Economic profiling of physicians: does omission of pharmacy claims bias performance measurement?
OBJECTIVE: To investigate the degree to which the absence of prescriber identifying information and the absence of pharmacy claims might affect the validity of physicians' economic profiles. STUDY DESIGN: The study database consisted of 4 years of claims from a mixed-model health maintenance organization. Using the grouper of Episode Treatment Groups by Symmetry Health Data Systems, Inc, 2 episode databases were created, with and without pharmacy claims included. For each database, the responsibility for defined episodes was attributed to physicians within specialty (1) on the basis of combined professional and prescribing costs and (2) on the basis of professional costs alone. METHODS: Using the different databases and attribution rules, physicians were ranked within specialty on the economic profiling metric, and the various rankings were compared for consistency. Analyses were performed for cardiologists, family practitioners, general surgeons, and neurologists. RESULTS: The absence of prescriber identifying information appears to have only a small effect on physicians' economic profiles. The absence of pharmacy claims, on the other hand, may affect economic profile performance, but the effects differ by specialty and depend on pharmacy costs as a percentage of episode total costs for the specialty and the correlation of episode costs with and without pharmacy costs included. CONCLUSIONS: Physicians' economic profile rankings are not greatly affected by the presence or absence of prescriber identifying information in pharmacy claims. If pharmacy claims are missing altogether, however, valid economic profiling remains feasible for some clinical specialties but not for others.