For patients with at least one additional cardiovascular risk factor, tight blood pressure control seems to decrease the risk of developing left ventricular hypertrophy and other clinical cardiovascular events, a 2-year open-label trial has concluded.
Although the findings need to be evaluated in a randomized controlled trial, they do lend credence to the idea that tight control of hypertension could benefit nondiabetic patients, just as it has been shown to benefit those with diabetes, Dr. Paolo Verdecchia and his colleagues wrote (Lancet 2009;374:525-33).
“Present evidence lends support to reduced thresholds of diastolic blood pressure in patients with type 2 diabetes,” wrote Dr. Verdecchia of the Hospital Santa Maria Misericordia, Perugia, Italy. However, recent European hypertension control guidelines emphasized the need for “urgent research” into just how low the target systolic blood pressure should be in the general population of hypertensive patients.
The Italian Study on the Cardiovascular Effects of Systolic Blood Pressure Control (Cardio-Sis) enrolled 1,111 nondiabetic patients aged 55 years and older who continued to have elevated systolic blood pressure (at least 150 mm Hg) despite 12 weeks of antihypertensive therapy. All patients had at least one additional cardiovascular risk factor.
Patients were randomized to either tight control (less than 130 mm Hg systolic pressure) or usual control (less than 140 mm Hg). Physicians were allowed to prescribe any antihypertensive therapy they deemed appropriate. In the tight-control group, one systolic reading of more than 130 mm Hg triggered more intensive treatment; in the usual control group, one reading of below 130 mm Hg triggered a down-titration of treatment.
The primary outcome was the prevalence of electrocardiographic left ventricular hypertrophy at 2 years. The secondary composite end point included all-cause mortality, heart attack, stroke, congestive heart failure, angina, and other cardiovascular events.
In both groups, the patients' mean age was 67 years. Their mean baseline systolic blood pressure was 163/90 mm Hg. About 20% were smokers and 76% had dyslipidemia.
At the study's end, systolic blood pressure had decreased by 28 mm Hg in the usual-control group and by 31 mm Hg in the tight-control group. The final end-of-study mean pressures were 136/79 in the usual-control group and 132/77 in the tight-control group.
The primary end point of left ventricular hypotrophy occurred in 17% of the usual-control group and 11% of the tight-control group—a significant difference. A more detailed analysis revealed that tight control significantly decreased the likelihood of hypertrophy at both 1 and 2 years (62% and 69%, respectively). However, usual control did not significantly reduce the risk at either time point (18% and 32%).
The composite secondary end point occurred in significantly more of the usual-control group than the tight-control group (9% vs. 5%). The difference was driven by more new-onset atrial fibrillation and coronary revascularization in the usual-control group. There were no significant differences in heart attack, heart failure, stroke, transient ischemic attack, or death.
Adverse reactions to drug therapy were rare, mild, and similar between groups. Patients in both groups generally needed more drugs to control their blood pressure as the study advanced. At baseline, all patients were taking a mean of two drug classes, but were up to three classes by years 1 and 2. Patients in the tight-control group were significantly more likely to get diuretics and angiotensin-receptor blockers than were those in the usual-care group, but the use of beta-blockers, calcium-channel blockers, and angiotensin-converting enzyme inhibitors was similar between the groups.
The study was funded by Boehringer-Ingelheim Pharmaceuticals Inc., Sanofi-Aventis, and Pfizer Inc. Several of the researchers disclosed having received lecture and consulting fees from those and other pharmaceutical companies.