Table 1.

Baseline characteristicsa

CharacteristicNo 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 (%)b5458 (52)125 (57)363 (59)149 (56)
White, n (%)b8844 (85)189 (86)532 (86)231 (86)
Black, n (%)123 (1)3 (1)13 (2)3 (1)
Iodine load, mean (SD), g37.6 (21.3)34.1 (9.1)35.5 (14.5)34.5 (11.2)
Volume of contrast, mean (SD), ml122.6 (68.8)109.0 (28.1)113.1 (44.0)110.9 (35.5)
Average prior creatinine, mean (SD), mg/dl1.05 (0.41)1.38 (0.58)1.29 (0.42)1.20 (0.64)
Total hydration, mean (SD), mlc3218 (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.