IJE Advance Access originally published online on April 6, 2009
International Journal of Epidemiology 2009 38(4):997-1007; doi:10.1093/ije/dyp171
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Unprotected sex following HIV testing among women in Uganda and Zimbabwe: short- and long-term comparisons with pre-test behaviour
1Department of Epidemiology, University of North Carolina, Chapel Hill, Chapel Hill, NC, USA.
2Departments of Epidemiology and Medicine, University of California, Chapel Hill, Chapel Hill, NC, USA.
3Department of Obstetrics, Gynecology and Reproductive Sciencies, University of California, San Francisco, San Francisco CA, USA.
4Department of Obstetrics and Gynaecology, University of Zimbabwe, Harare, Zimbabwe.
5Department of Obstetrics and Gynaecology, Makerere University, Kampala, Uganda.
6Department of Medicine, Case Western Reserve University, Cleveland, OH, USA.
7Family Health International, Durham, NC, USA.
8Present address: RTI International, San Francisco, CA, USA.
9Present address: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada.
Deceased 28 March 2008.
* Corresponding author. Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, McGavran-Greenberg Hall, CB #7435, Chapel Hill, NC 27599-7435, USA. E-mail: ant{at}unc.edu
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Abstract |
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Background Despite widespread condom promotion for HIV prevention, prospective measurement of condom use before and after HIV testing is infrequent.
Methods We analysed data from a prospective study of hormonal contraception and HIV acquisition among Zimbabwean and Ugandan women (1999–2004), in which HIV testing and counselling were performed approximately every 3 months. We used zero-inflated negative binomial (ZINB) models to examine the number and proportion of unprotected sex acts, comparing behaviour reported 2–6 months before HIV testing with behaviour reported both 2–6 months (short-term analysis) and 12–16 months (long-term analysis) after HIV testing.
Results Short- and long-term analyses were similar, so we present only long-term findings from 151 HIV-infected and 650 uninfected participants. The proportion of HIV-infected women reporting any unprotected acts in a typical month declined from 74% (pre-infection behaviour) to 56% (12–16 months after HIV diagnosis). In multivariable models, HIV-infected women were twice as likely to report that all sex acts were protected by condoms after diagnosis compared with beforehand [adjusted odds ratio (aOR): 1.99, 95% confidence interval (CI): 1.12–3.53]; uninfected women were somewhat less likely to report that all acts were protected (aOR: 0.82, 95% CI: 0.64–1.04). HIV-infected women also reduced their number of unprotected acts by 38% (95% CI: –16 to –55%). However, their proportion of unprotected acts changed little (7% reduction, 95% CI: –18 to + 6%). Uninfected women reported little change in number or proportion of unprotected acts over the same time period.
Conclusions HIV-infected women reduced the number, but not the proportion, of unprotected acts. HIV-negative women did not increase condom use after testing and counselling, but neither did they decrease condom use, suggesting that testing negative was not interpreted as endorsement of risky behaviour.
Keywords Zero-inflated, negative binomial, HIV/AIDS, male condom, risk behaviour, positive prevention, women, Uganda, Zimbabwe, unprotected sex
Accepted 2 March 2009