Confidence Intervals for Population Attributable Fractions Using Complex Survey Data

• Activity Number: 516 - Estimation with Complex Samples
• Type: Contributed
• Date/Time: Wednesday, August 2, 2017 : 10:30 AM to 12:20 PM
• Sponsor: Survey Research Methods Section
• Author(s): Akhil Vaish* and Olga Khavjou
• Companies: Research Triangle Institute and Research Triangle Institute
• Keywords: SUDAAN ; VARGEN ; population attributable fraction ; Taylor series linearization (delta method) ; survey variance estimation ; confidence intervals

Abstract

This paper describes an easy-to-implement method for producing confidence intervals (CIs) for population attributable fraction (PAF) statistics using survey data. The PAF is used by epidemiologists and policymakers to assess how much of the disease burden in a population could be reduced if the exposure to certain risk factors were eliminated. The PAF is defined as p(rr-1)/rr , where p denotes the proportion of cases exposed to a risk factor and rr denotes the model-based relative risk comparing the proportion of cases among the exposed group with the proportion of cases among the unexposed group. The rr is obtained by modeling the log of the prevalence of the disease as a linear function of covariates where exposure to the risk factor is included as one of the model covariates. The proposed methodology is based on the Taylor series linearization and properly accounts for survey design features in estimating the variances and covariances of the estimated quantities. The methodology is implemented using the VARGEN procedure of SUDAAN® version 11.0 software on 2013 Behavioral Risk Factor Surveillance System data to produce state-by-age group PAF estimates and CIs of hypertension with diabetes as the risk factor.