July 2003-June 2005 when voluntary annual testing was offered. Seroconverters were less likely to report sex (OR [odds ratio] = 0.02, 95% CI [confidence interval]: 0-0.10) and tattooing (OR = 0.03, 95% CI: <0.01-0.20) in prison after their HIV diagnosis than before. Of 67 seroconverters' specimens tested, 33 (49%) fell into one of 10 genetically-related clusters; of these, 25 (76%) reported sex in prison before their HIV diagnosis. The HIV strains of 8 (61%) of 13 antiretroviral-naïve and 21 (40%) of 52 antiretroviral-treated seroconverters were antiretroviral-resistant.

DISCUSSION

Half of all HIV seroconversions were identified when routine voluntary testing was offered, and seroconverters reduced their risks following their diagnosis. Most genetically-related seroconverters reported sex in prison, suggesting HIV transmission through sexual networks. Resistance testing before initiating antiretroviral therapy is important for newly-diagnosed inmates.

Assessing mediation in HIV intervention studies

OBJECTIVES

A mediator is a psychosocial construct that is targeted by an intervention to bring about behavior change. Recent literature suggests that a widely used approach for assessing mediation, namely the causal steps method, can be severely statistically underpowered. This article describes three standard methods for assessing mediation: causal steps, difference in coefficients, and product of coefficients. We also demonstrate the use of asymmetric confidence limits (ACLs) in testing mediation.

METHODS

We compared the results obtained by ACL construction with results obtained based on the causal steps and product of coefficients approaches to analyze data from the Seropositive Urban Men's Intervention Trial.

RESULTS

ACL construction uncovered previously unidentified mediating factors. We also identified a marginally significant suppressor, which means that, with regard to this factor, the intervention had effects that were opposite from the desired direction.

CONCLUSIONS

ACLs are preferred for this type of analysis because of their statistical power and because they are informative regardless of whether the intervention has a significant effect on the outcome. Furthermore, ACLs present the size of the mediating effect rather than just a binary decision regarding significance.

Hematologic changes associated with Zidovudine following single-drug substitution from stavudine in a home-based AIDS care program in rural Uganda

BACKGROUND

The authors evaluated hematologic changes associated with zidovudine (ZDV) following single-drug substitution from stavudine (D4T) in HIV-infected persons in Uganda.

METHODS

From May 2003 through February 2007, the authors evaluated incidence rates (IR) of hematologic abnormalities from quarterly blood draws among adults prescribed highly active antiretroviral therapy (HAART) before and after single-drug substitution of D4T to ZDV.

RESULTS

A total of 1089 adults received D4T-containing HAART (median observation time, 35.9 months), and 290 (27%) had ZDV substituted for D4T. While taking D4T, IR for anemia was 0.35/100 person-months (PMs), leukopenia was 0.29/100 PM, and thrombocytopenia was 0.32/100 PM. While taking ZDV, IR for anemia was 0.44/100 PM, leukopenia was 1.05/100 PM, and thrombocytopenia was 0.30/100 PM.

CONCLUSIONS

Patients had a higher incidence of anemia and leukopenia after substitution from D4T to ZDV, but hematologic toxicity was not a major complication in this population. Patients on ZDV-containing HAART regimens are still at risk for anemia and need close monitoring.

Willingness of men who have sex with men (MSM) in the United States to be circumcised as adults to reduce the risk of HIV infection

Background

Circumcision reduces HIV acquisition among heterosexual men in Africa, but it is unclear if circumcision may reduce HIV acquisition among men who have sex with men (MSM) in the United States, or whether MSM would be willing to be circumcised if recommended.

Methods

We interviewed presumed-HIV negative MSM at gay pride events in 2006. We asked uncircumcised respondents about willingness to be circumcised if it were proven to reduce risk of HIV among MSM and perceived barriers to circumcision. Multivariate logistic regression was used to identify covariates associated with willingness to be circumcised.

Results

Of 780 MSM, 133 (17%) were uncircumcised. Of these, 71 (53%) were willing to be circumcised. Willingness was associated with black race (exact odds ratio [OR]: 3.4, 95% confidence interval [CI]: 1.3–9.8), non-injection drug use (OR: 6.1, 95% CI: 1.8–23.7) and perceived reduced risk of penile cancer (OR: 4.7, 95% CI: 2.0–11.9). The most commonly endorsed concerns about circumcision were post-surgical pain and wound infection.

