In an urban South African setting, the integrated mother-child postnatal clinic at McCord Hospital achieved good outcomes in the first 13 months of its inception. These outcomes included infant HIV testing of 83% and HIV transmission risk of 2.7% at six weeks in returning HIV-exposed infants whose mothers received PMTCT at McCord Hospital. However, LTFU by six months was substantial, limiting our ability to determine HIV-free survival at 18 months.
In developed countries vertical transmission of HIV to infants occurs in 1-2% of pregnancies in HIV infected women, achieved through a combination of interventions, including antiretroviral therapy regimens that optimally suppress viral load, elective Caesarean section and complete avoidance of breastfeeding [25–30]. In developing countries the caesarean section proportion ranges from 3% to 12.6% [11, 12, 31]. The high proportion of caesarean sections at McCord Hospital may reflect the ability of the women in this setting to choose the best possible care for their infants and the hospital's capacity to deliver a comprehensive package of interventions to reduce the vertical transmission of HIV.
Although the rate of LTFU at McCord Hospital was comparable to other PMTCT programmes in public settings in sub-Saharan Africa [11, 14, 32–34], the high rate of early dropout in our setting may in part be due to women changing to service providers nearer to their residences. The period of greatest attrition was in the first week of life. This data may support the explanation of mothers returning to clinics in closer proximity to their homes. A similar finding was noted in a PMTCT programme at a centralized hospital in Malawi . The authors suggested that the LTFU of mother-infant pairs may have been due to women from rural areas returning to their peripheral clinics following delivery . The revised South African PMTCT guidelines may improve the follow-up of mothers and infants in this setting as HIV-infected women attend for their own health, and infants who are breastfed beyond six weeks require repeated access to nevirapine until one week after cessation of breastfeeding.
Late antenatal presentation (28 weeks of gestation or later) was a strong predictor of LTFU. There may be several reasons for late antenatal clinic attendance at McCord Hospital: women may have been minimizing expenses related to antenatal care; lack of awareness of the value of early antenatal care; or poor maternal health seeking behaviours. These results highlight the importance of identifying late antenatal attendees to determine the risk factors which contribute to attrition following delivery. Moreover, the fee-paying nature of the hospital needs to be taken into account when assessing the attrition of late antenatal attendees.
In prior studies, poor socio-demographic circumstances have been associated with patient attrition. In Malawi HIV-exposed infants born to parents who were less educated and in farming occupations were more likely to be LTFU . In our multivariable model, there was no association between socio-demographic characteristics and infant LTFU (maternal employment and marital status). Since the parental level of education was not routinely collected at the time this study was conducted, the association with LTFU could not be assessed. In the Ugandan study lack of understanding of the importance of follow-up was noted as a reason for attrition . In Johannesburg, maternal unemployment, geographical relocation and lack of paternal support were noted as reasons for poor retention . Maternal education and support regarding the importance of follow-up care for their own and their infants’ health may improve patient retention and facilitate early diagnosis of infant morbidity and HIV transmission risk.
This study demonstrated that relative to infants of HIV-infected women with CD4 + counts 200 cells/mm3 or less, infants born to mothers with CD4+ counts above 200 cells/mm3 were more likely to be lost to follow-up. This finding was not statistically significant. Maternal well-being may be a risk factor for poor retention in our setting as mothers do not perceive themselves or their infants to be at risk for disease. These mothers may be less likely to seek health care. A similar correlation between infant wellbeing and loss to follow-up was shown in a study in rural Uganda, where infant illness was a protective against loss to follow-up in the PMTCT programme .
A key strength of this study was the ability to determine if patients were not returning for care. Clinic staff at McCord Hospital routinely contacted patients if they missed a scheduled appointment at the clinic, noting reasons for the missed appointment and rescheduling another. If these patients decided to attend other health care facilities, they were not considered LTFU as the reason for their non-attendance was known. Moreover, routine monitoring allowed early detection of infants requiring follow-up care.
A limitation of this study was the selection of the study population. According to the selection criteria, only infants whose mothers attended the PMTCT programme at McCord Hospital, and/or were delivered at McCord Hospital, and/or were brought back to the hospital for follow-up care were included in the study. Accordingly, the outcomes of infants who were not brought back to McCord Hospital for further care remained unknown. In addition, since the service was not available, the study could not include a comparison group of infants born to HIV-uninfected women from McCord Hospital. Inclusion of this comparison group would have made it possible to determine the background risk of HIV-exposed uninfected infants in terms of loss to follow-up. Finally, errors in the routine maternal and infant records and assignment of LTFU status may have constituted information bias.
The results of this study may not be generalizable to the HIV-exposed infant population in the public sector in South Africa. Moreover, formula feeding was reported as the predominant infant feeding modality. The impact of feeding practices on infant mortality requires further consideration. The results from this new integrated postnatal mother and baby clinic at McCord Hospital provide important lessons for other PMTCT services in developing settings. The attrition of HIV-exposed infants, particularly those born to women who attended antenatal services at McCord Hospital after 28 weeks highlights the need to identify late antenatal attendees for follow up care and to determine the HIV transmission risk and mortality of HIV-exposed infants.