The AIDS epidemic in India: a new method for estimating current human immunodeficiency virus (HIV) incidence rates.
Department of Biostatistics, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
Human immunodeficiency virus (HIV) incidence rates in India were estimated using a new method that accounts for follow-up bias. Follow-up bias arises in epidemiologic cohort studies when the incidence rate among individuals who do and do not return for follow-up are different. The new method combines data on the prevalence of p24 antigenemia among all those initially screened together with the longitudinal follow-up data on the subset of patients who returned for follow-up. Using these methods, the current HIV incidence rate among patients attending sexually transmitted disease clinics in Pune, India, was 18.6% per year. It was found that follow-up bias can cause significant underestimation in HIV incidence rates, perhaps by as much as 60%. These incidence estimates, together with other HIV seroprevalence studies, suggest the HIV epidemic in India is growing rapidly.
PIP: Follow-up bias develops in epidemiologic cohort studies when the incidence rate among individuals who do and do not return for follow-up differ. The authors estimated the rates of HIV incidence in India using a new method which accounts for follow-up bias. This new method combines data on the prevalence of p24 antigenemia among all individuals initially screened together with the longitudinal follow-up data on the subset of patients who return for follow-up. The current annual rate of HIV incidence among patients attending sexually transmitted disease clinics in Pune, India, was found to be 18.6%. The study found that follow-up bias can lead to significant underestimation in HIV incidence rates, perhaps by as much as 60%. These incidence estimates, together with findings from other HIV seroprevalence studies, suggest that the HIV epidemic in India is growing rapidly.
PMID: 7572940 [PubMed - indexed for MEDLINE]