A recent landmark clinical trial study called Systolic Blood Pressure Intervention Trial (SPRINT), involving researchers at UT Southwestern Medical Center and sponsored by the National Institutes of Health (NIH), suggest that intensive management of hypertension results in a significant reduction of cardiovascular disease and thus, a lower risk of death in patients over 50 years suffering from hypertension.
Hypertension, also called high blood pressure, is a medical condition characterized by persistent elevated blood pressure in the arteries. Blood pressure is quantified by measurement of maximum (systolic) and minimum (diastolic) pressures indicative of the contraction/relaxation mechanism of the cardiac system. Normal blood pressure is measured in the range of 100–140 millimeters mercury (mm Hg) systolic and 60–90 mm Hg diastolic. Patients with hypertension have a blood pressure above 140/90 mm Hg.
It is believed that hypertension is caused by genetic and environmental risk factors like diet (salt, caffeine/nicotine consumption), lack of exercise, obesity, stress, and depression. Symptoms of hypertension may go unnoticed, but some patients may experience headaches and visual problems. Hypertension can be dangerous as it increases the risk of many other conditions related to cardiovascular diseases such as stroke and heart failure. It can also increase the risk of developing cognitive impairment, dementia, chronic kidney disease, and pulmonary embolism.
It has been suggested that reduction of blood pressure can reduce the risk of stroke, ischemic heart disease, heart failure, dementia, as well as mortality from cardiovascular disease. The latter is partially confirmed by the SPRINT study, which shows that more intensive management of hypertension below the usual suggested blood pressure could noticeably reduce cardiovascular diseases, hence decreasing the risk of death in adults above 50 years with hypertension.
In the SPRINT study, a total of 9,300 patients over 50 years have participated through 100 medical centers and clinical practices in the United States and Puerto Rico. The study population included women, racial/ethnic minorities, and elderly but excluded patients with diabetes, prior stroke, or polycystic kidney disease. Started in 2009, SPRINT is considered the largest study of its kind to date to examine the effect of lowering systolic blood pressure below the recommended 140 mm Hg on cardiovascular and kidney diseases.
Depending on patient’s age and disease, SPRINT evolved by adjusting gradually the decrease in blood pressure from 140, 130 to below 120 mm Hg, and because the results were so significant, NIH stopped the intervention earlier in order to quickly disclose the important findings. The results suggest that adjustment of blood pressure using appropriate medication to reach a target systolic pressure of 120 mm Hg reduced the rates of cardiovascular incidents like heart attack/failure and stroke by about a third, and the risk of death by about a quarter if compared to the recommended target systolic pressure of 140 mm Hg. This is the first study demonstrating that lowering systolic blood pressure to 120 mm Hg compared to 140 mm Hg in patients over 50 years old with hypertension reduces the rate of incidents by about 30 percent.
“This is a stunning finding that led the data and safety monitoring board to recommend termination of the usual blood pressure control arm of 140 mm Hg. Because high blood pressure afflicts more than 50 million Americans, the results of this landmark study will have a profound effect on healthcare for years to come,” said in a news release Dr. Robert Toto, the principal investigator for the trial at UT Southwestern Medical Center.
In conclusion, the findings provide important evidence that treating hypertension to a lower goal in patients over 50 years or high-risk patients could be beneficial and yield better health outcomes. From a practical standpoint, the data constitute potentially lifesaving information useful to health care providers to consider the best treatment options for patients with hypertension of different ages and severity. As future plans, SPRINT study is examining kidney disease, cognitive function, and dementia and the results, currently under analysis, will be communicated next year.
“We are delighted to have achieved this important milestone in the study in advance of the expected closure date for the SPRINT trial and look forward to quickly communicating the results to help inform patient care and the future development of evidence-based clinical guidelines,” concluded Dr. Gary H. Gibbons, Director of the National Heart, Lung, and Blood Institute (NHLBI).