Table 1.
Selected baseline characteristics of study patients treated with either proton pump inhibitors (PPI) or H2 receptor antagonists (H2RA) for stress ulcer prophylaxis after coronary artery bypass grafting. Values are numbers (percentages) unless stated otherwise
| Before PS matching | After PS matching | IV analysis | ||||||
|---|---|---|---|---|---|---|---|---|
| PPI (n=9830) | H2RA (n=11 384) | PPI (n=7537) | H2RA (n=7537) | PPI preference (n=8697) | H2RA preference (n=7103) | |||
| Demographic characteristics | ||||||||
| Median (IQR) age | 66.0 (58.0-74.0) | 66.0 (57.0-74.0) | 66.0 (58.0-74.0) | 66.0 (58.0-74.0) | 66.0 (57.0-74.0) | 66.0 (58.0-74.0) | ||
| Ethnicity: | ||||||||
| White | 7318 (74.4) | 7896 (69.4) | 5441 (72.2) | 5422 (71.9) | 5970 (68.6) | 5383 (75.8) | ||
| Black | 573 (5.8) | 850 (7.5) | 490 (6.5) | 482 (6.4) | 684 (7.9) | 396 (5.6) | ||
| Other | 387 (3.9) | 556 (4.9) | 336 (4.5) | 338 (4.5) | 427 (4.9) | 276 (3.9) | ||
| Female sex | 2516 (25.6) | 3114 (27.4) | 1968 (26.1) | 1999 (26.5) | 2462 (28.3) | 1766 (24.9) | ||
| Surgical characteristics | ||||||||
| Type of admission: | ||||||||
| Emergency | 7064 (71.9) | 7796 (68.5) | 5234 (69.4) | 5281 (70.1) | 5905 (67.9) | 5077 (71.5) | ||
| Elective | 2699 (27.5) | 3504 (30.8) | 2261 (30.0) | 2207 (29.3) | 2719 (31.3) | 1970 (27.7) | ||
| Unknown | 67 (0.7) | 84 (0.7) | 42 (0.6) | 49 (0.7) | 73 (0.8) | 56 (0.8) | ||
| Surgery done with cardiopulmonary bypass | 8460 (86.1) | 9093 (79.9) | 6294 (83.5) | 6264 (83.1) | 6877 (79.1) | 6154 (86.6) | ||
| Comorbidities | ||||||||
| Median (IQR) Charlson comorbidity score | 2.0 (1.0-3.0) | 2.0 (1.0-3.0) | 2.0 (1.0-3.0) | 2.0 (1.0-3.0) | 2.0 (1.0-3.0) | 2.0 (1.0-3.0) | ||
| Chronic hypertension | 7599 (77.3) | 8921 (78.4) | 5902 (78.3) | 5893 (78.2) | 6875 (79.1) | 5466 (77.0) | ||
| Chronic obstructive pulmonary disease and allied conditions | 2153 (21.9) | 2662 (23.4) | 1664 (22.1) | 1709 (22.7) | 2078 (23.9) | 1547 (21.8) | ||
| Previous myocardial infarction | 1544 (15.7) | 1722 (15.1) | 1168 (15.5) | 1167 (15.5) | 1335 (15.4) | 1138 (16.0) | ||
| Chronic renal disease | 1074 (10.9) | 929 (8.2) | 739 (9.8) | 746 (9.9) | 716 (8.2) | 800 (11.3) | ||
| Diabetes | 3988 (40.6) | 4721 (41.5) | 3095 (41.1) | 3084 (40.9) | 3633 (41.8) | 2921 (41.1) | ||
| Inpatient use of drugs and services before surgery | ||||||||
| β blocker | 8392 (85.4) | 9511 (83.5) | 6372 (84.5) | 6407 (85.0) | 7223 (83.1) | 6087 (85.7) | ||
| Aspirin | 6830 (69.5) | 8442 (74.2) | 5424 (72.0) | 5456 (72.4) | 6545 (75.3) | 4848 (68.3) | ||
| Clopidogrel | 1642 (16.7) | 2012 (17.7) | 1307 (17.3) | 1300 (17.2) | 1585 (18.2) | 1169 (16.5) | ||
| Statin | 7496 (76.3) | 8214 (72.2) | 5642 (74.9) | 5641 (74.8) | 6270 (72.1) | 5518 (77.7) | ||
| Nitrates | 5818 (59.2) | 6916 (60.8) | 4495 (59.6) | 4534 (60.2) | 5216 (60.0) | 4156 (58.5) | ||