Conclusions

Over half of uncircumcised MSM, especially black MSM, expressed willingness to be circumcised. Perceived risks and benefits of circumcision should be a part of educational materials if circumcision is recommended for MSM in the United States.

Effect of a brief video intervention on incident infection among patients attending sexually transmitted disease clinics

BACKGROUND

Sexually transmitted disease (STD) prevention remains a public health priority. Simple, practical interventions to reduce STD incidence that can be easily and inexpensively administered in high-volume clinical settings are needed. We evaluated whether a brief video, which contained STD prevention messages targeted to all patients in the waiting room, reduced acquisition of new infections after that clinic visit.

METHODS AND FINDINGS

In a controlled trial among patients attending three publicly funded STD clinics (one in each of three US cities) from December 2003 to August 2005, all patients (n = 38,635) were systematically assigned to either a theory-based 23-min video depicting couples overcoming barriers to safer sexual behaviors, or the standard waiting room environment. Condition assignment alternated every 4 wk and was determined by which condition (intervention or control) was in place in the clinic waiting room during the patient's first visit within the study period. An intent-to-treat analysis was used to compare STD incidence between intervention and control patients. The primary endpoint was time to diagnosis of incident laboratory-confirmed infections (gonorrhea, chlamydia, trichomoniasis, syphilis, and HIV), as identified through review of medical records and county STD surveillance registries. During 14.8 mo (average) of follow-up, 2,042 patients (5.3%) were diagnosed with incident STD (4.9%, intervention condition; 5.7%, control condition). In survival analysis, patients assigned to the intervention condition had significantly fewer STDs compared with the control condition (hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.84 to 0.99).

CONCLUSIONS

Showing a brief video in STD clinic waiting rooms reduced new infections nearly 10% overall in three clinics. This simple, low-intensity intervention may be appropriate for adoption by clinics that serve similar patient populations.

TRIAL REGISTRATION

http://www.ClinicalTrials.gov (#NCT00137670).

Components of variation in serum carotenoid concentrations: the Polyp Prevention Trial

OBJECTIVES

The intra- and interindividual variations and season and center effects were estimated from a series of serum carotenoid concentrations in the Polyp Prevention Trial (PPT) participants.

SUBJECTS/METHODS

Fasting blood was collected annually for 4 years in all 1905 participants, and a subcohort of 901 participants were selected within each (of eight) center(s), by gender and dietary arm of the study, for measurement of five major carotenoid peaks. Using variance of component methods, the variation in serum carotenoid concentrations about the underlying mean was partitioned into explanatory components attributed to various sources.

RESULTS

The contributions of the inter- and intraindividual variances to the overall variation in carotenoid concentrations were in the range of 61-70 and 20-35%, respectively, whereas center and center-by-season effects provided 2.6-9.5 and 0.2-1.4%, respectively. The highest percent (35%) of intraindividual variation was exhibited by lycopene, and the highest percent (70% apiece) of interindividual variation was exhibited by lutein/zeaxanthin and beta-carotene. Serum lycopene had the highest ratio of intra- to interindividual variation of 0.57, whereas lutein had the lowest ratio of 0.29. We estimate that the ratio of intra- to interindividual variance around the mean carotenoid concentration can be reduced greatly by collecting 3-4 compared to 1 blood measurement in large-scale trials like the PPT.

CONCLUSION

In the largest study of components of variation in individuals at high risk for colorectal cancer, the largest contributors to variation in serum carotenoid concentrations were intra- and interindividual effects followed by center and center-by-season effects.

Constructing binomial confidence intervals with near nominal coverage by adding a single imaginary failure or success

In this paper we present a simple method for constructing (1- alpha)100 per cent confidence intervals for binomial proportions with near nominal coverage for all underlying proportion parameters on the unit interval. This new method uses, with a slight modification, the standard normal approximation technique taught in introductory statistics classes. Specifically, we first augment the observed binomial data with an imaginary failure to compute the lower bound and an imaginary success to compute the upper bound. By contrast, the Agresti-Coull method adds the same number of imaginary successes and failures to the observed data, yet it can still give somewhat subnominal coverage. As motivation, we discuss the relationship between this new method and the Clopper-Pearson exact method. We also present numerical calculations to illustrate the satisfactory performance of this new method compared with several common alternatives. Finally, we argue that for certain statistical applications, such as the design and analysis of clinical trials with adverse events, this new method represents a valuable complementary approach.

