Dynamic use of historical controls in clinical trials for rare disease research: A re-evaluation of the MILES trial.

BACKGROUND: Randomized controlled trials offer the best design for eliminating bias in estimating treatment effects but can be slow and costly in rare disease research. Additionally, an equal randomization approach may not be optimal in studies in which prior evidence of superiority of one or more treatments exist. Supplementing prospectively enrolled, concurrent controls with historical controls can reduce recruitment requirements and provide patients a higher likelihood of enrolling in a new and possibly superior treatment arm. Appropriate methods need to be employed to ensure comparability of concurrent and historical controls to minimize bias and variability in the treatment effect estimates and reduce the chances of drawing incorrect conclusions regarding treatment benefit. METHODS: MILES was a phase III placebo-controlled trial employing 1:1 randomization that led to US Food and Drug Administration approval of sirolimus for treating patients with lymphangioleiomyomatosis. We re-analyzed the MILES trial data to learn whether substituting concurrent controls with controls from a historical registry could have accelerated subject enrollment while leading to similar study conclusions. We used propensity score matching to identify exchangeable historical controls from a registry balancing the baseline characteristics of the two control groups. This allowed more new patients to be assigned to the sirolimus arm. We used trial data and simulations to estimate key outcomes under an array of alternative designs. RESULTS: Borrowing information from historical controls would have allowed the trial to enroll fewer concurrent controls while leading to the same conclusion reached in the trial. Simulations showed similar statistical performance for borrowing as for the actual trial design without producing type I error inflation and preserving power for the same study size when concurrent and historical controls are comparable. CONCLUSION: Substituting concurrent controls with propensity score-matched historical controls can allow more prospectively enrolled patients to be assigned to the active treatment and enable the trial to be conducted with smaller overall sample size, while maintaining covariate balance and study power and minimizing bias in response estimation. This approach does not fully eliminate the concern that introducing non-randomized historical controls in a trial may lead to bias in estimating treatment effects, and should be carefully considered on a case-by-case basis. Borrowing historical controls is best suited when conducting randomized controlled trials with conventional designs is challenging, as in rare disease research. High-quality data on covariates and outcomes must be available for candidate historical controls to ensure the validity of these designs. Additional precautions are needed to maintain blinding of the treatment assignment and to ensure comparability in the assessment of treatment safety.MILES ClinicalTrials.gov Number: NCT00414648.

Effectiveness of a Universally Offered Chlamydia and Gonorrhea Screening Intervention in the Pediatric Emergency Department.

PURPOSE: Adolescents represent more than half of the newly diagnosed sexually transmitted infections in the U.S. annually. Emergency departments (EDs) may serve as an effective, nontraditional setting to screen for chlamydia/gonorrhea (CT/GC). The objective was to evaluate the effectiveness of a universally offered CT/GC screening program in two pediatric ED settings. METHODS: This was a prospective, delayed start pragmatic study conducted over 18 months in two EDs within the same academic institution among ED adolescents aged 14-21 years with any chief complaint. Using a tablet device, adolescents were confidentially informed of CT/GC screening recommendations and were offered screening. If patients agreed to CT/GC testing, a clinical decision support tool was triggered to inform the provider and order testing. The main and key secondary outcomes were the proportion of CT/GC testing and positive CT/GC test results in each respective ED. RESULTS: Both EDs experienced modest but statistically significant increases in CT/GC testing post- versus pre-intervention (main: 11.5% vs. 7.9%; confidence interval [CI]: 2.9-4.2; p < .0001 and satellite: 3.8% vs. 2.6%; 95% CI: .7-1.7; p < .0001). Among those tested, the positivity rate at the main ED did not significantly change post- versus pre-intervention (24.1% vs. 23.2%; 95% CI: -1.9 to 3.8; p = .71) but significantly decreased at the satellite ED (7.6% vs. 14.8%; 95% CI: -12.2 to -2.2; p = .01). CONCLUSIONS: A universally offered screening intervention increased the proportion of adolescents who were tested at both EDs and the detection rates for CT/GC at the main ED, but patient acceptance of screening was low.

Information Technology-Assisted Screening for Gonorrhea and Chlamydia in a Pediatric Emergency Department.

