Characteristics of Initial Study Population by Study Group
| CRC Cases | Controls (n = 81,669) | ||
|---|---|---|---|
| Stage 0–1 (n = 8,865) | Stage 2–3 (n = 13,296) | ||
| Age, years* | |||
| 67–69 | 15.6 | 13.8 | 19.5 |
| 70–74 | 29.4 | 27.5 | 32.3 |
| 75–79 | 28.0 | 27.5 | 25.1 |
| 80–89 | 27.1 | 31.2 | 23.1 |
| Female* | 53.9 | 56.6 | 62.8 |
| Race/ethnicity* | |||
| White | 86.6 | 87.2 | 84.8 |
| Asian | 3.5 | 3.3 | 3.8 |
| Black | 6.3 | 6.1 | 6.6 |
| Hispanic | 1.0 | 1.1 | 2.2 |
| Other | 2.6 | 2.3 | 2.7 |
| National Cancer Institute combined comorbidity index during the phase before diagnosis year* | |||
| ≤0 | 71.7 | 74.7 | 76.1 |
| >0–0.5 | 14.6 | 13.5 | 12.4 |
| >0.5–1.0 | 8.1 | 7.5 | 7.4 |
| >1.0 | 5.6 | 4.4 | 4.1 |
| Hospitalizations during the phase before diagnosis year† | |||
| 0 | 85.3 | 86.9 | 86.6 |
| 1 | 11.1 | 10.1 | 10.1 |
| 2 | 2.6 | 2.1 | 2.4 |
| 3 | 0.8 | 0.6 | 0.6 |
| 4 | 0.2 | 0.3 | 0.2 |
| ≥5 | 0.1 | 0.1 | 0.1 |
| Annual visits to cancer care physicians (mean [SD])‡ | |||
| Phase after initial treatment* | 1.4 (3.2) | 4.6 (7.1) | 0.3 (1.4) |
| Surveillance phase* | 0.7 (1.7) | 1.3 (2.1) | 0.3 (1.4) |
| Survival phase* | 0.5 (1.5) | 0.8 (1.6) | 0.4 (1.5) |
| Visits to noncancer care physicians during the phase before diagnosis year* | |||
| ≤7 | 42.6 | 50.0 | 50.1 |
| 8–15 | 33.0 | 30.2 | 29.2 |
| 16–25 | 16.6 | 14.2 | 14.2 |
| >25 | 7.8 | 5.6 | 6.5 |
| Reason for Medicare eligibility§ | |||
| Age ≥65 years | 94.1 | 94.7 | 93.9 |
| Disability/end-stage renal disease | 5.9 | 5.3 | 6.1 |
| Percent of those ≥25 years old who graduated from high school in ZIP code*‖ | |||
| 0–50 | 1.7 | 1.7 | 2.1 |
| 50–75 | 16.0 | 16.2 | 17.6 |
| 75–90 | 54.8 | 54.5 | 52.2 |
| >90 | 27.6 | 27.7 | 28.1 |
| Median annual household income in ZIP code*‖ | |||
| ≤$30,000 | 8.2 | 8.6 | 10.3 |
| >$30,000–45,000 | 38.4 | 39.0 | 38.2 |
| >$45,000 | 53.4 | 52.4 | 51.5 |
Values provided as % unless otherwise specified.
* P ≤ .001.
† P ≤ .05.
‡ Cancer care physicians include general surgeons, colorectal surgeons, medical oncologists, radiation oncologists.
§ P ≤ .01.
‖ Missing values: people ≥25 years old who graduated from high school in ZIP code (%): stage 0–1, n = 207 (2.3%); stage 2–3, n = 300 (2.3%); controls, n = 2274 (2.8%); median annual household income in ZIP code: stage 0–1, n = 210 (2.4%); stage 2–3, n = 301 (2.3%); controls, n = 2286 (2.8%).
CRC.