Background and objectives: Demonstration of antihypertensive beneficial role in population settings is difficult. Relationships of antihypertensive treatment, blood pressure control, risk factors and cardiovascular outcomes were investigated in the Gubbio study.
Material and methods: Among 2248 cardiovascular disease-free men and women aged 35-74 years, individuals were classified as nonhypertensive, controlled hypertensive, uncontrolled hypertensive and untreated hypertensive based on cut-off limits of 140/90 mmHg for SBP/DBP and/or the use of antihypertensive drugs. End-point was the first major coronary, cerebrovascular or peripheral hard event [cardiovascular disease (CVD)] during a 15-year average. Univariate and multivariate analyses were run.
Results: Nonhypertensive individuals were about 10 years younger and had lower risk factor levels than the other categories. The relative risk (and 95% confidence interval) for CVD versus nonhypertension was 1.78 (1.02-3.10) for controlled hypertension, 3.76 (2.79-5.06) for uncontrolled hypertension and 3.30 (2.59-4.21) for untreated hypertension (UTH). After adjusting for covariates, such as sex, age, achieved blood pressure and other risk factors, the CVD risk of controlled hypertension was practically equal to that of nonhypertension, and remained unchanged even when blood pressure was excluded from the model (1.03, 0.58-1.82). The higher cardiovascular risk of uncontrolled hypertension and UTH was reduced after adjusting for covariates, but remained significantly higher than in nonhypertension, with no significant differences between uncontrolled hypertension and UTH.
Conclusions: A higher level of baseline risk is not due to treatment per se, the risk being similar in uncontrolled hypertension and UTH. Adjustment for risk factors reduces the risk only in controlled hypertension, suggesting that there may be structural alterations scarcely reversible by antihypertensive treatment.