PURPOSE: The aim of the study was to design and implement a novel, universally offered, computerized clinical decision support (CDS) gonorrhea and chlamydia (GC/CT) screening tool embedded in the emergency department (ED) clinical workflow and triggered by patient-entered data. METHODS: The study consisted of the design and implementation of a tablet-based screening tool based on qualitative data of adolescent and parent/guardian acceptability of GC/CT screening in the ED and an advisory committee of ED leaders and end users. The tablet was offered to adolescents aged 14-21 years and informed patients of Centers for Disease Control and Prevention GC/CT screening recommendations, described the testing process, and assessed whether patients agreed to testing. The tool linked to CDS that streamlined the order entry process. The primary outcome was the patient capture rate (proportion of patients with tablet data recorded). The secondary outcomes included rates of patient agreement to GC/CT testing and provider acceptance of the CDS. RESULTS: Outcomes at the main and satellite EDs, respectively, were as follows: 1-year patient capture rates were 64.6% and 64.5%; 9.9% and 4.4% of patients agreed to GC/CT testing, and of those, the provider ordered testing for 73% and 72%. CONCLUSIONS: Implementation of this computerized screening tool embedded in the clinical workflow resulted in patient capture rates of almost two-thirds and clinician CDS acceptance rates >70% with limited patient agreement to testing. This screening tool is a promising method for confidential GC/CT screening among youth in an ED setting. Additional interventions are needed to increase adolescent agreement for GC/CT testing.

Accounting for misclassification bias of binary outcomes due to underscreening: a sensitivity analysis.

BACKGROUND: Diagnostic tests are performed in a subset of the population who are at higher risk, resulting in undiagnosed cases among those who do not receive the test. This poses a challenge for estimating the prevalence of the disease in the study population, and also for studying the risk factors for the disease. METHODS: We formulate this problem as a missing data problem because the disease status is unknown for those who do not receive the test. We propose a Bayesian selection model which models the joint distribution of the disease outcome and whether testing was received. The sensitivity analysis allows us to assess how the association of the risk factors with the disease outcome as well as the disease prevalence change with the sensitivity parameter. RESULTS: We illustrated our model using a retrospective cohort study of children with asthma exacerbation that were evaluated for pneumonia in the emergency department. Our model found that female gender, having fever during ED or at triage, and having severe hypoxia are significantly associated with having radiographic pneumonia. In addition, simulation studies demonstrate that the Bayesian selection model works well even under circumstances when both the disease prevalence and the screening proportion is low. CONCLUSION: The Bayesian selection model is a viable tool to consider for estimating the disease prevalence and in studying risk factors of the disease, when only a subset of the target population receive the test.

Prostate-specific antigen concentration in vaginal fluid after exposure to semen.

OBJECTIVE: Prostate-specific antigen (PSA) is the best established biomarker of semen exposure. PSA in vaginal fluid returns to pre-exposure concentrations within 24-48 h, but the speed of decay during the first 10 h is unknown. We sought to determine how fast PSA concentrations decline during the first 10 h after exposure to semen. STUDY DESIGN: Women in the 50 enrolled couples were intravaginally inoculated with 10, 20, 100 and 200 µl of their partner's semen and then collected vaginal swabs immediately after, 30 min, 4 h and 10 h after exposure. Forty-seven sets of samples were tested for PSA. Mixed linear models for repeated measures examined the association between log-transformed PSA values and sampling time and semen exposure volume. Sensitivity analyses excluded data from nonabstainers. Fixed-effect estimates from the statistical models were graphed. RESULTS: PSA values were highest at 200 µl inoculation volumes and at earlier post-exposure time points, then decline steadily. The lowest inoculation volume (10 µl) corresponded to the smallest concentration of PSA throughout the post-inoculation time points. Average PSA levels return to clinically non-detectable levels within 10 h only at the lowest semen exposures. The PSA decay curve assumes a very similar profile across all time points and semen amounts. CONCLUSIONS: The PSA decay curve is similar for varying semen exposure volumes, with average PSA concentrations remaining above clinical thresholds 10 h after exposure at all except the very smallest semen exposure levels. PSA is an objective marker of recent exposure to semen, permitting such detection with high accuracy. IMPLICATIONS: This study clarifies how PSA values vary at different semen exposure levels and time points during the first 10 h post-exposure. Future contraceptive studies that use PSA as a semen biomarker will be better informed about PSA concentrations at different sampling times and exposure amounts.

A Qualitative Analysis of Adolescent and Caregiver Acceptability of Universally Offered Gonorrhea and Chlamydia Screening in the Pediatric Emergency Department.

