| Characteristic | Readmission hospital; no. (%) of patients | p value | |
|---|---|---|---|
| Original hospital n = 161 974 | Alternative hospital n = 36 175 | ||
| Age, yr* | |||
| < 65 | 63 578 (39.3) | 13 064 (36.1) | < 0.001 |
| 65–74 | 33 471 (20.7) | 7 602 (21.0) | < 0.001 |
| 75–84 | 41 941 (25.9) | 9 650 (26.7) | < 0.001 |
| ≥ 85 | 22 984 (14.2) | 5 859 (16.2) | < 0.001 |
| Sex, female | 80 941 (50.0) | 17 654 (48.8) | < 0.001 |
| Neighbourhood average household income† | |||
| Highest quintile | 29 375 (18.1) | 6 675 (18.5) | < 0.001 |
| Next to highest quintile | 29 277 (18.1) | 6 381 (17.6) | < 0.001 |
| Middle quintile | 30 910 (19.1) | 6 609 (18.3) | < 0.001 |
| Next to lowest quintile | 35 262 (21.8) | 7 653 (21.2) | < 0.001 |
| Lowest quintile | 36 696 (22.7) | 8 732 (24.1) | < 0.001 |
| Rural residence† | 3 198 (2.0) | 465 (1.3) | < 0.001 |
| Additional admissions to hospital in previous year* | 81 549 (50.3) | 19 428 (53.7) | < 0.001 |
| ≥ 7 physician clinic visits in previous year* | 125 726 (77.6) | 28 540 (78.9) | < 0.001 |
| Charlson Comorbidity Index ≥ 2* | 84 955 (52.4) | 19 704 (54.5) | < 0.001 |
| Most responsible diagnosis for primary admission‡ | |||
| Malignant neoplasm | 19 590 (12.1) | 4 303 (11.9) | 0.292 |
| Injury | 10 666 (6.6) | 2 724 (7.5) | < 0.001 |
| Acute coronary syndrome | 9 000 (5.6) | 2 115 (5.8) | 0.030 |
| Heart failure | 9 258 (5.7) | 1 856 (5.1) | < 0.001 |
| Pneumonia | 6 696 (4.1) | 1 588 (4.4) | 0.028 |
| Obstructive lung disease | 6 742 (4.2) | 1 316 (3.6) | < 0.001 |
| Chronic ischemic heart disease | 3 168 (2.0) | 2 440 (6.7) | < 0.001 |
| Cardiac arrhythmia | 4 318 (2.7) | 824 (2.3) | < 0.001 |
| Cerebrovascular disease | 3 708 (2.3) | 1 135 (3.1) | < 0.001 |
| Miscellaneous | 49 237 (30.4) | 10 652 (29.4) | < 0.001 |
| Primary length of stay* greater than cohort median | 92 533 (57.1) | 20 843 (57.6) | 0.089 |
| Hospital-free interval* greater than cohort median | 80 749 (49.9) | 20 321 (56.2) | < 0.001 |
| Residence in chronic care facility at readmission | 16 479 (10.2) | 5 446 (15.1) | < 0.001 |
| Arrival by ambulance at readmission | 70 523 (43.5) | 20 677 (57.2) | < 0.001 |
*Analyzed as continuous data, but presented here in categories to facilitate interpretation. †Missing data were coded as such and included in analyses; however, this was uncommon (< 0.003% of all data) and not presented here. ‡The 10 most common diagnostic categories were selected for presentation. For a full listing of diagnosis categories and their frequency at primary and secondary admissions to hospital, see eTables 4 and 5 in Appendix 1.