Controlling confounding by frailty when estimating influenza vaccine effectiveness using predictors of dependency in activities of daily living.

ABSTRACT:

Purpose

To improve control of confounding by frailty when estimating the effect of influenza vaccination on all-cause mortality by controlling for a published set of claims-based predictors of dependency in activities of daily living (ADL).

Methods

Using Medicare claims data, a cohort of beneficiaries >65 years of age was followed from September 1, 2007, to April 12, 2008, with covariates assessed in the 6 months before follow-up. We estimated Cox proportional hazards models of all-cause mortality, with influenza vaccination as a time-varying exposure. We controlled for common demographics, comorbidities, and health care utilization variables and then added 20 ADL dependency predictors. To gauge residual confounding, we estimated pre-influenza season hazard ratios (HRs) betw

SUBMITTER: Zhang HT 

PROVIDER: S-EPMC5716904 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature