Table 1.
Baseline characteristicsa
| Characteristic | No Treatment (n = 10,411) | Sodium Bicarbonate + NAC (n = 221) | NAC Alone (n = 616) | Sodium Bicarbonate Alone (n = 268) |
|---|---|---|---|---|
| Age, mean (SD) | 60.2 (17.1) | 70.9 (12.4) | 68.6 (14.5) | 64.4 (16.8) |
| Male, n (%)b | 5458 (52) | 125 (57) | 363 (59) | 149 (56) |
| White, n (%)b | 8844 (85) | 189 (86) | 532 (86) | 231 (86) |
| Black, n (%) | 123 (1) | 3 (1) | 13 (2) | 3 (1) |
| Iodine load, mean (SD), g | 37.6 (21.3) | 34.1 (9.1) | 35.5 (14.5) | 34.5 (11.2) |
| Volume of contrast, mean (SD), ml | 122.6 (68.8) | 109.0 (28.1) | 113.1 (44.0) | 110.9 (35.5) |
| Average prior creatinine, mean (SD), mg/dl | 1.05 (0.41) | 1.38 (0.58) | 1.29 (0.42) | 1.20 (0.64) |
| Total hydration, mean (SD), mlc | 3218 (2580) | 2517 (2810) | 2038 (2429) | 3005 (3998) |
| Any prior contrast exposure, n (%) | 3096 (30) | 106 (48) | 223 (36) | 114 (43) |
| Type of study | ||||
| computerized tomography, n (%) | 9126 (88) | 166 (75) | 438 (71) | 223 (83) |
| noncardiac angiography, n (%) | 572 (5) | 8 (4) | 54 (9) | 19 (7) |
| coronary catheterization, n (%) | 584 (6) | 47 (21) | 124 (20) | 26 (10) |
| plain film, n (%) | 129 (1) | 0 (0) | 0 (0) | 0 (0) |
| Comorbid diseases | ||||
| diabetes mellitus, n (%) | 1617 (16) | 74 (33) | 193 (31) | 49 (18) |
| hypertension, n (%) | 4230 (41) | 137 (62) | 402 (65) | 146 (54) |
| congestive heart failure, n (%) | 898 (9) | 54 (24) | 130 (21) | 46 (17) |
| renal disease, n (%) | 128 (1) | 10 (5) | 26 (4) | 10 (4) |
| multiple myeloma, n (%) | 138 (1) | 6 (3) | 14 (2) | 4 (1) |
| Medications | ||||
| ACE inhibitors, n (%) | 1796 (17) | 71 (32) | 196 (32) | 73 (27) |
| ARBs, n (%) | 757 (7) | 35 (16) | 84 (14) | 21 (8) |
| acetylsalicylic acid, n (%) | 3190 (31) | 106 (48) | 261 (42) | 106 (40) |
| β-blockers, n (%) | 2166 (21) | 101 (46) | 193 (31) | 98 (37) |
| diuretics, n (%) | 2512 (24) | 95 (43) | 274 (44) | 87 (32) |
| NSAIDs, n (%) | 1526 (15) | 11 (5) | 46 (7) | 27 (10) |
a
No Treatment, neither sodium bicarbonate nor N-acetylcysteine; NAC, N-acetylcysteine; ACE, angiotensin-converting enzyme; ARB, angiotensin receptor blocker; NSAIDs, nonsteroidal antiinflammatory drugs.
b
Race was available in 90%, 91%, 90%, and 91% of the no treatment, sodium bicarbonate + NAC, NAC alone, and sodium bicarbonate along groups, respectively.
c
Total volume of hydration in the 24 h before contrast administration was available for 100% of the cases that received N-acetylcysteine, sodium bicarbonate, or both agents. Hydration information was available in 3785 (36%) of the No Treatment group because of the vast majority of outpatients in this group compared to the other three groups.