Patients with diabetes mellitus (DM) are at increased risk of contrast-associated nephropathy irrespective of their baseline creatinine (Cr). We tested the efficacy of N-acetylcysteine (NAC) relative to hydration in unselected patients (irrespective of baseline Cr) with DM.

We conducted a randomized open-label study comparing hydration alone (combined oral and rapid intravenous hydration, n = 69) to NAC plus hydration (similar hydration protocol plus NAC 600 mg BID × 4 doses, n = 68) in diabetic patients (mean age 65 ± 10 years, 65% men) undergoing elective coronary angiography. The primary end point was the mean change in serum Cr measured up to 96 hours postangiography.

Baseline Cr was 1.14 ± 0.43 mg/dL (Cr ≥1.3 mg/dL in 37 subjects). Baseline characteristics including blood urea nitrogen, Cr, and contrast volume were similar between the 2 groups. The mean Cr change in the NAC group was 0.14 ± 0.47 versus 0.08 ± 0.11 mg/dL in the hydration only group (P = NS). Contrast-associated nephropathy, defined as a ≥0.5 mg/dL increase in Cr, was significantly more common in the NAC group, 9.2% versus 1.4%, P = .043. Similar results were found in the subgroup of participants with either an increased baseline serum Cr (≥1.3 mg/dL) or in those receiving high contrast volumes (>100 mL).

N-Acetylcysteine provides no benefit over an aggressive hydration protocol in patients with DM undergoing coronary angiography.