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Judging the effectiveness of antihypertensive therapy in an individual patient
1Channing Laboratory, Harvard Medical School, Department of Medicine, Boston, MA 02115.
Insights
Determining if hypertension medication is effective is challenging due to blood pressure variability. Significant blood pressure drops or numerous visits are needed to confirm treatment success, especially when starting new antihypertensive drugs.
Area of Science:
- Clinical Medicine
- Cardiovascular Research
- Pharmacology
Background:
- Assessing the efficacy of antihypertensive medications is complex.
- Blood pressure (BP) variability, regression to the mean, and habituation to BP measurement can obscure treatment effects.
Purpose of the Study:
- To develop algorithms for determining the certainty of a drug's hypotensive effect.
- To establish criteria for acceptable certainty regarding blood pressure lowering.
Main Methods:
- Presentation of algorithms for visit frequency and required mmHg drop.
- Analysis of factors influencing the certainty of treatment response.
Main Results:
- High BP variability necessitates a substantial BP decrease or numerous pre- and post-therapy visits for confident efficacy assessment.
- Fewer visits and/or a smaller BP fall may suffice when adjusting or adding antihypertensive medications due to minimized regression to the mean.
Conclusions:
- Clinicians need high thresholds for BP change and/or extensive monitoring to confirm antihypertensive therapy effectiveness.
- Adjusting or adding antihypertensive drugs requires less stringent criteria for confirming a real BP decline.
Abstract:
The physician's decision as to whether a hypertensive drug has produced satisfactory blood pressure lowering is more difficult than it is usually perceived to be. Variability of blood pressure, regression to the mean and habituation to the taking of blood pressure all conspire to blur the significance of the observed drop. We present algorithms outlining the number of visits before and after the initiation of therapy and the mmHg drop required for determination with acceptable certainty that any response to the hypotensive drug has occurred. Our conclusion is that the variability of blood pressure limits the clinician's ability to confidently conclude that antihypertensive therapy is effective unless the change in blood pressure exceeds a relatively high threshold and/or the number of visits both before and after the initiation of antihypertensive therapy is large. Because regression to the mean will be minimized, fewer visits and/or a lesser blood pressure fall in the treated patient changing or adding medications will be necessary to determine that a real decline has occurred.