Table 1.
Selected characteristics of the overall cohort and distribution across patients receiving vs not receiving benzodiazepines.
| Category | Descriptor | Overall cohort, median/n (IQR/%) (n=65 508) |
Benzodiazepine administered |
Standardised differences | |
|---|---|---|---|---|---|
| Yes, median/n (IQR/%) (n=58 004) |
No, median/n (IQR/%) (n=7504) |
||||
| Patient-level characteristics | |||||
| Anthropometric/demographic data | Age, yr (continuous) | 66 (16) | 65 (16) | 72 (14) | 0.56 |
| Age (categorical) | 0.59 | ||||
| 18–50 | 9160 (14.0) | 8684 (15.0) | 476 (6.3) | ||
| 51–60 | 13 340 (20.4) | 12 472 (21.5) | 868 (11.6) | ||
| 61–70 | 21 541 (32.9) | 19 469 (33.6) | 2072 (27.6) | ||
| 71–80 | 17 230 (26.3) | 14 387 (24.8) | 2843 (37.9) | ||
| >80 | 4237 (6.5) | 2992 (5.2) | 1245 (16.6) | ||
| Height, cm | 172.7 (14.9) | 172.7 (15.2) | 172 (15.3) | 0.11 | |
| Weight, kg | 84.5 (26.0) | 85 (26.3) | 81.8 (25.0) | 0.17 | |
| BMI∗ | 0.13 | ||||
| Underweight | 772 (1.2) | 665 (1.2) | 107 (1.4) | ||
| Normal | 16 016 (24.5) | 13 911 (24) | 2105 (28.1) | ||
| Overweight | 23 676 (36.1) | 20 878 (36.0) | 2798 (37.3) | ||
| Class I Obesity | 14 908 (22.8) | 13 390 (23.1) | 1518 (20.2) | ||
| Class II Obesity | 6535 (10) | 5891 (10.2) | 644 (8.6) | ||
| Class III Obesity | 3601 (5.5) | 3269 (5.6) | 332 (4.4) | ||
| Sex | 0.05 | ||||
| Male | 44 147 (67.4) | 39 245 (67.7) | 4902 (65.3) | ||
| Female | 21 361 (32.6) | 18 759 (32.3) | 2602 (34.7) | ||
| Race/ethnicity | 0.09 | ||||
| Caucasian | 52 528 (80.2) | 46 568 (80.3) | 5960 (79.4) | ||
| Black | 4141 (6.3) | 3614 (6.2) | 527 (7.0) | ||
| Hispanic | 545 (0.8) | 498 (0.9) | 47 (0.6) | ||
| Other or Multiracial | 2579 (3.9) | 2245 (3.9) | 334 (4.5) | ||
| Unknown | 5715 (8.7) | 5079 (8.8) | 636 (8.5) | ||
| Year of surgery | 0.32 | ||||
| 2014 | 8603 (13.1) | 7995 (13.8) | 608 (8.1) | ||
| 2015 | 9982 (15.2) | 9193 (15.9) | 789 (10.5) | ||
| 2016 | 11 518 (17.6) | 10 302 (17.8) | 1216 (16.2) | ||
| 2017 | 13 223 (20.2) | 11 778 (20.3) | 1445 (19.3) | ||
| 2018 | 14 268 (21.8) | 12 158 (21.0) | 2110 (28.1) | ||
| 2019 | 7914 (12.1) | 6578 (11.3) | 1336 (17.8) | ||
| Patient medical history† | Congestive heart failure | 24 572 (37.5) | 21 402 (36.9) | 3170 (42.2) | 0.14 |
| Cardiac arrhythmia | 33 163 (50.6) | 28 471 (49.1) | 4692 (62.5) | 0.33 | |
| Valvular disease | 38 847 (59.3) | 34 246 (59.0) | 4601 (61.3) | 0.10 | |
| Pulmonary circulation disorders | 8711 (13.3) | 7500 (12.9) | 1211 (16.1) | 0.12 | |
| Hypertension | 44 682 (68.2) | 39 164 (67.5) | 5518 (73.5) | 0.20 | |
| Other neurological disorders | 3300 (5.0) | 2785 (4.8) | 515 (6.9) | 0.11 | |
| Chronic pulmonary disease | 13 225 (20.2) | 11 684 (20.1) | 1541 (20.5) | 0.06 | |
| Diabetes mellitus | 13 570 (20.7) | 11 656 (20.1) | 1914 (25.5) | 0.16 | |
| Renal failure | 11 706 (17.9) | 9950 (17.2) | 1756 (23.4) | 0.18 | |
| Liver disease | 2877 (4.4) | 2552 (4.4) | 325 (4.3) | 0.06 | |
| Obesity | 12 997 (19.8) | 11 825 (20.4) | 1172 (15.6) | 0.13 | |
| Alcohol abuse | 535 (0.8) | 496 (0.9) | 39 (0.5) | 0.07 | |
| Drug abuse | 1574 (2.4) | 1461 (2.5) | 113 (1.5) | 0.09 | |
