Table 1.
Demographic and clinical characteristics of patients who died from colorectal cancer and matched controls
| Characteristics, n (%) | Cases (n=1747) | Controls (n= 3460) |
|---|---|---|
| Used for case–control matching | ||
| Age at diagnosis, years* | ||
| 50–54 | 23 (1.3) | 65 (1.9) |
| 55–64 | 570 (32.6) | 1107 (32.0) |
| 65–74 | 504 (28.8) | 983 (28.4) |
| 75–84 | 556 (31.8) | 1103 (31.9) |
| 85–89 | 94 (5.4) | 202 (5.8) |
| Female | 883 (50.5) | 1756 (50.8) |
| Study sites | ||
| KPNC | 1443 (82.6) | 2881 (83.3) |
| KPSC | 304 (17.4) | 579 (16.7) |
| Length of enrolment with health plan before reference date, years | ||
| 5.0–7.4 | 304 (17.4) | 600 (17.3) |
| 7.5–9.9 | 315 (18.0) | 636 (18.4) |
| ≥10 | 1128 (64.6) | 2224 (64.3) |
| Characteristics not used for matching | ||
| Race ethnicity | ||
| Non-Hispanic white | 1170 (67.0) | 2318 (67.0) |
| Non-Hispanic black | 208 (11.9) | 244 (7.1) |
| Hispanic | 164 (9.4) | 374 (10.8) |
| Asian/Pacific Islander | 156 (8.9) | 397 (11.5) |
| Other/unknown | 49 (2.8) | 127 (3.7) |
| Per cent with at least a high school diploma, quartiles† | ||
| 1 | 374 (21.4) | 871 (25.2) |
| 2 | 419 (24.0) | 873 (25.2) |
| 3 | 435 (24.9) | 833 (24.1) |
| 4 | 482 (27.6) | 824 (23.8) |
| Unknown | 37 (2.1) | 59 (1.7) |
| Family history (chart audit)‡ | 115 (6.6) | 202 (5.8) |
| Primary care outpatient visits§ | ||
| 0 | 83 (4.8) | 71 (2.1) |
| 1 | 45 (2.6) | 50 (1.4) |
| 2 | 96 (5.5) | 110 (3.2) |
| 3+ | 1523 (87.2) | 3227 (93.3) |
| Charlson score at beginning of observation window | ||
| 0 | 1184 (67.8) | 2626 (75.9) |
| 1 | 293 (16.8) | 461 (13.3) |
| 2+ | 268 (15.3) | 369 (10.7) |
| Unknown | 2 (0.1) | 4 (0.1) |
| Screening sigmoidoscopy | 365 (20.9) | 1030 (29.8) |
| Screening faecal occult blood test | 702 (40.2) | 1542 (44.6) |
*The age at time of diagnosis, the date used to assess exposure and covariate information is shown.
†Data were obtained from the 2000 US Census data at the tract level.
‡Patients for whom the family history of colorectal cancer documented during the observation period did not meet the exclusion criteria. The exclusion was based on a history of colorectal cancer in one or more first-degree relatives before age 50 or in two or more second-degree relatives at any age, or other familial colorectal cancer syndromes.
§Defined based on outpatient clinical visits to family practice, gerontology/geriatrics, internal medicine, obstetrics/gynaecology and “primary care” clinics.