Prevalence and incidence of hypertension in a population cohort of people aged 65 years or older in Spain

OBJECTIVE: To estimate the prevalence and incidence of hypertension in a Spanish cohort of people aged at least 65 years with 13 years' follow-up. This is the first study to provide age-adjusted and sex-adjusted incidence rates of hypertension in a Mediterranean-based population aged 65 years or older. METHODS: Population-based longitudinal study set in the city of Leganes, Spain. The cross-sectional prevalence of hypertension was estimated using data available for the 1993, 1995, 1999, and 2006 cohorts. The incidence density (incident cases of hypertension/person-years) was calculated for 522 individuals without hypertension at baseline. Individuals were classified as hypertensive if they were taking physician-prescribed medication for hypertension or if their blood pressure was equal to or greater than 140/90 mmHg. RESULTS: Hypertension prevalence increased progressively with time, from 53.5% in 1993 to 86.2% in 2006. In all four waves, women had a higher prevalence of hypertension than men (P < 0.05). The total incidence density of hypertension was 7.6 [95% confidence interval (CI) 6.6-8.7] cases per 100 person-years of follow-up: 9.0 (95% CI 7.2-11.2) in women and 6.9 (95% CI 5.8-8.3) in men. In all age groups, the incidence density was nonsignificantly higher in women than in men (P > 0.05). CONCLUSION: Both the incidence and prevalence of hypertension in this population of people aged at least 65 years were high, and the prevalence increased dramatically over time, especially among women.