We appreciate the opportunity afforded to us by the letter from Escobar et al concerning our article1 on the use of antihypertensive medication in Spain. For decades, studies on pharmaceutical drug use (or on the consumption of prescription drugs) have been used in public health activities. Using relatively simple methods, studies can be carried out to determine which drugs are used in real-world clinical practice and in what amounts, the patterns of their use over time, and the economic impact, as well as to establish comparisons among geographic regions for the purpose of identifying possible variations in medical practice.

It is true that the information from aggregate data on the use of pharmaceutical drugs can be linked to clinical variables, in what are known as ecological studies. Some ecological studies can help to describe a disease or a risk factor in relation to variables of interest, for example, health services. In this respect, our work has recently enabled the correlation of hospital admissions due to dehydration with the consumption of antihypertensive drugs,2 and could serve in the formulation of new hypotheses, although without losing sight of possible aggregation biases (the ecological fallacy).

We also agree that a number of causes could explain the growth observed in the use of antihypertensive medication. In addition to population aging, we stressed that the major reason is the increase in the prevalence of treated hypertension (which would include mild hypertension, when lifestyle and dietary measures fail, and hypertension in young people).

Finally, we also appreciate the references to the PRESCAP study (PRESión arterial en la población española en los Centros de Atención Primaria [Blood pressure control in the Spanish hypertensive population attended to in the primary care setting]) and recognize its important contributions to knowledge on the management of hypertension in Spain. However, the available epidemiological evidence (including the PRESCAP study, together with other studies)3,4 appears to indicate that little progress has been made in the control of hypertension in recent years and reveals that there is considerable room for improvement. Given that this is an unsolved public health problem, priority should be given to policies that reinforce programs for the prevention and control of high blood pressure.