[Why do we need clinical epidemiology?]

Epidemiology as a tool of objective reasoning in health science is more evident. Its application in medical care is called clinical epidemiology; nevertheless, this term has been controversial through time as it has increased its application in both research and clinical care. The field covers issues of health services research, medical economics, clinical decisions analysis and medical social sciences; moreover, the proper epidemiology issues. We propose the role that this discipline should have in medical care practice and in clinical investigation, and we describe the usefulness of its applications.