Table I. Baseline Characteristics of Patients in the Development and Validation Cohorts.
| Risk Factor | Development Cohort | Validation Cohort | ||
|---|---|---|---|---|
| Frequency | Readmitted* | Frequency | Readmitted* | |
| n(%) | n(%) | n(%) | n(%) | |
| Age | ||||
| Mean (SD) | 7.5 (0.7) | 7.5 (0.7) | ||
| 65-70 | 60,726 (31.3) | 5,554 (9.1) | 60,892 (31.4) | 5,564 (9.1) |
| 71-75 | 47,596 (24.5) | 4,927 (10.4) | 47,529 (24.5) | 4,981 (10.5) |
| 76-80 | 42,359 (21.8) | 5,030 (11.9) | 42,354 (21.8) | 4,962 (11.7) |
| 81-85 | 29,331 (15.1) | 4,210 (14.4) | 29,441 (15.2) | 4,235 (14.4) |
| 86+ | 13,887 (7.2) | 2,315 (16.7) | 13,963 (7.2) | 2,302 (16.5) |
| Female | ||||
| No | 114,557 (59.1) | 11,357 (9.9) | 114,293 (58.9) | 11,269 (9.9) |
| Yes | 79,342 (40.9) | 10,679 (13.5) | 79,886 (41.1) | 10,775 (13.5) |
| BMI | ||||
| Mean (SD) | 26.9 (3.3) | 26.9 (3.3) | ||
| ≤ 25 | 52,304 (27.0) | 7,134 (13.6) | 52,335 (27.0) | 7,121 (13.6) |
| ≤ 27.5 | 40,073 (20.7) | 4,326 (10.8) | 40,530 (20.9) | 4,359 (10.8) |
| > 27.5 | 101,522 (52.4) | 10,576 (10.4) | 101,314 (52.2) | 10,564 (10.4) |
| History of heart failure | ||||
| No | 165,733 (85.5) | 16,703 (10.1) | 166,031 (85.5) | 16,823 (10.1) |
| Yes | 28,166 (14.5) | 5,333 (18.9) | 28,148 (14.5) | 5,221 (18.5) |
| Previous valvular surgery | ||||
| No | 190,423 (98.2) | 21,496 (11.3) | 190,641 (98.2) | 21,489 (11.3) |
| Yes | 3,476 (1.8) | 540 (15.5) | 3,538 (1.8) | 555 (15.7) |
| Cerebrovascular disease | ||||
| No | 161,808 (83.4) | 17,350 (10.7) | 162,321 (83.6) | 17,253 (10.6) |
| Yes | 32,091 (16.6) | 4,686 (14.6) | 31,858 (16.4) | 4,791 (15.0) |
| Peripheral vascular disease | ||||
| No | 163,057 (84.1) | 17,269 (10.6) | 163,241 (84.1) | 17,407 (10.7) |
| Yes | 30,842 (15.9) | 4,767 (15.5) | 30,938 (15.9) | 4,637 (15.0) |
| Chronic lung disease | ||||
| No | 157,416 (81.2) | 16,045 (10.2) | 157,210 (81.0) | 16,146 (10.3) |
| Yes | 36,483 (18.8) | 5,991 (16.4) | 36,969 (19.0) | 5,898 (16.0) |
| Diabetes | ||||
| None | 128,941 (66.5) | 13,513 (10.5) | 128,896 (66.4) | 13,556 (10.5) |
| Non-insulin diabetes | 43,897 (22.6) | 5,015 (11.4) | 43,989 (22.7) | 5,007 (11.4) |
| Insulin diabetes | 21,061 (10.9) | 3,508 (16.7) | 21,294 (11.0) | 3,481 (16.3) |
| GFR | ||||
| Not measured | 8,772 (4.5) | 860 (9.8) | 8,750 (4.5) | 918 (10.5) |
| GFR < 30 | 8,401 (4.3) | 2,100 (25.0) | 8,528 (4.4) | 2,049 (24.0) |
| 30 ≤ GFR <60 | 68,431 (35.3) | 8,968 (13.1) | 68,684 (35.4) | 8,867 (12.9) |
| 60 ≤ GFR < 90 | 89,670 (46.2) | 8,282 (9.2) | 89,943 (46.3) | 8,368 (9.3) |
