[General practice in a modern health care system--consequences for medical research, education and practice]

This first of two articles describes the far-reaching changes to the practice and theory of general practice that are leading from the old-style general practitioner changing to the modern-day primary health care specialist. These already partly accomplished changes, whilst bringing into focus the future role of general practice in a modern health care system, are altering the self-awareness of the profession and the way it defines itself. Specifics of the theory and practice of decision-making in primary health care, within this context of vital importance but as yet barely taken into account, are explained on the basis of Bayes' theorem and with the aid of examples of empirical data on the rational diagnosis of thyroid dysfunction. Making use of examples of coronary heart disease diagnostics, the second part of this article illustrates important differences between health care-service levels and the consequences arising from these differences for medical research, education and practice.