Browsing by Author "Glynn, Judith R."

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Age-Specific Mortality Patterns in HIV-Infected Individuals: A Comparative Analysis of African Community Study Data
    (Aids, 2007) Zaba, Basia; Marston, Milly; Crampin, Amelia C.; Isingo, Raphael; Biraro, Sam; Ba¨rnighausen, Till; Lopman, Ben; Lutalo, Tom; Glynn, Judith R.; Todd, Jim
    Describe age-specific mortality patterns of HIV-infected adults in African communities before introduction of HAART.Mortality data (deaths and person-years observed) for HIV-positive subjects aged 15–65 from six African community studies in five different countries were pooled, combining information from 1793 seroconverters and 8534 HIV positive when first tested. Age-specific mortality hazards were modelled using parametric regression based on the Weibull distribution, to investigate effects of sex, and site-specific measures of mean age at incidence, crude mortality rate of uninfected, and measures of epidemic maturity.The combined studies yielded a total of 31 777 person-years of observation for HIV-positive subjects, during which time 2602 deaths were recorded. Mortality rates rose almost linearly with age, from below 50/1000 at ages < 20 years, up to 150/1000 at 50 years +. There was no significant difference between men and women in level or age pattern of mortality. Weibull regression analysis suggested that intersite variation could be explained by HIV prevalence trend, and by the ratio of HIV proportional mortality to current HIV prevalence. A model representation was constructed with a common age pattern of mortality, but allowing the level to be adjusted by specifying HIV prevalence indicators.The linear age trend of mortality in HIV-infected populations was satisfactorily represented by a Weibull function providing a parametric model adaptable for representing different levels of HIV-related mortality. This model might be simpler to use in demographic projections of HIV-affected populations than models based on survival post-infection.
  • Thumbnail Image
    Item
    Estimating ‘net’ HIV-related Mortality and the Importance of Background Mortality Rates
    (AIDS, 2007) Marston, Milly; Todd, Jim; Glynn, Judith R.; Nelson, Kenrad E.; Rangsin, Ram; Lutalo, Tom; Urassa, Mark; Biraro, Sam; Paal, Lieve Van der; Sonnenberg, Pam; Żaba, Basia
    To estimate mortality directly attributable to HIV in HIV-infected adults in low and middle income countries and discuss appropriate methodology.Illustrative analysis of pooled data from six studies across sub-Saharan Africa and Thailand with data on individuals with known dates of seroconversion to HIV.Five of the studies also had data from HIV-negative subjects and one had verbal autopsies. Data for HIV-negative cohorts were weighted by the initial age and sex distribution of the seroconverters. Using the survival of the HIV-negative group to represent the background mortality, net survival from HIV was calculated for the seroconverters using competing risk methods. Mortality from all causes and ‘net’ mortality were modelled using piecewise exponential regression. Alternative approaches are explored in the dataset without information on mortality of uninfected individuals.The overall effect of the net mortality adjustment was to increase survivorship proportionately by 2 to 5% at 6 years post-infection. The increase ranged from 2% at ages 15–24 to 22% in those 55 and over. Mortality rate ratios between sites were similar to corresponding ratios for all-cause mortality.Differences between HIV mortality in different populations and age groups are not explained by differences in background mortality, although this does appear to contribute to the excess at older ages. In the absence of data from uninfected individuals in the same population, model life tables can be used to calculate background rates.
  • Thumbnail Image
    Item
    Herpes simplex virus type 2: a key role in HIV incidence
    (Aids, 2009) Glynn, Judith R.; Biraro, Samuel; Weiss, Helen A.
    Many epidemiological studies have found a strong association between HSV-2 infection and HIV infection, including longitudinal studies in which it was known that the HSV-2 infection preceded the HIV infection [1]. However, two recent trials of suppressive therapy of HSV-2 with acyclovir (400 mg b.i.d) showed no reduction in HIV incidence [2,3]. Although this may simply reflect the difficulty of adequately suppressing HSV-2 reactivations with the drug regimen used, the results have led some to challenge the importance of HSV-2 infection as a risk factor for HIV [4]. In this issue, Tobian et al.[5] use data from the Rakai male circumcision trial to assess the effect of prevalent and incident HSV-2 infection on HIV incidence. They found that prevalent HSV-2 infection increased HIV incidence three-fold, and that men who acquired HSV-2 during follow-up had a six-fold risk of HIV incidence, in analyses adjusted for sexual behaviour. These results are very similar to those found in a systematic review [1]. This included cohort and nested case–control studies up to 2004, and identified 18 that were adjusted for age and sexual behaviour. We have re-run the meta-analysis including more recent studies that fit the same criteria (Fig. 1). Six additional studies, as well as that by Tobian et al.[5], are included: one in men from the circumcision trial in South Africa [6]; two in women in the general population, in Uganda and Zimbabwe [7]; two in female sex workers in Kenya [8] and Tanzania [9]; and one in men who have sex with men (MSM) in the US [10]. Summary estimates of the relative risk (RR) show a strong and consistent association of prevalent HSV-2 and incident HIV after adjusting for age and measures of sexual behaviour [RRwomen = 3.4, 95% confidence interval (CI) 2.4–4.8; RRmen = 2.8, 2.1–3.7; RRsex workers = 1.5, 0.75–3.0; RRMSM = 1.6, 1.2–2.0). In addition, a cohort study in Uganda found an adjusted rate ratio of 8.7 (1.1–67.2) for men and women combined