Tag: open data

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Adding a little Usain Bolt to SPRINT

The SPRINT trial was a home run. The study showed compelling data that lowering blood pressure dramatically below what we were previously targeting was both well tolerated and yielded huge benefits to patients.

Now there are some questions to the method of blood pressure assessment and how this can be compared to previous blood pressure trials, but I believe that the BP assessment used in SPRINT is more reproducible in offices than the standardized BP typically used in trials that no one howls about (you mean your MA does not follow a 12 step checklist when checking patients in?).

One of the important corollaries that I emphasize when I teach SPRINT is that the study enrolled a very specific patient and we don’t know just how generalizable these findings are:

  • 50 years of age
  • Systolic blood pressure of 130 to 180 mm Hg
  • Increased risk of cardiovascular events defined by one or more of the following: 
    • Clinical or subclinical cardiovascular disease other than stroke
    • Chronic kidney disease, excluding polycystic kidney disease, with eGFR of 20 to 60
    • 10-year risk of cardiovascular disease of 15% or greater on the basis of the Framing- ham risk score
    • Age of 75 years or older
  • Patients with diabetes mellitus or prior stroke were excluded
After you accept the all of these concerns and limitations you are left with a study that reduced the risk of death by 27%. NNT for the primary outcome was 62. This is pretty darn good in medicine.
But when counseling a single patient, it is not very compelling. You have to expose 62 people to multiple drugs and the risks of over treatment in order to save one life. Those other 61 people, are all exposed with no benefit. This is just the nature of internal medicine. All we can do is give out a handful of pills in order to load the dice in patient’s favor. No guarantees. Just better odds.
But what if I told you I had a way 
to reduce that NNT from 62 to 26?

Is that something you might be interested in?
Francis Wilson, is pushing the data. He has dissected the SPRINT database further and can select patients that benefit from the aggressive blood pressure reduction while excluding those that won’t. He calls it an Uplift Model to Personalize Intensive Blood Pressure Control. This system allows him to reduce the NNT from 62 to 26. 
This is Wilson’s entry in the NEJM SPRINT Data Analysis. The voting is open until February 28th, go check out the site and vote for the best one, or just vote for the nephrologist.