| Psychoses | 308 (0.5) | 266 (0.5) | 42 (0.6) | 0.06 | |
| Depression | 7095 (10.8) | 6244 (10.8) | 851 (11.3) | 0.07 | |
| Preoperative status | ASA physical status | 0.12 | |||
| 1–3 | 18 731 (28.6) | 16 935 (29.2) | 1796 (23.9) | ||
| 4 | 46 777 (71.4) | 41 069 (70.8) | 5708 (76.1) | ||
| Baseline MAP‡ | 0.18 | ||||
| Hypotensive | 4951 (7.6) | 4404 (7.6) | 547 (7.3) | ||
| Normotensive | 47 955 (73.2) | 42 875 (73.9) | 5080 (67.7) | ||
| Stage 1 hypertension | 8620 (13.2) | 7476 (12.9) | 1144 (15.2) | ||
| Stage 2 hypertension | 3982 (6.1) | 3249 (5.6) | 733 (9.8) | ||
| Intraoperative | Procedure type | ||||
| CABG only | 24 674 (37.7) | 21 852 (37.7) | 2822 (37.6) | 0.01 | |
| Valve and CABG only | 7372 (11.3) | 6325 (10.9) | 1047 (14.0) | 0.09 | |
| Valve only | 25 806 (39.4) | 23 048 (39.7) | 2758 (36.8) | 0.06 | |
| Other cardiac¶ | 7653 (11.7) | 6776 (11.7) | 877 (11.7) | 0.01 | |
| Anaesthesia duration (h) | 6.1 (2.2) | 6.1 (2.2) | 6.2 (2.2) | 0.03 | |
| Surgical duration (h) | 4.2 (1.8) | 4.2 (1.8) | 4.3 (1.9) | 0.01 | |
| Cardiopulmonary bypass use documented | 52 583 (80.3) | 47 042 (81.1) | 5541 (73.8) | 0.18 | |
| Provider characteristics | |||||
| Mean provider case volume per year | 0.32 | ||||
| <2 | 298 (0.5) | 261 (0.5) | 37 (0.5) | ||
| 2–9.5 | 2301 (3.5) | 2135 (3.7) | 166 (2.2) | ||
| 9.5–19.5 | 7835 (12.0) | 6800 (11.7) | 1035 (13.8) | ||
| 19.5–37.5 | 14 834 (22.7) | 12 293 (21.2) | 2541 (33.9) | ||
| >37.5 | 40 240 (61.4) | 36 515 (63.0) | 3725 (49.6) | ||
| Institutional characteristics | |||||
| Mean case institutional volume per year | 0.51 | ||||
| <291.5 | 12 067 (18.4) | 10 864 (18.7) | 1203 (16.0) | ||
| 291.5–451.7 | 15 364 (23.5) | 12 692 (21.9) | 2672 (35.6) | ||
| 451.7–704.3 | 11 673 (17.8) | 9971 (17.2) | 1702 (22.7) | ||
| 704.3–2488.5 | 11 473 (17.5) | 11 064 (19.1) | 409 (5.5) | ||
| >2488.5 | 14 931 (22.8) | 13 413 (23.1) | 1518 (20.2) | ||
| University affiliation | 0.50 | ||||
| Non-academic | 9015 (13.8) | 8880 (15.3) | 135 (1.8) | ||
| Academic | 56 493 (86.2) | 49 124 (84.7) | 7369 (98.2) | ||
CABG, coronary artery bypass grafting; IQR, inter-quartile range.
BMI categorised using WHO categories29: Underweight (<18.5 kg m−2); Normal (18.5–24.9 kg m−2, reference); Overweight (25.0–29.9 kg m−2); Class I Obesity (30.0–34.9 kg m−2); Class II Obesity (35.0–39.9 kg m−2); Class III Obesity (>40.0 kg m−2).
Comorbidities as defined by the Elixhauser Comorbidity Enhanced International Classification of Diseases, Ninth and Tenth Revisions, Clinical Modification Algorithm.30
As defined by the Seventh Report of the Joint National Committee31 and National Heart, Lung, and Blood Institute’s Health Information for the Public32: hypotensive (<70 mm Hg), normotensive (70–107 mm Hg, reference), stage 1 hypertension (108–120 mm Hg), and stage 2 hypertension (>120 mm Hg).
Including Maze procedures, open atrial/ventricular septal defect repairs, cardiac mass excisions, pericardiectomies, isolated open epicardial lead placement, and coronary artery bypass or valve procedures involving pericardiectomy, atrial/ventricular septal defect repair.