Table 1.
Patient and Mammogram Characteristics in the Matched Breast Cancer Surveillance Consortium and Medicare Claims Samples*
| Characteristic | All (N=383,730) |
Training (N=191,865) |
Testing (N=191,865) |
|---|---|---|---|
| Age | n (%) | n (%) | n (%) |
| 66–74 | 223,155 (58.2) | 111,654 (58.2) | 111,501 (58.1) |
| 75–84 | 140,364 (36.6) | 70,010 (36.5) | 70,354 (36.7) |
| 85+ | 20,211 (5.3) | 10,201 (5.3) | 10,010 (5.2) |
| Race | |||
| White, non-Hispanic | 310,397 (80.9) | 155,180 (80.9) | 155,217 (80.9) |
| Black | 30,466 (7.9) | 15,243 (7.9) | 15,223 (7.9) |
| Asian/Pacific Islander | 8,905 (2.3) | 4,457 (2.3) | 4,448 (2.3) |
| American Indian/Alaskan Native | 1,624 (0.4) | 776 (0.4) | 848 (0.4) |
| Hispanic | 6,149 (1.6) | 3,105 (1.6) | 3,044 (1.6) |
| Other/mixed/unknown | 26189 (6.8) | 13,104 (6.8) | 13,085 (6.8) |
| Months since previous mammogram | |||
| 0–18 | 282,898 (73.7) | 141,352 (73.7) | 141,546 (73.8) |
| 19–30 | 49,192 (12.8) | 24,673 (12.9) | 24,519 (12.8) |
| 31–42 | 15,086 (3.9) | 7,581 (4) | 7,505 (3.9) |
| >42 | 14,456 (3.8) | 7,246 (3.8) | 7,210 (3.8) |
| Missing/unknown | 22,098 (5.8) | 11,013 (5.7) | 11,085 (5.8) |
| Mammogram Type | |||
| Film-screen | 356,848 (93) | 178,299 (92.9) | 178,549 (93.1) |
| Digital | 26,871 (7) | 13,562 (7.1) | 13,309 (6.9) |
| Missing/unknown | 11 (0) | 4 (0) | 7 (0) |
| Year of Mammogram | |||
| 1999 | 45,582 (11.9) | 19,735 (11.2) | 22,829 (11.9) |
| 2000 | 47,361 (12.3) | 20,326 (11.6) | 23,714 (12.4) |
| 2001 | 53,436 (13.9) | 24,455 (13.9) | 26,683 (13.9) |
| 2002 | 64,901 (16.9) | 30,267 (17.2) | 32,588 (17) |
| 2003 | 62,430 (16.3) | 31,308 (16.3) | 31,122 (16.2) |
| 2004 | 57,094 (14.9) | 28,578 (14.9) | 28,516 (14.9) |
| 2005 | 52,926 (13.8) | 26,513 (13.8) | 26,413 (13.8) |
| Charlson comorbidity index** | |||
| 0 | 279,265 (72.8) | 139,809 (72.9) | 139,456 (72.7) |
| 1 | 78,213 (20.4) | 38,915 (20.3) | 39,298 (20.5) |
| >=2 | 26,252 (6.8) | 13,141 (6.8) | 13,111 (6.8) |
| Prior History of Breast Cancer | |||
| No | 351,166 (91.5) | 175,591 (91.5) | 175,575 (91.5) |
| Yes | 32,564 (8.5) | 16,274 (8.5) | 16,290 (8.5) |
*
Descriptive data derived from Medicare claims except for months since previous mammography, mammogram type, and prior history of breast cancer, which were derived from Breast Cancer Surveillance Consortium (BCSC). In Classification and Regression Tree analysis, classification variables were derived only from Medicare claims. Individual women may have received more than one mammogram.