When Do Clinical Decision Rules Improve Patient Care?

Clinical decision rules are everywhere in medicine today. These impressive-looking decision algorithms and scoring systems are widely promoted as tools to either improve diagnosis or decrease expensive testing. As clinicians, we find decision rules psychologically appealing because they would appear to create order out of disorder. Medicine is inherently subjective; however, decision rules strive to transform such murky complexity into structured and tangible tools. Certainly a scientific decision instrument statistically derived from 10,000 or more patients must be superior to the frailty and variability of clinician judgment, mustn’t it? Many would assume so. Despite their many strengths, decision rules can also have important limitations. Before adoption, I suggest that readers scrutinize each such rule on the following questions. Three high-quality articles in this issue of Annals will help illustrate the principles discussed—the first a derivation of a rule to decrease abdominal computed tomography (CT) in children with blunt torso trauma, the second a contrast of the relative accuracy of decision rules for pulmonary embolism risk stratification when compared with unstructured clinical judgment, and the third an attempted validation of the modified Alvarado score—a previously described decision rule for appendicitis.