Table 1 Baseline and clinical characteristics of study patients by BMI categories
Variables | Total | Underweight (BMI < 18.5 kg/m2) | Normal weight (18.5 kg/m2 ≤ BMI < 25 kg/m2) | Overweight (25 kg/m2 ≤ BMI < 30 kg/m2) | Obesity grade 1 (30 kg/m2 ≤ BMI < 35 kg/m2) | Obesity grade 2 (35 kg/m2 ≤ BMI < 40 kg/m2) | Obesity grade 3 (BMI ≥ 40 kg/m2) |
|---|---|---|---|---|---|---|---|
Number of patients | 148,783 (100%) | 6328 (4.3%) | 43,960 (29.5%) | 43,923 (29.5%) | 27,584 (18.5%) | 13,881 (9.3%) | 13,107 (8.8%) |
Age | |||||||
 Median, years | 65 (53,76) | 67 (54,80) | 67 (53,80) | 66 (54,77) | 64 (53,74) | 62 (52,72) | 60 (49,68) |
 ≤ 30 | 8348 (6) | 506 (8) | 3530 (8) | 2107 (5) | 1082 (4) | 544 (4) | 579 (4) |
 31–40 | 8683 (6) | 314 (5) | 2503 (6) | 2399 (5) | 1547 (6) | 891 (6) | 1029 (8) |
 41–50 | 14,947 (10) | 467 (7) | 3801 (9) | 4056 (9) | 2963 (11) | 1712 (12) | 1948 (15) |
 51–60 | 27,739 (19) | 1086 (17) | 6836 (16) | 7847 (18) | 5519 (20) | 3119 (22) | 3332 (25) |
 61–70 | 33,442 (22) | 1193 (19) | 8304 (19) | 9728 (22) | 6933 (25) | 3698 (27) | 3586 (27) |
 71–80 | 30,823 (21) | 1277 (20) | 8604 (20) | 9926 (23) | 6179 (22) | 2790 (20) | 2047 (16) |
 > 80 | 24,801 (17) | 1485 (23) | 10,382 (24) | 7860 (18) | 3361 (12) | 1127 (8) | 586 (4) |
Gender: male | 80,294 (54) | 2669 (42) | 23,526 (54) | 26,247 (60) | 15,617 (57) | 6973 (50) | 5262 (40) |
BMI, kg/m2 | 27.5 (23.5, 32.7) | 17.1 (16, 17.9) | 22.4 (20.9, 23.7) | 27.3 (26.1, 28.5) | 32.1 (30.9, 33.4) | 37 (35.9, 38.3) | 44.7 (41.9, 49.6) |
Ethnicity | |||||||
 Caucasian | 114,199 (77) | 4766 (75) | 33,565 (76) | 33,786 (77) | 21,462 (78) | 10,696 (77) | 9924 (76) |
 African American | 16,537 (11) | 837 (13) | 4597 (10) | 4364 (10) | 2975 (11) | 1753 (13) | 2011 (15) |
 Hispanic | 5763 (4) | 197 (3) | 1754 (4) | 1909 (4) | 1034 (4) | 467 (3) | 402 (3) |
 Asian | 2494 (2) | 191 (3) | 1146 (3) | 745 (2) | 277 (1) | 85 (1) | 50 (0) |
 Native American | 1090 (1) | 33 (1) | 290 (1) | 303 (1) | 198 (1) | 128 (1) | 138 (1) |
 Others/unknown | 8700 (6) | 304 (5) | 2608 (6) | 2816 (6) | 1638 (6) | 752 (5) | 582 (4) |
Comorbidities | |||||||
 Hypertension | 74,964 (50) | 2536 (40) | 19,663 (45) | 22,171 (50) | 15,088 (55) | 7887 (57) | 7619 (58) |
 Diabetes mellitus | 43,420 (29) | 1058 (17) | 9333 (21) | 11,840 (27) | 9432 (34) | 5620 (40) | 6137 (47) |
 Stroke | 12,315 (8) | 590 (9) | 3920 (9) | 3716 (8) | 2195 (8) | 1015 (7) | 879 (7) |
 Tumor | 22,356 (15) | 1295 (20) | 7465 (17) | 6674 (15) | 3736 (14) | 1772 (13) | 1414 (11) |
 Respiratory disease | 22,912 (15) | 1565 (25) | 6733 (15) | 5736 (13) | 3838 (14) | 2252 (16) | 2788 (21) |
 CHF | 21,868 (15) | 734 (12) | 5683 (13) | 5904 (13) | 4164 (15) | 2463 (18) | 2920 (22) |
 Cirrhosis | 4144 (3) | 175 (3) | 1308 (3) | 1224 (3) | 755 (3) | 362 (3) | 320 (2) |
 CKD | 18,134 (12) | 663 (10) | 5131 (12) | 5186 (12) | 3441 (12) | 1813 (13) | 1900 (14) |
ICU types | |||||||
 Med-SurgICU | 82,057 (55) | 3724 (59) | 24,922 (57) | 23,652 (54) | 14,738 (53) | 7519 (54) | 7502 (57) |
 Cardiac ICU | 10,711 (7) | 511 (8) | 3047 (7) | 3148 (7) | 2028 (7) | 1000 (7) | 977 (7) |
 CCU-CTICU | 12,555 (8) | 354 (6) | 3186 (7) | 3894 (9) | 2655 (10) | 1371 (10) | 1095 (8) |
 CSICU | 5528 (4) | 183 (3) | 1492 (3) | 1802 (4) | 1114 (4) | 531 (4) | 406 (3) |
 CTICU | 4685 (3) | 138 (2) | 1246 (3) | 1533 (3) | 1032 (4) | 457 (3) | 279 (2) |
 MICU | 12,758 (9) | 677 (11) | 3861 (9) | 3566 (8) | 2163 (8) | 1190 (9) | 1301 (10) |
 Neuro ICU | 11,245 (8) | 357 (6) | 3445 (8) | 3457 (8) | 2182 (8) | 1003 (7) | 801 (6) |
 SICU | 9244 (6) | 384 (6) | 2761 (6) | 2871 (7) | 1672 (6) | 810 (6) | 746 (6) |
ICU scoring systems | |||||||
 SOFA score | 4 (2, 7) | 5 (2, 7) | 4 (2, 7) | 4 (2, 6) | 4 (2, 6) | 4 (2, 7) | 4 (2, 7) |
 APS | 38 (27, 53) | 42 (30, 59) | 38 (28, 54) | 37 (26, 52) | 36 (26, 52) | 37 (26, 53) | 39 (27, 55) |
 APACHE IV score | 50 (37, 68) | 56 (42, 74) | 52 (38, 69) | 50 (37, 67) | 49 (36, 66) | 49 (35, 66) | 49 (36, 67) |
ICU LOS, days | 2 (1, 4) | 2 (1, 4) | 2 (1, 4) | 2 (1, 4) | 2 (1, 4) | 2 (1, 4) | 2 (1, 4) |
Hospital LOS, days | 5 (3, 8) | 5 (3, 9) | 5 (3, 8) | 5 (3, 8) | 5 (3, 8) | 5 (3, 9) | 5 (3, 9) |
ICU mortality | 7938 (5) | 506 (8) | 2592 (6) | 2182 (5) | 1269 (5) | 705 (5) | 684 (5) |
Hospital mortality | 12,867 (9) | 897 (14) | 4289 (10) | 3536 (8) | 2032 (7) | 1064 (8) | 1049 (8) |