Prognostic impact of hypertension grading.

BACKGROUND: Most Hypertension Guidelines grade hypertension according to various cut-off values. We sought to investigate the prognostic impact of Grades 1 (140-159 and/or 90-99 mmHg), 2 (160-179 and/or 100-109 mmHg) and 3 (≥180 and/or ≥110 mmHg).

METHODS: We followed for an average of 10 years a cohort of 3,150 initially untreated hypertensive patients (mean age 50 years, 44 % women) with no previous cardiovascular disease at entry. All patients underwent diagnostic tests including 24-hour ambulatory blood pressure (BP) monitoring.

RESULTS: At entry, average clinic BP was 156/97 mmHg and average 24-hour BP was 137/87 mmHg. During follow-up, 314 patients experienced a first major cardiovascular event (composite of non-fatal myocardial infarction or stroke, cardiovascular death, or hospitalization for heart failure). Event rate was not formally dissimilar between Grade 1 and Grade 2 (0.73 vs 0.95 per 100 patient-years, respectively; p = 0.06). It was higher in Grade 3 (1.93 per 100 patient-years; p < 0.01 vs Grade 1 and Grade 2). After adjustment for a robust set of covariables, the hazard ratio was not dissimilar between Grade 1 and Grade 2 (p = 0.27), and higher in Grade 3 than in Grade 1 (p < 0.01), but the excess risk in Grade 3 was no longer significant (hazard ratio: 1.25, 95 % CI 0.87-1.78; p = 0.22) after adjustment for 24-hour ambulatory systolic BP.

CONCLUSIONS: We were unable to find a significant difference in the relative hazard of cardiovascular events tied to hypertension Grades 1 and 2. Conversely, Grade 3 (clinic BP ≥180/110 mmHg) portends a higher cardiovascular risk, which is associated with higher levels of 24-hour ambulatory BP.