Lower SBP Target Reduces CVD Events, Mortality in Elderly

The findings warrant reconsideration of blood pressure targets for many patients older than 75, according to an editorial.
The findings warrant reconsideration of blood pressure targets for many patients older than 75, according to an editorial.

Certain hypertension patients older than 75 experience fewer cardiovascular events and lower mortality rates when their systolic blood pressure (SBP) is treated to less than 120 mm Hg, according to a newly published subgroup analysis of the Systolic Blood Pressure Intervention Trial (SPRINT).

Jeff D. Williamson, MD, MHS, of Wake Forest School of Medicine in Winston-Salem, NC, and colleagues compared the effects of intensive treatment to standard treatment in community dwelling adults older than 75 with hypertension. All participants were at increased risk for cardiovascular disease (CVD) due to chronic kidney disease, subclinical CVD, or an elevated Framingham risk score. Importantly, the study excluded patients with diabetes, heart failure, or prior stroke. SPRINT investigators randomly assigned 1,317 patients to intensive treatment with a SBP target of less than 120 mm Hg and 1,310 patients to standard treatment with a SBP goal of less than 140 mm Hg.

After a median 3.14 years, fewer cardiovascular events (e.g., myocardial infarction, stroke, and heart failure) occurred in the intensive treatment group (102 vs 148). Mortality was also lower (73 vs 107 deaths), according to results published in JAMA. Average SBP was 123 mm Hg for the intensive treatment group, however, which was above the target of less than 120 mm Hg. Average diastolic blood pressure during follow-up was 62.0 mm Hg in the intensive treatment group and 67.2 mm Hg in the standard treatment group.

The researchers found no substantial rise in major clinical adverse events. Roughly half of patients in each group experienced a life-threatening event, such as disability or hospitalization. There were small increases in hypotension, syncope, and decreases in renal function, in the intensely treated group.

Acute kidney injury occurred more frequently in the intensive therapy group (5.5% vs 4%). The study authors attributed the difference to a reversible intrarenal hemodynamic effect of reducing blood pressure as well as more frequent use of diuretics, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers.

“Considering the high prevalence of hypertension among older persons, patients and their physicians may be inclined to underestimate the burden of hypertension or the benefits of lowering BP, resulting in undertreatment,” Dr Williamson and colleagues stated. “On average, the benefits that resulted from intensive therapy required treatment with 1 additional antihypertensive drug and additional early visits for dose titration and monitoring.”

In an editorial accompanying the study, Aram V. Chobanian, MD, of Boston University Medical Center added, “Although the story is incomplete, the available evidence supports a stepwise approach to treatment beginning with an initial SBP goal of less than 140 mm Hg. If lowering SBP to that level is tolerated well, further titration with careful monitoring should be considered to achieve an SBP goal of less than 130 mm Hg.”

Community dwelling adults were studied so results may not apply to frail individuals who are homebound or reside in nursing homes. The researchers did conduct exploratory analyses on frailty. Although most frail patients had higher rates of heart disease and death, tighter blood pressure control resulted in fewer deaths (3.9 vs 5.8% for CVD and 2.95 vs 4.28 for mortality). Collectively, SPRINT results reinforce results from the Hypertension in the Very Elderly Trial (HYVET) that showed reductions in risk for cardiovascular events and mortality result from treatment regardless of patients' frailty status, according to the investigators.

Whether the findings will change guidelines remains to be seen. The long-term effects of treatment on cognitive functions, such as thinking and memory, are being studied. 

Sources

  1. Williamson JD, Supiano MA, Applegate WB, et al. Intensive vs Standard Blood Pressure Control and Cardiovascular Disease Outcomes in Adults Aged ≥75 Years. JAMA. doi:10.1001/jama.2016.7050.
  2. Chobanian AV. SPRINT Results in Older Patients: How Low to Go? JAMA. doi:10.1001/jama.2016.7070.
  3. Even frail, older adults could benefit from intensive blood pressure reduction [news release]. University of Utah Health Sciences, May 19, 2016.
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