June 2013

Published on June 12, 2013 by

Modelling – a universal practice in all of science

Welcome to a special edition of SACEMA quarterly epidemiological update – dedicated to SACEMA’s annual ‘research days’ event and other SACEMA related work. This is a glimpse into exciting trends in public health research, where mathematical methods are increasingly applied to a range of problems, to help leverage limited data, think about prospects for interventions, and formulate new hypotheses and experiments. The article also includes a reflection on modelling as a universal practice in all of science and all that differs are the kinds of models, and the techniques used to set them up and manipulate them.

Published on June 12, 2013 by

PURE-ifying research on chronic non-communicable diseases in South Africa

Chronic non-communicable diseases (NCDs) such as diabetes, cardiovascular disease (CVD) and cancers are a major public health problem. In an effort to increase awareness about the behavioural risk factors for NCDs a community-based project was implemented in Khayelitsha. Informed by the results of this study the School of Public Health at the University of the Western Cape joined the Prospective Urban and Rural Epidemiology (PURE) study in January 2009. The study seeks to scientifically document the root-causes of the traditional risk factors for NCDs by following-up adults aged 30 to 75 years for 12 to 15 years and collecting individual-, household-, community- and national-level information. Responding effectively to the growing burden of NCDs incorporates addressing societal and biological pathways from environmental causes to primordial predispositions and adequately managing the primary risk factors.

Published on June 12, 2013 by

Rheumatoid arthritis disease progression in a South African cohort: Bayesian multistate chronic disease, dynamic modelling.

The primary goal of this article is to model the forces (rates) of recovery, relapse and mortality for patients started on rheumatoid arthritis (RA) standard treatment and the effect of adjusting for body functionality. A four state model inclusive of the absorbing state death was fit to these data. A consequence of an improved health is better body functionality, which was measured using a health assessment disability index (HAQ-DI). The modelling was done using a member of the generalised additive mixed models (GAMMs) which utilise nonparametric functions adjusting for over-dispersion and correlation. Based on the results we advocate that patients should be treated until the disease activity score is in remission or lowest possible to enable greater physical functionality whilst alleviating disability and mortality due to RA.

Published on June 12, 2013 by

20th Conference for Retroviruses and Opportunistic Infections: Highlights, and Developments in HIV Incidence Estimation

The headline-grabber at the 20th Conference for Retroviruses and Opportunistic Infections (CROI) was the ‘functional cure’ of an HIV-infected child. A key success of the ‘Mississippi miracle’ is that no latent reservoir of replication-competent HIV developed in the infant. The study of latent reservoirs, and prospects for eliminating these through treatment, in adults and infants, was the topic of many sessions. Apart from the laboratory science, a number of results from studies and modelling exercises were presented, assessing a number of risk factors and interventions for various conditions. Of particular relevance to the work of SACEMA is the topic of HIV incidence estimation. CEPHIA hosted a satellite session, focussed on the first independent assessments of incidence assays for HIV incidence estimation in cross-sectional studies.