Intensive BP lowering benefit varies by baseline CVD risk
Intensive BP treatment yielded more harm than benefit in patients who had lower baseline CVD risk, whereas more benefit from intensive BP treatment was seen in those with higher baseline risk, according to new data from the SPRINT trial.
“Upward of 10 million Americans have a 10-year risk between 10% to 18.2%, and therefore would not qualify for the [less than] 130 mm Hg goal” suggested in the new American College of Cardiology/American Heart Association hypertension guideline, Robert A. Phillips, MD, PhD, FACC, professor of cardiology at the Institute of Academic Medicine at Houston Methodist Hospital, told Cardiology Today. “On the other hand, these results confirm that intensive blood pressure control is beneficial for those at high risk for a CV event, including the elderly and virtually all those age 75 and older.”
Researchers used data from the SPRINT trial to calculate 10-year risk with risk prediction equations from the 2013 American College of Cardiology/American Heart Association Guideline on the Assessment of Cardiovascular Risk. Patients were then stratified based on their 10-year CVD risk. Other parameters were calculated, including absolute risk reduction, RR reduction, absolute serious adverse event risk increase, number needed to treat and number needed to harm.
Serious adverse events were defined as life-threatening or fatal events that led to or prolonged hospitalization, resulted in disability or represented significant harm or hazard to the patient. Some of these conditions included syncope, hypotension, electrolyte abnormalities, bradycardia, injurious falls, acute kidney injury or acute renal failure.
Researchers also developed a predictive model to calculate the benefit-to-harm ratio as a function of the 10-year CVD risk quartiles.
Patients in all quartiles of the intensive treatment group had a lower rate for all-cause mortality and primary outcome events compared with those who received standard care, according to the researchers.
Number needed to treat, harm
The number needed to treat patients to prevent primary outcomes decreased from 91 to 38 from the first (lowest baseline risk) to fourth (highest baseline risk) quartiles. The number needed to harm for all-cause serious adverse events increased from 62 in the first quartile to 250 in the fourth quartile.
In the predictive model, benefit-to-harm ratios for patients in the intensive treatment group progressively increased according to CVD risk (first quartile, 0.5; second quartile, 0.78; third quartile, 2.13; fourth quartile, 4.8; P for trend < .001). A significant difference was seen in all possible pairwise comparisons of the between-quartile mean values of benefit-to-harm ratios (P < .001).
“Our findings support the emerging paradigm of taking risk for CVD into account when determining the intensity of blood pressure treatment,” Phillips said in an interview.
In a related editorial, William B. White, MD, professor of medicine and chief of the hypertension and clinical pharmacology division at University of Connecticut School of Medicine in Farmington, wrote: “If one believes that fairly large increases in serious adverse events such as acute kidney injury, hypotension, syncope and falls are as clinically important as relatively smaller reductions in heart failure or CV mortality, then one might not treat patients with higher-risk hypertension in quartiles 1 and 2 to intensively reduced levels of systolic BP.”
He concluded that the findings “are important and should be helpful for physicians who manage high-risk patients with hypertension, particularly older individuals.” – by Darlene Dobkowski
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Robert A. Phillips, MD, PhD, FACC, can be reached at email@example.com.
Disclosures: The authors and White report no relevant financial disclosures.