STUDY OBJECTIVE: We qualitatively explore adolescent and parent or guardian attitudes about benefits and barriers to universally offered gonorrhea and chlamydia screening and modalities for assessing interest in screening in the pediatric emergency department (ED). METHODS: A convenience sample of forty 14- to 21-year-olds and parents or guardians of adolescents presenting to an urban and community pediatric ED with any chief complaint participated in individual, semistructured, confidential interviews. Topics included support of universally offered gonorrhea and chlamydia screening, barriers and benefits to screening, and modalities for assessing interest in screening. Data were analyzed with framework analysis. RESULTS: Almost all adolescents (37/40; 93%) and parents (39/40; 98%) support offering ED gonorrhea or chlamydia screening. Benefits included earlier diagnosis and treatment, convenience and transmission prevention (cited by both groups), and improved education and long-term health (cited by parents/guardians). Barriers included concerns about confidentiality and cost (cited by both groups), embarrassment (cited by adolescents), and nondisclosure to parents or guardians (cited by parents/guardians). Adolescents preferred that the request for gonorrhea or chlamydia screening be presented in a private room, using tablet technology. Both groups noted that the advantages to tablets included confidentiality and adolescents' familiarity with technology. Adolescents noted that tablet use would address concerns about bringing up gonorrhea or chlamydia screening with clinicians, whereas parents or guardians noted that tablets might increase screening incidence but expressed concern about the lack of personal interaction. CONCLUSION: Universally offered gonorrhea and chlamydia screening in a pediatric ED was acceptable to the adolescents and parents or guardians in this study. Offering a tablet-based method to assess interest in screening may increase participation.

Sexual Relationship Power and Semen Exposure Among Female Patients at a Sexually Transmitted Infection Clinic in Kingston, Jamaica.

Women's power in sexual relationships is thought to be an important predictor of condom use. However, research on correlates of condom use often relies on participant reporting of behavior, which has questionable validity. We evaluated the association between scores from the modified Sexual Relationship Power Scale (SRPS-M) and biological detection of semen exposure in a prospective study of adult women attending a sexually transmitted infection clinic in Kingston, Jamaica with cervicitis or abnormal vaginal discharge in 2010-2011. At enrollment, women were counseled to avoid sex while on treatment and were asked to return in 6 days for a follow-up visit. At both study visits, women were administered a questionnaire and had vaginal swabs collected to test for prostate-specific antigen (PSA), a biological marker of recent semen exposure. We found no significant association at enrollment or follow-up between SRPS-M scores and semen exposure, as measured with either self-reported data or PSA positivity. Semen biomarkers could be used to develop and validate new scales on relationship power and self-efficacy related to condom use.

Cervical Microbiota Associated with Higher Grade Cervical Intraepithelial Neoplasia in Women Infected with High-Risk Human Papillomaviruses.

It is increasingly recognized that microbes that reside in and on human body sites play major roles in modifying the pathogenesis of several diseases, including cancer. However, specific microbes or microbial communities that can be mechanistically linked to cervical carcinogenesis remain largely unexplored. The purpose of the study was to examine the association between cervical microbiota and high-grade cervical intraepithelial neoplasia (CIN 2+) in women infected with high-risk (HR) human papillomaviruses (HPV) and to assess whether the cervical microbiota are associated with oxidative DNA damage as indicated by the presence of cervical cells positive for 8-hydroxy-2'-deoxyguanosine. The study included 340 women diagnosed with CIN 2+ (cases) and 90 diagnosed with CIN 1 (non-cases). Microbiota composition was determined by Illumina sequencing of the 16S rRNA gene amplified from DNA extracted from cervical mucus samples. Measures of alpha/beta-diversity were not associated with either CIN severity or oxidative DNA damage. However, a cervical mucosal community type (CT) dominated by L. iners and unclassified Lactobacillus spp was associated with CIN 2+ (OR = 3.48; 95% CI, 1.27-9.55). Sequence reads mapping to Lactobacillaceae, Lactobacillus, L. reuteri, and several sub-genus level Lactobacillus operational taxonomic units were also associated with CIN 2+ when examined independently (effect size >2.0; P < 0.05). Our 16S rRNA sequencing results need confirmation in independent studies using whole-genome shotgun sequencing and that would allow sharpening the suggested associations at finer taxonomic levels. Our results provide little evidence that DNA oxidative damage mediates the effect of the microbiome on the natural history of HPV infection and CIN severity. Cancer Prev Res; 9(5); 357-66. ©2016 AACR.

