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Diagnostic algorithms for cervical infection based on clinical signs and symptoms and/or on behavioral characteristics have been tested in several developing countries, mainly in pregnant women and in high-risk groups. Clinical algorithms as well as non-hierarchical scoring systems have been tested by several groups in Africa. Most authors conclude that scoring systems that include risk markers as well as signs and symptoms may be affordable alternative methods of screening for gonococcal and/or chlamydial infections among women in resource-poor settings. Table 1 shows which of the risk factors were found to be significant. The positive predictive values of the different algorithms are low but negative predictive values are all above 90 percent, which is an acceptable level of accuracy (Table 2). These scoring systems need further evaluation in terms of validity and feasibility in different settings (Vuylsteke et al 1993).

Table 1. Predictors of STDs: Example from Kinshasa, Zaire

Factors Found Significant Factors Found Not Significant Risk determination Age < 25 Single status >1 sex partner in last year Age > 25 Never having used a condom Symptoms Vaginal discharge Vaginal itch Dysuria Lower abdominal pain Signs Vaginal discharge Cervical motion tenderness Malodor Endocervical mucopus Cervical erosion Cervical friability Results of simple tests and microscopy LED test on urine ~500 PMNs/µL Positive swab test Leukocytes > 10/hpf on vaginal smear Leukocytes > 10/hpf on cervical smear gram-negative diplococci: intracellular or extracellular

 

Table 2. Performance of Different Scoring Systems in Mwanza

Scoring System Sensitivity Specificity Positive Predictive Value Negative Predictive Value Correct Treatment Rate Over- treatment Rate WHO 62% 65% 18% 89% 64% 36% Kinshasa 89% 50% 19% 97% 54% 50% Mwanza 69% 52% 16% 93% 54% 48%

The Mwanza R2 Simple Algorithm on Risk Assessment uses the following markers as predictors of disease: age less than 25, unmarried status, polygamous marriage, having any previous child, having previous child born more than 5 years ago, and having more than one sex partner in the past year. If any three items are found, the client is considered positive for gonorrhea and chlamydia. When the algorithm was applied to data from Kenya (see below), sensitivity was found to be 48 percent, specificity was 57 percent and the positive predictive value was 12 percent. When applied to data from Mwanza, sensitivity was 69 percent, specificity was 54 percent and the positive predictive value was 12 percent.

The “Supermarket Model” for women’s reproductive health was a demonstration intervention project carried out in 1994 in Nairobi, Kenya. Its objectives were to measure the burden of STDs, HIV and cervical dysplasia in clients at a family planning clinic and to determine priorities for reproductive health interventions. Clients at the Ribiero Clinic were randomly selected for inclusion in the project. Baseline data were collected from them, and they received information and counseling, a gynecological examination, blood tests for STDs and cervical cytology. Twenty-four percent of the clients used IUDs.

Screening a group of family planning clients from the “Supermarket Model” project for STDs by history and laboratory investigation revealed the findings shown in Table 3.

Table 3. Results of Screening for Sexually Transmitted Diseases

STD History N (%) STD Detection N (%) Vaginal discharge 178 (34) Chlamydia 20 (4) Genital ulcers 51 (10) Gonorrhea (cult.) 11 (2) Genital warts 15 (3) Syphilis 11 (2) PID 22 (4) Warts (clinical) 6 (1) Ophth. neonatorum 17 (3) GUD (RPR negative) 6 (1)

The WHO algorithm and the Zaire scoring system were applied to the “Supermarket” model data (Table 4).

Table 4. Comparison of WHO Algorithm and Zaire Scoring System Applied to the Kenya "Supermarket" Data

Sensitivity Specificity Positive Predictive Value WHO Algorithm 50% 79% 23% Zaire Scoring System 19% 75% 10%

 

When the WHO algorithm was applied to pregnant women in Nairobi, sensitivity was 50 percent, specificity was 79 percent and the positive predictive value was 23 percent. When the Kinshasa scoring system was applied to the same women, sensitivity was 19 percent, specificity was 75 percent and the positive predictive value was 10 percent.

In general, the relatively simple WHO algorithm was found to be a better predictor of disease than the more complex Kinshasa scoring system. Neither method of predicting disease, however, was found to have high levels of sensitivity and specificity.

Conclusions

• Screening for STDs in MCH/FP clinics remains a major challenge in women’s health care.
• The WHO diagnostic algorithms may be useful in symptomatic women but are not sensitive enough to be used as a screening tool.
• Incorporating risk determinants, signs, symptoms and simple laboratory tests into a non-hierarchical scoring system can improve sensitivity and specificity. Specific models to be used have to be adapted to the setting and field tested.
• Even in “low risk” populations, the prevalence of STDs may be high.
• The association of the classic clinical symptoms and signs with the presence of gonorrhea and/or chlamydia was weak in both low- and high-prevalence populations.
• No single sign or symptom reached an acceptable level of sensitivity or specificity.
• The hierarchical algorithms based on interviews, with or without clinical examination, were insensitive for the screening of high- or low-risk populations, because of the low level of sensitivity of the one variable based algorithm.
• The score-driven method yielded a higher positive predictive value than those obtained with the WHO diagnostic models.
• The scoring system needs further evaluation in terms of field validity, acceptability and feasibility in different settings.
• More data on STD management in family planning clinics are urgently required.

Recommendations

It is clear that there is still an enormous amount of work to be done, including social action, education and restructuring of primary health care systems in general as well as specific family planning, mother-child health and STD programs.

• Research and evaluation of new preventive and curative interventions are needed to reduce the STD/HIV burden.
• Sexually transmitted disease case detection and management does not seem to be feasible and affordable.
• Score-driven systems including signs, symptoms and risk markers should be developed and field tested for different populations.
• Women and men must be taught how to recognize signs of infection so that they can seek treatment for themselves and their partners. People currently know more about HIV than other STDs because of the many educational messages about HIV. In contrast, few messages exist about STDs (Moses et al 1992).
• The industrialized world realized during both world wars that STDs had economic repercussions. Measures such as wide distribution of condoms, walk-in clinics where no referral or appointment was required, anonymity and free services helped to reduce the spread of STDs. Treatment of partners of presenting clients became the norm. Many physicians, including gynecologists, however, do not consider investigations or referral of the male partner in cases of PID. Nowadays, there is an enormous need for comprehensive reproductive health services with well-trained personnel capable of identifying and managing STDs, especially in developing countries. These services should be comprehensive and integrated into primary health care and MCH/FP clinics.
• Inexpensive, simple, rapid, accurate, stable and convenient STD diagnostics should be developed and tested.
• Recommended treatment schedules for STDs should be efficacious, affordable and safe. Today, new single-dose regimens of second generation antibiotics are available which improve compliance. Still more research is needed to identify and test “the STD drug.”
• User charges for STDs should be exempted for the poor, and this policy should be supported by national bodies and international donor organizations.

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