| 90 ≤ GFR | 18,625 (9.6) | 1,826 (9.8) | 18,274 (9.4) | 1,842 (10.1) |
| Renal failure - dialysis | ||||
| No | 189,997 (98.0) | 20,942 (11.0) | 190,143 (97.9) | 20,964 (11.0) |
| Yes | 3,902 (2.0) | 1,094 (28.0) | 4,036 (2.1) | 1,080 (26.8) |
| Hypertension | ||||
| No | 30,301 (15.6) | 2,939 (9.7) | 30,437 (15.7) | 2,999 (9.9) |
| Yes | 163,598 (84.4) | 19,097 (11.7) | 163,742 (84.3) | 19,045 (11.6) |
| History of tobacco use | ||||
| No | 170,318 (87.8) | 19,180 (11.3) | 170,609 (87.9) | 19,138 (11.2) |
| Yes | 23,581 (12.2) | 2,856 (12.1) | 23,570 (12.1) | 2,906 (12.3) |
| Previous PCI | ||||
| No | 119,613 (61.7) | 14,033 (11.7) | 120,021 (61.8) | 14,137 (11.8) |
| Yes | 74,286 (38.3) | 8,003 (10.8) | 74,158 (38.2) | 7,907 (10.7) |
| Current heart failure | ||||
| No | 169,335 (87.3) | 17,179 (10.1) | 169,709 (87.4) | 17,195 (10.1) |
| Yes | 24,564 (12.7) | 4,857 (19.8) | 24,470 (12.6) | 4,849 (19.8) |
| Symptoms on admission | ||||
| No MI | 138,393 (71.4) | 14,033 (10.1) | 138,550 (71.4) | 13,918 (10.0) |
| MI within 24 hrs | 44,490 (22.9) | 6,261 (14.1) | 44,805 (23.1) | 6,402 (14.3) |
| MI after 24 hrs | 11,016 (5.7) | 1,742 (15.8) | 10,824 (5.6) | 1,724 (15.9) |
| EF percentage | ||||
| Not measured | 54,945 (28.3) | 6,714 (12.2) | 55,680 (28.7) | 6,792 (12.2) |
| EF < 30 | 8,014 (4.1) | 1,589 (19.8) | 8,058 (4.1) | 1,555 (19.3) |
| 30 ≤ EF < 45 | 23,587 (12.2) | 3,406 (14.4) | 23,579 (12.1) | 3,457 (14.7) |
| 45 ≤ EF | 107,353 (55.4) | 10,327 (9.6) | 106,862 (55.0) | 10,240 (9.6) |
| PCI status | ||||
| Elective | 94,097 (48.5) | 8,324 (8.8) | 94,398 (48.6) | 8,318 (8.8) |
| Urgent | 74,544 (38.4) | 10,104 (13.6) | 74,463 (38.3) | 10,121 (13.6) |
| Emergency | 24,969 (12.9) | 3,554 (14.2) | 25,034 (12.9) | 3,548 (14.2) |
| Salvage | 289 (0.1) | 54 (18.7) | 284 (0.1) | 57 (20.1) |
| Highest risk lesion | ||||
| Unknown | 81,297 (41.9) | 8,726 (10.7) | 81,349 (41.9) | 8,758 (10.8) |
| pRCA/mLAD/pCIRC | 73,992 (38.2) | 8,609 (11.6) | 74,329 (38.3) | 8,572 (11.5) |
| pLAD | 33,537 (17.3) | 4,018 (12.0) | 33,607 (17.3) | 3,994 (11.9) |
| Left Main | 5,073 (2.6) | 683 (13.5) | 4,894 (2.5) | 720 (14.7) |
| Max prePCI TIMI flow: none | ||||
| No | 175,628 (90.6) | 19,591 (11.2) | 175,990 (90.6) | 19,608 (11.1) |
| Yes | 18,271 (9.4) | 2,445 (13.4) | 18,189 (9.4) | 2,436 (13.4) |
*
Readmitted within 30-days of index discharge for any reason. Abbreviations: BMI, body mass index; MI, myocardial infarction; GFR, glomular filtration rate; PCI, percutaneous coronary intervention; EF, ejection fraction.