02447nas a2200289   4500000000100000008004100001100001300042700001800055700001100073700001300084700001700097700001500114700001800129700001700147700001100164700001300175700001300188700001200201700001500213700001500228245017500243250001500418300001000433490000700443520166100450020004602111       2010                            d1 aHayen A.1 aAsselbergs F.1 aFox K.1 aRemme W.1 avan Gilst W.1 aRemuzzi G.1 aRuggenenti P.1 aMacaskill P.1 aTeo K.1 aCraig J.1 aIrwig L.1 aBell K.1 aNeal Bruce1 aMacmahon S00aMonitoring initial response to Angiotensin-converting enzyme inhibitor-based regimens: an individual patient data meta-analysis from randomized, placebo-controlled trials  a2010/07/14  a533-90 v563 a<p>
Most clinicians monitor blood pressure to estimate a patient's response to blood pressure-lowering therapy. However, the apparent change may not actually reflect the effect of the treatment, because a person's blood pressure varies considerably even without the administration of drug therapy. We estimated random background within-person variation, apparent between-person variation, and true between-person variation in blood pressure response to angiotensin-converting enzyme inhibitors after 3 months. We used meta-analytic mixed models to analyze individual patient data from 28 281 participants in 7 randomized, controlled trials from the Blood Pressure Lowering Trialists Collaboration. The apparent between-person variation in response was large, with SDs for change in systolic blood pressure/diastolic blood pressure of 15.2/8.5 mm Hg. Within-person variation was also large, with SDs for change in systolic blood pressure/diastolic blood pressure of 14.9/8.45 mm Hg. The true between-person variation in response was small, with SDs for change in systolic blood pressure/diastolic blood pressure of 2.6/1.0 mm Hg. The proportion of the apparent between-person variation in response that was attributed to true between-person variation was only 3% for systolic blood pressure and 1% for diastolic blood pressure. In conclusion, most of the apparent variation in response is not because of true variation but is a consequence of background within-person fluctuation in day-to-day blood pressure levels. Instead of monitoring an individual's blood pressure response, a better approach may be to simply assume the mean treatment effect.
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