A Principal Stratification Approach to Evaluate the Causal Effect of A Patient Activation Intervention For Bone Health Outcomes

• Activity Number: 292 - SPEED: Statistics in Epidemiology
• Type: Contributed
• Date/Time: Tuesday, August 1, 2017 : 8:30 AM to 10:20 AM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): YIYUE LOU* and Michael P. Jones and Stephanie W. Edmonds and Fredric D. Wolinsky and Peter Cram
• Companies: University of Iowa and University of Iowa and University of Iowa and University of Iowa and University of Iowa
• Keywords: Causal Inference ; Clinical Trials ; Principal Stratification ; Intermediate Variable ; Principal Score Weighting

Abstract

The Patient Activation after DXA Result Notification (PAADRN) study is a multi-center, pragmatic randomized clinical trial designed to improve bone health. 7749 participants presenting for DXA were randomly assigned to either intervention group with usual care augmented by a tailored patient-activation DXA results letter accompanied by an educational brochure, or control group with usual care only. The primary analyses followed the standard intention-to-treat (ITT) principle, which provided a valid estimate for the intervention assignment. However, findings might underestimate the effect of intervention itself because PAADRN might not have an effect if the patient did not read, remember and act on the letter. We applied principal stratification to evaluate the effectiveness of PAADRN for subgroups, defined by the self-reported receipt of DXA result letter, while maintaining the constraints of randomization.