Cost-effectiveness of a 12-dose regimen for treating latent tuberculous infection in the United States

SETTING

A large randomized controlled trial recently showed that for treating latent tuberculous infection (LTBI) in persons at high risk of progression to tuberculosis (TB) disease, a 12-dose regimen of weekly rifapentine plus isoniazid (3HP) administered as directly observed treatment (DOT) can be as effective as 9 months of daily self-administered isoniazid (9H).

OBJECTIVES

To assess the cost-effectiveness of 3HP compared to 9H.

DESIGN

A computational model was designed to simulate individuals with LTBI treated with 9H or 3HP. Costs and health outcomes were estimated to determine the incremental costs per active TB case prevented and per quality-adjusted life year (QALY) gained by 3HP compared to 9H.

RESULTS

Over a 20-year period, treatment of LTBI with 3HP rather than 9H resulted in 5.2 fewer cases of TB and 25 fewer lost QALYs per 1000 individuals treated. From the health system and societal perspectives, 3HP would cost respectively US$21,525 and $4294 more per TB case prevented, and respectively $4565 and $911 more per QALY gained.

CONCLUSIONS

3HP may be a cost-effective alternative to 9H, particularly if the cost of rifapentine decreases, the effectiveness of 3HP can be maintained without DOT, and 3HP treatment is limited to those with a high risk of progression to TB disease.

Tuberculin skin test result and risk of death among persons with active TB

Background

Although the tuberculin skin test (TST) is frequently used to aid in the diagnosis of tuberculosis (TB) disease and to identify persons with latent TB infection, it is an imperfect test and approximately 10–25% of persons with microbiologically confirmed TB disease have a negative TST. Previous studies have suggested that persons with a negative TST are more likely to present with severe TB disease and have an increased rate of TB-related death.

Methods

We analyzed culture-confirmed TB cases captured in US TB surveillance data from 1993 to 2008 and performed multivariate logistic regression analysis to determine the association between TST result and death.

Results

Of 284,866 cases of TB reported in the US, 58,180 persons were eligible for inclusion in the analysis and 3,270 of those persons died after initiating TB treatment. Persons with a negative TST accounted for only 14% of the eligible cases but accounted for 42% of the deaths. Persons with a TST≥15 mm had 67% lower odds of death than persons with a negative TST (adjusted odds ratio 0.33, 95% confidence interval 0.30–0.36).

Conclusions

A negative TST is associated with an increased risk of death among persons with culture-confirmed TB disease, even after adjustment for HIV status, site of TB disease, sputum smear AFB status, drug susceptibility, age, sex, and origin of birth. In addition to indicating risk of developing disease, the TST may also be a marker for increased risk of death.

Association between tuberculin skin test result and clinical presentation of tuberculosis disease

Background

The tuberculin skin test (TST) is used to test for latent tuberculosis (TB) infection and support the diagnosis of active TB. However, little is known about the relationship between the TST result and the clinical presentation of TB disease.

Methods

We analyzed US TB surveillance data, 1993–2010, and used multinomial logistic regression to calculate the association between TST result (0–4 mm [negative], 5–9 mm, 10–14 mm, and ≥ 15 mm) and clinical presentation of disease (miliary, combined pulmonary and extrapulmonary, extrapulmonary only, non-cavitary pulmonary, and cavitary pulmonary). For persons with pulmonary disease, multivariate logistic regression was used to calculate the odds of having acid-fast bacilli (AFB) positive sputum.

Results

There were 64,238 persons with culture-confirmed TB included in the analysis, which was stratified by HIV status and birthplace (US- vs. foreign-born). Persons with a TST ≥ 15 mm were less likely to have miliary or combined pulmonary and extrapulmonary disease, but more likely to have cavitary pulmonary disease than non-cavitary pulmonary disease. Persons with non-cavitary pulmonary disease with a negative TST were significantly more likely to have AFB positive sputum.

Conclusions

Clinical presentation of TB disease differed according to TST result and persons with a negative TST were more likely to have disseminated disease (i.e., miliary or combined pulmonary and extrapulmonary). Further study of the TST result may improve our understanding of the host-pathogen relationship in TB disease.

