Sepsis bundles – why sensitivity and specificity matter

Graham Walker(@grahamwalker) tweeted this in response to yesterday’s blog post: Agree w @medrants on Abx usage.  Sepsis guidelines mandating Abx for anything that COULD be sepsis is the problem I responded that his example is brilliant.  Let’s dissect the problem. Sepsis is a severe problem that responds better to early aggressive treatment. Those invested in diagnosing sepsis desire bundles that have a high sensitivity.  In case you forgot the definition of sensitivity, it is the true positive rate.  Sensitivity here represents the percentage of sepsis patients that you treat promptly.  Sounds good – we do not want to miss any patients with sepsis. But wait!  All tests or bundles have both false negatives and false positives.  We want to minimize our false negatives, but we cannot do that without increasing the false positives.  Since specificity equals 1 – the false positive rate, we have a tautology.  Increasing sensitivity means decreasing specificity. Anyone who spends some time considering this problem will understand that a sepsis bundle that errs on the side of diagnosing sepsis will have the expected consequence of giving antibiotics to a significant number of patients who do not have sepsis, but rather other reasons for matching the criteria in the sepsis bundle. We love antibiotics when appropriately used, but antibiotics are not benign.  Patients who received broad spectrum antibiotics suffer the risk of antibiotic associated diar...
Source: DB's Medical Rants - Category: Internal Medicine Authors: Tags: Medical Rants Source Type: blogs