Introduction: Risk adjustment is essential before comparing patient outcomes across hospitals. With this aim several risk adjustment systems have been developed, including the well-known diagnosis related groups.
Material and methods: Narrative review on risk assessment framework from administrative databases, including data quality and system pitfalls.
Results: The risk adjustment systems developed for cost-control aims to group different patient typologies in relation to the predicted use of resources with the aim to develop incentives to cost-reduction; the systems developed for measuring effectiveness have the objective to assess the health care quality. Both systems are useful for clinical, management and health public uses, but they have several pitfalls and their results should be interpreted cautiously.
Conclusions: Managers and physicians should consider the risk adjustment systems as a valuable resource for decision-making and reducing uncertainty, but not as the scientific referee of hospital quality or hospital efficiency.