Accumulating Evidence and Research Organization (AERO) model: a new tool for representing, analyzing, and planning a translational research program

BACKGROUND

Maximizing efficiency in drug development is important for drug developers, policymakers, and human subjects. Limited funds and the ethical imperative of risk minimization demand that researchers maximize the knowledge gained per patient-subject enrolled. Yet, despite a common perception that the current system of drug development is beset by inefficiencies, there remain few approaches for systematically representing, analyzing, and communicating the efficiency and coordination of the research enterprise. In this paper, we present the first steps toward developing such an approach: a graph-theoretic tool for representing the Accumulating Evidence and Research Organization (AERO) across a translational trajectory.

METHODS

This initial version of the AERO model focuses on elucidating two dimensions of robustness: (1) the consistency of results among studies with an identical or similar outcome metric; and (2) the concordance of results among studies with qualitatively different outcome metrics. The visual structure of the model is a directed acyclic graph, designed to capture these two dimensions of robustness and their relationship to three basic questions that underlie the planning of a translational research program: What is the accumulating state of total evidence? What has been the translational trajectory? What studies should be done next?

RESULTS

We demonstrate the utility of the AERO model with an application to a case study involving the antibacterial agent, moxifloxacin, for the treatment of drug-susceptible tuberculosis. We then consider some possible elaborations for the AERO model and propose a number of ways in which the tool could be used to enhance the planning, reporting, and analysis of clinical trials.

CONCLUSION

The AERO model provides an immediate visual representation of the number of studies done at any stage of research, depicting both the robustness of evidence and the relationship of each study to the larger translational trajectory. In so doing, it makes some of the invisible or inchoate properties of the research system explicit - helping to elucidate judgments about the accumulating state of evidence and supporting decision-making for future research.

Lessons from a randomised clinical trial for multidrug-resistant tuberculosis

BACKGROUND

The treatment of multidrug-resistant tuberculosis (MDR-TB) is currently based upon expert opinion and findings from case series, rather than upon randomised clinical trials (RCTs).

OBJECTIVE

To describe the challenges encountered during an RCT for the treatment of MDR-TB.

METHODS

Tuberculosis Trials Consortium Study 30 was a pilot, Phase I/II, double-blind, placebo-controlled, RCT of the safety and tolerability of 16 weeks of daily, low-dose linezolid treatment for MDR-TB.

RESULTS

A total of 36 patients, 56% of the target of 64 patients, consented to participate, for an average of 0.69 enrolments per week. Of the 36 patients enrolled, only 25 (69%) completed at least 90 doses of study treatment. Among the 12 (33%) patients who did not complete all 112 doses of the study treatment, the median time to study withdrawal was 15 days (range 0-92). After the study, we discovered discordance between treatment assignment and study drug for at least 9 (25%) of the 36 patients.

CONCLUSIONS

Recruitment and retention in this MDR-TB clinical trial posed substantial challenges, suggesting the need for a large, multidisciplinary group of study staff to support the participants. Withdrawal tended to occur early in study treatment. The discrepancy in assigned study medication reflects the need for stronger administrative controls for study drugs.

Common roots: a contextual review of HIV epidemics in black men who have sex with men across the African diaspora

Pooled estimates from across the African diaspora show that black men who have sex with men (MSM) are 15 times more likely to be HIV positive compared with general populations and 8·5 times more likely compared with black populations. Disparities in the prevalence of HIV infection are greater in African and Caribbean countries that criminalise homosexual activity than in those that do not criminalise such behaviour. With the exception of US and African epidemiological studies, most studies of black MSM mainly focus on outcomes associated with HIV behavioural risk rather than on prevalence, incidence, or undiagnosed infection. Nevertheless, black MSM across the African diaspora share common experiences such as discrimination, cultural norms valuing masculinity, concerns about confidentiality during HIV testing or treatment, low access to HIV drugs, threats of violence or incarceration, and few targeted HIV prevention resources.

Comparisons of disparities and risks of HIV infection in black and other men who have sex with men in Canada, UK, and USA: a meta-analysis

BACKGROUND

We did a meta-analysis to assess factors associated with disparities in HIV infection in black men who have sex with men (MSM) in Canada, the UK, and the USA.

METHODS

We searched Embase, Medline, Google Scholar, and online conference proceedings from Jan 1, 1981, to Dec 31, 2011, for racial comparative studies with quantitative outcomes associated with HIV risk or HIV infection. Key words and Medical Subject Headings (US National Library of Medicine) relevant to race were cross-referenced with citations pertinent to homosexuality in Canada, the UK, and the USA. Data were aggregated across studies for every outcome of interest to estimate overall effect sizes, which were converted into summary ORs for 106,148 black MSM relative to 581,577 other MSM.

