Literature review > Issue_5 > Review on Vuylsteke et al. 

In the syndromic approach to the management of vaginal discharge and lower abdominal pain in women, WHO recommends the use of algorithms that incorporate a risk assessment. In the literature, such assessments typically incorporate a mix of behavioral, clinical, and laboratory factors. In most settings, female sex workers generally score positive on such risk assessments on both initial and follow-up visits. Attempts have been made to refine risk assessments for sex workers with a view to minimising over-treatment while maintaining high sensitivity for the detection of STIs, particularly cervical infections. Such approaches continue to be necessary in the absence of affordable, simple, rapid screening or diagnostic tests for cervical STIs.

This study followed the authors' 1994 attempt to design algorithms to detect cervical infections with Neisseria gonorrhoeae and Chlamydia trachomatis among sex workers in Côte D'Ivoire [1] and assessed the current validity of and adherence to the algorithms by health care workers. In contrast to the study that informed the design of the original algorithms, this study measured the performance in returning patients rather than first-time attendees.

In the earlier evaluation of the 1994 algorithms, the prevalence of cervical infections among invited (presumably first-time) clinic attendees was 35% (gonococcal and chlamydial cervicitis: 31% and 11% respectively). Comparable rates in the current study were 8.2% for either gonococcal and/or chlamydial cervicitis (5.5% and 3.8% respectively). These lower rates of infection would dramatically reduce the expected positive predictive value of the algorithms being used.

It would be anticipated that prevalence in returning attendees would be reduced on the basis that most initial infections would have been treated appropriately on the first visit and that risk behaviors for re-infection would be lower in repeat vs. initial attendees. The observed poor compliance by health workers with the protocols is also important but is unlikely to be the major contributor to the performance of the algorithms in returning patients.

Steen and others have explored the role of periodic presumptive treatment (PPT) of cervicitis as a supplement to the use of syndromic algorithms with risk assessment or as an intervention to reduce STI prevalence rapidly [2, 3]. While this approach effectively increases sensitivity to almost 100%, it suffers from declining positive predictive value as the prevalence of cervical infection declines in subsequent visits. This "conundrum of success", as it has been described, predictably affected the findings of the current study as shown above.

In response to the South African study by Steen [2], Van Dam et al. proposed that long-term success in STI control among sex workers and their partners will also require strengthening of clinical services employing syndromic management supported by strong and effective behavior change interventions [4].

Approaches for female sex workers that integrate presumptive treatment with clinical services based on syndromic management have now been studied in a number of settings. For example, Behets offered syphilis screening and presumptive treatment for gonococcal and chlamydial cervicitis and trichomonal vaginitis to female sex workers at two sites in Madagascar [5]. The approach did not require microscopy, which was deemed to be burdensome in the local context. A risk assessment was employed for follow-up visits using a score based on criteria such as age, number of partners in the previous week, vaginal pH and clinical signs of cervicitis. The overall sensitivity and specificity of this approach for detection of cervical infections were 83.7% and 36.6% respectively with a positive predictive value of 27.3%.

While presumptive treatment is clearly of great value in reducing infection rates in initial visits by female sex workers, there remains a great need for improved approaches for managing infections in women in follow-up visits. It seems unlikely that approaches dependent on risk assessments will perform sufficiently well for them to obviate the need for improved, affordable screening and diagnostic tests for gonorrhea and chlamydia.

References:

1. Diallo MO, Ghys P, Vuylsteke B, et al. Evaluation of simple diagnostic algorithms for Neisseria gonorrhoeae and Chlamydia trachomatis cervical infections in female sex workers in Abidjan, Côte D'Ivoire. Sex Transm Infect 1998;74(Suppl 1):S106-S111.

2. Steen R, Vuylsteke B, De Coito T, et al. Evidence of declining STD prevalence in a South African mining community following a core-group intervention. Sex Transm Dis 2000;27:1-8.

3. Steen R. Dallabetta G. Sexually transmitted infection control with sex workers: regular screening and presumptive treatment augment efforts to reduce risk and vulnerability. Reproductive Health Matters 2003;11:74-90.

4. Van Dam CJ, Holmes KK. STD prevention: effectively reaching the core and a bridge population with a four-component intervention. Sex Transm Dis 2000;27:9-11.

5. Behets FMTF, Rasolofomanana JR, Van Damme K, Vaovola G, Andriamiadana J, Ranaivo A, McClamroch K, Dallabetta G, van Dam J, Rasamilalao D, Rasamindra A and the Mad-STI Working Group. Evidence-based treatment guidelines for sexually transmitted infections developed with and for female sex workers. Trop Med Int Hlth 2003;8:251-258.

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