Factors associated with antibiotic prescribing in a managed care setting: an exploratory investigation

This multi-site, cross-sectional, observational study sought to identify attitudinal and social normative factors associated with the prescribing of oral antibiotics to ambulatory patients in a managed care setting. Participants were 25 physicians specializing in internal medicine, family practice or pediatrics from five ambulatory care clinics within a large, fully integrated health care system in a major midwestern U.S. city. The main outcome measure was number of prescriptions per physician written in the fourth quarter of 1994 for each of seven selected antibiotics. Correlational and multiple regression analyses revealed that behavioral intentions were significantly associated (P < 0.05) with both attitudes and subjective norms. However, physicians' attitudes, subjective norms and intentions were not predictive of actual antibiotic prescribing behavior. Prescribing behavior may have been a function of patient-specific rather than general beliefs about antibiotics. Methodological limitations related to the sample size and the sparseness of the utilization data may also have prevented a significant effect of intentions on behavior from being detected. Alternatively, in managed care settings, it is hypothesized that prescribing behavior may have been influenced more by non-psychological factors, such as management systems, formularies and therapeutic substitution programs, than they were by internal, psychological factors such as attitudes, subjective norms and intentions. Managed care is altering the role of the physician as an autonomous decision-maker. In response, models of prescribing must either incorporate variables such as perceived behavioral control to aid in the prediction of non-volitional behavior, model the decision-making of non-physician managers, or forego psychological models in favor of structural or system-level models of drug utilization.