FINDINGS

We analysed seven studies from Canada, 13 from the UK, and 174 from the USA. In every country, black MSM were as likely to engage similarly in serodiscordant unprotected sex as other MSM. Black MSM in Canada and the USA were less likely than other MSM to have a history of substance use (odds ratio, OR, 0·53, 95% CI 0·38-0·75, for Canada and 0·67, 0·50-0·92, for the USA). Black MSM in the UK (1·86, 1·58-2·18) and the USA (3·00, 2·06-4·40) were more likely to be HIV positive than were other MSM, but HIV-positive black MSM in each country were less likely (22% in the UK and 60% in the USA) to initiate combination antiretroviral therapy (cART) than other HIV-positive MSM. US HIV-positive black MSM were also less likely to have health insurance, have a high CD4 count, adhere to cART, or be virally suppressed than were other US HIV-positive MSM. Notably, despite a two-fold greater odds of having any structural barrier that increases HIV risk (eg, unemployment, low income, previous incarceration, or less education) compared with other US MSM, US black MSM were more likely to report any preventive behaviour against HIV infection (1·39, 1·23-1·57). For outcomes associated with HIV infection, disparities were greatest for US black MSM versus other MSM for structural barriers, sex partner demographics (eg, age, race), and HIV care outcomes, whereas disparities were least for sexual risk outcomes.

INTERPRETATION

Similar racial disparities in HIV and sexually transmitted infections and cART initiation are seen in MSM in the UK and the USA. Elimination of disparities in HIV infection in black MSM cannot be accomplished without addressing structural barriers or differences in HIV clinical care access and outcomes.

FUNDING

None.

Seasonality of tuberculosis in the United States, 1993-2008

BACKGROUND

Although seasonal variation in tuberculosis incidence has been described in several recent studies, the mechanism underlying this seasonality remains unknown. Seasonality of tuberculosis disease may indicate the presence of season-specific risk factors that could potentially be controlled if they were better understood. We conducted this study to determine whether tuberculosis is seasonal in the United States and to describe patterns of seasonality in specific populations.

METHODS

We performed a time series decomposition analysis of tuberculosis cases reported to the Centers for Disease Control and Prevention from 1993 through 2008. Seasonal amplitude of tuberculosis disease (the difference between the months with the highest and lowest mean case counts), was calculated for the population as a whole and for populations with select demographic, clinical, and epidemiologic characteristics.

RESULTS

A total of 243 432 laboratory-confirmed tuberculosis cases were reported over a period of 16 years. A mean of 21.4% more cases were diagnosed in March, the peak month, compared with November, the trough month. The magnitude of seasonality did not vary with latitude. The greatest seasonal amplitude was found among children aged <5 years and in cases associated with disease clusters.

CONCLUSIONS

Tuberculosis is a seasonal disease in the United States, with a peak in spring and trough in late fall. The latitude independence of seasonality suggests that reduced winter sunlight exposure may not be a strong contributor to tuberculosis risk. Increased seasonality among young children and clustered cases suggests that disease that is the result of recent transmission is more influenced by season than disease resulting from activation of latent infection.

Improving participant understanding of informed consent in an HIV-prevention clinical trial: a comparison of methods

Empirical research on informed consent has shown that study participants often do not fully understand consent information. This study assessed participant understanding of three mock consent approaches describing an HIV-prevention clinical trial in Lilongwe, Malawi prior to trial implementation. Pregnant women (n = 297) were systematically selected from antenatal-care waiting lines and sequentially allocated to receive an enhanced standard consent form (group 1), a context-specific consent form (group 2), or context-specific counseling cards (group 3). Understanding of research concepts and study procedures was assessed immediately postintervention and at 1-week follow-up. At postintervention, participants in groups 2 and 3 understood more about research concepts and study procedures compared with group 1. Group 3 participants also understood more about study procedures compared with group 2. At follow-up, participants in groups 2 and 3 continued to understand more about research concepts and study procedures. Context-specific approaches improved understanding of consent information in this study.

Ethical justification for conducting public health surveillance without patient consent

Public health surveillance by necessity occurs without explicit patient consent. There is strong legal and scientific support for maintaining name-based reporting of infectious diseases and other types of public health surveillance. We present conditions under which surveillance without explicit patient consent is ethically justifiable using principles of contemporary clinical and public health ethics. Overriding individual autonomy must be justified in terms of the obligation of public health to improve population health, reduce inequities, attend to the health of vulnerable and systematically disadvantaged persons, and prevent harm. In addition, data elements collected without consent must represent the minimal necessary interference, lead to effective public health action, and be maintained securely.

