Antihypertensive therapy among newly treated patients: An analysis of adherence and cost of treatment over years

Abstract

Objective:

To perform a time-trend analysis of adherence and cost of antihypertensive treatment over four years.

Methods:

A population-based retrospective cohort study was conducted. We included subjects ≥18 years, and newly treated for hypertension with diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, or angiotensin receptor blockers between 01 January 2004 and 31 December 2007. One-year adherence to antihypertensive therapy was calculated and classified as low, low-intermediate, intermediate, high-intermediate, and high. The direct cost of antihypertensive medications was evaluated.

Results:

We included data for a total of 105,512 patients. The number of newly treated subjects decreased from 27,334 in 2004 to 23,812 in 2007, as well as antihypertensive drug therapy cost which decreased from €2,654,166 in 2004 to €2,343,221 in 2007. On the other hand, in the same time frame, the percentage of adherent newly treated subjects increased from 22.9% to 28.0%. Compared with subjects initiated on angiotensin receptor blockers (odds ratio [OR] = 1), the risk of nonadherence was higher in those initiated on angiotensin-converting enzyme inhibitors (OR = 1.19), combination therapy (OR = 1.44), beta-blockers (OR = 1.56), calcium channel blockers (OR = 1.67), and diuretics (OR = 4.28).

Conclusions:

The findings of the present study indicate that suboptimal adherence to antihypertensive medication occurs in a substantial proportion of treated patients, and improvements in treatment adherence were obtained but are still unsatisfactory.

Keywords:

• antihypertensive therapy
• adherence
• cost
• administrative databases

Acknowledgements

The cooperation of Dr Alessandra Fionda in this research is gratefully acknowledged.

Disclosure

This study was funded by Takeda Italia Farmaceutici. Otherwise there is no conflict of interest in this work and there were no persons who contributed to the work who did not meet the criteria for authorship.