Table 1. Characteristics of the Study Cohort and Note Events.
| Characteristic | Data Seta | |
|---|---|---|
| Development (n = 24 229) | Validation (n = 2692) | |
| Age, mean (SD), yb | 74.8 (13.2) | 75.0 (12.6) |
| Diedc | 11 138 (46.0) | 1247 (46.3) |
| Female sex | 14 628 (60.4) | 1631 (60.6) |
| Race | ||
| White | 20 734 (85.6) | 2305 (85.6) |
| Black | 1302 (5.4) | 159 (5.9) |
| Others | 515 (2.1) | 47 (1.7) |
| Unknown | 1678 (6.9) | 182 (6.8) |
| Ethnicity | ||
| Non-Hispanic | 22 190 (91.6) | 2471 (91.8) |
| Hispanic | 1400 (5.8) | 147 (5.5) |
| Unknown | 639 (2.6) | 74 (2.7) |
| Marital status | ||
| Married or partnered | 10 490 (43.3) | 1162 (43.2) |
| Single, divorced, or widowed | 12 324 (50.9) | 1378 (51.2) |
| Unknown | 1415 (5.8) | 152 (5.6) |
| Educational level | ||
| College and above | 6955 (28.7) | 755 (28.0) |
| High school or equivalent | 7392 (30.5) | 812 (30.2) |
| Did not complete high school | 2181 (9.0) | 239 (8.9) |
| Unknown | 7701 (31.8) | 886 (32.9) |
| No. of total note eventsd | 863 160 | 96 468 |
| No. of note events per patient, mean (SD) | 35.6 (49.2) | 38.8 (49.8) |
| No. of note events in time before death, mo | ||
| 0-3 | 47 219 (5.5) | 5238 (5.4) |
| 4-6 | 28 472 (3.3) | 3223 (3.3) |
| 7-12 | 49 709 (5.8) | 5684 (5.9) |
| 13-24 | 82 767 (9.6) | 9465 (9.8) |
| ≥25e | 654 993 (75.9) | 72 858 (75.5) |
a
Unless otherwise indicated, data are expressed as number (percentage) of patients. Percentages have been rounded and may not total 100.
b
Calculated at the beginning of the study period (ie, January 1, 2011).
c
Collected from January 1, 2011, through September 18, 2018.
d
The note events met the following inclusion criteria: (1) can be labeled in terms of 2-year mortality and (2) have more than 10 words after the natural language processing preprocessing.
e
A significant increase of note events documented more than 2 years before death was due to the inclusion of patients who were still living as of the most recent date of encounter recorded in the patient’s record in our health care system.