A formal decision analysis identifies an optimal treatment strategy in a resource-poor setting.

OBJECTIVE: Decision analytic techniques use formal specifications of utility for the four fundamental decision events: true positives, false positives, true negatives, and false negatives. An optimal policy is the one with the lowest expected net cost. In this paper, decision analytic techniques for treatment selection based on patient characteristics are applied to a resource-poor setting. STUDY DESIGN AND SETTING: A cohort of 986 female sex workers in Antananarivo and Tamatave, Madagascar were tested for cervical infection at baseline and again 2 months later after presumptive treatment for gonorrhea and chlamydia. RESULTS: Three equivalent approaches to identify the optimal policy based on patient characteristic subgroups are demonstrated. Two of them require exhaustive searches of all possible alternatives. The third identifies the optimal policy as an analytic expression that compares a decision function with a threshold and leads to a closed-form solution. With this approach, the optimal policy can be expressed in four equivalent forms using basic epidemiological measures: likelihood ratio, predicted probability of disease, logistic regression parameters, and total risk score. CONCLUSION: These methods illustrate the application of a decision analysis to clinical epidemiology. Management of cervical infection for sex workers in Madagascar occurs under severe resource constraints, and therefore requires an algorithm for identifying optimal treatment regimens.

Evidence-based planning of a randomized controlled trial on diaphragm use for prevention of sexually transmitted infections.

OBJECTIVES: We conducted formative research to evaluate the acceptability and feasibility of continuous diaphragm use among low-income women highly exposed to sexually transmitted infections (STIs) in Madagascar. GOAL: To identify potential obstacles to researching the effectiveness of diaphragm use for STI prevention in a randomized controlled trial. STUDY DESIGN: Mixed methods to collect complex information. In a quantitative pilot study, women were asked to use diaphragms continuously (removing once daily for cleaning) for 8 weeks and promote consistent male condom use; they were interviewed and examined clinically during follow-up. Focus group discussions (FGDs) were conducted pre-/postpilot study. Audiotaped FGDs were transcribed, translated, coded, and analyzed. RESULTS: Ninety-three women participated in prepilot FGDs, 91 in the pilot study, and 82 in postpilot FGDs. Diaphragm use was acceptable and feasible, but participants reported lower condom use in FGDs than during interviews. Most participants reported in interviews that they used their diaphragms continuously, but FGDs revealed that extensive intravaginal hygiene practices may impede effective continuous diaphragm use. Despite counseling by study staff, FGDs revealed that participants believed the diaphragm provided effective protection against STIs and pregnancy. CONCLUSIONS: Mixed methods formative research generated information that the prospective pilot study alone could not provide and revealed contradictory findings. Results have methodological and ethical implications that affect trial design including provision of free hormonal contraceptives, and additional instructions for vaginal hygiene to avoid displacing the diaphragm. Mixed methods formative research should be encouraged to promote evidence-based study design and implementation.

Genetic typing of the porin protein of Neisseria gonorrhoeae from clinical noncultured samples for strain characterization and identification of mixed gonococcal infections.

Molecular methods that characterize the Neisseria gonorrhoeae porin protein Por are needed to study gonococcal pathogenesis in the natural host and to classify strains from direct clinical samples used with nucleic acid amplification-based tests. We have defined the capabilities of por variable region (VR) typing and determined suitable conditions to apply the method to direct clinical specimens. Nested PCR from spiked urine samples detected 1 to 10 copies of template DNA; freezing spiked whole urine greatly reduced the ability to amplify porB. In a laboratory model of mixed gonococcal infections, the por type of one strain could be determined in the presence of a 100-fold excess of another. por VR typing was used to examine clinical samples from women enrolled in studies conducted in Baltimore, Md., and Madagascar. por type was determined from 100% of paired cervical swab and wick samples from 20 culture-positive women from Baltimore; results for eight individuals (40%) suggested infection with more than one strain. In frozen urine samples from Madagascar, porB was amplified and typed from 60 of 126 samples from ligase chain reaction (LCR)-positive women and 3 samples from LCR-negative women. The por VR types of 13 samples (21%) suggested the presence of more than one gonococcal strain. Five por types, identified in >45% of women with typed samples, were common to both geographic areas. Molecular typing is an important adjunct to nucleic acid amplification-based diagnostics. Methods that utilize direct clinical samples and can identify mixed infections may contribute significantly to studies of host immunity, gonococcal epidemiology, and pathogenesis.

Participatory mapping of sex trade and enumeration of sex workers using capture-recapture methodology in Diego-Suarez, Madagascar.

BACKGROUND: Capture-recapture methodology has been employed to estimate the size of hidden or difficult-to-reach human populations such as sex workers, homeless persons, and intravenous drug users. This study took place in the context of efforts to improve the quality of curative and preventive services for sexually transmitted infections offered to sex workers in Diego-Suarez, Madagascar in partnership with sex workers. GOAL: The goal of this study was to better understand sex-trading practices, map out sex work sites, and estimate the size of a mobile sex-worker population in Diego-Suarez, Madagascar using methods that can be reproduced in other resource-poor settings. STUDY DESIGN: Forty sex workers were trained to function as field researchers. Key informants in designated neighborhoods were identified and interviewed. Basic maps of sex-trade sites were designed by hand. The number of sex workers in Diego-Suarez was estimated using capture-recapture methodology. An educational brochure was used to "capture" sex workers during a first phase, and "recapture" 2 weeks later. RESULTS: Most sex trade was street based and mobile. Capture-recapture methods estimated a total of 2684 sex workers (95% CI: 2588-2780) in Diego-Suarez, or approximately 12% of the 15- to 49-year-old female population in the city. CONCLUSION: Geographic mapping and capture-recapture proved to be low-cost and relatively easy to use techniques for counting a hard-to-reach population, such as female street-based sex workers. Sex workers can be capable fieldworkers, and their active participation in research concerning sex work should be considered whenever possible. A high proportion of women of reproductive age were found to engage in sex work, indicating that there is an urgent need to scale up sexually transmitted infection and HIV prevention activities targeting sex workers, their sexual partners, and the general population.

Evidence-based treatment guidelines for sexually transmitted infections developed with and for female sex workers.

BACKGROUND: Sex work is frequently one of the few options women in low-income countries have to generate income for themselves and their families. Treating and preventing sexually transmitted infections (STIs) among sex workers (SWs) is critical to protect the health of the women and their communities; it is also a cost-effective way to slow the spread of HIV. Outside occasional research settings however, SWs in low-income countries rarely have access to effective STI diagnosis. OBJECTIVES: To develop adequate, affordable, and acceptable STI control strategies for SWs. METHODS: In collaboration with SWs we evaluated STIs and associated demographic, behavioural, and clinical characteristics in SWs living in two cities in Madagascar. Two months post-treatment and counselling, incident STIs and associated factors were determined. Evidence-based STI management guidelines were developed with SW representatives. RESULTS: At baseline, two of 986 SWs were HIV+; 77.5% of the SWs in Antananarivo and 73.5% in Tamatave had at least one curable STI. Two months post-treatment, 64.9% of 458 SWs in Antananarivo and 57.4% of 481 women in Tamatave had at least one STI. The selected guidelines include speculum exams; syphilis treatment based on serologic screening; presumptive treatment for gonorrhoea, chlamydia, and trichomoniasis during initial visits, and individual risk-based treatment during 3-monthly follow-up visits. SWs were enthusiastic, productive partners. CONCLUSIONS: A major HIV epidemic can still be averted in Madagascar but effective STI control is needed nationwide. SWs and health professionals valued the participatory research and decision-making process. Similar approaches should be pursued in other resource-poor settings where sex work and STIs are common and appropriate STI diagnostics lacking.