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Increasing the validity and efficiency of blood pressure estimates using ambulatory and clinic measurements and
Matthew J Zawadzki1, John W Graham, William Gerin
1Department of Psychology, The Pennsylvania State University, University Park, Pennsylvania, USA.
Insights
The two-method measurement (TMM) design offers a cost-effective solution for blood pressure research. This method increases statistical power or reduces costs without compromising the predictive validity of ambulatory blood pressure monitoring (ABPM) compared to clinic BP measurements (CBP).
Area of Science:
- Cardiovascular Research
- Biostatistics
- Medical Technology
Background:
- Ambulatory blood pressure monitoring (ABPM) is the gold standard for blood pressure (BP) measurement, outperforming clinic BP measurements (CBP) in predicting cardiovascular events.
- The high cost of ABPM presents a significant challenge for researchers, often forcing a choice between less accurate CBP or expensive ABPM.
- The two-method measurement (TMM) design emerges as a solution to balance cost and data quality in BP research.
Purpose of the Study:
- To evaluate the effectiveness of the TMM design in improving statistical power and reducing costs in blood pressure research.
- To assess the impact of the TMM design on the predictive validity of blood pressure measurements in relation to target organ damage, such as left ventricular mass (LVM).
Main Methods:
- The study applied the TMM design, incorporating a bias correction structural equation model.
- Data from a study including ABPM, CBP, and echocardiographic LVM measurements were utilized to test the TMM approach.
- Participants received either CBP or both CBP and ABPM, with a focus on planned missing data strategies.
Main Results:
- The TMM design demonstrated a significant increase in statistical power when comparing ABPM to CBP, assuming a fivefold cost difference.
- Alternatively, the TMM design allows for substantial reductions in overall blood pressure measurement costs.
- These benefits were achieved without any loss in the predictive validity of the BP-LVM association.
Conclusions:
- The TMM design is a promising strategy for optimizing resource allocation in cardiovascular research.
- This approach can effectively decrease study costs and/or enhance the power to detect significant effects.
- The TMM design maintains the predictive validity of blood pressure measurements, making it a valuable tool for future studies.
Background:
Ambulatory blood pressure monitoring (ABPM) is considered the gold standard for BP measurement, compared to clinic BP measurements (CBP), which are a less valid predictor of target organ damage and cardiovascular events. However, ABPM is considerably more expensive than CBP, leaving BP researchers with a difficult dilemma: Use the less efficient CBP measure, or bear the cost of the more expensive ABPM. Recent developments in missing data methods, notably the two-method measurement (TMM) design, address this problem. With the TMM design, all research participants receive the less expensive CBP measure, but only a random subset receives the more expensive ABPM. The total number of participants must be increased, with additional participants receiving only CBP measurements. Even so, the TMM still reduces costs.
Methods:
We applied the TMM approach, which makes use of a "bias correction" structural equation model, to an empirical data set in which data were available for ABPM and CBP, as well as an echocardiographic measure of left ventricular mass (LVM).
Results:
Based on an estimated fivefold difference in cost for using ABPM compared to CBP, we found that statistical power can be considerably increased, or that BP measurement costs can be considerably reduced, when using this planned missing data design.
Conclusions:
These benefits were observed with no loss of predictive validity (i.e., the observed association between BP and LVM). This suggests that the TMM design is a promising technique that in some studies may be able to decrease costs and/or increase one's power to detect effects.
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