The SPRINT to Nowhere: Why Dogma is Winning the Race Against Evidence (2)

I understand that my last article—heavy on scientific studies and statistics—may not have been everyone’s cup of tea. Let me try to help by summarising the picture I was trying to paint.

There was once a foundational idea in the medical community that treating blood pressure could prevent stroke. This is clearly true for sick patients with extreme hypertension (NNT of 3), but the jury is still out for the rest of the general public. While studies have been conducted, the results remain inconclusive. Notwithstanding this lack of data, industry-influenced guidelines and policymakers helped shape medical opinion into believing the benefit is beyond question. Talk to any doctor today and you will leave with a dire stroke prognosis if you question their hypertension treatment. I wonder: which crystal ball are they peeking into?

Imagine a dogma so strong that the failure of the 2008 ACCORD study went largely unnoticed. Instead, some argued—as I mentioned previously—that ACCORD was actually further proof of why treating hypertension works to prevent stroke. The medical community was waiting for the next study, but they weren’t ready to shift their paradigm if it negated their beliefs. However, if a study suggested they were right even in the slightest way, they were ready to treat it as the "Holy Grail."

In this context, SPRINT 2015 landed. The study included over 9,300 subjects without diabetes or prior stroke, in contrast with ACCORD or Freis’ original 1964 study. It didn’t aim to answer whether treatment was better than no treatment; the baseline assumption was that treatment is always superior. In SPRINT, the focus was on how much to treat. Two groups were assigned a systolic treatment target of either <120 or <140 mmHg. The study was stopped prematurely after three years because investigators claimed it was "unethical" to continue studying an "obviously" life-saving treatment. SPRINT was hailed as a massive success in preventing major cardiovascular events in the intensive arm. Their Number Needed to Treat (NNT)? 61.

With a massive push from Big Pharma, doctors rushed to claim this as definitive proof that intensive treatment should be the new normal. Not a month went by where my inbox wasn't hit by a Pharma-sponsored event featuring specialists explaining how GPs must now hit patients with three or more antihypertensive agents to save them from heart attacks, quoting SPRINT as their evidence. I was definitely affected by this pitch—until reality intervened.

In 2016, while practicing in the UK, I prescribed three antihypertensive agents to a patient to reach the desired SPRINT level. He collapsed and was hospitalised. I immediately knew it was my fault. I called him, the hospital, other doctors, and even my medical indemnity insurer to apologise. And guess what? No one thought my treatment was wrong. The consensus was: "These things happen. You’ve got to do what you’ve got to do. Don’t worry, you’re a good doctor." That is when I realised I needed to take matters into my own hands. No more putting blind faith in pharma-interpreted studies.

Setting the pharma interpretation aside, let’s look at the secrets hidden within SPRINT. For a start, a three-year NNT of 61 for a major cardiovascular event isn’t actually that impressive if we are honest. What about death? The number needed to treat to prevent a single death is 90. While someone might avoid a heart attack in those three years, the all-cause mortality rate barely shifted. And the NNT for stroke in those three years? A staggering 500. We are none the wiser when it comes to stroke outcomes.

I wondered: if we need to treat 61 people for three years to prevent one major heart issue, how many of those people will suffer a major side effect like my patient did? I wasn’t surprised to find that the NNH (Number Needed to Harm) is 45. This means that before we save one person from a cardiovascular event, we are guaranteed to have at least one person suffer a major adverse event from the treatment itself. And I mean major: death, life-threatening complications, hospitalisation, or disability. Do you think Big Pharma volunteered that information to doctors? No way.

Beyond the data, I and many other journal-reading doctors have issues with how the SPRINT trial was conducted, though that is outside the scope of this article. Suffice it to say, SPRINT is not proof of anything other than the fact that we still lack evidence that treating non-severe, uncomplicated hypertension is generally beneficial to the public. Through the lens of personalised medicine, I do believe some individuals will benefit; therefore, please consult your doctor regarding your individual health decisions.

However, SPRINT is proof of something massive. It is proof that most doctors (including the younger me) only process information via the pharmaceutical industry’s PR and marketing teams. It is proof that dogma prevails over medicine. It is proof that human psychology is not neutral, but leans toward bias. It is proof that wealth can control the masses and public opinion.

SPRINT is not just a defeat for evidence-based medicine in the fight against hypertension; it is the deathbed of our intellect, purchased by an industry seeking to silence voices like Dr Julian Hart’s. Since SPRINT 2015, there have been other attempts to seal this fate further—such as the Chinese STEP trial and the UK/Australian BPLTTC in 2021—but their NNTs are no better than those of SPRINT.

The industry knows it reached the summit first. Its flag is planted deep, and it has no intention of letting critically minded doctors reach the same peak.

In memory of Julian Tudor Hart, RIP 2018.