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Blood Pressure: How Low Do You Go?

Sunday, November 15, 2015 // Uncategorized

retro This article got a lot of press and a lot of patient’s questions when the study was ended prematurely several months ago.  I couldn’t answer patient’s questions on the news release because the study hadn’t been published.  Now it has been on November 9th and the results only apply to high risk patients who are being treated for  hypertension.

Bottom line:Treating to a lower blood pressure goal in high risk individuals may be of benefit, but it comes at a potential cost.

Here is the summary from Journal Watch.

SPRINT: Intensive Blood Pressure Control Tied to Lower Adverse CV Events

By Allan S. Brett, MD

Dr. Brett is editor-in-chief of NEJM Journal Watch General Medicine, from which this summary was adapted. See full coverage at the link below.

Treating to a systolic blood pressure target of 120 mm Hg lowered the incidence of adverse cardiovascular events in a high-risk population, according to the SPRINT study published in the New England Journal of Medicine and presented at the American Heart Association’s annual meeting.

Researchers enrolled roughly 9400 patients (age 50 or older) with a systolic BP of 130 to 180 mm Hg and high cardiovascular risk but without diabetes or stroke. Patients were randomized to either intensive or standard treatment (systolic BP targets, 120 or 140 mm Hg, respectively). The researchers were permitted discretion in choosing drug regimens.

The trial was terminated early after a median follow-up of 3.3 years, during which participants’ average systolic BPs were 121.5 mm Hg and 134.6 mm Hg in the intensive- and standard-treatment groups, respectively. The primary composite outcome (myocardial infarction, non-MI acute coronary syndrome, stroke, heart failure, or CV-related death) occurred in 5.2% of intensive-treatment patients and 6.8% of standard-treatment patients. Two individual components of the composite outcome were significantly lower with intensive treatment — heart failure (1.3% vs. 2.1%) and CV-related death (0.8% vs. 1.4%). All-cause mortality also was significantly lower with intensive treatment (3.3% vs. 4.5%).

Several serious adverse events were significantly more common with intensive than with standard treatment: incidences of hypotension, syncope, and electrolyte abnormalities were each about 1 percentage point higher, and incidence of acute kidney injury was about 2 percentage points higher. Among patients without CKD at baseline, the incidence of a >30% decline in glomerular filtration rate was significantly greater with intensive treatment (3.8% vs. 1.1%).

SPRINT has demonstrated that aiming for a systolic BP of 120 mm Hg can lower the rate of adverse cardiovascular events; to prevent 1 event, 61 patients had to be treated for 3.3 years. Keep in mind that SPRINT was limited to middle-aged and older patients at above-average CV risk and that diabetic patients were excluded. Whether the decline in GFR associated with intensive treatment represents a harmless hemodynamic effect or more-serious renal injury is unclear.

Clinicians must understand that BP measurements in this study were based on the average of the three readings, taken automatically at 5-minute intervals with no clinician in the room. This method yields substantially lower readings than does a single measurement by a clinician. If SPRINT is applied without attention to proper BP measurement, substantial overtreatment — with a higher rate of adverse events — likely will occur.

Finally, note that the average achieved systolic BP in the intensive-treatment group (121.5 mm Hg) remained higher than the 120 mm target. This likely represents judicious balancing by treating clinicians who tried to approximate the 120 mm goal while avoiding side effects and excessive polypharmacy.

 

retro SPRINT: Intensive Blood Pressure Control Tied to Lower Adverse CV Events

By Allan S. Brett, MD

Dr. Brett is editor-in-chief of NEJM Journal Watch General Medicine, from which this summary was adapted. See full coverage at the link below.

Treating to a systolic blood pressure target of 120 mm Hg lowered the incidence of adverse cardiovascular events in a high-risk population, according to the SPRINT study published in the New England Journal of Medicine and presented at the American Heart Association’s annual meeting.

Researchers enrolled roughly 9400 patients (age 50 or older) with a systolic BP of 130 to 180 mm Hg and high cardiovascular risk but without diabetes or stroke. Patients were randomized to either intensive or standard treatment (systolic BP targets, 120 or 140 mm Hg, respectively). The researchers were permitted discretion in choosing drug regimens.

The trial was terminated early after a median follow-up of 3.3 years, during which participants’ average systolic BPs were 121.5 mm Hg and 134.6 mm Hg in the intensive- and standard-treatment groups, respectively. The primary composite outcome (myocardial infarction, non-MI acute coronary syndrome, stroke, heart failure, or CV-related death) occurred in 5.2% of intensive-treatment patients and 6.8% of standard-treatment patients. Two individual components of the composite outcome were significantly lower with intensive treatment — heart failure (1.3% vs. 2.1%) and CV-related death (0.8% vs. 1.4%). All-cause mortality also was significantly lower with intensive treatment (3.3% vs. 4.5%).

Several serious adverse events were significantly more common with intensive than with standard treatment: incidences of hypotension, syncope, and electrolyte abnormalities were each about 1 percentage point higher, and incidence of acute kidney injury was about 2 percentage points higher. Among patients without CKD at baseline, the incidence of a >30% decline in glomerular filtration rate was significantly greater with intensive treatment (3.8% vs. 1.1%).

SPRINT has demonstrated that aiming for a systolic BP of 120 mm Hg can lower the rate of adverse cardiovascular events; to prevent 1 event, 61 patients had to be treated for 3.3 years. Keep in mind that SPRINT was limited to middle-aged and older patients at above-average CV risk and that diabetic patients were excluded. Whether the decline in GFR associated with intensive treatment represents a harmless hemodynamic effect or more-serious renal injury is unclear.

Clinicians must understand that BP measurements in this study were based on the average of the three readings, taken automatically at 5-minute intervals with no clinician in the room. This method yields substantially lower readings than does a single measurement by a clinician. If SPRINT is applied without attention to proper BP measurement, substantial overtreatment — with a higher rate of adverse events — likely will occur.

Finally, note that the average achieved systolic BP in the intensive-treatment group (121.5 mm Hg) remained higher than the 120 mm target. This likely represents judicious balancing by treating clinicians who tried to approximate the 120 mm goal while avoiding side effects and excessive polypharmacy.

Why We Chose This as Our Top Story:

André Sofair, MD, MPH: This well-designed study reiterates the importance of individualized blood pressure control. It demonstrates that in certain high-risk patients, more aggressive BP targets may be warranted.

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