A Comparative Analysis of Mixed Effects Models and Related Methods to Assess Physical and Mental Functional Status After Receipt of Anthrax Vaccine in a Human Clinical Trial

• Activity Number: 87
• Type: Contributed
• Date/Time: Sunday, July 31, 2011 : 4:00 PM to 5:50 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Brock Stewart*+ and Charles Rose and Michael M. McNeil
• Companies: Centers for Disease Control and Prevention and Centers for Disease Control and Prevention and Centers for Disease Control and Prevention
• Keywords: Mixed Effects Model ; Vaccine Adsorbed (AVA) ; Health Related Quality of Life ; SF-36 Health Survey

Abstract

Following a mandate from the US Congress, in 2002 CDC initiated a randomized, double-blind, placebo-controlled phase 4 clinical trial to assess the safety and serological noninferiority of alternate schedules and routes of administration of Anthrax Vaccine Adsorbed (AVA). As a substudy, subjects completed SF-36v2 health surveys (Medical Outcomes Trust, Boston, MA) at time-points corresponding to doses 1 and 5-8 (months 0, 12, 18, 30, and 42) of the then-current US licensed AVA dosing schedule; there were 6822 observations from 1557 subjects included in the analysis. The study included seven treatment groups differentiated by whether subjects received AVA or saline placebo at full or reduced dosing schedules and by route of administration (subcutaneous or intramuscular). Our goal was to determine whether physical and mental functional status, as measured by the survey, changed differently over time between the study treatment groups. We assessed the use of a mixed-effects modeling approach for this purpose and compared it to related methods. Preliminary results suggest no difference of physical or mental functional status between the treatment groups.