Table 1.
Comprehensive list of potentially confounding variables for MAP threshold groups < 55 mmHg, < 65 mmHg, < 75 mmHg and < 85 mmHg
| Variable group | Variable type | Min. MAP < 55 mmHg (n = 3308) | Min. MAP < 65 mmHg (n = 6310) | Min. MAP < 75 mmHg (n = 8039) | Min. MAP < 85 mmHg (n = 8609) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mortality n (%)** | Mortality n (%) | Mortality n (%) | Mortality n (%) | ||||||||||
| Yes | No | p value | Yes | No | p value | Yes | No | p value | Yes | No | p value | ||
| Gender* | Male | 329 (44%) | 1079 (42%) | 0.522 | 51 (47%) | 2343 (45%) | 0.302 | 592 (48%) | 3183 (47%) | 0.473 | 617 (48%) | 3481 (48%) | 0.521 |
| Race | African American | 77 (10%) | 234 (10%) | 0.243 | 120 (11%) | 502 (10%) | 0.240 | 137 (11%) | 705 (10%) | 0.380 | 142 (11%) | 801 (11%) | 0.592 |
| Caucasian | 585 (78%) | 206 (81%) | 858 (78%) | 4164 (80%) | 964 (78%) | 5400 (79%) | 994 (78%) | 5777 (79%) | |||||
| Other | 74 (10%) | 211 (9%) | 97 (9%) | 455 (9%) | 107 (9%) | 586 (8%) | 110 (9%) | 635 (9%) | |||||
| Unknown | 19 (3%) | 48 (2%) | 26 (2%) | 88 (2%) | 28 (2%) | 112 (2%) | 28 (2%) | 122 (2%) | |||||
| Age (years)* | Mean | 70 | 65 | < 0.001 | 69 | 63 | < 0.001 | 69 | 62 | < 0.001 | 69 | 63 | < 0.001 |
| Admission type | Elective | 40 (5%) | 119 (5%) | 0.779 | 62 (6%) | 213 (4%) | 0.065 | 70 (6%) | 274 (4%) | 0.025 | 73 (6%) | 291 (4%) | 0.009 |
| Emergency | 671 (89%) | 2276 (89%) | 975 (89%) | 4711 (90%) | 1092 (88%) | 6173 (91%) | 1125 (88%) | 6672 (91%) | |||||
| Trauma Center | 5 (0.7%) | 12 (0.5%) | 3 (0.3%) | 10 (0.2%) | 4 (0.3%) | 11 (0.2%) | 4 (0.3%) | 11 (0.2%) | |||||
| Urgent | 2 (0.3%) | 4 (0.2%) | 53 (5%) | 257 (5%) | 62 (5%) | 321 (5%) | 64 (5%) | 337 (5%) | |||||
| Unknown | 37 (5%) | 142 (6%) | 8 (0.7%) | 18 (0.4%) | 8 (0.7%) | 24 (0.4%) | 8 (0.6%) | 24 (0.3%) | |||||
| Discharge year | 2010 | 3 (0.4%) | 23 (0.9%) | 0.009 | 6 (0.5%) | 44 (0.8%) | 0.009 | 9 (0.7%) | 53 (0.8%) | 0.001 | 9 (0.7%) | 55 (0.8%) | < 0.001 |
| 2011 | 31 (4.1%) | 79 (3%) | 41 (4%) | 172 (3%) | 49 (4%) | 220 (3%) | 50 (4%) | 232 (3%) | |||||
| 2012 | 82 (10.9%) | 185 (7%) | 115 (11%) | 383 (7%) | 130 (11%) | 510 (8%) | 134 (11%) | 539 (7%) | |||||
| 2013 | 141 (19%) | 434 (17%) | 196 (18%) | 848 (16%) | 215 (17%) | 1064 (16%) | 223 (18%) | 1125 (15%) | |||||
| 2014 | 183 (24%) | 679 (27%) | 270 (25%) | 1320 (25%) | 305 (25%) | 1685 (25%) | 313 (25%) | 1818 (25%) | |||||
