The most widely employed theoretical model in health services research is Andersen and Newmans conceptual framework (1973) for examining the determinants of medical care utilization. It describes the use of individual health services as a function of societal determinants (technology, norms), health system determinants (resources, organization) and individual determinants (predisposing, enabling and health status). The development of theoretical models of patient health outcomes has lagged behind although the Anderson and Newman framework can serve as a starting point for thinking about the contributors to patient outcomes.
Iezzoni (2003) recently outlined the concepts underpinning the risk-adjustment of health care outcomes, highlighting the importance of the medical meaningfulness of risk-adjusters. She lists 26 potential risk factors in the following five broad categories (page 35):
- Demographic characteristics;
- Clinical factors;
- Socioeconomic factors;
- Health-related behaviors and activities;
- Attitudes and perceptions.
Iezzoni points out that data limitations will constrain the range of potential risk-adjusters and that an a priori conceptual model of which risk factors should be in a risk-adjustment method for a given outcome is necessary to evaluate the credibility of risk-adjusted findings (page 33).