This study was featured in Academic Emergency Medicine as one of their CME articles – theoretically, an article with additional value presented with incentives to motivate a closer reading of the content. I don't mean to imply this is somehow a bad article – but it's just interesting to step back out of the tunnel vision of statistics and boggle at the inadequacy of the current state of medicine.
This is a prospective study of patients evaluated for pulmonary embolism attempting to evaluate how many patients were "inappropriately" scanned. This definition of "inappropriate" scanning was determined by patients who were either PERC negative or had low-risk Wells' score followed by a negative d-Dimer. Overall, of 152 patients, 11.8% were ultimately diagnosed with PE. However, the authors state that application of the PERC rule might have eliminated 9.2% of these scans while Wells'/d-Dimer would have obviated 13.8%.
While I certainly don't discount the beneficial effect of even small reductions in the number of individuals evaluated for pulmonary embolism, these are still terrible numbers. 90% of CT scans for PE are negative? And using these decision instruments gets us to ~75% negative scans? This would be comically wasteful performance and innovative performance improvement in any other industry.
We pretty clearly need to do better.
"Overuse of Computed Tomography Pulmonary
Angiography in the Evaluation of Patients with
Suspected Pulmonary Embolism in the