Statistics in Medicine
Volume 26, Issue 2, 2007, Pages 309-319

Analysis of interval-censored data from circular migrant and non-migrant sexual partnerships using the EM algorithm (Article)

Zuma K.* , Lurie M. , Jorgensen M.
  • a Human Sciences Research Council, Private Bag 41, Pretoria 0001, South Africa, Department of Statistics, University of Waikato, Hamilton, New Zealand
  • b Department of Community Health, Brown University School of Medicine, Miriam Hospital, Providence, RI, United States
  • c Department of Statistics, University of Waikato, Hamilton, New Zealand

Abstract

In epidemiological studies where subjects are seen periodically on follow-up visits, interval-censored data occur naturally. The exact time the change of state (such as HIV seroconversion) occurs is not known exactly, only that it occurred sometime within a specific time interval. Methods of estimation for interval-censored data are readily available when data are independent. However, methods for correlated interval-censored data are not well developed. This paper considers an approach for estimating the parameters when data are interval-censored and correlated within sexual partnerships. We consider the exact event times for interval-censored observations as unobserved data, only known to be between two time points. Dependency induced by sexual partnerships is modelled as frailties assuming a gamma distribution for frailties and an exponential distribution on the time to infection. This formulation facilitates application of the expectation-maximization (EM) algorithm. Maximization process maximizes the standard survival frailty model. Results show high degree of heterogeneity between sexual partnerships. Intervention strategies aimed at combating the spread of HIV and other sexually transmitted infections (STI)s should treat sexual partnerships as social units and fully incorporate the effects of migration in their strategies. Copyright © 2006 John Wiley & Sons, Ltd.

Author Keywords

Interval censored frailty Sexual partnerships EM algorithm HIV

Index Keywords

Models, Biological HIV Infections sexual behavior Human immunodeficiency virus infection seroconversion survival rate HIV correlation analysis follow up human Longitudinal Studies rural population controlled study social aspect research subject Human immunodeficiency virus Algorithms human relation sexually transmitted disease South Africa epidemiological data Humans Adolescent male female observational study mathematical analysis Article disease transmission infection control Risk-Taking major clinical study adult migration Age Factors data analysis Models, Statistical expectation Transients and Migrants time
Link
https://www.scopus.com/inward/record.uri?eid=2-s2.0-33846211006&doi=10.1002%2fsim.2539&partnerID=40&md5=8b912744abc65ea14852f87480b4f5dd
DOI: 10.1002/sim.2539
ISSN: 02776715
Original Language: English