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) |
Data are median (interquartile range) or no./total (%)
BMI body mass index, CHF chronic heart failure, CKD chronic kidney disease, ICU intensive care unit, CCU coronary care unit, CTICU cardiothoracic ICU, CSICU cardiac surgery ICU, MICU medical ICU, SICU surgical ICU, SOFA Sequential Organ Failure Assessment, APS Acute Physiology Score, APACHE Acute Physiology and Chronic Health Evaluation, LOS length of stay