Study designs of evaluations included in the review
Randomised controlled trials were eligible for inclusion in the review. All included studies were placebo controlled.
Specific interventions included in the review
Studies on NAC in conjunction with coronary angiography for patients receiving intravenous fluids and low osmolarity non-ionic contrast media were eligible for inclusion. The included studies varied in the NAC dose given before and after contrast exposure, the method of intake (oral or intravenous), and the time NAC was introduced before and tapered after the procedure. The intravenous fluid regimen was most commonly 0.45% saline, 1 mL per kg, 12 hours before and 12 hours after contrast.
Participants included in the review
Studies of patients with impaired renal function with a creatinine level over 1.2 mg/dL were eligible for inclusion. The proportion of diabetic patients in the included studies ranged from 36 to 63%, and the mean baseline serum creatinine level ranged from 1.2 to 2.8 mg/dL.
Outcomes assessed in the review
The primary outcome was CIN, defined as an increase in creatinine level of either at least 0.5 mg/dL or more than 25% from baseline to 48 hours after contrast administration. The secondary outcome was the occurrence of acute renal failure requiring dialysis. The review also reported the baseline and mean 48-hour serum creatinine level for the intervention and control groups and the mean contrast volume.
How were decisions on the relevance of primary studies made?
Two reviewers independently screened the studies. Any disagreements were resolved by discussion.