Homocysteinemia is Associated with a Lower Degree of PBMC LINE-1 Methylation and a Higher Risk of CIN 2C in the U.S. Post-Folic Acid Fortification Era.

The primary aim of the study was to determine whether plasma concentrations of homocysteine (Hcy), a functional indicator of methyl donor nutrients, are associated with altered risk of higher grades of cervical intraepithelial neoplasia (CIN 2+) and the degree of methylation in long interspersed nucleotide elements (LINE-1s) of peripheral blood mononuclear cells, a potential biomarker of CIN 2+ in a population of women exposed to the United States folic acid fortification program. The secondary aim was to assess the determinants of plasma Hcy in the same population. The study included 457 women diagnosed with either CIN 2+ (cases, n = 132) or ≤ CIN 1 (non-cases, n = 325). Unconditional logistic regression models were used to test the associations after adjusting for relevant risk factors of cervical cancer. Women with higher Hcy concentrations were at a greater risk of being diagnosed with CIN 2+ [odds ratio (OR) = 1.86, P = 0.005]. Higher plasma folate concentrations were a significant determinant of lower Hcy (OR = 0.40, P = 0.0002). Women with higher Hcy concentrations were more likely to have a lower degree of LINE-1 methylation (OR = 2.30, P = 0.0007). These results suggested that further improvement in folate status in this population may be beneficial for lowering Hcy and improving the degree of LINE-1 methylation.

A lower degree of PBMC L1 methylation in women with lower folate status may explain the MTHFR C677T polymorphism associated higher risk of CIN in the US post folic acid fortification era.

BACKGROUND: Studies in populations unexposed to folic acid (FA) fortification have demonstrated that MTHFR C677T polymorphism is associated with increased risk of higher grades of cervical intraepithelial neoplasia (CIN 2+). However, it is unknown whether exposure to higher folate as a result of the FA fortification program has altered the association between MTHFR C677T and risk of CIN, or the mechanisms involved with such alterations. The current study investigated the following in a FA fortified population: 1) The association between MTHFR C677T polymorphism and risk of CIN 2+; 2) The modifying effects of plasma folate concentrations on this association; and 3) The modifying effects of plasma folate on the association between the polymorphism and degree of methylation of long interspersed nucleotide elements (L1s), in peripheral blood mononuclear cell (PBMC) DNA, a documented biomarker of CIN risk. METHODS: The study included 457 US women diagnosed with either CIN 2+ (cases) or ≤ CIN 1 (non-cases). Unconditional logistic regression models were used to test the associations after adjusting for relevant risk factors for CIN. RESULTS: The 677CT/TT MTHFR genotypes were not associated with the risk of CIN 2+. Women with CT/TT genotype with lower folate, however, were more likely to be diagnosed with CIN 2+ compared to women with CT/TT genotype with higher folate (OR = 2.41, P = 0.030). Women with CT/TT genotype with lower folate were less likely to have a higher degree of PBMC L1 methylation compared to women with CT/TT genotype with higher folate (OR = 0.28, P = 0.017). CONCLUSIONS: This study provides the first evidence that the MTHFR 677CT/TT genotype-associated lower degree of PBMC L1 methylation increases the risk of CIN 2+ in women in the US post-FA fortification era. Thus, even in the post-FA fortification era, not all women have adequate folate status to overcome MTHFR 677CT/TT genotype-associated lower degree of L1 methylation.

Functional variants in CYP1A1 and GSTM1 are associated with clearance of cervical HPV infection.

OBJECTIVE: We evaluated time to clearance of high risk (HR) HPV infection in relation to functional variants in three genes (CYP1A1, GSTT1, and GSTM1). METHODS: The study group consisted of 450 HR-HPV infected women from the Atypical squamous cells of undetermined significance-low-grade squamous intraepithelial Lesion Triage Study (ALTS) cohort followed up at the clinical center at Birmingham, Alabama. The Cox proportional hazard model with the Wei-Lin-Weisfeld (WLW) approach was used, controlling for relevant covariates. RESULTS: Women who were polymorphic for CYP1A1 experienced an HR-HPV clearance rate that was 20% (HR=0.80, p=0.04) lower than women without the polymorphism for CYP1A1, adjusting for all other cofactors. The GSTM1 null genotype was associated with higher HR-HPV clearance rate (HR=1.39, p=0.006). The polymorphism in GSTT1 was not significantly associated with time to clearance of HR-HPV. CONCLUSIONS: Xenobiotic metabolism genes may influence the natural history of HR-HPV infection and its progression to cervical cancer.