Development of a standardized screening rule for tuberculosis in people living with HIV in resource-constrained settings: individual participant data meta-analysis of observational studies

BACKGROUND

The World Health Organization recommends the screening of all people living with HIV for tuberculosis (TB) disease, followed by TB treatment, or isoniazid preventive therapy (IPT) when TB is excluded. However, the difficulty of reliably excluding TB disease has severely limited TB screening and IPT uptake in resource-limited settings. We conducted an individual participant data meta-analysis of primary studies, aiming to identify a sensitive TB screening rule.

METHODS AND FINDINGS

We identified 12 studies that had systematically collected sputum specimens regardless of signs or symptoms, at least one mycobacterial culture, clinical symptoms, and HIV and TB disease status. Bivariate random-effects meta-analysis and the hierarchical summary relative operating characteristic curves were used to evaluate the screening performance of all combinations of variables of interest. TB disease was diagnosed in 557 (5.8%) of 9,626 people living with HIV. The primary analysis included 8,148 people living with HIV who could be evaluated on five symptoms from nine of the 12 studies. The median age was 34 years. The best performing rule was the presence of any one of: current cough (any duration), fever, night sweats, or weight loss. The overall sensitivity of this rule was 78.9% (95% confidence interval [CI] 58.3%-90.9%) and specificity was 49.6% (95% CI 29.2%-70.1%). Its sensitivity increased to 90.1% (95% CI 76.3%-96.2%) among participants selected from clinical settings and to 88.0% (95% CI 76.1%-94.4%) among those who were not previously screened for TB. Negative predictive value was 97.7% (95% CI 97.4%-98.0%) and 90.0% (95% CI 88.6%-91.3%) at 5% and 20% prevalence of TB among people living with HIV, respectively. Abnormal chest radiographic findings increased the sensitivity of the rule by 11.7% (90.6% versus 78.9%) with a reduction of specificity by 10.7% (49.6% versus 38.9%).

CONCLUSIONS

Absence of all of current cough, fever, night sweats, and weight loss can identify a subset of people living with HIV who have a very low probability of having TB disease. A simplified screening rule using any one of these symptoms can be used in resource-constrained settings to identify people living with HIV in need of further diagnostic assessment for TB. Use of this algorithm should result in earlier TB diagnosis and treatment, and should allow for substantial scale-up of IPT.

An algorithm for tuberculosis screening and diagnosis in people with HIV

BACKGROUND

Tuberculosis screening is recommended for people with human immunodeficiency virus (HIV) infection to facilitate early diagnosis and safe initiation of antiretroviral therapy and isoniazid preventive therapy. No internationally accepted, evidence-based guideline addresses the optimal means of conducting such screening, although screening for chronic cough is common.

METHODS

We consecutively enrolled people with HIV infection from eight outpatient clinics in Cambodia, Thailand, and Vietnam. For each patient, three samples of sputum and one each of urine, stool, blood, and lymph-node aspirate (for patients with lymphadenopathy) were obtained for mycobacterial culture. We compared the characteristics of patients who received a diagnosis of tuberculosis (on the basis of having one or more specimens that were culture-positive) with those of patients who did not have tuberculosis to derive an algorithm for screening and diagnosis.

RESULTS

Tuberculosis was diagnosed in 267 (15%) of 1748 patients (median CD4+ T-lymphocyte count, 242 per cubic millimeter; interquartile range, 82 to 396). The presence of a cough for 2 or 3 weeks or more during the preceding 4 weeks had a sensitivity of 22 to 33% for detecting tuberculosis. The presence of cough of any duration, fever of any duration, or night sweats lasting 3 or more weeks in the preceding 4 weeks was 93% sensitive and 36% specific for tuberculosis. In the 1199 patients with any of these symptoms, a combination of two negative sputum smears, a normal chest radiograph, and a CD4+ cell count of 350 or more per cubic millimeter helped to rule out a diagnosis of tuberculosis, whereas a positive diagnosis could be made only for the 113 patients (9%) with one or more positive sputum smears; mycobacterial culture was required for most other patients.

