Browsing by Author "Ayella, Emingtone O."

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    Differences in fertility by HIV serostatus and adjusted HIV prevalence data from an antenatal clinic in northern Uganda
    (Tropical Medicine & International Health, 2006) Fabiani, Massimo; Nattabi, Barbara; Ayella, Emingtone O.; Ogwang, Martin; Declich, Silvia
    To estimate differences in fertility by HIV serostatus and to validate an adjustment method for estimating the HIV prevalence in the general female population using data from an antenatal clinic. methods We used Cox regression models to retrospectively estimate the age-specific relative fertility (RF) of HIV-positive compared to HIV-negative women among 3314 antenatal clinic attenders in northern Uganda. RF and the age distribution of women in the general female population were used to extrapolate the antenatal clinic-based HIV prevalence. This procedure was indirectly validated by comparing the adjusted estimate with those based on standard adjustment factors derived from general female populations in Uganda and Tanzania. results HIV-positive women reported a lower fertility than HIV-negative women [age-adjusted RF ¼ 0.83, 95% confidence interval (CI): 0.75–0.93]. Except for girls aged 15–19 (RF ¼ 0.96, 95% CI: 0.74– 1.24) HIV-positive women in all age groups were less fertile (20–24 year: RF ¼ 0.83, 95% CI: 0.67– 1.01; 25–29 years: RF ¼ 0.79, 95% CI: 0.62–1.00; 30–49 year: RF ¼ 0.79, 95% CI: 0.65–0.96]. Adjusting the antenatal clinic-based HIV prevalence (11.6%) for these differences yields a higher estimate (13.8%) that is lower than those based on standard adjustment factors derived from general female populations (from 14.6% to 17.7%). conclusions The age-specific pattern of differential fertility by HIV serostatus derived from antenatal clinic data is consistent with findings from population-based studies conducted in Africa. However, differences in fertility between HIV positive and HIV-negative clients underestimate those in the general female population yielding inaccurate estimates when used to extrapolate the HIV prevalence.
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    Using prevalence data from the programme for the prevention of mother-to-child-transmission for HIV-1 surveillance in North Uganda
    (AIDS, 2005) Fabiani, Massimo; Nattabi, Barbara; Ayella, Emingtone O.; Ogwang, Martin; Declich, Silvia
    To validate the use of data from a programme for the prevention of motherto- child transmission (PMTCT) in estimating HIV-1 prevalence in North Uganda. Methods: The study was conducted at St. Mary’s Hospital Lacor. We compared the estimated prevalence for 3580 attendees at the antenatal clinic who were selected for anonymous surveillance to that for 6785 pregnant women who agreed to undergo voluntary counselling and testing (VCT) for enrolment in the PMTCT programme. Logbinomial regression models were used to identify the factors associated with both VCT uptake and HIV-1 infection, which could bias the prevalence estimates based on PMTCT data. Results: In 2001–2003, the age-standardized prevalence was similar (11.1% in the anonymous surveillance group and 10.9% in the VCT group). The estimates were also similar when compared for each year tested. Analogously, no important differences were observed in age-specific prevalence. Of the factors associated with HIV-1 infection, only time of residence at current address [prevalence proportion ratio (PPR) ¼ 1.05; 95% confidence interval (CI), 1.00–1.10], marital status (PPR ¼ 1.05; 95% CI, 1.01–1.10) and partner’s occupation (PPR ¼ 1.05; 95% CI, 1.01–1.10) were associated with VCT uptake, yet the associations were weak. Conclusions: The prevalence estimated based on the VCT data collected as part of the PMTCT programme could be used for HIV-1 surveillance in North Uganda. At the national level, however, it needs to be evaluated whether PMTCT data could replace, or instead be combined with, the data from sentinel surveillance.