Use of Medicare claims data to measure county-level variation in breast carcinoma incidence and mammography rates.
BACKGROUND
National-level population-based data about breast carcinoma incidence and its association with screening mammography are currently not available.


METHODS
Inpatient, hospital outpatient and physician/supplier Medicare claims were used to identify incident cases of breast carcinoma in women > or = 65 years from 1996 to 1997 and calculate county-level incidence rates. The 1994-1995 claims data were used to determine county-level rates of mammography, and determine the correlation with incidence.


RESULTS
The median 2-year incidence rate for women > or = 65 was 979/100,000, and substantial variation in incidence between counties was observed. (i.e. 25th percentile 789/100,000, 75th percentile 1186/100,000). Two-year county-level mammography rates also varied among counties (i.e. 25th percentile 30.5%, 75th percentile 40.9%) and were higher in white women than in black women (median 36.8 and 26.3%, respectively). Counties with higher rates of mammography also had higher age-adjusted incidence rates.


CONCLUSIONS
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. The data highlight the geographic variation in incidence and screening rates that may be useful for targeted interventions, and also suggest that mammography remains in a growth phase.
Cooper
Gregory S
GS
Department of Medicine, Cancer Research Center, Case Western Reserve University, Cleveland, OH 44106, USA. gxc12@po.cwru.edu
Yuan
Zhong
Z
Jethva
Reena N
RN
Rimm
Alfred A
AA
D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology*; D002277:Carcinoma / Q000453:epidemiology*; D005260:Female; D005843:Geography; D006801:Humans; D015994:Incidence; D016014:Linear Models; D009111:Local Government; D008327:Mammography / Q000706:statistics & numerical data*; D006278:Medicare / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology