Improving the management of sexually transmitted infections among pregnant women in sub-Saharan Africa : An evaluation of the syndromic management of sexually transmitted infections andAn economic evaluation of costs and health consequences of the existingversus new chlamydia management strategies

Abstract

Sexually transmitted infections (STIs) are a major health problem in many parts of the developing world. STIs cause substantial morbidity and mortality, which disproportionately affect women. Because many of the complications are pregnancy-related (1, 2), adequate diagnosis and effective treatment of STIs in pregnancy is critical. Additionally, there is substantial evidence that the presence of other STIs increases both HIV infectiousness and susceptibility (3, 4), and a long-term STI-control program is emphasized as one of the cornerstones of HIV prevention (5). Striving for optimal strategies and high performance in the STI program is essential; in countries where health care budgets are limited, the potential for improvement is often larger and can have a substantial effect on the overall burden of disease.<br><br>

In countries without laboratory support, the diagnosis and treatment of STIs are based on the syndromic approach, in which simple flowcharts (usually called algorithms) are used to classify presenting symptoms and clinical signs into defined syndromes (6). Asymptomatic patients are not diagnosed with this strategy – thereby risking the development of complications and transmission of the infection. Low specificity results in high levels of overtreatment, which increases drug costs and the risk of drug resistance. Patients who are diagnosed and treated with an STI they don’t have, unnecessarily experience anxiety, stigma, and side effects of drugs. The strategy relies heavily on the quality of care provided, and it is a recognized problem that health care providers frequently fail to follow the guidelines (7-10). Also, STI clients who actually are adequately assessed must overcome a series of hurdles before they can be considered cured: obtain prescribed drugs, comply with treatment, and ensure that their partners are treated to avoid reinfection (11). There has long been a consensus that for chlamydia and gonorrhoea, simple, affordable and preferably on-site tests are needed to improve the management (12). Major progress has recently been made, and several tests are now on the market. <br><br>

This study has two components. In a cross-sectional study, 703 antenatal care (ANC) attendees were interviewed and examined, and specimens were collected to identify the prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, bacterial vaginosis, Candida species and syphilis. We evaluated the syndromic approach for the detection of vaginal and cervical infections in pregnancy, and determined if risk scores could improve the diagnostic accuracy. Subsequently, we used data from the epidemiological study to conduct an economic evaluation of the STI management. A decision analytic model was developed to compare the costs and health consequences of using point-of-care (POC) tests versus syndromic management to diagnose chlamydia among antenatal care attendees in sub-Saharan Africa, using Botswana as a case. In this analysis we also compared erythromycin with azithromycin treatment and universal with age-based chlamydia management. We chose to focus on chlamydia, which is more common than gonorrhoea in this population, but the model can be adapted to the economic evaluation of the management of other STIs such as gonorrhoea and trichomoniasis. <br><br>

The aim of the first paper in this thesis is to draw attention to the effectiveness (or the lacking effectiveness) of the extensive prescription of antibiotics to STI patients in Botswana and to discuss possibilities for improving the cure rates. We found that many of the women had a history of STI symptoms in their current pregnancies and had been prescribed STI treatment. There was no significant difference in the prevalence of chlamydia among the women who had and the women who had not been prescribed erythromycin four times daily for ten days. Contrarily, none of the women who had been prescribed a single dose of ceftriaxone had gonorrhoea. The different effectiveness between the two drugs may reflect low compliance with the complex erythromycin regimen. We conclude that interventions to increase compliance could improve cure rates, and the use of a simpler drug regimen should be considered when low compliance is likely. This is discussed in the economic evaluation. In paper two and three, we evaluate the syndromic approach, and discuss that diagnosis and treatment of cervical and vaginal infections among pregnant women in sub-Saharan Africa presents major challenges. Chlamydia and gonorrhoea were found in one out of ten of the pregnant women in the cross-sectional study, whereas one of two had trichomoniasis or bacterial vaginosis. Although in extensive use, the syndromic management is not suited to detect these conditions among pregnant women. The high prevalences among women who had gone through routine antenatal care, as well as the evaluation of the syndromic approach for study purposes, indicate that management guidelines for trichomoniasis and bacterial vaginosis in antenatal care should be revised. For chlamydia and gonorrhoea, the conclusion is even clearer: Without diagnostic tests, there are no adequate management strategies for cervical infections in pregnant women in Botswana, a situation which also is likely to apply to other countries in sub-Saharan Africa. The results of the economic evaluation of chlamydia management are presented in the last paper. Azithromycin was less costly and more effective than was erythromycin. The specific POC tests resulted in more cases cured than the syndromic approach, substantially reduced the overtreatment with antibiotics and improved partner management. The incremental costs of POC tests appeared acceptable, especially when testing was restricted to younger women. Our findings indicate that changes in the management of chlamydia among pregnant women in sub-Saharan Africa have the potential to improve people’s health, reduce unnecessary costs and improve the cost effectiveness of the current strategy.