| 2015 | 165 (22%) | 584 (23%) | 236 (21%) | 1202 (23%) | 265 (21%) | 1592 (23%) | 275 (22%) | 1733 (24%) | |||||
| 2016 | 150 (20%) | 569 (22%) | 237 (22%) | 1240 (24%) | 263 (21%) | 1679 (25%) | 270 (21%) | 1833 (25%) | |||||
| Census region | Midwest | 93 (12%) | 365 (14%) | < 0.001 | 141 (13%) | 772 (15%) | < 0.001 | 161 (13%) | 1054 (16%) | < 0.001 | 167 (13%) | 1137 (16%) | < 0.001 |
| Northeast | 308 (41%) | 793 (31%) | 430 (39%) | 1501 (29%) | 477 (39%) | 1922 (28%) | 484 (38%) | 2062 (28%) | |||||
| South | 213 (28%) | 905 (36%) | 336 (31%) | 2003 (39%) | 388 (31%) | 2654 (39%) | 404 (38%) | 2873 (39%) | |||||
| West | 141 (19%) | 490 (19%) | 194 (18%) | 933 (18%) | 210 (17%) | 1173 (17%) | 219 (17%) | 1263 (17%) | |||||
| Hospital bed size | < 100 | 44 (6%) | 208 (8%) | < 0.001 | 63 (6%) | 443 (9%) | < 0.001 | 70 (6%) | 603 (9%) | < 0.001 | 74 (6%) | 665 (9%) | < 0.001 |
| 100–199 | 91 (12%) | 403 (16%) | 141 (13%) | 871 (17%) | 159 (13%) | 1149 (17%) | 162 (13%) | 1232 (17%) | |||||
| 200–299 | 115 (15%) | 496 (19%) | 174 (16%) | 994 (19%) | 192 (16%) | 1332 (20%) | 197 (16%) | 1457 (20%) | |||||
| 300–499 | 191 (25%) | 558 (22%) | 296 (27%) | 1220 (23%) | 344 (28%) | 1612 (24%) | 356 (28%) | 1746 (24%) | |||||
| 500+ | 314 (42%) | 888 (35%) | 427 (39%) | 1681 (32%) | 471 (38%) | 2107 (31%) | 485 (38%) | 2235 (31%) | |||||
| ICU type | General ICU | 472 (63%) | 1722 (68%) | 0.001 | 675 (61%) | 3465 (67%) | 0.001 | 765 (62%) | 4549 (67%) | 0.002 | 791 (62%) | 4920 (67%) | < 0.001 |
| Medical ICU | 95 (13%) | 278 (11%) | 156 (14%) | 668 (13%) | 172 (14%) | 880 (13%) | 178 (14%) | 947 (13%) | |||||
| Surgical ICU | 46 (6%) | 181 (7%) | 69 (6%) | 309 (6%) | 75 (6%) | 382 (6%) | 75 (6%) | 407 (6%) | |||||
| Cardiac ICU | 70 (9%) | 138 (5%) | 99 (9%) | 301 (6%) | 103 (8%) | 392 (6%) | 109 (9%) | 418 (6%) | |||||
| Coronary care unit | 72 (10%) | 234 (9%) | 102 (9%) | 466 (9%) | 121 (10%) | 600 (9%) | 121 (10%) | 643 (9%) | |||||
| Drugs received | Diuretics received | 171 (23%) | 341 (13%) | < 0.001 | 264 (24%) | 653 (13%) | < 0.001 | 291 (23%) | 838 (12%) | < 0.001 | 303 (24%) | 897 (12%) | < 0.001 |
| ACE inhibitors received | 68 (9%) | 232 (9%) | 0.946 | 115 (11%) | 453 (9%) | 0.066 | 130 (11%) | 594 (9%) | 0.044 | 137 (11%) | 648 (9%) | 0.028 | |