A simple hybrid variance estimator for the Kaplan-Meier survival function

In this paper, we propose a hybrid variance estimator for the Kaplan-Meier survival function. This new estimator approximates the true variance by a Binomial variance formula, where the proportion parameter is a piecewise non-increasing function of the Kaplan-Meier survival function and its upper bound, as described below. Also, the effective sample size equals the number of subjects not censored prior to that time. In addition, we consider an adjusted hybrid variance estimator that modifies the regular estimator for small sample sizes. We present a simulation study to compare the performance of the regular and adjusted hybrid variance estimators to the Greenwood and Peto variance estimators for small sample sizes. We show that on average these hybrid variance estimators give closer variance estimates to the true values than the traditional variance estimators, and hence confidence intervals constructed with these hybrid variance estimators have more nominal coverage rates. Indeed, the Greenwood and Peto variance estimators can substantially underestimate the true variance in the left and right tails of the survival distribution, even with moderately censored data. Finally, we illustrate the use of these hybrid and traditional variance estimators on a data set from a leukaemia clinical trial.

Efficient estimation of the risk of a disease by quantile-categories of a key predictor variable using generalized additive models

Suppose that one wishes to make inference to the risk of a disease by the population quartile-categories of a key continuous predictor variable. When one collects data on a prospective cohort, the standard method is simply to categorize the key predictor variable by the empirical quartiles. One may then include indicator variables for these empirical quartile-categories as predictors, along with other covariates, in a generalized linear model (GLM), with the observed health status of each subject as the response. The standard GLM method, however, is relatively inefficient, because it treats all observations that fall in the same quartile-category of the predictor variable identically, regardless of whether they lie in the centre or near the boundaries of that category. Alternatively, one may include the key predictor variable, along with other covariates, in a generalized additive model (GAM), again with the observed health status of each subject as the response. The alternative GAM method non-parametrically estimates the functional relationship between the key predictor variable and the response. One may then compute statistics of interest, such as proportions and odds ratios, from the fitted GAM equation using the empirical quartile-categories. Simulations show that both the GLM and GAM methods are nearly unbiased, but the latter method produces smaller variances and narrower bootstrap confidence intervals. An example from nutritional epidemiology illustrates the use of these methods.

Carotenoids, vitamin A and risk of adenomatous polyp recurrence in the polyp prevention trial

One trial reported beta-carotene supplementation was protective of adenomatous polyp recurrence in nonsmokers. We now examine the relation of serum and dietary carotenoids and vitamin A to adenomatous polyp recurrence in a subcohort of 834 participants in a low fat, high fiber, high fruit and vegetable dietary intervention, the Polyp Prevention Trial. Multivariate odds ratio (OR) and 95% confidence intervals (CI) of polyp recurrence were obtained using baseline or the average (first 3 years of the trial) carotenoid and vitamin A values after adjustment for covariates. Compared to the lowest quartile of baseline alpha-carotene concentrations, the OR of multiple polyp recurrence for the highest quartile was 0.55 (95% CI = 0.30-0.99) and the OR of right-sided recurrence was 0.60 (95% CI = 0.37-0.95). Baseline dietary intakes of alpha-carotene and vitamin A from food with/without supplements were inversely associated with any recurrence (p for linear trend = 0.03-alpha-carotene; p = 0.004 and p = 0.007 -intakes of vitamin A). Compared to the lowest quartile of averaged beta-carotene concentrations, the OR of multiple adenomas for the highest quartile was 0.40 (95% CI = 0.22-0.75) with an inverse trend (p = 0.02). The risk was inversely related to averaged: alpha-carotene concentrations and right-sided polyps; alpha-carotene intake and recurrence of any, multiple and right-sided polyps; beta-carotene intake and multiple adenoma recurrence; vitamin A from food (with supplements) and each adverse endpoint. Thus, alpha-carotene and vitamin A may protect against recurrence in nonsmokers and nondrinkers or be indicative of compliance or another healthy lifestyle factor that reduces risk.

Phase II trial of thalidomide and carmustine for patients with recurrent high-grade gliomas

PURPOSE

The use of thalidomide as an antiangiogenic agent has met with only limited success in the treatment of malignant gliomas. On the basis of preclinical data demonstrating synergistic antitumor activity when antiangiogenic agents are combined with cytotoxic agents, we explored the clinical activity of the combination of thalidomide and carmustine (BCNU) in patients with recurrent high-grade gliomas.

