This study follows a few other recent observational studies that have come to the same conclusion,[2,3] and a similar study limited to patients aged 65 years and older had the same outcome. Although all of these studies have been observational, their unanimity makes it hard to imagine that they could all be wrong. Moreover, a prospective randomized controlled trial would be ethically difficult to perform and probably irrelevant as soon as microbial resistances change and advances in antibiotics occur, which both are certain to do. The risk reduction for mortality varied from around 5% in the first 30 days in the previous studies to 30% in McCabe and colleagues' study. As few as 3 to 20 patients with CAP must be treated according to guidelines in order to save a single life.
Note that adherence to guidelines is not to be confused with satisfaction of performance measures.