viernes, diciembre 04, 2015
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“Sprint Trial: A Small Subset of Hypertension Patients Get a Change in Goal”
N Engl J Med. 2015 Nov 26;373(22):2103-16 (http://www.ncbi.nlm.nih.gov/pubmed/26551272)
Methods:
This is a randomized controlled trial of over 9,000 patients over the age of 50. For inclusion, they had to have a systolic blood pressure between 130 and 180 AND be of high cardiovascular risk (defined as having one or more of the following: known symptomatic or asymptomatic cardiovascular disease, chronic kidney disease (with GFR between 20 and 59 mL/min/1.73 m2), or a 10 year Framingham cardiovascular risk score of > 15% or age > 75 years.) Patients with diabetes* or who had a history of stroke were excluded. Patients were randomized to either intensive blood pressure lowering treatment or standard treatment. Intensive treatment goals were a systolic blood pressure ≤ 120 mmHg whereas standard/control goal was < 140. The choice of antihypertensive combinations were left to the discretion of the study physicians.
Outcomes:
On average, intensive treated patients required three drugs to obtain the goal whereas those in the standard arm were given two drugs. The trial was stopped after a mean follow-up of 3.3 years. At that time intensive treatment blood pressures were averaging 121.5 mmHg whereas standard treatments averaged 134.6 mmHg.
The study’s primary composite outcome of myocardial infarction, non-MI acute coronary syndrome, stroke, heart failure, or cardiovascular related death occurred in 5.2% of the intensive treatment patients and 6.8% in the standard treatment patients (p<0.001). For this composite outcome the number needed to treat was 62.5. On individual outcomes, significance was found only for reductions in heart failure (1.3% vs. 2.1%) and cardiovascular related death (0.8% vs. 1.4%). Additionally, all cause mortality was significantly lower in the intensive arm (3.3% vs. 4.5%). Adverse events were frequent and significantly greater in the intensive arm vs. the standard treatment arm. These included hypotension, syncope, electrolyte abnormalities, and acute kidney injury.
Conclusion:
For the small subset of patients who are over the age of 50 and have a systolic blood pressure between 130 and 180 who are at high cardiovascular risk, blood pressure reduction to a goal of 120 mmHg improves composite cardiovascular outcomes as well as heart failure and cardiovascular death risk.
Discussion:
This trial has received enormous media play and prompted significant discussion among health care providers. Before you alter your practice, a variety of issues must be noted.
1. Inclusion Criteria. Identifying patients who meet the criteria of this study will take some work. This will include those with known cardiovascular disease but not stroke, as well as those with a Framingham cardiovascular risk > 15%. Finding these patients will be challenging as they need to have multiple risk factors without the presence of diabetes, so before you consider being aggressive with a patient’s hypertension treatment, calculate that risk and make certain it meets criteria. It is estimated that about 15% of our patients with hypertension will meet this criteria, meaning that 85% of patients with hypertension do not.
2. Blood Pressure Measurement. Blood pressure readings were conducted in a unique manner that is probably not the standard in our office. Patients were asked to sit quietly for 5 minutes before blood pressure readings were measured by an automated unit. Three readings were obtained over several minutes with no clinician in the room. The systolic blood pressure was then determined based upon the average of these three readings. Thus, setting up a protocol and buying an automated cuff to track these readings is necessary.
3. GFR. The presence of renal insufficiency was part of the inclusion data. But, aggressive treatment actually made acute kidney injury more common. Before embarking on aggressive treatment in patients with renal insufficiently, a plan should be in place to track creatinine and GFR, remind patients about concomitant use of NSAIDs and other medications and alcohol (which can decrease GFR), and an admonition to the patient to follow-up as soon as possible should they develop signs of worsening kidney function.
4. Age. Age over 75 was part of the inclusion criteria. This population is at very high risk for orthostatic hypotension from aggressive antihypertensive treatment. Because the study was stopped after only 3 years, rates of falls and hip fractures were not found to be different between groups. But one wonders, if over time, this rate would begin to increase.
Finally, when looking from the clinical practice side of implementing this strategy, one needs to consider the overall benefit and harm. The number needed to treat prevent one of the combined cardiovascular outcomes was 61, but the number needed to cause one serious harm was 43. This implies using this intervention is actually more dangerous than beneficial
How should you change your practice? Probably very little. Identify those who are at highest risk for cardiovascular adverse events. If they do not have diabetes, and meet the remainder of the inclusion criteria, consider checking their blood pressure as was done in this study. Optimize their cardiovascular risk, implement aggressive lifestyle changes which should include aerobic exercise. For those who are hesitant to exercise, refer them to cardiac rehabilitation. And if their blood pressure still remains elevated, offer patients the opportunity to try to lower their blood pressure in a more aggressive manner, noting close follow-up for orthostatic hypotension and adverse effects on the kidney and electrolytes.
* Why was diabetes excluded? BP lowering has been studied in patients with diabetes in the past to determine if aggressive blood pressure lowering improved outcomes. The Accord Trial found no benefit to aggressive blood pressure lowering and diabetic systolic goal remains at 140 mmHg. ((N Engl J Med 2010;362:1575-85))
