Adherence to Antihypertensive Therapy Prior to the First Presentation of Stroke in Hypertensive Adults: Population-Based Study
What is the excess risk of stroke associated with nonadherence to antihypertensive drug therapy among hypertensive patients?
The investigators conducted a population-based study using records from Finnish national registers for January 1, 1995, to December 31, 2007. The authors used binary and multinomial logistic regression to assess the year-by-year association between adherence to antihypertensive therapy and nonfatal or fatal stroke. These models were adjusted for age, sex, length of antihypertensive therapy (i.e., the number of years from the start of the diagnosed continuous need for antihypertensive medication to the time term entered in the model), education, household income, diabetes mellitus, and history of cancer.
Of the 73,527 hypertensive patients ages 30 years or older and without pre-existing stroke or cardiovascular disease, 2,144 died from stroke and 24,560 were hospitalized due to stroke during the follow-up. At the 2- and 10-year follow-up after the start of continuous antihypertensive medication, nonadherent patients had 3.81 (95% confidence interval [CI], 2.85-5.10) and 3.01 (95% CI, 2.37-3.83) times higher odds of stroke death when compared with the adherent patients. The corresponding odds ratio (OR) for stroke hospitalization was 2.74 (95% CI, 2.35-3.20) at year 2, and 1.71 (95% CI, 1.49-1.96) at year 10. In the stroke-event year, the ORs were higher, 5.68 (95% CI, 5.05-6.39) for stroke death and 1.87 (95% CI, 1.72-2.03) for hospitalization. Among those using agents acting on the renin–angiotensin system combined with diuretics or beta-blockers, these ORs were 7.49 (95% CI, 5.62-9.98) and 3.91 (95% CI, 3.23-4.75), respectively. The associations between nonadherence and stroke followed a dose–response pattern—the poorer the adherence, the greater the risk of death and hospitalization due to stroke.
The authors concluded that poor adherence to antihypertensive therapy substantially increases near- and long-term risk of stroke among hypertensive patients.
In this large-scale, population-based linkage study, hypertensive patients who subsequently died or were hospitalized due to stroke had a lower adherence to antihypertensive medication for continuous antihypertensive therapy than did the patients who did not experience stroke during the follow-up. Furthermore, a dose–response analyses based on categories of high, intermediate, and low adherence to antihypertensive medication confirmed that the near- and long-term risk of fatal and nonfatal stroke increased at each step down the level of adherence. These findings underscore the importance of hypertensive patients remaining adherent to antihypertensive therapy in order to prevent such serious complications as fatal and nonfatal stroke events.
Keywords: Risk, Stroke, Diuretics, Renin-Angiotensin System, Hospitalization, Hypertension
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