Potential Outcomes of SPRINT Intensive Blood Pressure Regimen
What are the potential benefits and risks of the SPRINT (Systolic Blood Pressure Intervention Trial) intensive systolic blood pressure (SBP) goal of <120 mm Hg versus <140 mm Hg if implemented in all eligible US adults at high cardiovascular disease (CVD) risk?
SPRINT eligibility criteria were applied to the 1999-2006 National Health and Nutrition Examination Survey (NHANES) data and linked with the National Death Index through December 2011. SPRINT eligibility included age ≥50 years, SBP of 130-180 mm Hg, and high CVD risk. Exclusion criteria were diabetes, stroke, heart failure, and severe chronic kidney disease. Hazard ratios for all-cause mortality and heart failure and absolute risks for serious adverse events (SAEs) in SPRINT were used to estimate the number of potential deaths and heart failure cases prevented and SAEs incurred with intensive SBP treatment.
SPRINT achieved a mean SBP of 121 mm Hg in the intensive treatment arm and 136 mm Hg in the standard treatment arm, resulting in a 27% reduction in all-cause mortality. The mean age was 68.6 years. The annual mortality rate was 2.20% (95% confidence interval, 1.91%-2.48%) and intensive SBP treatment was projected to prevent about 107,500 deaths per year and give rise to 56,100 episodes of hypotension, 34,400 episodes of syncope, 43,400 serious electrolyte disorders, and 88,700 cases of acute kidney injury per year. The analysis of extremes approach indicated that the range of estimated lower and upper bound number of deaths prevented per year with intensive SBP control was 34,600 to 179,600. Intensive SBP control was projected to prevent 46,100 cases of heart failure annually.
If fully implemented in eligible US adults, intensive SBP treatment in patients at high risk for CVD could prevent about 107,500 deaths per year compared to standard BP treatment. A consequence of this treatment strategy, however, could be an increase in SAEs.
While a well-designed BP trial, several issues have precluded acceptance. Among the most important is that the automated BP measurement in SPRINT results in about a 10 mm Hg lower SBP than clinical practice. Should practitioners target to a SBP of 120 mm Hg using standard office techniques, the incidence of falls, syncope, acute renal failure, and serious electrolyte disorders would be much higher. Further, the frequency of visits to adjust medication and obtain laboratory testing and increased hospitalization for very SAEs would be unacceptable to patients and physicians alike.
Keywords: Acute Kidney Injury, Blood Pressure, Blood Pressure Determination, Cardiovascular Diseases, Electrolytes, Heart Failure, Hypertension, Hypotension, Metabolic Syndrome X, Primary Prevention, Risk Assessment, Syncope, Treatment Outcome
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