PATIENTS AND METHODS

Patients with a histologic diagnosis of high-grade glioma and radiographic evidence of tumor progression after standard surgery, radiation, and chemotherapy were eligible for the study. Patients received BCNU 200 mg/m2 on day 1 of every 6-week cycle, and 800 mg/d of thalidomide that was escalated to a maximal dose of 1,200 mg/d as tolerated.

RESULTS

A total of 40 patients (38 with glioblastomas, two with anaplastic gliomas) were accrued to the study. The combination of thalidomide and BCNU was well tolerated; mild myelosuppression and mild to moderate sedation were the most common side effects. The median progression-free survival (100 days) and the objective radiographic response rate (24%) for patients with glioblastoma compared favorably with data from historical controls.

CONCLUSION

This is one of the first clinical trials to evaluate the strategy of combining a putative antiangiogenic agent with a cytotoxic agent in patients with primary brain tumors. Our data demonstrate that thalidomide in combination with BCNU is well tolerated and has antitumor activity in patients with recurrent high-grade gliomas. Although the combination seems to be more active than either agent alone, such conclusions await confirmatory trials.

Using lowess to remove systematic trends over time in predictor variables prior to logistic regression with quantile categories

In case-control studies one may employ logistic regression to model the relationship between binary responses and continuous predictor variables that have been categorized by the empirical quartiles of the controls. Sometimes, however, systematic trends over time (or drifts) contaminate the laboratory measurements of predictor variables. In this paper we consider the use of locally weighted robust regression (lowess) to estimate and remove these systematic trends when the trends for the cases and controls have a common shape. One can then use the lowess adjusted data in the desired logistic regression model. We illustrate these methods with a case-control study that was designed to assess the risk of oesophageal cancer as a function of the quartile categories of sphinganine levels in the blood serum. Upon examination of the data, it was discovered that the sphinganine laboratory measurements were contaminated by a systematic trend, the magnitude of which depended only on the day of analysis. This trend needed to be removed before performing further analyses of the data. In addition, we present simulations to examine the use of lowess methods to estimate and remove various shapes of trends from contaminated predictor data before constructing logistic regression models with quartile categories. We found that using the trend-contaminated data tends to give attenuated parameter estimates and hence lower significance and power levels than using the uncontaminated data. Conversely, using appropriate lowess methods to adjust the data tends to give nearly unbiased parameter estimates, near nominal significance levels, and improved power.

Autoantibodies associated with volatile anesthetic hepatitis found in the sera of a large cohort of pediatric anesthesiologists

Anesthetic-induced hepatitis is thought to have an immune-mediated basis, in part because many patients who develop hepatitis have serum autoantibodies that react with specific hepatic proteins. The present study shows that pediatric anesthesiologists also have these serum autoantibodies. Moreover, levels of these autoantibodies are higher than those of general anesthesiologists. We collected sera from 105 pediatric and 53 general anesthesiologists (including 3 nurse anesthetists), 20 halothane hepatitis patients, and 20 control individuals who were never exposed to inhaled anesthetics. Serum cytochrome P450 2E1 (P450 2E1) and 58-kd hepatic endoplasmic reticulum protein (ERp58) autoantibodies were measured by enzyme-linked immunosorbent assays. Positive values were 2 SD above median control values. Two multiple regression models were constructed. Pediatric anesthesiologists, like halothane hepatitis patients, had higher serum autoantibody levels of ERp58 and P450 2E1 than general anesthesiologists and controls, which was possibly because of their increased occupational exposures to anesthetics. Female anesthesiologists had higher levels of ERp58 autoantibodies than male anesthesiologists, whereas female pediatric anesthesiologists had higher levels of P450 2E1 autoantibodies than all other anesthesiologists. One female pediatric anesthesiologist had symptoms of hepatic injury. Because most anesthesiologists do not develop volatile anesthetic-induced hepatic injury, the findings suggest that pathogenic ERp58 and P450 2E1 autoantibodies may not directly cause volatile anesthetic hepatitis. Female anesthesiologists have high levels of these autoantibodies; however, the majority of these individuals do not develop hepatitis, suggesting that autoantibodies may not have a pathological role in volatile anesthetic-induced hepatitis.

