The purpose is to determine wether an electronic decision support system based on national guidelines is effective to improve the follow-up and the treatment of two conditions: hypertension and diabetes, in primary care practices.

Existing computer-based ordering systems for physicians provide drug-centred checks but offer little assistance for optimizing the overall patient-centred treatment strategy.

The ASTI project aims :

1. to design a guideline-based decision support system for diabetic and/or hypertensive patients, to help general practitioners :

   1. to carry out procedures (clinical and biological tests) according to guidelines (the recommended procedure at the recommended moment), and to get a synthetic view of all the elements they need to follow-up the patient
   2. to avoid prescription errors and to improve compliance with therapeutic guidelines. The " critic mode " operates as a background process and corrects the physician's prescription on the basis of automatically triggered elementary rules that account for isolated guideline recommendations. The " guided mode " directs the physician to the best treatment by browsing a comprehensive guideline knowledge base represented as a decision tree.

2. To measure the impact of ASTI when it is implemented with an electronic medical record system. We adopt a randomized design, with the practice as the unit of randomization.

Inclusion Criteria:

• Hypertension
• Mellitus diabetes
• Follow-up by GP's