Table 1.
Hospital characteristics and baseline, in-hospital, and discharge patient characteristics stratified by hospital ICU utilization
| Hospital ICU utilization | |||||
|---|---|---|---|---|---|
| Variable* | Overall | Low ICU Utilization (n = 8,900 patients, 110 hospitals) |
Intermediate ICU Utilization (n = 15,580 patients, 193 hospitals) |
High ICU Utilization (n = 3,538 patients, 43 hospitals) |
p-value |
| Hospital characteristics | |||||
| Region | 0.15 | ||||
| West | 45 (13) | 19 (17.3) | 17 (8.8) | 9 (20.9) | |
| Northeast | 20 (5.8) | 9 (8.2) | 9 (4.7) | 2 (4.7) | |
| Midwest | 113 (32.7) | 34 (30.9) | 66 (34.2) | 13 (30.2) | |
| South | 168 (48.6) | 48 (43.6) | 101 (52.3) | 19 (44.2) | |
| Available services | 0.94 | ||||
| No cath lab | 4 (1.2) | 1 (0.9) | 2 (1.0) | 1 (2.3) | |
| Diagnostic cath only | 5 (1.4) | 2 (1.8) | 3 (1.6) | 0 (0.0) | |
| PCI only, no CT surgery | 54 (15.6) | 19 (17.3) | 29 (15.0) | 6 (14.0) | |
| PCI and CT surgery | 283 (81.8) | 88 (80.0) | 159 (82.4) | 36 (83.7) | |
| Academic hospital+ | 56 (16.2) | 19 (17.3) | 30 (15.5) | 7 (16.3) | 0.94 |
| Rural hospital | 46 (13.3) | 13 (11.8) | 24 (12.4) | 9 (20.9) | 0.29 |
| Total hospital beds | 317 (212, 452) | 285 (183, 423) | 328 (221, 485) | 267 (182, 401) | 0.20 |
| Patient characteristics | |||||
| Demographic characteristics | |||||
| Age (years) | 77 (71, 84) | 77 (71, 84) | 78 (71, 85) | 77 (71, 85) | 0.06 |
| Female | 13,055 (46.6) | 4057 (45.6) | 7339 (47.1) | 1659 (46.9) | 0.07 |
| Non-white | 3931 (14.0) | 1075 (12.1) | 2333 (15.0) | 523 (14.8) | < 0.001 |
| Clinical characteristics | |||||
| BMI (kg/m2) | 27 (24, 31) | 27 (24, 31) | 27.1 (24, 31) | 27.0 (24, 31) | 0.22 |
| Current/recent smoker (< 1 year) | 3576 (12.8) | 1170 (13.1) | 1956 (12.6) | 450 (12.7) | 0.41 |
| Diabetes mellitus | 11,210 (40.0) | 3448 (39.9) | 6238 (40.0) | 1424 (40.2) | 0.92 |
| Prior MI | 8731 (31.2) | 2981 (33.5) | 4573 (29.4) | 1117 (33.3) | < 0.001 |
| Prior HF | 6762 (24.1) | 2214 (24.9) | 3673 (23.6) | 875 (24.7) | 0.04 |
| Prior PCI | 8107 (28.9) | 2644 (29.7) | 4403 (28.3) | 1060 (30.0) | 0.02 |
| Prior CABG | 6929 (24.7) | 2279 (25.6) | 3773 (24.2) | 877 (24.8) | 0.05 |
| Prior stroke | 3807 (13.6) | 1203 (13.5) | 2095 (13.4) | 509 (14.4) | 0.31 |
| Prior PAD | 4553 (16.3) | 1593 (17.9) | 2399 (15.4) | 561 (15.9) | < 0.001 |
| Currently on dialysis | 1112 (4.0) | 321 (3.6) | 634 (4.1) | 157 (4.4) | 0.06 |
| ECG Findings | < 0.001 | ||||
| ST depression | 5716 (20.4) | 1882 (21.1) | 3162 (20.3) | 672 (19.0) | |
| T wave inversion | 3378 (12.1) | 1088 (12.2) | 1852 (11.9) | 438 (12.4) | |
| Transient ST elevation | 384 (1.4) | 153 (1.7) | 168 (1.1) | 63 (1.8) | |
| Admission Features | |||||
| HF signs or symptoms | 7140 (25.5) | 2176 (24.4) | 4090 (26.3) | 874 (24.7) | 0.004 |
| Heart rate (bpm) | 85 (72, 101) | 84 (71, 100) | 85 (72, 102) | 84 (72, 101) | 0.001 |
| Systolic blood pressure (mmHg) | 146 (125, 169) | 147 (126, 169) | 146 (125, 169) | 145 (126, 168) | 0.21 |
| Initial serum creatinine (mg/dl)‡ | 1.1 (0.9, 1.5) | 1.1 (0.9, 1.5) | 1.1 (0.9, 1.5) | 1.1 (0.9, 1.5) | 0.02 |
| Initial hemoglobin (g/dl) | 12.9 (11.4, 14.2) | 12.9 (11.4, 14.2) | 12.9 (11.4, 14.2) | 12.9 (11.4, 14.3) | 0.01 |
| Initial troponin (× ULN) | 2.4 (0.7, 11.9) | 2.6 (0.8, 12.2) | 2.4 (0.6, 11.8) | 2.4 (0.8, 11.7) | 0.01 |
| ACTION risk score | 33 (27, 40) | 33 (27, 39) | 33 (27, 40) | 33 (27, 40) | 0.06 |