IMPLICATIONS

Environmental exposure of anesthesiology personnel to certain inhaled anesthetics can induce the formation of autoantibodies that have been associated with anesthetic hepatitis. Female anesthesiologists have high levels of these autoantibodies; however, the majority of these individuals do not develop hepatitis, suggesting that autoantibodies may not have a pathological role in volatile anesthetic-induced hepatitis.

Autoantibodies associated with volatile anesthetic hepatitis found in the sera of a large cohort of pediatric anesthesiologists

Anesthetic-induced hepatitis is thought to have an immune-mediated basis, in part because many patients who develop hepatitis have serum autoantibodies that react with specific hepatic proteins. The present study shows that pediatric anesthesiologists also have these serum autoantibodies. Moreover, levels of these autoantibodies are higher than those of general anesthesiologists. We collected sera from 105 pediatric and 53 general anesthesiologists (including 3 nurse anesthetists), 20 halothane hepatitis patients, and 20 control individuals who were never exposed to inhaled anesthetics. Serum cytochrome P450 2E1 (P450 2E1) and 58-kd hepatic endoplasmic reticulum protein (ERp58) autoantibodies were measured by enzyme-linked immunosorbent assays. Positive values were 2 SD above median control values. Two multiple regression models were constructed. Pediatric anesthesiologists, like halothane hepatitis patients, had higher serum autoantibody levels of ERp58 and P450 2E1 than general anesthesiologists and controls, which was possibly because of their increased occupational exposures to anesthetics. Female anesthesiologists had higher levels of ERp58 autoantibodies than male anesthesiologists, whereas female pediatric anesthesiologists had higher levels of P450 2E1 autoantibodies than all other anesthesiologists. One female pediatric anesthesiologist had symptoms of hepatic injury. Because most anesthesiologists do not develop volatile anesthetic-induced hepatic injury, the findings suggest that pathogenic ERp58 and P450 2E1 autoantibodies may not directly cause volatile anesthetic hepatitis. Female anesthesiologists have high levels of these autoantibodies; however, the majority of these individuals do not develop hepatitis, suggesting that autoantibodies may not have a pathological role in volatile anesthetic-induced hepatitis.

IMPLICATIONS

Environmental exposure of anesthesiology personnel to certain inhaled anesthetics can induce the formation of autoantibodies that have been associated with anesthetic hepatitis. Female anesthesiologists have high levels of these autoantibodies; however, the majority of these individuals do not develop hepatitis, suggesting that autoantibodies may not have a pathological role in volatile anesthetic-induced hepatitis.

Sphingolipids as biomarkers of fumonisin exposure and risk of esophageal squamous cell carcinoma in china

OBJECTIVE

Ecologic studies of esophageal squamous cell carcinoma (ESCC) have reported an association with consumption of maize contaminated with Fusarium verticillioides, which produce fungal toxins referred to as fumonisins. Fumonisins disrupt sphingolipid metabolism and serum sphingolipids have been proposed as biomarkers of fumonisin exposure. We conducted a prospective nested case-control study to examine the relationship between serum sphingolipids and ESCC incidence.

METHODS

Cases and controls were selected from a large prospective trial conducted in Linxian, People's Republic of China. Ninety-eight ESCC cases were randomly selected from the 639 incident ESCC ascertained during the initial 5.25 years of follow-up: 185 controls were also randomly selected based on the distribution of cases among six age and sex strata. Concentrations of sphinganine and sphingosine were determined by high-performance liquid chromatography in serum collected at the study baseline.

RESULTS

No significant associations were found between serum sphingosine, sphinganine, or the sphinganine/ sphingosine ratio and ESCC incidence in conditional and unconditional logistic regression models with adjustment for age, sex, tobacco use. and alcohol use.

CONCLUSION

Our study is the first prospective study to assess the relationship between sphingolipid levels, as biomarkers of fumonisin exposure, and cancer incidence. We found no significant association between sphingolipid levels and risk of ESCC.

