Using knowledge modelling to measure how clinical practice could actually be evidence-based: a preliminary analysis with arterial hypertension management.

ASTI is a guideline-based decision support system to be used in primary care. We analyzed the knowledge modelling carried out in the development of ASTI knowledge base (KB) from French clinical practice guidelines (CPGs) on arterial hypertension management to evaluate the evidence status of therapeutic propositions issued by the system. We defined three status: "evidence-based" (EB) when propositions are graded A, B, or C, "consensus-based" (CB) when propositions are explicitly mentioned in CPGs but supported by professional agreement (grade D), and "non-supported" (NS) when propositions are expert-based and provided by a domain specialist. We compared the distributions of evidence status on the 44,571 theoretical patient profiles extracted from ASTI KB, and on a data set of 435 actual hypertensive patients. Only 8.3% of actual patients, managed by 0.5% of the KB, have an EB profile and 46.9% of patients, managed by 12.6% of the KB, have a CB profile. Thus, there is no CPG recommendation for nearly half of the patients (44.8% have a NS profile)