Interpreting and evaluating the Centor score

In response to a twitter request,  this post will in detailed fashion discuss the score, how I recommend using it and how to evaluate it.  I will go into more detail than I generally do, because the questions require that detail. The original study, published in 1981 based on data collected in 1980, used logistic regression to evaluate predictors of positive group A beta hemolytic streptococcal cultures taken from adults (aged 16 and above) coming to an emergency department for a chief complaint of sore throat. We collected candidate symptoms and physical examination signs. The idea was always to use the resulting scores to stratify patients.  We never favored dichotomizing the scores.  Dichotomizing means transforming the scores into two parts (e.g., negative if the score is 2 or less and positive if the score is 3 or greater).  Using the score in this way loses information.  We found (as do the majority of validation studies) that the higher the score, the higher the probability of a positive throat culture. In one of our early papers, we suggested reassuring patients with a score of 0 or 1, testing patients with a score of 2 and empirically treating 3s and 4s.   Almost all authors and guidelines agree with the reassurance for 0s and 1s.  Some guidelines urge testing for 2s, 3s and 4s.  Others favor empiric antibiotics for 4s. Sensitivity and specificity arguments miss the point of the score.  We should not consider the score as a positive or negative test, but ra...
Source: DB's Medical Rants - Category: Internal Medicine Authors: Tags: Medical Rants Source Type: blogs