A cross-sectional study of human serum sphingolipids, diet and physiologic parameters

Sphinganine and sphingosine, the two sphingoid base backbones of sphingolipids, are highly bioactive compounds that are of increasing interest to nutritionists because they occur in food and their metabolism can be altered by fungal toxins that contaminate some foods. Nonetheless, no studies of diet and sphinganine or sphingosine concentrations in serum have yet been reported. Here we describe a cross-sectional study of 265 residents of Linxian, People's Republic of China, which examines potential demographic, physiologic and dietary correlates of serum sphinganine and sphingosine in this population. Median concentrations of serum sphinganine and sphingosine were compared among strata for 29 different variables. For sphinganine, no significant differences were found. For sphingosine, significant differences were seen among strata of age, menstruation status, serum cholesterol, carotenoids, retinol, tocopherols, fresh and dried vegetable and fresh fruit consumption. Using multivariate linear regression with stepwise selection, we found that the significant predictors for serum sphingosine included total tocopherols, age, serum selenium and retinol, with a final R(2) = 0.22; for sphinganine, tooth loss was the sole correlate, with R(2) = 0.015. Analyses using ranked sphingolipid data or principal components analysis, to simplify the food variables, did not materially alter these results. This study represents the largest report of human serum sphingolipid concentrations to date and provides insight into potential explanatory variables that can be incorporated into future studies.

Prognostic factors for atherosclerosis progression in saphenous vein grafts: the postcoronary artery bypass graft (Post-CABG) trial. Post-CABG Trial Investigators

OBJECTIVES

The study was done to assess patients in the Post-Coronary Artery Bypass Graft (Post-CABG) trial to determine prognostic factors for atherosclerosis progression.

BACKGROUND

Saphenous vein grafts (SVGs) are effective in relieving angina and, in certain patient subsets, in prolonging life. However, the progression of atherosclerosis in many of these grafts limits their usefulness.

METHODS

The Post-CABG trial studied moderate versus aggressive lipid-lowering and low-dose warfarin versus placebo in patients with a history of coronary artery bypass surgery and found that more aggressive lipid lowering was effective in preventing progression of atherosclerosis in SVGs, but warfarin had no effect. Using variables measured at baseline, we sought the independent prognostic factors for atherosclerosis progression in SVGs, employing the statistical method of generalized estimating equations with a logit-link function.

RESULTS

Twelve independent prognostic factors for atherosclerosis progression were found. In the order of their importance they were: maximum stenosis of the graft at baseline angiography, years post-SVG placement; the moderate low-density lipoprotein-cholesterol (LDL-C) lowering strategy; prior myocardial infarction; high triglyceride level; small minimum graft diameter; low high-density lipoprotein-cholesterol (HDL-C); high LDL-C; high mean arterial pressure; low ejection fraction; male gender; and current smoking.

CONCLUSIONS

This study identified Post-CABG patient and SVG characteristics associated with saphenous vein graft atherosclerosis progression. These data provide a basis for rational risk factor management to prevent progression of SVG atherosclerosis.

Effect of angiotensin converting enzyme inhibition on sudden cardiac death in patients following acute myocardial infarction. A meta-analysis of randomized clinical trials

Estimate the effect of angiotensin converting enzyme (ACE) inhibitors on the risk of sudden cardiac death (SCD) following myocardial infarction (MI).

BACKGROUND

Trials in post-MI patients have shown that ACE inhibitor therapy reduces mortality. However, the effect on SCD as a mechanism has not been clarified.

METHODS

Trials of ACE inhibitor therapy following MI reported between January, 1978 and August, 1997 were identified. Studies were included if they met the following criteria: 1) randomized comparison of ACE inhibitor to placebo within 14 days of MI; 2) study duration/blinded follow-up of > or =6 weeks; 3) the number of deaths and modes of death were reported or could be obtained from the investigators.

RESULTS

We identified 374 candidate articles, of which 15 met the inclusion criteria. The 15 trials included 15,104 patients, 2,356 of whom died. Most (87%) fatalities were cardiovascular and 900 were SCDs. A significant reduction in SCD risk or a trend towards this was observed in all of the larger (N > 500) trials. Overall, ACE inhibitor therapy resulted in significant reductions in risk of death (random effects odds ratio [OR] = 0.83; 95% confidence interval [CI] 0.71-0.97), cardiovascular death (OR = 0.82; 95% CI 0.69-0.97) and SCD (OR = 0.80; 95% CI 0.70-0.92).

CONCLUSIONS

This analysis is consistent with prior reports showing that ACE inhibitors decrease the risk of death following a recent MI by reducing cardiovascular mortality. Moreover, this analysis suggests that a reduction in SCD risk with ACE inhibitors is an important component of this survival benefit.

