Objective: To study the relation between hypertension and cardiovascular events--stroke, myocardial infarction (MI), heart failure (HF), and chronic renal failure (CRF)--and to define implications for cardiovascular disease prevention.
Design: Cross-sectional study, in two stages, but with retrospective information about major cardiovascular events.
Setting: Primary care health centers (Lisbon Regional Health Administration).
Participants: 3228 patients, 1100 male (439 aged up to 60 years and 661 aged 60 years) and 2128 females (860 aged up to 60 years and 1268 aged 60 years). The study covered stroke, myocardial infarction, heart failure, chronic renal failure with co-variables of age, gender, body mass index (BMI), blood pressure, heart rate, antihypertensives, diabetes, total cholesterol, dyslipidemic therapy, and smoking. The group without hypertension (normotensives) and hypertensives--treated with antihypertensives and/or with systolic/diastolic blood pressure > or = 140/90 mmHg (n = 2169)--were compared, using logistic regression, to identify nonfatal cardiovascular complications associated with hypertension. Forward conditional logistic regression was used to test the multivariate models. The level of significance was taken to be 5%. The statistical packages Stata and SPSS were used.
Results: The analysis included 2839 cases (389 missing). The absolute frequencies of categorical variables were: smoking (n = 343); stroke (n = 150); myocardial infarction (n = 90); heart failure (n = 174); renal failure (n = 34); hypercholesterolemia (n = 864); diabetes (n = 375); male gender (n = 976) and female gender (n = 1863). The regression equation included the following factors: age (p < 0.001; OR = 1.068 and 95% CI 1061-1.075); body weight (p = 0.001; OR = 1.020 and 95% CI 1.008-1.032); stroke (p = 0.007; OR = 2.523 and 95% CI 1.286-4.951); HF (p = 0.013; OR = 2.449 and 95% CI 1.205-4.979); diabetes (p < 0.001; OR = 1.894 and 95% CI 1.328-2.701); hypercholesterolemia (p < 0.001; OR = 1.693 and 95% CI 1.350-2.123); and BMI (p < 0.001; OR = 1.006 and 95% CI 1.003-1.010).
Conclusions: Nonfatal stroke was associated with hypertension, as was heart failure, but neither nonfatal myocardial infarction nor chronic renal failure were. Control of hypertension is therefore expected to be more efficacious in reducing cerebrovascular events than those caused by coronary heart disease.