Objectives: We aimed to evaluate socio-demographic factors associated with HIV and syphilis seroreactivity in pregnant Malawians presenting for antenatal care in late third trimester of pregnancy. Methods: Between December 2000 and March 2004 at Queen Elizabeth Central Hospital Blantyre, Malawi, we collected cross-sectional clinical and socioeconomic data from consenting women. HIV-1 status was determined using rapid HIV antibody tests and syphilis seroreactivity was determined using Rapid Plasma Reagin (RPR) and confirmed with Treponema pallidum hemagglutination assay (TPHA). Results: Of 3,824 women screened for HIV, 1156 (30%) were HIV seropositive and 198 (5%) were RPR and TPHA seroreactive. In the multivariate analysis, HIV infection was positively associated with elevated socio-economic status, being formerly married, and age, but not with education level. HIV prevalence was lower in women of Yao ethnicity than in other women (OR: 0.78, 95%CI: 0.64 – 0.95). Increased maternal education was negatively associated with syphilis seroreactivity. Conclusions: The seroprevalence of HIV and syphilis among women attending the antenatal ward in Blantyre remains unacceptably high. Demographic correlates of HIV and syphilis infections were different. Our results demonstrate the need for better strategies to prevent HIV and syphilis in women and calls for optimizing antenatal syphilis screening and treatment in Malawi.
Women seeking care at the Queen Elizabeth Central Hospital (QECH) antenatal ward (ANW) in Blantyre, Malawi, from December 2000 until March 2004 were evaluated. QECH is the main tertiary referral hospital in southern Malawi and also functions as the district hospital for Blantyre; it handles approximately 15,000 deliveries per year. In general, pregnant women in Malawi attend prenatal care 16 to 20 weeks into the pregnancy, soon after quickening begins (fetal kicking). Women admitted to the ANW were screened and if eligible and consenting, enrolled in a study on malaria and mother to child transmission of HIV. The study had two goals, 1) to document the socio-demographic features associated with HIV infection in pregnant women, and 2) to investigate the effects of placental malaria on HIV mother-to-child transmission. Enrollment details and the results from the longitudinal cohort study of the HIV-infected women have been described5. Although documenting syphilis cases was not a stated goal of the study, in accordance with the Malawi Standard Treatment Guide, participants were tested serologically for syphilis as described below. Owing to logistical constraints and the short time period between enrollment and delivery (median 4.5 days), syphilis testing was done in batches, and as a result, many of the syphilis-seroreactive women and their children were treated with benzathine penicillin postnatally. A standard questionnaire was used to collect socio-demographic data. Marital status was categorized as single, married, or formerly married (separated or divorced or widowed). The cost of materials used in the construction of the primary residence was considered a surrogate of socio-economic status, with mud and pole construction representing the least expensive materials, brick walls with a grass-thatched roof representing a moderate expense, and brick walls with iron sheets representing the most expensive materials. For married women, their husband’s occupation was categorized into 21 informal categories according to the perceived similarity of the level of training required for that career. Additionally, the women were asked if they had ever been diagnosed with HIV, a sexually transmitted infection (STI), or tuberculosis (TB). Previous STIs, except HIV and syphilis, and TB infection, were not verified by medical tests or medical records. HIV status was determined simultaneously with the Determine™ HIV-1/2 Rapid Antibody Test (Abbott Laboratories, IL, USA) and the SeroCard™ HIV-1/2 Rapid Test (Trinity Biotech Plc, Co Wicklow, Ireland); discordant results were resolved with the HIVSPOT HIV-1/2 Rapid Test (Genelabs Diagnostics, Singapore). Women were tested for syphilis using the Rapid Plasma Reagin test ([RPR], Omega Diagnostics, Alloa, Scotland), and all RPR reactive sera were tested with the Treponema pallidum Hemagglutination Assay ([TPHA], Omega Diagnostics, Alloa, Scotland). Clinical signs of syphilis or recent treatment were not evaluated, and women with a reactive RPR followed by a reactive TPHA were considered syphilis seroreactive. Hemoglobin concentration was measured using a hemoglobinometer (HemoCue AB, Ängelholm Sweden), with anemia defined as a hemoglobin concentration less than 11 g/dL. Peripheral malaria infection was assessed on thick blood films stained with Field’s stain. Data were entered into Microsoft Access in duplicate, cross-checked, and analyzed with Stata v8.2 (StataCorp, College Station, TX, USA). The association between nominal categorical variables and infection was evaluated with the chi-squared test for independence; monotonic trends in ordinal categorical variables were tested with a chi-squared statistic for trend (“ptrend” module, Stata). Previous studies have suggested an inverse association between HIV status and Islamic faith, and therefore we decided a priori to test the association between HIV and belonging to the Yao tribe, the predominant Muslim tribe in Malawi. Prevalence odds ratios (ORs) of binary variables associated with HIV and syphilis infection were calculated from contingency tables and tested with a chi-squared statistic or Fisher’s exact test. In order to determine the independent correlates of HIV and syphilis seroreactivity, demographic features associated with either HIV or syphilis in the univariate analysis (p<0.1) were included in a multivariable model. The study was approved by the Malawi College of Medicine Research and Ethics Committee and by the Institutional Review Boards at both the University of Michigan and the University of North Carolina at Chapel Hill. Informed consent was received from all participants.
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