Determination of county-level prostate carcinoma incidence and detection rates with Medicare claims data.

Abstract

To the authors' knowledge, national-level population-based data regarding prostate carcinoma incidence and detection currently are not available. The availability of such data could identify those regions with a disproportionately high cancer incidence as well as the population-level association between prostate carcinoma detection and incidence. Inpatient, hospital outpatient, and physician/supplier Medicare claims from 1997 were used to identify incident cases of prostate carcinoma in men age > or = 65 years and to calculate state and county-level incidence rates. The 1991 and 1997 claims data were used to determine small area rates of prostate-specific antigen (PSA) testing and prostate biopsy and to determine their correlation with incidence. The calculated incidence rates for 1997 were 890 per 100,000 and 1196 per 100,000, respectively, in white males and African-American males and varied substantially between counties (i.e., 25--75th percentile, 676--1124 per 100,000). Rates of PSA and prostate biopsy increased markedly from 1991 to 1997 in both white men (1580 per 100,000 to 24,286 per 100,000) and African-American men (1277 per 100,000 to 15,190 per 100,000), and considerable variation in detection between counties was observed. Counties that had higher rates of prostate biopsy also had higher age-adjusted incidence rates, and county-level PSA testing was found to be associated with incidence in African-American patients, but not in white patients. Medicare claims may provide an alternative source of population-based data, particularly for areas in which registry data are not readily available or are of limited scope. In addition, claims provide otherwise unavailable national data concerning cancer detection.