The timing of the blood pressure measurement may affect the result in patients with acute stroke.

The Timing of the Blood Pressure Measurement May Affect the Result in Patients With Acute Stroke To the Editor: I have read the article by M Willmoth et al (Hypertension 2004;43:18–24) in which a high blood pressure in acute stroke patients was associated with poor outcome, with great interest. I wonder, however, why the blood pressure timing, even though recorded, was not included in the analysis. Some have reported that blood pressure spontaneously decreased in the first hours after stroke onset in patients with mild to moderate stroke.1,2 Consequently, the timing of the blood pressure measurements may affect the results. It might be an oversimplification to pool blood pressure data from patients with acute stroke within a period of 7 days. In most patients blood pressure rapidly declines after admission, possibly as a consequence of the passing stress of admission. On the contrary, blood pressure in patients with cerebral herniation increases. In patients with essential hypertension higher blood pressure is found at all times. I agree with the authors that the hypothesis that blood pressure reduction in acute stroke should be tested in large randomized trials. In my opinion it would improve the quality of both observational studies and clinical trials concerned with blood pressure in acute stroke to include the timing of blood pressure measurement in the analysis, because otherwise we may mix up different biological mechanisms.