| Beta blockers received | 157 (21%) | 378 (15%) | < 0.001 | 252 (23%) | 773 (15%) | < 0.001 | 282 (23%) | 1020 (15%) | < 0.001 | 298 (23%) | 1105 (15%) | < 0.001 | |
| Calcium channel blockers received | 82 (11%) | 156 (6%) | < 0.001 | 136 (12%) | 332 (6%) | < 0.001 | 156 (13%) | 465 (9%) | < 0.0001 | 165 (13%) | 519 (7%) | < 0.001 | |
| *Modified APACHE III score | Mean | 76 | 65 | < 0.001 | 74 | 62 | < 0.001 | 73 | 60 | < 0.001 | 72 | 59 | < 0.001 |
| Serum lactate | No reading available | 335 (44%) | 125 (49%) | < 0.001 | 505 (46%) | 2745 (53%) | < 0.001 | 592 (48%) | 3729 (55%) | < 0.001 | 614 (48%) | 4077 (56%) | < 0.001 |
| Normal < 2 mmol/L | 183 (24%) | 813 (32%) | 279 25%) | 1555 (30%) | 304 (25%) | 1934 (28%) | 309 (24%) | 2045 (28%) | |||||
| Mild 2 to < 5 mmol/L | 172 (23%) | 406 (16%) | 230 (21%) | 780 (15%) | 250 (20%) | 983 (15%) | 257 (20%) | 1050 (14%) | |||||
| Moderate 5 to < 8 mmol/L | 40 (5%) | 57 (2%) | 58 (5%) | 95 (2%) | 61 (5%) | 119 (2%) | 63 (5%) | 123 (2%) | |||||
| Severe ≥ 8 mmol/L | 25 (3%) | 20 (0.8%) | 29 (3%) | 34 (0.7%) | 29 (2%) | 38 (0.6%) | 31 (2%) | 40 (0.6%) | |||||
| Elixhauser index | Mean | 18 | 13 | < 0.001 | 18 | 13 | < 0.001 | 18 | 13 | < 0.001 | 18 | 12 | < 0.001 |
| Payer | Commercial | 102 (14%) | 403 (16%) | < 0.001 | 145 (13%) | 883 (17%) | < 0.001 | 165 (13%) | 1176 (17%) | < 0.001 | 168 (13%) | 1293 (18%) | < 0.001 |
| Medicaid | 53 (7%) | 334 (13%) | 93 (8%) | 696 (13%) | 114 (9%) | 917 (14%) | 116 (9%) | 989 (14%) | |||||
| Medicare | 494 (65%) | 145 (57%) | 700 (64%) | 2839 (55%) | 780 (63%) | 3668 (54%) | 807 (63%) | 3907 (53%) | |||||
| Other | 48 (6%) | 141 (6%) | 70 (6%) | 317 (6%) | 74 (6%) | 415 (6%) | 75 (6%) | 461 (6%) | |||||
| Unknown | 58 (7%) | 225 (9%) | 93 (9%) | 474 (9%) | 103 (8%) | 627 (9%) | 108 (9%) | 685 (9%) | |||||
| Teaching status | Yes | 516 (68%) | 1620 (64%) | 0.014 | 723 (65.7%) | 3161 (61%) | 0.002 | 803 (65%) | 4057 (60%) | < 0.001 | 824 (65%) | 4342 (59%) | 0.000 |
| Urban/rural status | Urban | 553 (73%) | 2029 (80%) | < 0.001 | 270 (25%) | 991 (19%) | < 0.001 | 930 (75%) | 5513 (81%) | < 0.001 | 963 (76%) | 5965 (81%) | < 0.001 |
| Hospital acute status | Acute | 755 (100%) | 2553 (100%) | 1101 (100%) | 5209 (100%) | 1235 (100%) | 6803 (100%) | 1273 (100%) | 7335 (100%) | ||||
| Elixhauser comorbidities | Congestive heart failure | 316 (42%) | 784 (31%) | < 0.001 | 438 (40%) | 1477 (28%) | < 0.001 | 477 (39%) | 1855 (27%) | < 0.001 | 494 (39%) | 1953 (27%) | < 0.001 |
