To the Editor:
I have read with interest the Letter to the Editor from Morales-Olivas and Estañ. First, I would like to thank him for his opinion on my recent editorial in the Revista Española de Cardiología. Some of his comments apply to one of the liveliest current scientific debates, namely, the choice of antihypertensive treatment in clinical practice. Researchers have been considering this issue for the last 25 years, although findings from recent studies on arterial hypertension (AHT) and new guidelines for clinical practice in this disorder have revived the debate. I would like to make the following observations on the topic.
Prevention of cardiovascular disease should be based on treatment that is adapted to the needs of the patient. Specifically, treatment of AHT may involve thiazide diuretics as one of the possible first line therapies. Strong evidence on the effectiveness of these diuretics collected over the last 40 years supports the widespread presence of such drug in the therapeutic recommendations of recent American guidelines (JNC VII). Recent studies, in particular the ALLHAT study, have further confirmed this benefit. Some would wish that we had similar evidence in other areas of pharmacological prevention of cardiovascular disease that currently go unquestioned.
It is important to realize that most patients with hypertension need combinations of drugs to control blood pressure. All guidelines for the management of AHT in clinical practice agree that when a diuretic is not the initial antihypertensive agent, it should preferably form part of a combination of drugs. The combination of diuretics with drugs that block of the renin-angiotensin system are particularly favored. Thus the importance of the initial treatment is of only relative importance.
In addition to the goal of lowering blood pressure, the choice of class of antihypertensive drug will largely depend on adverse effects of the drug. Metabolic alterations associated with the chronic administration of thiazide diuretics, particularly at high doses, have been well known for some decades. However, the excellent results observed with these compounds in the ALLHAT study and the recommendations of the JNC VII seem to reject the possibility that we are suffering from an epidemic of diabetes associated with their use. Arguments along these lines are, at the very least, speculative. The real long-term clinical impact remains to be demonstrated.
The limitations in the design and follow-up of the ALLHAT study are well known. But to be fair, this is the most extensive study to date on the prevention of cardiovascular disease. Rates of drug discontinuation in this study are similar to those observed in other clinical trials on prevention whose conclusions have been used in guidelines for clinical practice. The characteristics of the patients included in this study, in particular their high risk, make the results particularly important. In patients treated with diuretics, many of whom also received beta blockers, the cardiovascular prognosis was at least as good as in those treated with amlodipine and lisinopril, which were also combined with beta blockers in a large number of patients. This finding is of particular clinical relevance. In cardiovascular medicine, differences between therapeutic regimens are easier to observe if the risk of the study population is higher, as seen in studies of heart failure and myocardial infarction.
Finally, I believe that diuretics should remain as first line treatment for AHT and that they deserve particular attention when other compounds are not specifically indicated e.g. blockers of the renin-angiotensin system (in patients with diabetes, kidney and heart failure, ischemic heart disease or stroke) and beta blockers (ischemic heart disease). Diuretics should also be considered in combination with other groups of antihypertensives.