Thursday, April 28, 2005
3

Assessing the Benefit of Measuring B-type Natriuretic Peptide

Larry H. Bernstein and Madeleine Schlefer.


Context:
B-type natriuretic peptide, abbreviated BNP, increases in the circulation when the left ventricle is being stretched and expanded. For this reason, high levels of BNP in a person's body may be a way to diagnose heart failure early in it's course or indicate a person's risk of clinically overt heart failure, allow for delay in progression of disease, measure it's severity, and predict serious and mortality associated complications with higher levels of BNP indicating a higher risk factor.

Objective:
We investigate what other factors affect or do not affect BNP levels as well as what factors are effected by BNP levels.

Methods:
The factors selected were: troponin I levels, age, sex, number of heart related diagnoses, length of stay, and medications, troponin I, and ejection fraction. We considered that patients on medication would show a greater decrease in BNP levels than patients not on medication, patients with many heart related diagnoses would have higher BNP levels than patients with fewer diagnoses, and older patients would have higher BNP levels. Further, BNP levels would be associated with a longer hospital stay. What the relationship is between the BNP level and the troponin I level in CHF is not clear. How the BNP increases as the ejection fraction decreases also needs clarification. We extracted the data identified from over 700 patient records.

Results:
BNP levels and troponinI levels are not independent, increasing or decresing together. Since BNP and troponin I are dependent, high levels of both are associated with an increased hospital stay. As age and the number of heart related admissions to the hospital increases, so does the average BNP level of the patient. There is a relationship between increased BNP level and ejection fraction under 40%.

Conclusions:
This study is insufficient to show the effectiveness of medication.

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See more of The 2005 Institute for Quality in Laboratory Medicine Conference