A longitudinal analysis of the completeness of maternal HIV testing, including repeat testing in Cape Town, South Africa

Introduction: The virtual elimination of mother-to-child transmission of HIV cannot be achieved without complete maternal HIV testing. The World Health Organization recommends that women in high HIV prevalent settings repeat HIV testing in the third trimester, and at delivery or directly thereafter. The Western Cape Province (South Africa) prevention of mother-to-child transmission (PMTCT) guidelines recommend a repeat maternal HIV test between 32 and 34 weeks gestation and at delivery in addition to testing at the first antenatal visit (ideally <20 weeks gestation). There are few published longitudinal studies on the uptake of initial and repeated maternal HIV testing programmes in sub-Saharan Africa. We aimed to investigate the implementation of initial and repeat maternal HIV testing guidelines in Cape Town, South Africa. Methods: Between 2013 and 2016 we established an electronic PMTCT register that consolidated routine data from a primary healthcare facility and its secondary and tertiary referral sites in Cape Town. This provided a longitudinal record for each participant, from first antenatal visit to delivery. Utilizing these data, we conducted a retrospective analysis investigating the completeness of maternal HIV testing according to the PMTCT HIV testing guidelines in Cape Town, and predictors of complete testing, from 2014 to 2016. Results: Among 8558 enrolled pregnant women, 7213 (84%) were not known to be HIV positive at their first visit and thus eligible for HIV testing; 91% of them received ≥1 HIV test during pregnancy/delivery. Testing at the first visit was 98% among the 85% of women who attended antenatal care. Among women eligible to receive all three recommended HIV tests, only 11% achieved all three tests. Delivery HIV testing completion among all women without an HIV-positive diagnosis was 23%. HIV prevalence at delivery was 21% and HIV incidence between first visit and delivery in those with ≥2 HIV tests was 0.2%. Women who enrolled after 2014 were more likely to receive the three recommended tests (aOR: 1.41; 95% CI: 1.10 to 1.81) and retest at delivery (aOR: 1.20; 95% CI: 1.05 to 1.39). Conclusions: Implementation of maternal HIV testing in Cape Town improved between 2014 and 2016 but major gaps remain, particularly at delivery. This study was a retrospective analysis conducted on antenatal maternal HIV testing data that were prospectively collected for the Closing the Gaps (CTG) study which has been described previously 29. Briefly, the CTG study established an integrated electronic PMTCT register (e‐register) that consolidated routine data from a primary care obstetric facility, Mitchells Plain Midwife Obstetric Unit (MPMOU), and its referral sites: Mitchells Plain District Hospital (MPDH), Mowbray Maternity Hospital (MMH) and Groote Schuur Hospital (GSH), within the urban Klipfontein/Mitchells Plain Sub‐Structure of the WC, SA. In the Western Cape, women with uncomplicated pregnancies can access antenatal care at Midwife Obstetric Units (MOUs) which can manage normal deliveries, or basic antenatal care (BANC) facilities which provide outpatient services only (these women will present to the MOU for delivery). MPMOU is within the Mitchells Plain Community Health Centre which is accessed by approximately 1.2 million people. Among community members, an estimated 24% are unemployed and 16% have lower grade education. At the time of the study MPMOU (primary care) provided ANC, including HIV testing, counselling and treatment, as well as midwife‐assisted uncomplicated vaginal delivery services 30. High‐risk pregnancies or those requiring advanced care were referred from MPMOU to a secondary or tertiary care facility during the antenatal or peri‐partum period. MPDH and MMH (secondary level) are equipped with operating theatres and neonatal intensive care unit (ICU) facilities respectively while GSH (tertiary level) has both adult and neonatal ICU facilities. The 2015 WC antenatal HIV prevalence was reported to be 19% 31. In the CTG study, pregnant women, irrespective of HIV status, were passively enrolled at their first ANC visit at MPMOU, or alternatively, upon presentation for delivery if they had not received ANC. HIV tests (rapid antibody assay) were performed by community care workers as part of routine ANC services and by nurses in the labour ward of MPMOU and the labour/postnatal ward of the hospitals. We included data from the CTG e‐register for all enrolled women who delivered at MPMOU or one of its referral sites, between 1 July 2014 and 31 December 2016, with a live or still birth pregnancy outcome. We excluded data from women who (a) presented for delivery having attended ANC at a BANC since we did not have access to complete longitudinal HIV testing data for these individuals or (b) for whom no pregnancy outcome could be found as we could not exclude pregnancy loss, in which case PMTCT testing guidelines would no longer be applicable. Western Cape PMTCT HIV testing guidelines† 10: Note: The guidelines do not specify a minimum time period between tests. HIV