Getting the Right Target
Medscape: The BP goals in TASMIN-SR were quite demanding compared with current guidelines, although they were consistent with recommendations at the time.
Prof McManus: Yes. In fact, the intervention group reduced their BP to a mean of 128.2/73.8 mm Hg, so we have shown that we were able to achieve a target that many people would say was quite intensive without causing a lot of excess adverse effects. I was surprised that we achieved such good reduction in BP in this group; I thought it might be less, given that the patients were older and frailer. If you weren't told, you couldn't tell from the reported adverse effects which group was the intervention group and which was the control group. We saw even fewer symptoms related to the antihypertensive medication than in our previous study. Ankle edema, for example, which was probably due to calcium channel blocker use in TASMINH2, was not increased in this study, which is very reassuring.
Medscape: There isn't much evidence about targets in older patients like those in your study who were aged older than 70 years, and the latest guidelines seem to disagree about this.
Prof McManus: People are still arguing about how low you should go in older patients, and now we are pulling back on targets. The most recent US guidelines are contradictory,[26,27,28,29] but they all used the same evidence from a relatively limited number of trials. If you look only at targets, you can fail to reach a target but still have a significant reduction in BP. All data from both observational studies and trials suggest that every 10-mm Hg reduction in systolic BP is associated with about a 40% reduction in stroke risk and a 20% reduction in coronary heart disease risk. Obviously, if you start with a high risk, then you achieve a bigger absolute risk reduction. By looking at what happens to the overall means rather than the proportion below a particular target, we can better capture those differences than by just looking at a percentage who reaches a target
Medscape: In your study, patients measured their BP in the morning. Would that be your recommendation in future studies? Current guidelines seem to favor taking at least two home measurements, one in the morning and one in the evening.[5,6,7,8,9,10]
Prof McManus: We used morning measurements because there is evidence suggesting that morning BP is better associated with prognosis, particularly stroke risk, and we wanted to keep the intervention relatively simple. If people are measuring their BP twice a day, then you have to cope with discrepancies between morning and evening measurements. We had shown in TASMINH2 that measuring BP in the morning allowed us to see a significant reduction, so we decided to continue with that. There are theoretical reasons for measuring BP twice daily; and, as you noted, guidelines recommend measuring in the morning and evening so that that you can take into account the troughs before new medication, but there is actually very little evidence to show how often BP should be measured. We now have two good trials showing that self-titration from patients measuring their BP in the morning is effective.
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Cite this: Self-management of Hypertension: Are Patients and Providers Ready to Partner? - Medscape - Nov 24, 2014.