| In-hospital characteristics | |||||
| Peak troponin (× ULN) | 24.8 (6.4, 100.0) | 24.8 (6.5, 103.0) | 24.8 (6.3, 98.2) | 24.4 (6.5, 98.9) | 0.63 |
| Ejection fraction | 0.24 | ||||
| > 50% | 14,225 (56.3) | 4508 (56.7) | 7948 (56.3) | 1769 (55.3) | |
| 40–50% | 4794 (19.0) | 1526 (19.2) | 2657 (18.8) | 611 (19.1) | |
| 25–40% | 4620 (18.3) | 1413 (17.8) | 2603 (18.4) | 604 (18.9) | |
| < 25% | 1540 (6.1) | 470 (5.9) | 866 (6.1) | 204 (6.4) | |
| Medication within 24 hours | |||||
| Aspirin | 25,995 (96.6) | 8347 (97.4) | 14,377 (96.3) | 3271 (95.8) | < 0.001 |
| P2Y12 receptor inhibitor | 12,731 (45.4) | 4135 (46.5) | 7036 (45.2) | 1560 (44.1) | 0.03 |
| Beta blocker | 20,800 (83.3) | 6743 (84.9) | 11,406 (82.5) | 2651 (82.8) | < 0.001 |
| ACE inhibitor or ARB | 11,452 (44.1) | 3711 (45.2) | 6252 (43.3) | 1489 (44.8) | 0.01 |
| Statin | 16,039 (60.2) | 5289 (62.5) | 8759 (59.2) | 1991 (59.0) | < 0.001 |
| In-hospital procedures | |||||
| Diagnostic cath | 18,867 (67.3) | 6012 (67.6) | 10,418 (66.9) | 2437 (68.9) | 0.06 |
| PCI | 10,206 (36.4) | 3293 (37.0) | 5533 (35.5) | 1380 (39.0) | < 0.001 |
| CABG | 2221 (7.9) | 644 (7.2) | 1289 (8.3) | 288 (8.1) | 0.01 |
| Time to cath (hours) | 24 (13, 47) | 23 (13, 43) | 24 (13, 48) | 24 (14, 47) | < 0.001 |
| Overall length of stay (days) | 4 (2, 6) | 3 (2, 6) | 4 (3, 7) | 4 (2, 7) | < 0.001 |
| ICU length of stay (days)§ | 2 (1, 4) | 2 (1, 3) | 2 (1, 4) | 3 (2, 5) | < 0.001 |
| Discharge characteritics‖ | |||||
| Discharge medications | |||||
| Aspirin | 22,334 (96.9) | 7208 (97.7) | 12,297 (96.4) | 2829 (97.0) | < 0.001 |
| P2Y12 receptor inhibitor | 15,592 (64.7) | 5085 (66.2) | 8543 (64.0) | 1964 (64.6) | 0.004 |
| Beta blocker | 21,591 (95.7) | 6947 (96.4) | 11,925 (95.5) | 2719 (95.1) | < 0.001 |
| ACE inhibitor or ARB | 14,988 (68.8) | 4901 (70.8) | 8160 (67.6) | 1927 (68.8) | < 0.001 |
| Statin | 20,636 (90.1) | 6675 (91.4) | 11,387 (89.8) | 2574 (88.6) | < 0.001 |
| Discharge location‖ | < 0.001 | ||||
| Home | 19,869 (74.1) | 6389 (74.7) | 10,903 (73.3) | 257 (76.0) | |
| Other hospital | 1264 (4.7) | 450 (5.3) | 664 (4.5) | 150 (4.4) | |
| Nursing home | 2414 (9.0) | 697 (8.1) | 1429 (9.6) | 288 (8.5) | |
| Extended care | 2254 (8.4) | 695 (8.1) | 1297 (8.7) | 262 (7.7) | |
| Hospice | 759 (2.8) | 238 (2.8) | 436 (2.9) | 85 (2.5) | |
| Other | 141 (0.5) | 46 (0.5) | 84 (0.6) | 11 (0.3) | |
| Left against medical advice | 119 (0.4) | 38 (0.4) | 63 (0.4) | 18 (0.5) | |
*
Categorical variables presented as frequency (percent); continuous variables presented as median (25th, 75th percentiles).
+
Membership in the Council of Teaching Hospitals
‡
Among non-dialysis patients
§
Among patients with ICU stay
‖
Among patients discharged alive
Low ICU utilization hospitals treat < 30% of older NSTEMI patients in the ICU, intermediate ICU utilization hospitals treat 30–70% of older NSTEMI patients in the ICU, and high ICU utilization hospitals treat > 70% of older NSTEMI patients in the ICU. PCI = percutaneous intervention; CT = cardiothoracic; cath = cardiac catheterization; BMI = body mass index; MI = myocardial infarction; HF = heart failure; CABG = coronary artery bypass grafting; PAD = peripheral arterial disease; ECG = electrocardiogram; bpm = beats per minute; ULN = upper limit of normal; ACE = angiotensin converting enzyme; ARB = angiotensin II receptor blocker; GP = glycoprotein.