CONCLUSIONS

In persons with HIV infection, screening for tuberculosis should include asking questions about a combination of symptoms rather than only about chronic cough. It is likely that antiretroviral therapy and isoniazid preventive therapy can be started safely in people whose screening for all three symptoms is negative, whereas diagnosis in most others will require mycobacterial culture.

Substitution of moxifloxacin for isoniazid during intensive phase treatment of pulmonary tuberculosis

RATIONALE

Moxifloxacin has potent activity against Mycobacterium tuberculosis in vitro and in a mouse model of antituberculosis (TB) chemotherapy, but data regarding its activity in humans are limited.

OBJECTIVES

Our objective was to compare the antimicrobial activity and safety of moxifloxacin versus isoniazid during the first 8 weeks of combination therapy for pulmonary TB.

METHODS

Adults with sputum smear-positive pulmonary TB were randomly assigned to receive either moxifloxacin 400 mg plus isoniazid placebo, or isoniazid 300 mg plus moxifloxacin placebo, administered 5 days/week for 8 weeks, in addition to rifampin, pyrazinamide, and ethambutol. All doses were directly observed. Sputum was collected for culture every 2 weeks. The primary outcome was negative sputum culture at completion of 8 weeks of treatment.

MEASUREMENTS AND MAIN RESULTS

Of 433 participants enrolled, 328 were eligible for the primary efficacy analysis. Of these, 35 (11%) were HIV positive, 248 (76%) had cavitation on baseline chest radiograph, and 213 (65%) were enrolled at African sites. Negative cultures at Week 8 were observed in 90/164 (54.9%) participants in the isoniazid arm, and 99/164 (60.4%) in the moxifloxacin arm (P = 0.37). In multivariate analysis, cavitation and enrollment at an African site were associated with lower likelihood of Week-8 culture negativity. The proportion of participants who discontinued assigned treatment was 31/214 (14.5%) for the moxifloxacin group versus 22/205 (10.7%) for the isoniazid group (RR, 1.35; 95% CI, 0.81, 2.25).

CONCLUSIONS

Substitution of moxifloxacin for isoniazid resulted in a small but statistically nonsignificant increase in Week-8 culture negativity.

Risk Factors for Cesarean Delivery Among Puerto Rican Women

OBJECTIVE

The rate of primary cesarean delivery in Puerto Rico in 2002 was 52% higher than in 1996 and 85% higher than among Puerto Rican women delivering on the U.S. mainland. Reasons for these differences were explored using birth certificate data.

METHODS

Distributions of mothers' age, education, parity, level of prenatal care, pregnancy weight gain, medical risk factors, labor induction, labor or delivery complications, and infant birth weight among births in Puerto Rico in 2002 (n=40,489) were compared with births in Puerto Rico in 1996 (n=51,357) and births to Puerto Rican women delivering on the mainland in 2002 (n=47,800). Multivariable log-linear regression models were used to estimate relative risks for primary cesarean delivery by year, place of delivery, and selected risk factors.

RESULTS

Risk for cesarean delivery was higher in Puerto Rico in 2002 than in both 1996 (relative risk 2.1, 95% confidence interval 2.0, 2.3) and on the mainland in 2002 (relative risk 2.4, 95% confidence interval 2.2, 2.6). This translates into one additional cesarean delivery in Puerto Rico in 2002 for every 4.2 live births, controlled for examined risk factors. Higher rates of cesarean delivery in Puerto Rico in 2002 could not be explained by examined risk factors.

CONCLUSION

Until further research reveals ways to safely reduce the rate of cesarean delivery in Puerto Rico, physicians, public health practitioners, and other stakeholders may want to focus their efforts on reducing rates among low-risk women and those with no labor complications.

LEVEL OF EVIDENCE

II.

Nutritional biomarkers associated with gynecological conditions among US women with or at risk of HIV infection

BACKGROUND

Women infected with HIV face a combination of health threats that include compromised nutrition and adverse gynecological conditions. This relation among HIV, nutrition, and gynecological conditions is complex and has rarely been investigated.

OBJECTIVE

Our objective was to investigate nutritional biomarkers associated with several gynecological conditions among US women with or at risk of HIV infection.

DESIGN

Data on 369 HIV-infected and 184 HIV-uninfected women with both nutritional and gynecological outcomes were analyzed from a cross-sectional nutritional substudy of the HIV Epidemiology Research Study (HERS). We examined micronutrient distributions comparing HIV-infected with HIV-uninfected participants and both subgroups with the US population. We then modeled the relation of 16 micronutrient serum concentrations to various gynecological conditions, producing partially adjusted odds ratios, adjusted for study site, risk cohort, and HIV status.