Folate and vitamin B12 may play a critical role in lowering the HPV 16 methylation-associated risk of developing higher grades of CIN.

We previously reported that a higher degree of methylation of CpG sites in the promoter (positions 31, 37, 43, 52, and 58) and enhancer site 7862 of human papillomavirus (HPV) 16 was associated with a lower likelihood of being diagnosed with HPV 16-associated CIN 2+. The purpose of this study was to replicate our previous findings and, in addition, to evaluate the influence of plasma concentrations of folate and vitamin B12 on the degree of HPV 16 methylation (HPV 16m). The study included 315 HPV 16-positive women diagnosed with either CIN 2+ or ≤CIN 1. Pyrosequencing technology was used to quantify the degree of HPV 16m. We reproduced the previously reported inverse association between HPV 16m and risk of being diagnosed with CIN 2+. In addition, we observed that women with higher plasma folate and HPV 16m or those with higher plasma vitamin B12 and HPV 16m were 75% (P < 0.01) and 60% (P = 0.02) less likely to be diagnosed with CIN 2+, respectively. With a tertile increase in the plasma folate or vitamin B12, there was a 50% (P = 0.03) and 40% (P = 0.07) increase in the odds of having a higher degree of HPV 16m, respectively. This study provides initial evidence that methyl donor micronutrients, folate and vitamin B12, may play an important role in maintaining a desirably high degree of methylation at specific CpG sites in the HPV E6 promoter and enhancer that are associated with the likelihood of being diagnosed with CIN 2+.

GnRH agonist and GnRH antagonist protocols: comparison of outcomes among good-prognosis patients using national surveillance data.

Implantation and live birth rates resulting from IVF cycles using gonadotropin-releasing hormone (GnRH) agonist and (GnRH) antagonist IVF protocols were compared among good-prognosis patients using the Centers for Disease Control and Prevention's National Assisted Reproductive Technology Surveillance System 2009-2010 data (n = 203,302 fresh, autologous cycles). Bivariable and multivariable analyses were conducted between cycles to compare outcomes. Cycles were restricted as follows: age younger than 35 years, maximum FSH less than 10 mIU/mL, first assisted reproduction technology cycle and FSH dose less than 3601 IU. A subgroup analysis including only elective single embryo transfer was also carried out. Among good-prognosis patients, the GnRH-agonist protocol was associated with a lower risk of cancellation before retrieval (4.3 versus 5.2%; P < 0.05) or transfer (5.5 versus 6.8%; P < 0.05), and a higher live birth rate per transfer (adjusted odds ratio [OR] 1.13, confidence interval [CI] 1.03 to 1.25) than the GnRH-antagonist group. Among the elective single embryo transfer group, the GnRH-agonist protocol was associated with a higher implantation rate (adjusted odds ratio [OR] 1.36, CI 1.08 to 1.73) and a higher live birth rate (adjusted OR 1.33, CI 1.07 to 1.66) compared with the GnRH-antagonist protocol. The GnRH-antagonist group had lower rates of ovarian hyperstimulation syndrome. Among good-prognosis patients, agonist protocols decreased cancellation risk and increased odds of implantation and live birth. Antagonist protocols may confer decreased risk of hyperstimulation.

Does tenofovir gel or do other microbicide products affect detection of biomarkers of semen exposure in vitro?

OBJECTIVES: There is currently no information on whether products evaluated in HIV microbicide trials affect the detection of the semen biomarkers prostate-specific antigen (PSA) or Y chromosome DNA. STUDY DESIGN: We tested (in vitro) dilutions of tenofovir (TFV), UC781 and the hydroxyethylcellulose (HEC) placebo gels using the Abacus ABAcard and the quantitative (Abbott Architect total PSA) assays for PSA and Y chromosome DNA by real-time polymerase chain reaction. RESULTS: TFV gel and the HEC placebo adversely affected PSA detection using the ABAcard but not the Abbott Architect total PSA assay. UC781 adversely affected both the ABAcard and Abbott Architect total PSA assays. While there were some quantitative changes in the magnitude of the signal, none of the products affected positivity of the Y chromosome assay. CONCLUSIONS: The presence of TFV or HEC gels did not affect quantitative PSA or Y chromosome detection in vitro. Confirmation of these findings is recommended using specimens obtained following use of these gels in vivo. IMPLICATIONS: Researchers should consider the potential for specific microbicides or any products to affect the particular assay used for semen biomarker detection. The ABAcard assay for PSA detection should not be used with TFV UC781, or HEC.

Effect of lubricants and a vaginal spermicide gel on the detection of prostate specific antigen, a biomarker of semen exposure, using a quantitative (Abbott ARCHITECT) assay.

OBJECTIVES: Little is known about the effects of commonly used lubricants on detection of biomarkers of semen exposure. We investigated the in vitro effect of Gynol®, K-Y Jelly®, Replens®, Astroglide®, Carbopol, and Silicorel on quantitative detection of prostate specific antigen (PSA). STUDY DESIGN: A predetermined concentration of each of the gels was added to serially diluted semen samples. Additionally, serial dilutions of each of the gels were added to three different semen dilutions (high, medium, or low). The resulting samples were tested for PSA on the Abbott ARCHITECT System. RESULTS: When using the Abbott ARCHITECT system, the only products that inhibited PSA detection were Gynol® and Replens®. The inhibition caused by Gynol® was dose-dependent, but that of Replens was dose-independent. K-Y Jelly®-spiked samples had higher PSA values than controls. CONCLUSIONS: Caution is warranted when using the Abbott quantitative assay for PSA detection as a biomarker of semen exposure in settings where Gynol®, Replens® or K-Y Jelly® might also have been used. Neither Astroglide® nor Silicorel inhibited PSA detection. Additional studies evaluating other vaginal products, including microbicides, and their effects on other assays, are needed. In vivo studies will be especially important to optimize PSA detection from clinical samples. IMPLICATIONS: Researchers should consider the potential for specific lubricants or any vaginal products to affect the particular assay used for semen biomarker detection. The Abbott ARCHITECT's total PSA assay should not be used with the product Replens. Caution is warranted when using the assay in settings where Gynol or K-Y jelly may have been used.

A semiparametric approach to estimate rapid lung function decline in cystic fibrosis.

PURPOSE: Detecting the onset of rapid lung function decline is important to reduce mortality rates in cystic fibrosis (CF) and other lung diseases. The most common approach is conventional linear mixed modeling-estimating a population-level slope of lung function decline and using random effects to address serial correlation-but this ignores nonlinear features of disease progression and distinct sources of variability. The purpose of this article was to estimate patient-specific timing and degree of rapid decline while appropriately characterizing natural progression and variation in CF. METHODS: We propose longitudinal semiparametric mixed modeling and contrast it with the conventional approach, which restricts lung function (measured as forced expiratory volume in 1 second as a percentage of predicted, FEV1%) to linear decline. Each approach is applied to clinical encounter data from the United States CF Foundation Patient Registry. RESULTS: Timing and degree of rapid FEV1% decline vary across patients and as a function of key covariates. Patients experience maximal FEV1% loss by early adulthood more severe than indicated by conventional slope analysis. CONCLUSIONS: Semiparametric mixed modeling provides a means to estimate patient-specific changes in CF disease progression and may be used to inform prognostic decisions in chronic care settings and clinical studies.

Detection of two biological markers of intercourse: prostate-specific antigen and Y-chromosomal DNA.

BACKGROUND: Although biological markers of women's exposure to semen from vaginal intercourse have been developed as surrogates for risk of infection or probability of pregnancy, data on their persistence time and clearance are limited. STUDY DESIGN: During 2006-2008, 52 couples were enrolled for three 14-day cycles of abstinence from vaginal sex during which women were exposed in the clinic to a specific quantity (10, 100 or 1000 µL) of their partner's semen. Vaginal swabs were collected before and at 1, 6, 12, 24, 48, 72 and 144 h after exposure for testing for prostate-specific antigen (PSA) and Y-chromosome DNA (Yc DNA). RESULTS: Immediately after exposure to 1000 µL of semen, the predicted sensitivity of being PSA positive was 0.96; this decreased to 0.65, 0.44, 0.21 and 0.07 at 6, 12, 24 and 48 h, respectively. Corresponding predicted sensitivity of being Yc DNA positive was 0.72 immediately postexposure; this increased to 0.76 at 1 h postexposure and then decreased to 0.60 (at 6 h), 0.63 (at 12 h), 0.49 (at 24 h), 0.21 (at 48 h), 0.17 (at 72 h) and 0.12 (at 144 h). CONCLUSIONS: Overall findings suggest that PSA may be more consistent as a marker of very recent exposure and that Yc DNA is more likely to be detected in the vagina after 12 h postexposure compared to PSA.

