Are Blood Pressure Guidelines Low Enough

(October 30, 2009) - A new study is being launched to determine if the current guidelines for blood pressure are low enough. The study will try to determine whether lower blood pressure cuts the risk of heart and kidney diseases, stroke and cognitive decline. (Read about "Hypertension: High Blood Pressure" "Coronary Heart Disease" "Kidney Disease" "Stroke" "Dementia")

Called the Systolic Blood Pressure Intervention Trial (SPRINT), the nine-year, $114 million study will be conducted in more than 80 clinical sites across the United States.

Current clinical guidelines recommend systolic pressure (the top number in a blood pressure reading) of less than 140 millimeters of mercury (mm Hg) for healthy adults, and 130 mm Hg for adults with kidney disease or diabetes. (Read about "Diabetes") SPRINT will evaluate the potential benefits of maintaining systolic blood pressure at less than 120 mm Hg for adults who are at risk for heart disease or kidney disease. The study will also assess possible risks of this therapeutic strategy.

Study participants will be treated with commonly available blood pressure medications to achieve one of two different levels of blood pressure control - either less than 140 mm Hg (standard group) or less than 120 mm Hg (treatment group). Those in the treatment group will take an average of three to four medications; those in the standard group will take about two medications. SPRINT participants will be seen in clinics every few months at the beginning of the study and less frequently as their blood pressure is controlled. The study will include standard tests for determining the health of the heart, kidneys and brain. (Read about "The Brain")

The clinical trial is based in large part on observational studies that suggest that maintaining a lower blood pressure level than is currently recommended reduces the risk of cardiovascular diseases.

"To determine if a lower blood pressure goal reduces the risk of complications and death more than standard treatment to the current recommended goal level, we need evidence-based research. Only a large, long-term clinical trial comparing the two levels will give us the answer," said Elizabeth G. Nabel, M.D., director of the National Heart, Lung, and Blood Institute (NHLBI). "If this study shows that maintaining a lower systolic blood pressure has significant benefits for middle-aged and older adults - and doctors and patients meet the lower goal levels - we could see hundreds of thousands fewer heart attacks (Read about "Heart Attack") and stroke each year in the United States alone."

"On the other hand, if the results suggest no benefit from the lower goal level, then we will know that patients need not pursue more aggressive treatment than is currently recommended, which could save money and lower their risk of possible side effects from more intense treatment," added Nabel.