| Insulin | 2811 (28.6) | 2959 (26.0) | 2055 (27.3) | 2060 (27.3) | 2200 (25.3) | 2073 (29.2) | ||
| Oral anti-diabetes drugs | 3330 (33.9) | 3731 (32.8) | 2516 (33.4) | 2503 (33.2) | 2816 (32.4) | 2450 (34.5) | ||
| Angiotensin converting enzyme inhibitor | 4623 (47.0) | 5391 (47.4) | 3574 (47.4) | 3595 (47.7) | 4078 (46.9) | 3387 (47.7) | ||
| Inhaled β2 agonists | 1004 (10.2) | 1216 (10.7) | 794 (10.5) | 789 (10.5) | 912 (10.5) | 733 (10.3) | ||
| Intravenous heparin | 5008 (50.9) | 4930 (43.3) | 3518 (46.7) | 3552 (47.1) | 3768 (43.3) | 3810 (53.6) | ||
| Intravenous nitroglycerin | 2192 (22.3) | 3066 (26.9) | 1862 (24.7) | 1866 (24.8) | 2357 (27.1) | 1504 (21.2) | ||
| Intravenous inotropes | 909 (9.2) | 858 (7.5) | 602 (8.0) | 613 (8.1) | 605 (7.0) | 589 (8.3) | ||
| Intensive care unit admission | 4692 (47.7) | 6369 (55.9) | 3827 (50.8) | 3850 (51.1) | 4844 (55.7) | 3347 (47.1) | ||
| Cardiac resuscitation | 34 (0.3) | 52 (0.5) | 26 (0.3) | 26 (0.3) | 35 (0.4) | 24 (0.3) | ||
| Echocardiography | 4067 (41.4) | 4563 (40.1) | 3057 (40.6) | 3115 (41.3) | 3460 (39.8) | 3019 (42.5) | ||
| Mechanical ventilation | 60 (0.6) | 79 (0.7) | 50 (0.7) | 49 (0.7) | 63 (0.7) | 42 (0.6) | ||
| Dialysis | 146 (1.5) | 153 (1.3) | 107 (1.4) | 113 (1.5) | 123 (1.4) | 95 (1.3) | ||
| Hospital characteristics | ||||||||
| Teaching hospital | 5798 (59.0) | 5566 (48.9) | 4007 (53.2) | 4014 (53.3) | 4128 (47.5) | 4387 (61.8) | ||
| Urban hospital | 9036 (91.9) | 10 614 (93.2) | 6955 (92.3) | 6954 (92.3) | 8099 (93.1) | 6584 (92.7) | ||
IQR=interquartile range; IV=instrumental variable; PS=propensity score.
Age was modeled as categorical variable in propensity score/instrumental variable models. Additional covariates that were included in propensity score/instrumental variable models and balanced after matching include marriage status; number of grafts; previous coronary artery bypass graft (CABG); mammary graft; packed red blood cell transfusion; intra-aortic balloon pump placement; aortic, mitral, or tricuspid valve replacement or repair; ventricular aneurysm repair; chronic liver disease; cancer; previous stroke; previous endocarditis; peripheral vascular disease; chronic hemostatic disorder; smoking; alcohol or drug misuse; carotid artery stenosis; gastroesophageal reflux disease; calcium channel blockers; aspirin/dipyridamole; fibrates; digoxin; rhythm control drugs; warfarin; glycoprotein IIb/IIIa inhibitor; thiazide diuretics; loop diuretics; angiotensin receptor blockers; aldosterone antagonists; direct renin inhibitor; systemic steroids; inhaled steroids; leukotriene inhibitors; theophylline; probiotics; sucralfate; oxygen use; telemetry; percutaneous angioplasty or stent; continuous positive airway pressure; preoperative length of stay; third of CABG volume; and region.