Thread by @drjohnm

Be ready all. I will show you how coronary artery calcium scans' ability to allay fear is counterbalanced by how it wrongly classifies people up in risk —> fear and increased likelihood of interacting w doctors
Slides by @AndrewFoy82
They involve math.

One must remember that the benefit of CAC has to be additive to regular risk factors -- ones that do not include being radiated.

Numbers come from oft-cited paper ncbi.nlm.nih.gov/pubmed/26791059
This paper concluded the net reclassification improvement w CAC was +12% over the pooled cohort equation (PCE), which is just risk factors, nothing fancy. Sounds good right?
Here are the terms and conditions.

Here is the sensitivity side of the equation -- those with events

Here is part 2 or the specificity side of the equation. Those without events.

Here are the results using percentages ---like in the paper.

But here are results using RAW numbers. (much more truthful)

So here are the conclusions --
As you can see, CAC gives many more people the feeling that they should take a statin than those who may have had an event prevented on statins.