RESULTS

HIV-infected women's median antioxidant concentrations were lower than the medians of the US population. HERS women had lower median concentrations for vitamin A, selenium, and zinc irrespective of HIV status. Trichomoniasis prevalence was inversely related to serum alpha-carotene. Lower concentrations of vitamins A, C, and E and beta-carotene were associated with an increased risk of bacterial vaginosis. Higher concentrations of serum zinc were associated with lower risk of human papillomavirus. Candida colonization was higher among women with higher concentrations of total-iron-binding capacity.

CONCLUSION

We identified several significant associations of micronutrient concentrations with the prevalence of gynecological conditions. These findings warrant further investigation into possible causal relations.

Using formative research to develop a context-specific approach to informed consent for clinical trials

PARTICIPANT UNDERSTANDING is of particular concern when obtaining informed consent. Recommendations for improving understanding include disclosing information using culturallyappropriate and innovative approaches. To increase the effectiveness of the consent process for a clinical trial in Malawi on interventions to prevent mother-tochild transmission of HIV during breastfeeding, formative research was conducted to explore the community's understanding of medical research as well as how to explain research through local terms and meanings. Contextual analogies and other approaches were identified to explain consent information. Guided by theory, strategies for developing culturally appropriate interventions, and recommendations from the literature, we demonstrate how the formative data were used to develop culturally appropriate counseling cards specifically for the trial in Malawi. With appropriate contextual modifications, the steps outlined here could be applied in other clinical trials conducted elsewhere, as well as in other types of research.

Time to clearance of human papillomavirus infection by type and human immunodeficiency virus serostatus

Persistent infection with high-risk human papillomavirus (HPV) is central to cervical carcinogenesis. Certain high-risk types, such as HPV16, may be more persistent than other HPV types, and type-specific HPV persistence may differ by HIV serostatus. This study evaluated the association between HPV type and clearance of HPV infections in 522 HIV-seropositive and 279 HIV-seronegative participants in the HIV Epidemiology Research Study (HERS, United States, 1993-2000). Type-specific HPV infections were detected using MY09/MY11/HMB01-based PCR and 26 HPV type-specific probes. The estimated duration of type-specific infections was measured from the first HPV-positive visit to the first of two consecutive negative visits. Hazard ratios (HRs) and 95% confidence intervals (CIs) for HPV clearance were calculated using Cox models adjusted for study site and risk behavior (sexual or injection drugs). A total of 1,800 HPV infections were detected in 801 women with 4.4 years median follow-up. HRs for clearance of HPV16 and related types versus low-risk HPV types were 0.79 (95% CI: 0.64-0.97) in HIV-positive women and 0.86 (95% CI: 0.59-1.27) in HIV-negative women. HRs for HPV18 versus low-risk types were 0.80 (95% CI: 0.56-1.16) and 0.57 (95% CI: 0.22-1.45) for HIV-positive and -negative women, respectively. HPV types within the high-risk category had low estimated clearance rates relative to low-risk types, but HRs were not substantially modified by HIV serostatus.

Smoking and time to clearance of human papillomavirus infection in HIV-seropositive and HIV-seronegative women

Persistent human papillomavirus (HPV) infection seems central to cervical carcinogenesis. Smoking is associated with cervical cancer in HPV DNA-positive women, but its association with HPV persistence is unclear, particularly with respect to human immunodeficiency virus (HIV) serostatus. The authors evaluated smoking and HPV clearance by HIV serostatus among 801 women from the HIV Epidemiology Research Study (United States, 1993-2000). Type-specific HPV duration was defined as the interval between initial MY09/11 polymerase chain reaction positivity and the first of two consecutive HPV-negative study visits. Hazard ratios adjusted for study site and risk behaviors (sexual activity or injection drug use) were estimated using Cox regression. This analysis included 522 HIV-seropositive and 279 HIV-seronegative women (median follow-up, 4.4 years). Ever smoking was associated with reduced clearance of high-risk HPV in HIV-seronegative women (hazard ratio (HR) = 0.51, 95% confidence interval (CI): 0.30, 0.88) but not in HIV-seropositive women (HR = 0.96, 95% CI: 0.65, 1.42); similar results were found for current smoking. Current smoking was not associated with clearance of any type-specific HPV in HIV-seropositive (HR = 0.99, 95% CI: 0.82, 1.20) or HIV-seronegative (HR = 0.93, 95% CI: 0.68, 1.26) women. HPV clearance did not appear to vary by amount or duration of smoking. Smoking did not modify overall clearance but was associated with lower high-risk HPV clearance in HIV-seronegative women.

