Title: Clinic and ambulatory BP measurement: A valid and cost-effective approach using the two-method measurement design

Speaker: John W. Graham (ThePennsylvaniaStateUniversity)

Time: 11:00-12:00am, June 29^th

Place: Rm216, GSM New building

Abstract:

Researchers who study blood pressure (BP) have two measurement options: collect BP measures (1) using standard clinic-style methods (ClinBP), or (2) using Ambulatory BP (AmbBP) procedures. ClinBP is relatively inexpensive, but is known to be affected substantially by false positive, and false negative indications of hypertension. AmbBP is highly valid but costs 5 times as much to implement. Two-method measurement, a planned missing data design (Graham et al., 2006), offers a nice solution to the dilemma faced by BP researchers. With this approach, all subjects are measured using ClinBP, but only a small random sample of subjects also receive the more expensive, but more valid AmbBP measures. Results of our simulations showed that the two-method approach was as valid as, but much more powerful than using the AmbBP approach. For the same overall study costs, the two-method measurement approach yielded an effective N that was nearly double the N for the complete cases (AmbBP+ClinBP) design costing the same.