Markus J. Steiner

Biomarker Validation of Reports of Recent Sexual Activity: Results of a Randomized Controlled Study in Zimbabwe

Challenges in the accurate measurement of sexual behavior in human immunodeficiency virus (HIV) prevention research are well documented and have prompted discussion about whether valid assessments are possible. Audio computer-assisted self-interviewing (ACASI) may increase the validity of self-reported behavioral data. In 2006-2007, Zimbabwean women participated in a randomized, cross-sectional study that compared self-reports of recent vaginal sex and condom use collected through ACASI or face-to-face interviewing (FTFI) with a validated objective biomarker of recent semen exposure (prostate-specific antigen (PSA) levels). Of 910 study participants, 196 (21.5%) tested positive for PSA, an indication of semen exposure during the previous 2 days. Of these 196 participants, 23 (11.7%) reported no sex in the previous 2 days, with no difference in reported sexual activity between interview modes (12.5% ACASI vs. 10.9% FTFI; Fishers exact test: P = 0.72). In addition, 71 PSA-positive participants (36.2%) reported condom-protected vaginal sex only; their reports also indicated no difference between interview modes (33.7% ACASI vs. 39.1% FTFI; P = 0.26). Only 52% of PSA-positive participants reported unprotected sex during the previous 2 days. Self-report was a poor predictor of recent sexual activity and condom use in this study, regardless of interview mode, providing evidence that such data should be interpreted cautiously.

Dual protection against unintended pregnancy and sexually transmitted infections: What is the best contraceptive approach?

In the midst of the global epidemics of both unintended pregnancy and sexually transmitted infection, contraceptive options that provide dual protection are ideal. However, those contraceptives with the best record of preventing pregnancy under typical use conditions (sterilization, hormonal methods, intrauterine devices) provide little if any protection against sexually transmitted infection. Alternatively, barrier contraceptive methods (specifically, condoms), which can reduce risks of many sexually transmitted infections, are associated with relatively higher pregnancy rates for most users than other contraceptives. This situation has produced a dilemma for those wishing to promote dual protection: whether to advocate use of two methods (one primarily to prevent pregnancy and the other primarily to prevent infections) or whether to emphasize use of condoms for both purposes. Data comparing these two approaches are limited and often contradictory. We discuss the underlying concepts of exposure to both pregnancy and infection, provide a broad overview of the effectiveness of contraceptive methods against these two conditions, present approaches to optimize dual protection, and propose several new directions for necessary research. In the absence of evidence-based recommendations, we believe clinicians should assist clients in assessing their likelihood of exposure to infection, either by prevalence of sexually transmitted infection in the community or by the specific risk factors of the client. If exposure is likely, particularly to the more serious infections such as human immunodeficiency virus, the one-method approach should be given greater weight. However, in settings where unintended pregnancy is the greater concern, emphasizing the two-methods approach as a first option may be appropriate.

The time has come for common ground on preventing sexual transmission of HIV.

The HIV/AIDS pandemic is an urgent health and growing humanitarian crisis especially in the high-prevalence regions of sub-Saharan Africa where most new infections continue to occur. On World AIDS Day (Dec 1) two decades after the discovery of the virus that causes AIDS and after many millions of deaths we believe it is critical to reach consensus on a sound public-health approach to the prevention of sexually transmitted HIV. Although transmission from injecting drug use is a serious and increasing problem in some regions here we focus on sexual transmission which continues to account for most infections globally. Sexual behaviour is influenced by many factors not always under an individual’s control including gender norms and social and economic conditions. However the public-health community has an obligation to offer people the most accurate information available on how to avoid HIV and to encourage changes in societal norms to reduce the spread of the virus. Although prevention should encompass multiple integrated elements including links to expanded treatment access changing or maintaining of behaviours aimed at risk avoidance and risk reduction must remain the cornerstone of HIV prevention. We call for an end to polarising debate and urge the international community to unite around an inclusive evidence-based approach to slow the spread of sexually transmitted HIV on the basis of the following key principles. (excerpt)

Prostate-specific antigen to ascertain reliability of self-reported coital exposure to semen

Objective: The objective of this study was to assess the validity of women’s reports of recent unprotected sex by testing for prostate-specific antigen (PSA) in vaginal samples. Study Design: The authors conducted prospective research with 332 female sex workers attending 2 public dispensaries in Madagascar. Results: Among women who reported no sex or protected sex only within the past 48 hours, 21% and 39%, respectively, tested positive for PSA. Among those testing positive for PSA, no differences in PSA concentrations were found among those reporting no sex, protected sex only, or at least one unprotected act. Conclusions: The substantial disagreement between self-reports and measurement of a biologic marker of semen exposure in vaginal specimens substantiates that self-reports of sexual behavior cannot be assumed to be valid measures. Future sexually transmitted infection/HIV and pregnancy prevention studies should confirm the validity of self-reports or use end points that do not rely on self-reported data.

Identifying condom users at risk for breakage and slippage: findings from three international sites.

OBJECTIVES This study examined whether past condom failure (breakage, slippage, or both) can predict future failure and evaluated other predictors of condom failure. METHODS At each of 3 international sites, approximately 130 male condom users were enrolled and given 5 condoms to use for vaginal intercourse over a 3-week period. RESULTS Men at increased risk (history of 1 or more condoms that broke or slipped off) reported approximately twice as many condom failures as those not in this group. Condom failure increased with the number of adverse condom use behaviors reported per participant. Opening condom packages with sharp objects and unrolling condoms before donning were associated with breakage. Unrolling condoms before donning and lengthy or intense intercourse were associated with slippage. Of background characteristics evaluated, having less education was associated with condom failure. CONCLUSIONS These data suggest that a history of condom failure predicts future failure, a finding that may be useful for targeted intervention. Moreover, these data provide further evidence that certain behaviors and lower educational attainment are associated with condom failure.

Validity of Self-Reported 'Safe Sex' Among Female Sex Workers in Mombasa, Kenya-PSA Analysis

We assessed the validity of self-reported sex and condom use by comparing self-reports with prostate-specific antigen (PSA) detection in a prospective study of 210 female sex workers in Mombasa, Kenya. Participants were interviewed on recent sexual behaviours at baseline and 12-month follow-up visits. At both visits, a trained nurse instructed participants to self-swab to collect vaginal fluid specimens, which were tested for PSA using enzyme-linked immunosorbent assay (ELISA). Eleven percent of samples (n = 329) from women reporting no unprotected sex for the prior 48 hours tested positive for PSA. The proportions of women with this type of discordant self-reported and biological data did not differ between the enrolment and 12-month visit (odds ratio [OR] 1.1; 95% confidence interval [CI] 0.99, 1.2). The study found evidence that participants failed to report recent unprotected sex. Furthermore, because PSA begins to clear immediately after exposure, our measures of misreported semen exposure likely are underestimations.

Understanding risk: a randomized controlled trial of communicating contraceptive effectiveness.

OBJECTIVE To determine which of three different approaches increased womens understanding of risk of pregnancy associated with different contraceptive methods. METHODS We randomly assigned 461 reproductive-age women to one of three tables presenting pregnancy risk (Food and Drug Administration table with numbers, World Health Organization table with numbers and categories, or table with categories). We evaluated participant knowledge before and after being shown the assigned table. RESULTS The most important reason for choosing a contraceptive was how well it works (53%), followed by ease of use (13%), and protection against sexually transmitted disease or human immunodeficiency virus (11%). Before looking at the tables, about half the participants knew that hormone shots are more effective than pills (48%) and that pills are more effective than condoms (57%). For these two key comparisons, the category table compared to the Food and Drug Administration table with numbers improved knowledge significantly more (37% versus 20% and 27% versus 14%; both P <.05). Compared with those assigned to the Food and Drug Administration table with numbers, significantly fewer participants assigned to the category table said the table was difficult to read (6% versus 19%; P <.01). Most participants in all three groups said their assigned table provided enough information to choose a contraceptive method. CONCLUSION The table with categories communicated relative contraceptive effectiveness better than the tables with numbers. However, without being presented with numbers, participants grossly overestimated the absolute risk of pregnancy using contraceptives. A combination of categories and a general range of risk for each category may provide the most accurate understanding of both relative and absolute pregnancy risk.

Standardized protocols for condom breakage and slippage trials: a proposal.

In the absence of well-controlled studies on the clinical effectiveness of condoms against pregnancy and sexually transmitted diseases, breakage and slippage data may provide the best indication of the protection offered by condom use. According to the recent literature, condom breakage rates range from 0% to 12%, with many US studies falling in the 2% to 5% range. Few studies have collected slippage data. In addition to discussing methodological issues associated with these studies, we propose a standardized protocol for future condom breakage and slippage trials and discuss how results may be used to estimate perfect-use and typical-use pregnancy rates.

Can condom users likely to experience condom failure be identified

A study based on a convenience sample of 177 couples who each used 11 condoms found that 103 condoms (5.3%) broke before or during intercourse and 67 condoms (3.5%) slipped off during sex. Couples who had not used a condom in the past year were almost twice as likely to experience condom failure as were couples who had used at least one during that period (p < .001). Of the couples who had used a condom in the previous year, the failure rate among those who reported at least one condom break during that period was more than twice the failure rate among those who reported no breaks (p < .001). Among couples who had used condoms in the past year without breaking any, those who did not live with their partner and those who had a high school education or less were at increased risk of condom failure (adjusted odds ratios of 3.2 and 2.7, respectively).

Menstrual pattern changes from levonorgestrel subdermal implants and DMPA: systematic review and evidence-based comparisons

BACKGROUND Many women want a lengthy duration of contraception but are wary of the menstrual changes from depot medroxyprogesterone acetate (DMPA). A subdermal levonorgestrel (LNG) implant may be a reasonable alternative. However, information on menstrual changes from these methods has not been summarized and compared in an easy-to-understand form. STUDY DESIGN We systematically reviewed the published literature on these contraceptives to find research that used menstrual diaries and standard World Health Organization definitions. We attempted to find information on amenorrhea, number of bleeding or spotting episodes, number of bleeding or spotting days and normal patterns, as reported in four consecutive 90-day reference periods. RESULTS We found 16 published articles meeting our criteria and involving diaries of up to 1600 DMPA users and 2300 LNG implant users. We were able to compare the two methods on only three outcomes. For DMPA use, the weighted prevalence of amenorrhea at successive 90-day periods was 12%, 25%, 37% and 46%. The comparable estimates for the LNG implant were 11%, 13%, 9% and 13%. Levonorgestrel implant users experienced a higher average number of bleeding or spotting days compared to DMPA users, but this average was similar to what is expected naturally. At 12 months, normal menstrual patterns were experienced by 23% of LNG implant users compared to 11% of DMPA users. CONCLUSIONS Like most hormonal contraception, LNG implants usually produce menstrual changes; however, the changes do not appear to deviate from normal patterns as much as the changes from DMPA. Understanding these differences and other method attributes might help women make an informed choice about which contraceptive to use.