Effect of HIV Infection on Atypical Squamous Cells of Undetermined Significance

BACKGROUND

Detection of atypical squamous cells of undetermined significance (ASCUS) is a cervical cytologic finding that is suggestive but not definitive of squamous intraepithelial lesions (SILs).

METHODS

We examined the risk, characteristics, and progression of ASCUS in women with and without human immunodeficiency virus (HIV) infection. Cervical Papanicolou (Pap) test and colposcopy data were obtained at the first 10 semiannual visits for the HIV Epidemiology Research study of 774 HIV-infected and 480 demographically similar, HIV-uninfected women in the United States. Multiple logistic regression models and Cox proportional hazards models were utilized.

RESULTS

ASCUS was more common among HIV-infected women (odds ratio [OR], 1.6 [95% confidence interval {CI}, 1.3-2.0] to 2.6 [95% CI, 1.9-3.6]) after adjustment for human papillomavirus (HPV) infection and other risk factors (e.g., race, condyloma, and prior Pap test result). Among women with normal Pap test results at enrollment, the cumulative incidence of ASCUS was 78% among HIV-infected women and 38% among HIV-uninfected women. HIV-infected and HIV-uninfected women with ASCUS did not differ by prevalence of indices of inflammation (inflammation on Pap test and leukocytes on cervical gram stain). HPV infection, including high risk types, was more common among HIV-infected women with ASCUS. Among women with ASCUS, 60% of HIV-infected and 25% of HIV-uninfected women developed SILs (P < .01). Compared with HIV-infected women with higher CD4+ lymphocyte counts, HIV-infected women with CD4+ lymphocyte counts < 200 cells/microL were more likely to present subsequently with a SIL detected by Pap test (OR, 1.7; 95% CI, 0.8-3.6).

CONCLUSIONS

Higher risk of SIL following the appearance of ASCUS among HIV-infected women, especially women with low CD4+ lymphocyte counts, supports the need for follow up with colposcopy and histologic examination, as indicated, to allow early detection and treatment of SIL.

Vaginal flora morphotypic profiles and assessment of bacterial vaginosis in women at risk for HIV infection

Specific morphotypic profiles of normal and abnormal vaginal flora, including bacterial vaginosis (BV), were characterized. A prospective study of 350 women yielded concurrent Gram-stain data and clinical assessment (n = 3455 visits). Microbiological profiles were constructed by Gram stain. Eight profile definitions were based on dichotomizing the levels of Lactobacillus, Gardnerella, and curved, Gram-negative bacillus (Mobiluncus) morphotypes. Of these, two were rare, and the other six demonstrated a graded association with the clinical components of BV. The proposed profiles from the Gram stain reflect the morphotypic categories describing vaginal flora that may enable clearer elucidation of gynecologic and obstetric outcomes in various populations.

Extending McNemar's Test: Estimation and Inference When Paired Binary Outcome Data Are Misclassified

McNemar's test is popular for assessing the difference between proportions when two observations are taken on each experimental unit. It is useful under a variety of epidemiological study designs that produce correlated binary outcomes. In studies involving outcome ascertainment, cost or feasibility concerns often lead researchers to employ error-prone surrogate diagnostic tests. Assuming an available gold standard diagnostic method, we address point and confidence interval estimation of the true difference in proportions and the paired-data odds ratio by incorporating external or internal validation data. We distinguish two special cases, depending on whether it is reasonable to assume that the diagnostic test properties remain the same for both assessments (e.g., at baseline and at follow-up). Likelihood-based analysis yields closed-form estimates when validation data are external and requires numeric optimization when they are internal. The latter approach offers important advantages in terms of robustness and efficient odds ratio estimation. We consider internal validation study designs geared toward optimizing efficiency given a fixed cost allocated for measurements. Two motivating examples are presented, using gold standard and surrogate bivariate binary diagnoses of bacterial vaginosis (BV) on women participating in the HIV Epidemiology Research Study (HERS).

