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Estimating HIV incidence from age-specific prevalence data: comparison with concurrent cohort estimates in a study of male factory workers, Harare, Zimbabwe.
Gregson, S; Machekano, R; Donnelly, C A; Mbizvo, M T; Anderson, R M; Katzenstein, D A.
Afiliación
  • Gregson S; Wellcome Trust Centre for the Epidemiology of Infectious Disease, Zoology Department, Oxford University, UK.
AIDS ; 12(15): 2049-58, 1998 Oct 22.
Article en En | MEDLINE | ID: mdl-9814874
OBJECTIVE: To compare HIV incidence estimates from cross-sectional age-specific prevalence data with concurrent cohort estimates and to examine the sensitivity of the estimates to changes in age-categorization and survivorship assumptions. METHODS: Two previously described methods of estimating HIV incidence from cross-sectional prevalence data - the cumulative incidence and survival (CIS) and constant prevalence (CP) methods - are applied using data from a study of male factory workers in Harare, Zimbabwe. The methods are applied under two alternative groupings of the HIV prevalence data and under alternative survivorship assumptions: (a) Weibull distribution providing the best fit to the HIV prevalence data using the CIS method; (b) Weibull distribution matching data from an HIV natural history cohort study in Uganda; and (c) survivorship pattern as in (b) with survival periods reducing with increasing age at infection. Age-specific, age-standardized and cumulative HIV incidence estimates are calculated. The results are compared with concurrent longitudinal estimates from 3 years of follow-up of the Harare cohort (1993-1995). RESULTS: Age-standardized HIV incidence was estimated at 2.02 per 100 man years (95% CI, 1.57-2.47) in the cohort study. There was evidence of recent variability in HIV incidence in these data. Estimates from the cross-sectional methods ranged from 1.98 to 2.74 per 100 man years and were sensitive to changes in age-categorization of the HIV prevalence data and changes in survivorship assumptions. The cross-sectional estimates were higher at central ages and lower at older ages than the cohort estimates. The age-specific estimates from the CIS method were less sensitive to changes in age grouping than those from the CP method. CONCLUSIONS: HIV incidence remains high in Harare. Incidence estimates broadly consistent with cohort estimates can be obtained from single-round cross-sectional HIV prevalence data in established epidemics - even when the underlying assumption of stable endemic prevalence is not fully met. Estimates based on cross-sectional surveys should therefore be explored when reliable longitudinal estimates cannot be obtained. More data on post-HIV infection survivorship distributions in sub-Saharan Africa would facilitate the improvement of estimates of incidence based on cross-sectional surveys.
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Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Infecciones por VIH / Seroprevalencia de VIH Tipo de estudio: Etiology_studies / Incidence_studies / Observational_studies / Prevalence_studies / Prognostic_studies / Risk_factors_studies Límite: Adolescent / Adult / Humans / Male / Middle aged País/Región como asunto: Africa Idioma: En Revista: AIDS Asunto de la revista: SINDROME DA IMUNODEFICIENCIA ADQUIRIDA (AIDS) Año: 1998 Tipo del documento: Article
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Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Infecciones por VIH / Seroprevalencia de VIH Tipo de estudio: Etiology_studies / Incidence_studies / Observational_studies / Prevalence_studies / Prognostic_studies / Risk_factors_studies Límite: Adolescent / Adult / Humans / Male / Middle aged País/Región como asunto: Africa Idioma: En Revista: AIDS Asunto de la revista: SINDROME DA IMUNODEFICIENCIA ADQUIRIDA (AIDS) Año: 1998 Tipo del documento: Article