Immunochemical evidence against the involvement of cysteine conjugate beta-lyase in compound A nephrotoxicity in rats

BACKGROUND

Compound A, a degradation product of sevoflurane, causes renal corticomedullary necrosis in rats. Although the toxicity of this compound was originally hypothesized to result from the biotransformation of its cysteine conjugates into toxic thionoacyl halide metabolites by renal cysteine conjugate beta-lyase, recent evidence suggests that alternative mechanisms may be responsible for compound A nephrotoxicity. The aim of this study was to evaluate these issues by determining whether mercapturates and glutathione conjugates of compound A could produce renal corticomedullary necrosis in rats, similar to compound A, and whether renal covalent adducts of the thionacyl halide metabolite of compound A could be detected immunochemically.

METHODS

Male Wistar rats were administered, intraperitoneally, N-acetylcysteine conjugates (mercapturates) of compound A (90 or 180 micromol/kg) or glutathione conjugates of compound A (180 micromol/kg) with or without intraperitoneal pretreatments with aminooxyacetic acid (500 micromol/kg) or acivicin (250 micromol/kg). Rats were killed after 24 h, and kidney tissues were analyzed for toxicity by histologic examination or for protein adducts by immunoblotting or immunohistochemical analysis, using antisera raised against the covalently bound thionoacyl halide metabolite of compound A.

RESULTS

Mercapturates and glutathione conjugates of compound A both produced renal corticomedullary necrosis similar to that caused by compound A. Aminooxyacetic acid, an inhibitor of renal cysteine conjugate beta-lyase, did not inhibit the toxicity of the mercapturates, whereas acivicin, an inhibitor of gamma-glutamyltranspeptidase, potentiated the toxicity of both classes of conjugates. No immunochemical evidence for renal protein adducts of the thionacyl halide metabolite was found in rats 24 h after the administration of the mercapturates of compound A or in the kidneys of rats, obtained from a previous study, 5 and 24 h after the administration of compound A.

CONCLUSION

The results of this study are consistent with the idea that a mechanism other than the renal cysteine conjugate beta-lyase pathway of metabolic activation is responsible for the nephrotoxicity of compound A and its glutathione and mercapturate conjugates in male Wistar rats.

On measures of agreement calculated from contingency tables with categories defined by the empirical quantiles of the marginal distributions

Epidemiologists sometimes collect bivariate continuous data on a number of subjects, compute the empirical (sample) quantiles of the marginal data, and then use these values to partition the original data into two-way contingency tables. Tables created in this manner have row and column categories defined by the random empirical marginal quantiles rather than by preset cutpoints, so these tables have fixed marginal totals. Hence, instead of the conventional multinomial distribution, these tables have the empirical bivariate quantile-partitioned (EBQP) distribution. In this paper, the authors demonstrate how to use empirical methods appropriate for EBQP tables to make inferences and construct confidence intervals for three commonly used measures of agreement: kappa, weighted kappa, and another class of measures derived from conditional proportions in the extreme rows of the table. They also show that if one incorrectly applies conventional methods appropriate for multinomial tables to statistics calculated from EBQP tables, one can obtain substantially misleading results. In addition, the authors present alternative parametric methods for estimating these measures of agreement and illustrate corresponding methods of inference and confidence interval construction. Finally, they show that these empirical (EBQP) methods can have low efficiency compared with parametric methods for some of these measures of agreement.

Analyzing bivariate continuous data grouped into categories defined by empirical quantiles of marginal distributions

Epidemiologists sometimes study the association between two measurements of exposure on the same subjects by grouping the original bivariate continuous data into categories that are defined by the empirical quantiles of the two marginal distributions. Although such grouped data are presented in a two-way contingency table, the cell counts in this table do not have a multinomial distribution. We describe the joint distribution of counts in such a table by the term empirical bivariate quantile-partitioned (EBQP) distribution. Blomqvist (1950, Annals of Mathematical Statistics 21, 539-600) gave an asymptotic EBQP theory for bivariate data partitioned by the sample medians. We demonstrate that his asymptotic theory is not correct, however, except in special cases. We present a general asymptotic theory for tables of arbitrary dimensions and apply this theory to construct confidence intervals for the kappa statistic. We show by simulations that the confidence interval procedures we propose have near nominal coverage for sample sizes exceeding 60 for both 2 x 2 and 3 x 3 tables. These simulations also illustrate that the asymptotic theory of Blomqvist (1950) and the methods that Fleiss, Cohen, and Everitt (1969, Psychological Bulletin 72, 323-327) give for multinomial tables can yield subnominal coverage for kappa calculated from EBQP tables, although in some cases the coverage for these procedures is near nominal levels.