Research article
Adherence and virologic suppression during the first 24 weeks on antiretroviral therapy among women in Johannesburg, South Africa - a prospective cohort study
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* Corresponding author: Max Petzold max@nhv.se
1 Division of Global Health (IHCAR), Karolinska Institutet, Stockholm, Sweden
2 AIDS Virus Research Unit, National Institute for Communicable Diseases (NICD), Johannesburg, South Africa
3 Empilweni Services and Research Unit, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
4 International Center for AIDS Programs, Mailman School of Public Health, Columbia University, New York, USA
5 Nordic School of Public Health (NHV), Gothenburg, Sweden
6 Division of Infectious Diseases, Stanford University, California, USA
7 Gertrude H. Sergievsky Center, College of Physicians and Surgeons, and Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
BMC Public Health 2011, 11:88 doi:10.1186/1471-2458-11-88
Published: 8 February 2011Abstract
Background
Adherence is a necessary part of successful antiretroviral treatment (ART). We assessed risk factors for incomplete adherence among a cohort of HIV-infected women initiating ART and examined associations between adherence and virologic response to ART.
Methods
A secondary data analysis was conducted on a cohort of 154 women initiating non-nucleoside reverse transcriptase inhibitor (NNRTI)-based ART at a single site in Johannesburg, South Africa. Ninety women had been enrolled in a prevention of mother-to-child transmission (pMTCT) program and were exposed to single-dose nevirapine (sdNVP) >18 months earlier. Women were interviewed pre-treatment and clinical, virologic and adherence data were collected during follow-up to 24 weeks. Incomplete adherence to ART was defined as returning >5% of medications, estimated by pill counts at scheduled visits. Multivariable logistic regression analysis and unadjusted odds ratio (95%CI) were performed, using STATA/SE (ver 10.1).
Results
About half of the women (53%) were <30 years of age, 63% had <11 years of schooling, 69% were unemployed and 37% lived in a shack. Seven percent of women had a viral load >400 copies/ml at 24 weeks and 37% had incomplete adherence at one or more visits. Incomplete adherence was associated with less education (p = 0.01) and lack of financial support from a partner (p = 0.02) after adjustment for confounders. Only when adherence levels dropped below 80% was there a significant association with viremia in the group overall (p = 0.02) although adherence <95% was associated with viremia in the sdNVP-exposed group (p = 0.03). The main reasons for incomplete adherence were being away from home, busy with other things and forgetting to take their medication.
Conclusion
Virologic response to NNRTI-treatment in the cohort was excellent. However, women who received sdNVP were at greater risk of virologic failure when adherence was <95%. Women exposed to sdNVP, and those with less education and less social support may benefit from additional adherence counseling to ensure the long-term success of ART. More than 80% adherence may be sufficient to maintain virologic suppression on NNRTI-based regimens in the short-term, however complete adherence should be encouraged.