Birth cohort differences in hypertension control in a Brazilian population of older elderly: the Bambuí Cohort Study of Aging

We examined for cohort differences in hypertension control between participants in the Bambuí Cohort Study of Aging of aging born 1916-1926 and 1927-1937. Participants included hypertensive elderly aged 71-81 at baseline (n = 313) and at 11th wave follow up (n = 484). Prevalence of hypertension awareness (70.9% and 81.2%, respectively), median medical appointments in previous 12 months (2 and 3, respectively) and antihypertensive drug use (74.4% and 90.7% respectively) increased significantly from older to younger cohort. However, prevalence of appropriately controlled hypertension among those treated (< 140/< 90mmHg) was similar in both cohorts (44.6% and 40.1%, p = 0.255). Multivariate analysis returned schooling as the only factor independently associated with appropriately controlled hypertension. Despite increased medical appointments and drug use in the recent cohort, the prevalence of appropriately controlled hypertension remained as low as in the older cohort. Hypertension; Aged; Cohort Studies Introduction Worldwide, arterial hypertension is the main risk factor for mortality and the third most important cause 1 of years lived with disability. Prevalence of arterial hypertension is high in the overall population, and increases markedly with age. It is the most common chronic disease among older adults, with prevalence of 60% or more, both in high-income countries and in Latin America and the Caribbean 2. The World Health Organization (WHO) estimated in 2002 that at least 50% of cardiovascular diseases and 75% of strokes result from high blood pressure 3. Because of its high prevalence and severe consequences, efforts have been made worldwide to increase detection and control of existing arterial hypertension 4,5,6,7. Proper control of arterial hypertension is defined by systolic and diastolic pressures of less than 140 and 90 mmHg, respectively, among persons undergoing drug treatment. In the United States, results of the National Health and Nutrition Examination Survey (NHANES) showed that, in the overall population, prevalence of proper control of arterial hypertension increased among those undergoing treatment from 51% in 1988-94 to 69% in 2007 8. However, those observations were not corroborated in a more recent study based on the same survey, which found prevalence of appropriate control of arterial pressure among patients treated to be 44% for the period from 2005 to 2008 9. In Ontario, Canada, prevaARTIGO ARTICLE Firmo JOA et al. S428 Cad. Saúde Pública, Rio de Janeiro, 27 Sup 3:S427-S434, 2011 lence of proper control of arterial hypertension among patients treated was 66% in 2006, which is higher than observed in other population based surveys conducted in the early 1990s (12%) 10. The studies above showed discrepant results for control of arterial hypertension among older adults as compared with younger adults. While the first United States study 8 found that, among patients 60 years old or older, controlled arterial hypertension was less prevalent than among young and middle-age adults, the second study 9 found better control of arterial hypertension in the older and middle-aged adult groups than among the youngest age group, which agrees with what was observed in Canada 10. In middle-income countries, there is little information on appropriate control of arterial hypertension. One study in Mozambique (Africa) showed that, in 2005, in the overall population, 40% of hypertensive patients treated displayed appropriate arterial pressure levels 11. To our knowledge, there are no populationbased studies examining trends in appropriate control of arterial hypertension among older adults in Brazil. One cross-sectional study conducted on the baseline of the cohort study of older adults in Bambuí, Minas Gerais State, showed prevalence of arterial hypertension to be 62%. Among the 919 participants with arterial hypertension, 704 (77%) knew they were hypertensive, 578 (63%) were using some anti-hypertensive drug and, of these, 225 (39%) displayed appropriately controlled arterial hypertension 12. The present study used baseline and 11th wave data on the Bambuí cohort mentioned above, in order to examine for birth cohort differences in prevalence of appropriate control of arterial hypertension among older elderly adults, and in associated factors.