Efficacy of Antihypertensive Monotherapies Assessed by Ambulatory Blood Pressure Monitoring: Is There Really a Winner?

Present‐day guidelines recommend initiating antihypertensive treatment with a single agent, except if monotherapy has a low probability of success.1, 2, 3, 4, 5 Several drug classes are available for that purpose, including diuretics, β‐blockers, calcium antagonists, and blockers of the renin‐angiotensin system (RAS) (angiotensin II antagonists, converting enzyme inhibitors). How can we select a specific molecule for a specific patient? Some therapeutic classes may be more appropriate than others in presence of end‐organ damage, so that guidelines point to preferential indications. Age is also regarded as a potential factor. Indeed, many experts consider β‐blockers and RAS inhibitors to be more effective in younger patients than in elderly patients, the converse being true of diuretics and calcium antagonists. Another criterion is how the drug is being tolerated, since undesirable side effects may lead to treatment interruption. In that respect, RAS blockers seem to have an advantage over the other classes in terms of adherence to treatment.6 Cost sometimes comes in the balance, with diuretics then coming first. Of course, an essential consideration is antihypertensive efficacy, which is difficult to predict in individual patients because hypertension is a highly heterogeneous condition. Indeed, the same elevation of blood pressure (BP) can be caused by several pathophysiologic mechanisms, which potentially differ from one patient to the next.7

Why is the study by de la Sierra and colleagues8 important in that respect? Essentially because efficacy has been evaluated not only in the practitioner's office, but also with 24‐hour ambulatory BP monitoring (ABPM), a method of growing usefulness for the diagnosis and treatment of hypertension.9 The weight of the presented evidence is also increased by the large number of patients in whom ABPM data have been collected with great methodological care. Not a real surprise, ABPM indicated lower BP values, compared with measurements made in the office. To be reminded, though, that this statement applies to group means, and as such may not reflect the situation of individual patients, in whom the reverse is sometimes observed.

It is noteworthy that, as published, the paper gives no information on the level of BP before the institution of treatment. This is a somewhat unusual way of presenting results: the different treatments are compared in terms of absolute BP values rather than amplitude of BP‐lowering achieved under treatment. However, this approach allows investigating the proportion of patients in whom treatment led to BP normalization, whether considering measurements made in the office or with ABPM. Such data are particularly interesting because of the large study size. What important message do they convey? Probably those calcium antagonists do not appear as effective when evaluated with ABPM, compared with office measurements. Maybe also those agents of the same class are not necessarily equivalent in terms of BP control quality.

We think it is regrettable that the authors did not analyze their data in terms of the concordance between evaluations of BP control with office measurements vs ABPM. In other words, in what percentage of patients were normotensive values achieved irrespective of the evaluation method, and whether taking into consideration daytime, nighttime, or 24‐hour ABPM data? We would expect considerable heterogeneity in that respect.

Results were also analyzed after adjustment for several variables, including age. We regret that the authors did not take advantage of the large study size in order to more specifically investigate the impact of age on the quality of BP control achieved by the various therapeutic classes. How justifiable is it to prefer diuretics and calcium antagonists in the elderly and β‐blockers and RAS inhibitors in the young, taking as a single criterion the probability to normalize BP in the course of everyday life? We hope these considerations will prompt the authors to reexamine their data in order to answer this question.

Finally, we wish to emphasize the practical importance of the data provided by the Spanish ABPM Registry. We hope that these will encourage researchers to implement similar cohorts of patients cared for by practitioners. A lot remains to be learned on when and how ABPM should be used for the diagnosis and therapeutic monitoring of hypertension.