testing eligibility defined as per the PMTCT guidelines†: †The PMTCT guidelines assume best practice. Women do not attend ANC at recommended gestational ages and guidelines may be loosely implemented, for example, women may attended their first ANC visit and retest within the third trimester. We assessed HIV testing completeness as follows: Longitudinal HIV testing completion proportions among women with known gestational age who were eligible to receive all three recommended tests A longitudinal record, including HIV testing history from first antenatal visit (if attended) through to delivery, was extracted from the CTG e‐register for each woman. We categorized women as having attended ANC if they presented to a health facility >5 days before delivery. We defined early ANC attendance as ≤22 weeks gestation. We deemed all women eligible for an initial test if on their first visit, whether antenatally or at delivery, they were not already known to be HIV positive; and eligible for repeat testing if they had not had a prior positive antenatal HIV test. Tests were considered to be retests if women underwent an HIV test within the third trimester and/or at delivery following a prior negative HIV test. We considered women eligible for retesting in the third trimester if they delivered >35 weeks gestation. According to the guidelines there was no minimum time period between tests. The primary outcome was receipt of an HIV test (yes/no): (1) at first visit (ideally ≤22 weeks, but up to delivery); (2) in the third trimester as a repeat test; and (3) at delivery as a repeat test. The secondary outcome was HIV‐positive diagnoses (yes/no) at each test. We calculated testing completion at: Women who tested at first ANC visit were also categorized as having tested <28 weeks gestation, in the third trimester and/or at delivery. Testing completion at each recommended window was calculated only among women eligible to be tested at that respective window (Figure ​(Figure1;1; Table ​Table22 – column 1). Data abstracted from the e‐register did not record ANC visits between the first visit and delivery unless a test was recorded. Eligibility for repeat testing in the third trimester was hence based on prior ANC attendance. Flow chart illustrating the number of women eligible to be HIV tested within each testing point window. Only women for whom gestational age was available were included (n = 6917). aWomen who HIV tested <28 weeks gestation but delivered ≤35 gestation in the third trimester and therefore would not be eligible for repeat testing in the third trimester. bWomen who delivered prematurely were considered eligible for testing at delivery if not yet diagnosed HIV positive. HIV testing during pregnancy for women for whom gestational age data were available (n = 6917) ANC, antenatal care; n, number of participants. In addition, we calculated the testing completion restricted to the windows defined in the PMTCT guidelines (best practice) as follows: Individuals diagnosed HIV positive during the study period were coded as “diagnosed at enrolment” if they tested HIV positive at their initial ANC test, or as “seroconverts” if they tested HIV‐positive after a previous negative antenatal HIV test. We categorized women as having an “uncertain HIV status at delivery” if they tested HIV negative at least once during ANC but had not received a test within three months prior to or at delivery; and having an “unknown HIV status at delivery” if they never tested during the current pregnancy. For women with two pregnancies within the study period, we included the pregnancy for which most data were available. Premature delivery was defined as delivery <37 weeks gestation. Data analysis was carried out using Stata version 13.0 (Stata Corporation, College Station, Texas, USA). Differences between the characteristics of all participants, stratified by HIV status post delivery, were assessed using the two‐sample t‐test (normal distribution) or the Wilcoxon rank‐sum test (non‐normal distribution) for numerical data and the χ2 or Fishers Exact test for categorical data. A descriptive analysis (proportions) was used to assess HIV testing completion during pregnancy among participants for whom gestational age data was available. We used logistic regression to assess predictors of maternal HIV testing completeness. Multivariable models included several variables selected a priori as being possible risk factors (age at enrolment, gravidity, and year of enrolment) for the outcome. Additional variables were included by sequentially adding them based on univariable analysis of significance. Those that were either significantly associated with the outcome of interest after adjustment for other variables (p < 0.05) or that altered the odds ratios (ORs) for other variables in the model by ≥10% were retained 32. The University of Cape Town Human Research Ethics Committee and the Provincial Government of the Western Cape Department of Health Research Committee approved the study. The CTG study was granted a waiver of informed consent for the e‐register as all data had already been collected routinely by health services. No participant recruitment was required.