Risk assessment and other screening options for gonorrhoea and chlamydial infections in women attending rural Tanzanian antenatal clinics

Abstract

Sexually transmitted diseases (STDs) are a major cause of morbidity and mortality in developing countries and may play a key role in enhancing the heterosexual transmission of human immunodeficiency virus (HIV). Treatment of STDs is one of the most cost-effective of all health interventions in developing countries; however, STDs among women in rural populations have received little attention. In this study, we report that prevalences of STDs among 964 women attending antenatal clinics in a rural area of the United Republic of Tanzania. A total of 378 (39%) of these women were infected with at least one STD pathogen, 97 (10%) had syphilis, and 81 (8%) has Neisseria gonorrhoeae (NG) and/or Chlamydia trachomatis (CT) infection. The recommended syndromic approach to screening for NG/CT infection, based on reported genital symptoms, had a low sensitivity (43%) and failed to discriminate between infected and uninfected women. A risk score approach that we developed, based on sociodemographic and other factors associated with NG/CT infection, had a higher sensitivity and lower cost per true case treated than other approaches, although its positive predictive value was only about 20%.

PIP: During 1992-1993 in 12 rural health centers in Mwanza region, Tanzania, a baseline survey was conducted of 964 women attending a prenatal clinic to determine the prevalence of sexually transmitted diseases (STDs) and to evaluate various screening methods to identify those infected with Neisseria gonorrhoeae and Chlamydia trachomatis. Only 2.7% had ever used condoms. 66% had symptoms (vaginal discharge, genital itching, lower abdominal pain, painful or difficult urination, difficult or painful intercourse) associated with genital tract infection. 37% had abnormal vaginal discharge. 39% had a laboratory-confirmed STD. 49% had a reproductive tract infection. 10.1% had syphilis. 8.4% had gonorrhea and/or chlamydia. Sociodemographic factors associated with gonorrhea/chlamydia included age less than 25 (odds ratio [OR] = 2.2), unmarried status (OR = 3.2;), polygamous marriage (OR = 2.3), last child born more than 5 years earlier (OR = 3.2), and more than 1 sexual partner during the last year (OR = 1.7). When the researchers adjusted for these factors, the only signs or symptoms associated with gonorrhea/chlamydia were painful intercourse (OR = 2.1; p 0.02) and cervical discharge (OR = 3.2; p 0.06). The syndromic approach (based on vaginal discharge and/or genital itching and other symptoms related to the genital tract but not necessarily indicative of gonorrhea/chlamydia in pregnancy) had a higher sensitivity than the recommended syndromic approach based only on vaginal discharge and/or genital itching (72% vs. 43%). The risk score approach based on sociodemographic and other factors associated with gonorrhea/chlamydia infection had a higher sensitivity and lower cost/true case treated than other approaches. Yet, its positive predictive value was no greater than about 20%. A combination of case management using the World Health Organization syndromic approach for women with self-recognized genital infections together with screening for gonorrhea/chlamydia using a score-driven approach may be the most cost-effective approach to diagnosing and treating STDs.