Randomized controlled trial on the effectiveness of counseling messages for avoiding unprotected sexual intercourse during sexually transmitted infection and reproductive tract infection treatment among female sexually transmitted infection clinic patients.

BACKGROUND: The effectiveness of counseling messages to avoid unprotected sex during short-term treatment for curable sexually transmitted infections is unknown. METHODS: We randomized 300 female STI clinic patients 18 years or older with cervicitis and/or vaginal discharge in Kingston, Jamaica, in 2010 to 2011, to 1 of 2 counseling messages for their course of syndromic treatment: abstinence only or abstinence backed up by condom use. At a follow-up visit 6 days afterward, we collected vaginal swabs to test for prostate-specific antigen (PSA), a biological marker of recent semen exposure, and administered a questionnaire assessing sexual behavior. RESULTS: No differences were found in the proportions of women testing positive for PSA at follow-up in the abstinence-plus-condom group (11.9%) and abstinence-only group (8.4%) (risk difference, 3.5; 95% confidence interval, -3.5 to 10.5). There also was no significant difference in reporting of unprotected sex between groups. Reporting a history of condom use before enrollment significantly modified the effect of counseling arm on PSA positivity (P = 0.03). Among those reporting recent condom use, 10.3% in the abstinence-only arm and 4.8% in the abstinence-plus-condom arm tested positive for PSA. Conversely, among those not reporting recent condom use, 6.5% in the abstinence-only arm and 17.3% in the abstinence-plus-condom arm had PSA detected. CONCLUSIONS: We found no evidence to support the superiority of either counseling message. Post hoc analyses suggest that women with recent condom experience may benefit significantly more from abstinence-plus-condom messages, whereas women without such experience may benefit significantly more from abstinence-only messages. Providers should weigh individual condom use history when determining the most appropriate counseling message.

Exploring discordance between biologic and self-reported measures of semen exposure: a qualitative study among female patients attending an STI clinic in Jamaica.

We explored the use of qualitative interviews to discuss discrepancies between two sources of information on unprotected sex: biomarker results and self-reported survey data. The study context was a randomized trial in Kingston, Jamaica examining the effect of STI counseling messages on recent sexual behavior using prostate-specific antigen (PSA) as the primary study outcome. Twenty women were interviewed. Eleven participants were selected because they tested positive for PSA indicating recent semen exposure, yet reported no unprotected sex in a quantitative survey ("discordant"): 5 reported abstinence and 6 reported condom use. Nine participants who also tested positive for PSA but reported unprotected sex in the survey were interviewed for comparison ("concordant"). Qualitative interviews with 6 of the 11 discordant participants provided possible explanations for their PSA test results, and 5 of those were prompted by direct discussion of those results. Rapid PSA testing combined with qualitative interviews provides a novel tool for investigating and complementing self-reported sexual behavior.

Optimal methods for collecting and storing vaginal specimens for prostate-specific antigen testing in research studies.

BACKGROUND: Prostate-specific antigen (PSA) detected in vaginal fluid can be used in studies of HIV/sexually transmitted infection (STI) and pregnancy prevention as an alternative to relying on participant reports of exposure to semen. Optimal methods for collecting and storing specimens for this testing have not been determined. STUDY DESIGN: We conducted a controlled, in vitro experiment of 550 specimens spiked with semen to determine the effects of swab type (five types), storage conditions of the swabs (room temperature with or without desiccant or at -80°C without desiccant) and time from collection to testing (seven intervals over the course of 12 months) on the identification of PSA. We performed factorial analysis of variance to identify factors influencing PSA detection. RESULTS: Concentrations of PSA detected in the swabs declined with time of storage over the 1-year experiment (p<.01). The 1-mL, rayon-tipped swab stored immediately at -80°C following collection performed best. CONCLUSIONS: If immediate testing or freezer storage is not feasible, investigators should use a swab with 1-mL capacity with processing and testing as soon as possible after specimen collection.