Commentary

Is this hypertension treatment strategy based on SOR “A” evidence?


 

In the article, “Hypertension treatment strategies for older adults” (J Fam Pract. 2017;66:546-554), Hansell et al gave an “A” Strength of Recommendation (SOR) rating to the Practice Recommendation that read: “Target a systolic blood pressure (SBP) <120 mm Hg in community-dwelling, nondiabetic patients ≥75 years of age if it is achievable without undue burden.”

As justification for this SBP target, the authors cited a subgroup analysis from the Systolic Blood Pressure Intervention Trial (SPRINT),1 which consisted of patients ≥75 years of age.2 I posit that the inconsistencies of the data cited by Hansell et al contradict an “A” rating, and that the methodology used in SPRINT greatly mitigates the generalizability of the results.

Primary care physicians would do well to impact morbidity and mortality in older adults by working to achieve standard targets, such as an SBP of <140 mm Hg or <150 mm Hg.

First, Hansell et al admit that no consensus exists on an optimal BP target for older patients. SOR taxonomy requires that the evidence behind an SOR of “A” be based on consistent and good-quality patient-oriented evidence.3 One source cited by the authors states that evidence supporting lower targets is inconsistent,4 while a recent Cochrane review does not support low BP targets.5 Given that the evidence is inconsistent, the SOR should be a “B”, at best.

Second, the evidence to target a systolic BP <120 mm Hg primarily comes from SPRINT.1,2,4 In a Letter to the Editor that appeared in The New England Journal of Medicine, Dr. Marc A. Pfeffer addressed a key methodology issue of that trial: SPRINT protocol called for the withdrawal of antihypertensive therapy in the standard treatment group if a single systolic BP reading was <130 mm Hg, or if readings at 2 or more consecutive visits were <135 mm Hg, regardless of patient symptoms.6

The letter also questioned how frequently this withdrawal occurred, to which the SPRINT authors replied that 87% of participants required at least one reduction in the dose of medication to maintain the treatment target in the standard group, and complete withdrawal of medication was required in <7.5% of participants.7 While this dose adjustment may have been necessary to adequately test the SPRINT hypothesis that lower systolic BP targets are better, routine dose reduction in an asymptomatic patient is not standard practice.

Given the small benefit in absolute risk reduction in SPRINT’s aggressive hypertensive treatment arm of 0.54% per year for the primary composite outcome and 0.37% per year for all-cause mortality,2 the frequent medication dose reductions in the standard treatment arm likely contributed significantly to the statistical benefit seen in the aggressive treatment group in SPRINT.

If an SOR of “A” for BP targets is to be made, the print publication of Hansell et al’s article should communicate the degree of benefit, preferably in terms of absolute risk reduction. Only the online publication of TABLE W1 stated the degree of benefit in the SPRINT subgroup study, but it was stated in terms of relative risk.

Given the current suboptimal rates of hypertension control, primary care physicians would do well to impact morbidity and mortality in older adults by working to achieve standard targets, such as an SBP of <140 mm Hg or <150 mm Hg. Once standard targets are achieved, a conversation could then ensue about the potential benefits and harms of lower BP targets.

Chris Fallert, MD
St. Paul, Minn

1. Williamson JD, Supiano MA, Applegate WB, et al. Intensive vs standard blood pressure control and cardiovascular disease outcomes in adults aged ≥75 years: a randomized clinical trial. JAMA. 2016;315:2673-2682.

2. SPRINT Research Group, Wright JT Jr, Williamson JD, et al. A randomized trial of intensive versus standard blood-pressure control. N Engl J Med. 2015;373:2103-2106.

3. Ebell MH, Siwek J, Weiss BD, et al. Strength of recommendation taxonomy (SORT): a patient-centered approach to grading evidence in the medical literature. Am Fam Physician. 2004;69:548-556.

4. Weiss J, Freeman M, Low A, et al. Benefits and harms of intensive blood pressure treatment in adults aged 60 years or older: a systematic review and meta-analysis. Ann Intern Med. 2017;166:419-429.

5. Garrison SR, Kolber MR, Korownyk CS, et al. Blood pressure targets for hypertension in older adults. Cochrane Database Syst Rev. 2017;8:CD011575.

6. Pfeffer MA. A randomized trial of intensive versus standard blood-pressure control. N Engl J Med. 2016;374:2290.

7. Wright JT Jr, Whelton PK, Reboussin DM. A randomized trial of intensive versus standard blood-pressure control. N Engl J Med. 2016;374:2294.

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