Clinical research studyAntihypertensive Drug Persistence and Compliance Among Newly Treated Elderly Hypertensives in Ontario
Section snippets
Study Population and Data Sources
We used the Ontario Drug Benefit prescription drugs database to identify all Ontario residents aged more than 66 years who had received a new prescription for an antihypertensive agent in the 5 main classes of antihypertensives (Appendix-Supplementary Table 1) between January 1, 1997, and December 31, 2005. To avoid the pitfalls associated with defining patients as medication users on the basis of only 1 prescription, we followed recently published recommendations to define our inception cohort
Cohort Characteristics
We identified 207,473 patients (58.4% were women, mean age 74.2 years, 73.1% were comorbid-free) for our inception cohort, 41,236 of whom had diabetes. The characteristics of this cohort, both overall and stratified by diabetic status or initial antihypertensive drug class, are summarized in Table 1, Table 2. The majority of patients were urban residents initially prescribed either an angiotensin-converting enzyme inhibitor or a diuretic. Approximately two thirds of patients were therapy
Discussion
We found that therapy persistence and compliance were highest in those elderly patients who were initiated on an angiotensin-converting enzyme inhibitor compared with other antihypertensive drug classes. We also confirmed our earlier observations that persistence with antihypertensive therapy is improving over time12 and extend our earlier work by also demonstrating that compliance is improving over time. We found that persistence was higher in older individuals, rural residents, people with
Study Limitations
There are several limitations inherent in our study. First, medication possession ratio fails to capture poor compliance beyond unfilled prescriptions as in the cases of filled prescriptions not taken or inappropriately used; further, we did not account for medication hoarded over from previous prescriptions in determining persistence. Second, given the dynamic nature of both compliance and persistence,1 our results apply only to the first 2 years of treatment; as well, we did not address other
Conclusions
Overall, our data provide evidence of a general improvement in antihypertensive drug persistence and compliance across years, as well as significant differences across drug classes and other patient-level factors. Targeted efforts directed toward men, urban residents, and those of low socioeconomic status to increase antihypertensive drug persistence and compliance should be considered. Because all antihypertensive drug classes seem to exert similar benefits in cardiovascular risk reduction in
Acknowledgment
The authors thank Nadia Khan for helpful comments.
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Funding: Alberta Heritage Foundation for Medical Research.
Conflict of Interest: None of the authors have any conflicts of interest associated with the work presented in this manuscript.
Authorship: All authors had access to the data and played a role in writing this manuscript.