Primary care, avoidable hospitalization, and outcomes of care: a literature review and methodological approach

The purpose of this article is to review the literature on the relationships between primary care, potentially avoidable hospitalizations, and outcomes of care and to develop a methodology to study these relationships. The methodological approach includes developing criteria to select medical conditions, aggregating patient claims files of both ambulatory and acute care records, and delineating episodes of care. A taxonomy of physician visits is proposed that classifies visits on the basis of type of care, type of illness, and linkage to hospital episodes. A structural model of use and outcomes is specified that includes hazard rate models to estimate the likelihood of a potentially avoidable hospitalization, primary care and ad hoc physician visits, and mortality; the latter suggests a modification of the Health Care Financing Administration methodology that includes physician visit variables.