Longitudinal chronobiologic blood pressure monitoring for assessing the need and timing of antihypertensive treatment.
To examine the need for antihypertensive therapy and its timing, a 46 year-old woman with a 10-year history of "mild to moderate hypertension," treated for that span with 50 mg of hydrochlorothiazide per day, usually taken before retiring, carried out a study in a series of stages. Throughout the first 8 stages, she monitored her blood pressure and heart rate at 15-minute intervals around the clock for 70 consecutive days. In the first two stages, her medication was continued for a total of 10 days, of which the last 7 days constituted a double-blind study start. For the next 25 days, she was placed on a placebo once in the evening. For the ensuing week, she received three tablets per day (in the morning, noon and evening), with all three being placebo. Thereafter, for consecutive 7-day spans, she was placed on treatment, only in the morning, only at noon or only in the evening, with placebo at other times. The desirability of one vs. another treatment was assessed by a comparison of slopes fitted to the daily MESORs; on that basis, the morning or noon treatment appeared to be possibly superior to the evening treatment. Eventually the patient was taken off medication; 5 months later her sphygmochrons, based on two-to-six day monitoring, were acceptable by current standards. The slope of MESORs may be a useful endpoint to assess the need for medication, to optimize its timing or to establish the likelihood that medication is not needed. This approach should, however, be based on several (rather than a single) double-blind alternation of drug and placebo treatments for spans that are the longer the smaller the extent of apparent blood pressure elevation. Thus, in the case of apparent mild MESOR-hypertension, the blood pressure MESOR changes following the change in medication should be assessed during spans longer than one week. In the particular case studied, it seems possible that the patient had taken medication for 10 years, perhaps without justification. In cases of very mild blood pressure elevation, it seems desirable, by self-measurement or preferably automatic measurement, to take the patient off medication for spans measured in weeks or preferably months rather than days, in order to rule in or rule out the need for treatment, on the basis of repeated blood pressure profiles, to be compared eventually with reference standards from peers at low familial and personal risk of developing high blood pressure.