Sentara embedded an MRSA risk model in Epic, redesigned what nurses do when it fires, and cut hospital‑onset MRSA bacteremia about 45%. CMS publishes that exact measure for every hospital in the country. Here is what the measure can actually see.
Sentara Health put a predictive MRSA risk score into Epic and then did the part nobody writes up: they changed the flowsheet. Decolonization and line care started happening earlier because somebody redesigned what a nurse does when the number appears. Hospital-onset MRSA bacteremia fell roughly 45%, with about $1.18 million in infection-related costs avoided so far.
The score is the part you can buy. Before you do, it is worth asking what the national version of that number is capable of telling you — because CMS already computes it, for everybody, and publishes it.
Each circle is one hospital with a published MRSA bacteremia SIR. Horizontal position is the predicted number of cases — the denominator, the thing that decides how much the ratio is allowed to wobble. Vertical position is the SIR itself. The shaded funnel is the exact Poisson range you would expect if every hospital were performing identically at the benchmark and the only thing moving the dots was chance.
Nine and a half percent. That is the share of American hospitals whose MRSA bacteremia SIR is statistically distinguishable from 1.00 at all. Everything else on the list is a hospital that reported honestly and landed inside the noise.
Set the minimum denominator to 1 and the chart looks like wild variation in quality: hospitals at zero, hospitals at four times expected, a spread of more than four points. Push it to 10 and the field flattens into a band. Nothing improved. You just stopped looking at hospitals whose entire annual expectation is two cases.
Thirty of the thirty-eight. Across the whole file, 38 hospitals post a SIR above 2.0 — twice the expected number of MRSA bloodstream infections. Thirty of them have fewer than three predicted cases for the entire year. Their median denominator is 1.8. One extra infection moves a hospital like that from “better than benchmark” to “twice the national rate,” and one fewer moves it to a perfect zero.
The mirror image is worse. 317 hospitals report a SIR of exactly 0.00. 265 of them — 84% — also have fewer than three predicted cases. A zero at that volume is not an infection-prevention program. It is a small hospital having an ordinary year.
There is a second, quieter problem. The dots here are one year of one measure. Sentara’s 45% is a multi-year change across a multi-hospital system — a big enough denominator that the drop means something. At the US median hospital, with 3.6 predicted cases a year, a 45% drop is roughly what you would expect to see by chance about a third of the time with no intervention at all. The companion piece simulates exactly that.
The Sentara result is not evidence that a risk score works. It is evidence that a risk score plus a rewritten nursing workflow plus enough volume to measure it works. Two of those three are free. The expensive one is the one nobody sells you.
So before the score: pick one alert already live at your site, write down the exact action it is supposed to trigger, who performs it, and where that action gets documented. If you cannot fill all three boxes, you do not have an intervention — you have a notification. And check your own denominator first. If it is under three, you will not be able to tell whether anything you build worked.