Intensive Blood Pressure Therapy May Reduce Adverse Cardiovascular Outcomes and Mortality in Patients ≥ 75 years old with Hypertension

EBM Focus - Volume 11, Issue 22

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Reference - JAMA 2016 May 19 early online (level 2 [mid-level] evidence)

  • Hypertension is common in elderly patients, but recommended blood pressure targets in this population are usually higher than those recommended for patients < 60 years old.
  • A prespecified subgroup analysis of the SPRINT trial including 2,636 patients ≥ 75 years old found intensive blood pressure control with systolic blood pressure (SBP) targets < 120 mm Hg reduced cardiovascular adverse events and all-cause mortality compared to an SBP target < 140 mm Hg.
  • Intensive therapy did increase adverse renal outcomes, but the overall rate of these outcomes was low, suggesting the benefit of treatment may outweigh this risk.

Approximately 75% of Americans ≥ 75 years old have hypertension (Circulation 2015 Jan 27;131(4):e29), but guidelines for optimal blood pressure control in this population vary. Some guidelines recommend antihypertensive treatment for elderly patients with SBP ≥ 160 mm Hg, while others suggest the threshold for initiation of treatment be a SBP of 150 mm Hg or even 140 mm Hg (Eur Heart J 2013 Jul;34(28):2159, JAMA 2014 Feb 5;311(5):507, Can J Cardiol 2015 May;31(5):549, NICE 2011 Aug:CG127). SBP targets during antihypertensive therapy also vary, but most recommend treatment targets of 140 mm Hg to 150 mm Hg. The SPRINT trial recently found SBP targets < 120 mm Hg decreased cardiovascular adverse events and all-cause mortality in patients ≥ 50 with hypertension, increased cardiovascular risk, and without diabetes (N Engl J Med 2015 Nov 26;373(22):2103, EBM focus Volume 10, Issue 45) and while consistent results were reported for the subgroup of patients ≥ 75 years old, the details of those results were not reported. These details have now been reported in a prespecified subgroup analysis of the 2,636 community-dwelling patients ≥ 75 years old in the SPRINT trial randomized to antihypertensive treatment with an SBP target < 120 mm Hg (intensive therapy) vs. an SBP target < 140 mm Hg (standard therapy). Baseline characteristics were generally consistent between the two groups, except the intensive SBP target group had a higher proportion of patients using aspirin therapy (62.3% vs. 58%) and with frail status (33.4% vs. 28.4%). During the trial, the mean SBP was 123.4 mm Hg with intensive therapy vs. 134.8 mm Hg with standard therapy and the mean number of antihypertensive medications was 2.6 and 1.8, respectively. The primary composite outcome included myocardial infarction, acute coronary syndrome not resulting in a myocardial infarction, stroke, acute decompensated heart failure, and cardiovascular death. Over a median follow-up of 3.14 years, the primary outcome occurred in 7.7% with intensive therapy vs. 11.2% with standard therapy (p = 0.001, NNT 29). Intensive therapy also significantly reduced all-cause mortality (5.5% vs. 8.1%, p = 0.009, NNT 39) and heart failure (2.7% vs. 4.2%, p = 0.03, NNT 67). While the incidence of serious adverse events was similar overall, intensive therapy was associated with a nonsignificant increase in acute kidney injury, hypotension, and electrolyte abnormalities. In patients without chronic kidney disease at baseline, secondary chronic kidney disease developed in 5.1% with intensive therapy vs. 1.8% with standard therapy (p < 0.001, NNH 30), but there were no significant differences in primary chronic kidney disease in patients with chronic kidney disease at baseline. The results of this subgroup analysis suggest that patients ≥ 75 years of age without diabetes would benefit from intensive blood pressure therapy. One limitation of this study is the short duration of follow- up. This trial was stopped after only 3.26 years, therefore it is unknown if this benefit will persist. Although intensive treatment did result in an increased rate of renal adverse effects, the overall rate of these events was low, indicating the benefits of treatment may outweigh this risk. Overall, the results of this subgroup suggest current guidelines for hypertension in the elderly may need to be reconsidered.

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