HIV-1 subtype E progression among northern Thai couples: traditional and non-traditional predictors of survival

BACKGROUND

In the continuing effort to introduce antiretroviral therapy in resource-limited settings, there is a need to understand differences between natural history of HIV in different populations and to identify feasible clinical measures predictive of survival.

METHODS

We examined predictors of survival among 836 heterosexuals who were infected with HIV subtype CRF01_AE in Thailand.

RESULTS

From 1993 to 1999, 269 (49.4%) men and 65 (25.7%) women died. The median time from the estimated seroconversion to death was 7.8 years (95% confidence interval 7.0-9.1). Men and women with enrolment CD4 counts <200 cells/microl had about 2 and 11 times greater risk of death than those with CD4 counts of 200-500 and >500, respectively. Measurements available in resource-limited settings, including total lymphocyte count (TLC), anaemia, and low body mass index (BMI), also predicted survival. Men with two or more of these predictors had a median survival of 0.8 (0.5-1.8) years, compared with 2.7 (1.9-3.3) years for one predictor and 4.9 (4.1-5.2) years for no predictors.

CONCLUSIONS

The time from HIV infection to death appears shorter among this Thai population than among antiretroviral naive Western populations. CD4 count and viral load (VL) were strong, independent predictors of survival. When CD4 count and VL are unavailable, individuals at high risk for shortened HIV survival may be identified by a combination of low TLC, anaemia, and low BMI. This combination of accessible clinical measures of the disease stage may be useful for medical management in resource-limited settings.

Lymphocyte homeostasis in HIV-infected northern Thais

Cross-sectional laboratory data were used to model the patterns of total lymphocyte count and lymphocyte subpopulation counts among persons with chronic HIV-1 subtype E (CRF01_AE) infection during the 6.5 years preceding death. The data cover 331 HIV-infected decedents from a heterosexual HIV transmission study of 590 northern Thai couples enrolled in 1992-1998. From blood collected at enrollment, the lymphocyte phenotypes (CD3, CD8, CD4, natural killer, and B cells) were stained using two-color monoclonal antibody combinations and quantified by flow cytometry. Piecewise linear splines modeled the associations between lymphocyte levels and time before death. Mean CD3, CD8, and B cell levels showed no temporal associations from 6.5 to 2 years before death, but each declined significantly during the 2 years before death. CD3 levels declined 31.0% [95% confidence interval (-40.3%, -19.8%)] and CD8 levels declined 24.6% (-35.4%, -13.5%) annually in the 2 years prior to death. In contrast, CD4 and NK cell levels declined little from 6.5 to 4.5 years before death but declined significantly over the 4.5 years prior to death. CD4 levels declined 22.1% (-29.2%, -12.0%) annually from 4.5 to 2 years prior to death and 63.7% (-72.3%, -53.6%) annually over the remaining 2 years. Similar lymphocyte patterns have been reported in U. S. and European populations with HIV-1 subtype B infection.

Abnormal Vaginal Cytology in HIV-Infected and At-Risk Women After Hysterectomy

OBJECTIVE

To determine the frequency of and risk factors for abnormal vaginal Papanicolaou smears in HIV-infected women after hysterectomy.

METHODS

Data were from the HIV Epidemiology Research (HER) study, a prospective multisite study of HIV-infected and uninfected women. Semiannual vaginal Papanicolaou smears and colposcopy data were obtained from 102 HIV-infected and 46 at-risk women who had hysterectomy either before or during the study. Analytic models used include Cox proportional hazards (women with hysterectomy during the study) and multiple logistic regressions, which corrected for repeated measures (all women).

RESULTS

Among the HIV-infected women, evidence of cervical intraepithelial neoplasia before or at hysterectomy was associated with abnormal cytology during follow-up; 63% had squamous intraepithelial lesions (SIL) on vaginal Papanicolaou smears following hysterectomy. CD4 counts of <200 cells/microL at hysterectomy and HIV viral load of >10,000 copies/mL at hysterectomy were predictive of SIL vaginal cytology. Prevalent SIL vaginal cytology was associated with low CD4 count and human papillomavirus risk type. Of the 102 HIV-infected women, 16 (16%) had vaginal intraepithelial neoplasia on biopsy.

CONCLUSIONS

The high rate of SIL on vaginal Papanicolaou smears and the presence of high-grade vaginal intraepithelial neoplasia among HIV-infected women after hysterectomy demonstrate the need for continued follow-up for lower genital tract lesions.