| Valvular disease | 163 (22%) | 444 (17%) | 0.009 | 234 (21%) | 832 (16%) | < 0.001 | 259 (21%) | 1051 (16%) | < 0.001 | 264 (21%) | 1114 (15%) | < 0.001 | |
| Pulmonary circulation disease | 139 (18%) | 306 (12%) | < 0.001 | 190 (17%) | 596 (11%) | < 0.001 | 211 (17%) | 740 (11%) | < 0.001 | 218 (17%) | 777 (11%) | < 0.001 | |
| Peripheral vascular disease | 174 (23%) | 490 (19%) | 0.020 | 253 (23%) | 950 (18%) | 0.000 | 276 (22%) | 1218 (18%) | < 0.001 | 285 (22%) | 1302 (18%) | < 0.001 | |
| Paralysis | 68 (9%) | 301 (11%) | 0.033 | 101 (9%) | 588 (11%) | 0.041 | 117 (10%) | 726 (11%) | 0.203 | 125 (10%) | 766 (10%) | 0.495 | |
| Other neurological disorders | 250 (33%) | 875 (34%) | 0.554 | 368 (33%) | 1702 (33%) | 0.630 | 413 (33%) | 2202 (32%) | 0.470 | 422 (33%) | 2352 (32%) | 0.456 | |
| Chronic pulmonary disease | 333 (44%) | 1062 (42%) | 0.220 | 510 (46%) | 2159 (42%) | 0.003 | 565 (46%) | 2825 (42%) | 0.006 | 589 (46%) | 3019 (41%) | 0.00 | |
| Diabetes w/o chronic complications | 164 (22%) | 604 (24%) | 0.268 | 242 (22%) | 1223 (24%) | 0.285 | 273 (22%) | 1581 (23%) | 0.376 | 286 (23%) | 1721 (24%) | 0.430 | |
| Diabetes w/chronic complications | 117 (16%) | 341 (13%) | 0.135 | 161 (15%) | 695 (13%) | 0.260 | 184 (15%) | 950 (14%) | 0.392 | 189 (15%) | 1051 (14%) | 0.635 | |
| Hypothyroidism | 178 (24%) | 602 (24%) | 0.998 | 251 (23%) | 1182 (23%) | 0.939 | 281 (23%) | 1469 (22%) | 0.371 | 286 (23%) | 1556 (21%) | 0.321 | |
| Renal failure | 210 (28%) | 535 (21%) | < 0.001 | 304 (28%) | 1007 (19%) | < 0.001 | 336 (27%) | 1342 (20%) | < 0.001 | 344 (27%) | 1440 (20%) | < 0.001 | |
| Liver disease | 138 (18%) | 279 (11%) | < 0.001 | 210 (19%) | 587 (11%) | < 0.001 | 233 (19%) | 790 (12%) | < 0.001 | 241 (19%) | 852 (12%) | < 0.001 | |
| Peptic ulcer disease excl. bleeding | 9 (1%) | 28 (1%) | 0.827 | 15 (1%) | 53 (1%) | 0.314 | 16 (1%) | 64 (0.9%) | 0.249 | 16 (1%) | 69 (0.9%) | 0.294 | |
| Acquired immune deficiency syndrome | 6 (0.8%) | 27 (1%) | 0.523 | 10 (0.9%) | 43 (0.8%) | 0.785 | 11 (0.9%) | 58 (0.9%) | 0.896 | 12 (0.9%) | 63 (0.9%) | 0.769 | |
| Lymphoma | 29 (4%) | 72 (3%) | 0.152 | 52 (5%) | 160 (3%) | 0.006 | 59 (5%) | 188 (3%) | < 0.001 | 61 (5%) | 200 (3%) | < 0.001 | |
| Metastatic cancer | 112 (15%) | 174 (7%) | < 0.001 | 154 (14%) | 365 (7%) | < 0.001 | 184 (15%) | 458 (7%) | < 0.001 | 192 (15%) | 487 (7%) | < 0.001 | |
