In addition to the resource in today’s post, I reviewed and link to Number Needed to Treat: What It Is and What It Isn’ t, and Why Every Clinician Should Know How to Calculate It. Leslie Citrome, MD, MPH. J Clin Psychiatry 2011;72(3):412-413. This article is a great brief review.
Today, I link to and explore The NNT [Number Needed To Treat] Site: “Quick summaries of evidence-based medicine”.
All that follows is from the above resource.
- Home
- Reviews
- Therapy (NNT) Reviews
- “You’ll find all of our therapeutic/number needed to treat reviews, arranged by medical specialty, organ system, alphabetically, and by color rating.”
- Diagnosis (LR) Reviews
- “You’ll find all of our diagnostic/likelihood ratio reviews, arranged by medical specialty, organ system, and alphabetically.”
- About
- theNNT, Explained
- “There is a way of understanding how much modern medicine has to offer individual patients. It is a simple statistical concept called the “Number-Needed-to-Treat”, or for short the ‘NNT’. The NNT offers a measurement of the impact of a medicine or therapy by estimating the number of patients that need to be treated in order to have an impact on one person. The concept is statistical, but intuitive, for we know that not everyone is helped by a medicine or intervention — some benefit, some are harmed, and some are unaffected. The NNT tells us how many of each.
- theNNT Rating System
- Our Therapy (NNT) Approach
- “For every therapy we review, we provide a color-coded summary for you to use (borrowed from the traditional stoplight). As we state in our philosophy, we care about benefits and harms that matter to patients, not researchers. Patients care about death and illness, not a laboratory value or CT scan finding. We use this focus on “patient-important outcomes” to guide our recommendations.”
- The Green Rating
- “Green. Go.Therapies rated green are the best you can get – there is clear evidence of patient-important benefits, and these benefits clearly outweigh any associated harms. For example: Steroids for Asthma Attack: if you give steroids to 8 patients with asthma attack in the emergency department, you prevent one from having to be admitted to the hospital. There are definitely side effects to steroids – high blood sugar, hyperactivity – but these, to us, seem minor in comparison.”
- See All Therapy (NNT) Reviews Rated Green
- The Yellow Rating
- “For us at theNNT, therapies rated yellow require more study. We don’t think the data is conclusive or substantial enough to be able to give a clear rating yet. It’s the yellow therapies that we think would benefit from large, randomized controlled trials (when possible and appropriate) to give us a better sense of if we’re helping patients when these medicines are given or wether we’re harming them.”
- See All Therapy Reviews (NNT) Rated Yellow
- The Red Rating
- “Red suggests that benefits and harms may be equal or equivocal; while there may be some benefits, in our opinion the benefits don’t outweigh the harms. One extreme example: if a medicine were to save 2% of people’s lives, but cause strokes in 10% of people, it’s hard to say that this medicine clearly is overall helpful.”
- See All Therapy Reviews (NNT) Rated Red
- The Black Rating
- “Black is our “worst” or “lowest” rating. Therapies rated black have very clear associated harms to patients without any recognizable benefit. One example: liberal transfusions for patients with anemia. Patients who received more blood transfusions did not do any better than patients with fewer (more restrictive) blood transfusions, but were much more likely to develop pulmonary edema, which can be life-threatening and require intensive care to manage.
- See All Reviews (NNT) Rated Black
- Our Diagnosis (LR) Approach
- “For every diagnostic evaluation we review, we also provide a color-coded summary of how helpful each sign/symptom/test is for that particular disease process; the darker the blue, the more important or helpful the criteria. Because of the way that likelihood ratios affect disease risk and odds, we’ve also made criteria that are unlikely to help change a patient’s risk not usable with our dynamic risk calculators. You’ll notice these values are in grey, and can’t be clicked. These values are positive likelihood ratios less than 2 or negative likelihood ratios of greater than 0.5.”
- Caveats
- “As you’re probably aware if you’re reading this, there are downsides to trying to categorize everything into neat little boxes – some therapies may not fit well into our schema. While we acknowledge it’s not perfect, we still feel it’s a useful way to get a quick assessment of the utility of a therapy. Some of the ratings are certainly open to interpretation, so again, we’ve done our best to pick a rating that we can all support and agree upon, but if you feel strongly that our assessment is wrong, please feel free to contact us. We’d love to hear from you! This is also why we’ve chosen to provide a summary of our interpretation of the data along with links to the primary sources, so you can read for yourself if you disagree with our assessment.”
