Table 1.
Baseline characteristics of study sample
| Characteristics | Total eligible sample | No delirium group | Delirium group |
|---|---|---|---|
| No of patients | 626 467 | 55 211 | 55 211 |
| Age (years), mean (SD) | 78.0 (7.0) | 83.4 (6.5) | 83.5 (6.6) |
| Gender | |||
| Men | 286 430 (46) | 26 339 (48) | 26 339 (48) |
| Women | 340 037 (54) | 28 872 (52) | 28 872 (52) |
| Hospital frailty risk score, median (IQR) | 0.0 (0.0-0.0) | 1.3 (0.0-3.1) | 1.3 (0.0-3.2) |
| Length of stay—index episode (days), median (IQR) | 1 (1.0-5.0) | 6.0 (3.0-12.0) | 9.0 (5.0-17.0) |
| Length of stay—intensive care unit | |||
| None | 605 420 (96.6) | 51 045 (92.5) | 48 299 (87.5) |
| Less than one day | 4668 (0.7) | 814 (1.5) | 1122 (2.0) |
| One day or longer | 16 379 (2.6) | 3352 (6.1) | 5790 (10.5) |
| Primary diagnosis (categories) | |||
| Injury, poisoning, other consequences of external causes | 51 796 (8.3) | 9364 (17.0) | 8714 (15.8) |
| Diseases of the circulatory system | 72 572 (11.6) | 8965 (16.2) | 7989 (14.5) |
| Diseases of the respiratory system | 30 701 (4.9) | 5697 (10.3) | 5160 (9.3) |
| Symptoms, signs, and abnormal findings not classified elsewhere | 62 207 (9.9) | 3306 (6.0) | 5558 (10.1) |
| Neoplasms and blood diseases | 69 349 (11.1) | 4613 (8.4) | 4073 (7.4) |
| Diseases of the musculoskeletal system and connective tissue | 54 344 (8.7) | 4563 (8.3) | 4110 (7.4) |
| Diseases of the genitourinary system | 34 278 (5.5) | 4051 (7.3) | 3764 (6.8) |
| Factors influencing health status and contact with health services | 37 450 (6.0) | 4093 (7.4) | 2896 (5.2) |
| Diseases of the digestive system | 78 548 (12.5) | 3306 (6.0) | 2823 (5.1) |
| Other | 135 222 (21.6) | 7253 (13.1) | 10 124 (18.3) |
Data are numbers (%) unless specified otherwise. IQR, interquartile range; SD, standard deviation.