Anti-hypertensive drug utilization in Continental Portugal (1999-2004)

The estimated prevalence of arterial hypertension (HT) in Portugal in 2003 was 43%, with only 28.8% of patients undergoing antihypertensive treatment having their blood pressure controlled. In the light of this fact, if HT is detected early and adequately controlled, there is great potential for reducing cardiovascular morbidity and mortality.

This study aimed to analyze patterns of antihypertensive drug utilization in Portugal at the regional and national level, to compare them with other countries, and to evaluate trends in certain indicators regarding use of these drugs.

Data on antihypertensive drug utilization refer to drugs prescribed and dispensed in the ambulatory population covered by the Portuguese national health service, from January 1, 1999 to June 30, 2004. Data were expressed in defined daily doses (DDD) per 1000 inhabitants per day (DID).

Use of antihypertensives increased from 183 DID in the first half of 1999 to 256 DID in the first half of 2004, an increase of 40%. Angiotensin-converting enzyme inhibitors were the most frequently prescribed drug class, being used by 31% of the study population, followed by diuretics (16%) and calcium channel blockers (14%). Angiotensin receptor blockers (ARBs) accounted for most of the growth in antihypertensive use, although they represent the most expensive therapeutic option. This pattern of use had a strong impact on antihypertensive drug expenditure, which increased 60% over the study period. ARBs, plain or in combination formulations, accounted for 55% and 71% of the increase in utilization and expenditure respectively.

From the standpoint of health gains, the significant rise in antihypertensive drug utilization represents a potentially favorable development in terms of increased numbers of patients undergoing drug treatment. Compared to other European countries, the data showed greater use of drugs that act on the renin-angiotensin system in Portugal and less use of diuretics and beta-blockers. Most national and international guidelines recommend diuretics as first-line agents in HT treatment. Considering that these drugs have the lowest daily treatment cost, a high, and increasing, rate of utilization would be expected, but this is not the case in Portugal.

This study reveals not only significant differences in antihypertensive drug utilization at the regional level in Portugal but also a lack of adherence to national and international guidelines, and therefore more attention should be paid to their implementation in order to improve health gains.