Challenge of Evidence in Individualized Medicine

Kathleen Kraft; Wolfgang Hoffmann


Personalized Medicine. 2012;9(1):65-71. 

In This Article

Evidence-based Medicine or Individualized Therapy?

Healthcare systems have to ensure a high quality in medical care to maintain, and preferably, improve health-related quality of life in a population. As a prerequisite an accurate diagnosis determines the optimal therapy and this process involves a careful medical history as well as apply up-to-date medical knowledge. These features are shared by both evidence-based medicine (EBM) and individualized medicine.

David Sackett, founder of the first department of clinical epidemiology (McMaster University, ON, Canada in 1967) defined the principles of EBM as "the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients".[1,2] The practice of EBM means to integrate individual clinical expertise with the best available external clinical evidence gained in systematic research.[3]

The development of evidence-based guidelines is intended to function as a decision support for physicians in order to more readily determine the adequate management of specific diseases as well as individual patients. The main objective of EBM is to improve the quality of healthcare by a reduction of the heterogeneity of medical decisions and knowledge transfer.

In the recent past, EBM has become increasingly operationalized in guidelines. Recommendations are usually arranged based on the hierarchy of evidence (Table 1),[4] but often an expert consensus has an impact on the categorization of a recommendation as well.

Individualized medicine comprises curative, rehabilitative and preventive examination as well as treatment methods customized for the individual patient, and thus, provides a holistic and integrative approach.[5] Individualized medicine starts with the acknowledgement of the fact that the predisposition to specific diseases, the disease development, the natural course of disease and the response to therapeutic intervention are caused by a multidimensional interaction of age, gender, genetic background, environmental factors, lifestyle, culture and beliefs as well as social status. The expression of these factors varies largely from individual to individual.[6] Respecting these differences individualized medicine aims to categorize patients into clinically relevant subgroups. Hence, at the heart of the concept of individualized medicine is a stratification that 'individualizes' a one-size-fits-all standardized intervention into a group specific intervention.[7]

Tension between standardization and individualization has always been a characteristic of medical activity. Each patient has the right to receive the best medical care. However, this ethical imperative may as well be met by a therapy based on guideline recommendations derived from large multicenter trials or rather on an individual genetic biomarker.