| Solid tumor without metastasis | 73 (10%) | 234 (9%) | 0.676 | 110 (10%) | 461 (9%) | 0.231 | 119 (10%) | 574 (8%) | 0.170 | 122 (10%) | 608 (8%) | 0.128 | |
| Rheumatoid arthritis/collagen vascular diseases | 46 (6%) | 188 (7%) | 0.231 | 71 (7%) | 367 (7%) | 0.479 | 83 (7%) | 453 (7%) | 0.942 | 84 (7%) | 494 (7%) | 0.852 | |
| Coagulopathy | 285 (38%) | 650 (26%) | < 0.001 | 410 (37%) | 1244 (24%) | < 0.001 | 462 (37%) | 1570 (23%) | < 0.001 | 474 (37%) | 1654 (23%) | < 0.001 | |
| Obesity | 137 (18%) | 590 (23%) | 0.004 | 201 (18%) | 1186 (23%) | 0.001 | 229 (19%) | 1618 (24%) | < 0.001 | 237 (19%) | 1767 (24%) | < 0.001 | |
| Weight loss | 276 (37%) | 730 (29%) | < 0.001 | 405 (37%) | 1360 (26%) | <0.001 | 447 (36%) | 1674 (25%) | < 0.001 | 458 (36%) | 1752 (24%) | < 0.001 | |
| Fluid and electrolyte disorders | 638 (85%) | 1986 (78%) | <0.001 | 922 (84%) | 4007 (77%) | < 0.001 | 1032 (84%) | 5195 (76%) | <0.001 | 1063 (83%) | 5575 (76%) | < 0.001 | |
| Chronic blood loss anemia | 41 (5%) | 122 (5%) | 0.467 | 69 (6%) | 227 (4%) | 0.007 | 76 (6%) | 285 (4%) | 0.002 | 76 (6%) | 303 (4%) | 0.003 | |
| Deficiency anemias | 448 (59%) | 1399 (55%) | 0.027 | 644 (59%) | 2759 (53%) | 0.001 | 723 (59%) | 3516 (52%) | < 0.001 | 747 (59%) | 3744 (51%) | < 0.001 | |
| Alcohol abuse | 106 (14%) | 294 (12%) | 0.062 | 156 (14%) | 579 (11%) | 0.004 | 175 (15%) | 785 (12%) | 0.009 | 179 (14%) | 869 (12%) | 0.026 | |
| Drug abuse | 65 (9%) | 272 (11%) | 0.103 | 90 (8%) | 583 (11%) | 0.003 | 100 (8%) | 772 (11%) | 0.001 | 105 (8%) | 842 (12%) | 0.001 | |
| Psychoses | 88 (12%) | 353 (14%) | 0.123 | 13 (12%) | 750 (14%) | 0.044 | 150 (12%) | 990 (15%) | 0.025 | 156 (12%) | 1066 (15%) | 0.031 | |
| Depression | 197 (26%) | 722 (28%) | 0.238 | 294 (27%) | 1464 (28%) | 0.346 | 325 (26%) | 1876 (28%) | 0.353 | 339 (27%) | 2022 (28%) | 0.480 | |
| Hypertension | 556 (74%) | 1782 (70%) | 0.042 | 808 (73%) | 3606 (69%) | 0.006 | 914 (74%) | 4741 (70%) | 0.003 | 944 (74%) | 5140 (71%) | 0.004 | |
Because of rounding, categories will not always add to 100%
APACHE III score includes physiology, chronic health investigation, and age variables [18]
*Variables included in the adjustment of regression models for myocardial injury
**Percentages for the variables types in this table are calculated by using a denominator which is the total number of patients within that particular variable group