NEW YORK (Reuters Health) – Acute kidney injury induced by contrast medium exposure increases the risk of serious adverse events (AEs) during the following year, prospective study findings indicate.

Retrospective studies have established an association between contrast-induced nephropathy (CIN) and AEs, but without prospective studies, the cause-effect relationship was not clear, investigators in the US and Canada note in the June 25 online issue of the Clinical Journal of the American Society of Nephrology.

The research team, led by Dr. Richard J. Solomon at the University of Vermont, Burlington, collected 1-year follow-up data on 294 participants in the prospective, double-blinded Cardiac Angiography in Renally Impaired Patients (CARE) Study. Seventy-eight percent were age 65 or older.

In the original study, patients were randomly assigned to receive either the low-osmolar, nonionic monomer iopamidol (Isovue) or the iso-osmolar, nonionic dimer iodixanol (Visipaque) while undergoing cardiac angiography.

Results at 12 months showed that 31% of the patients experienced adverse events, and 13% experienced a major event (death, stroke, MI, or end-stage renal disease requiring dialysis). When CIN was defined as a 15% or greater increase in serum cystatin C, the overall incidence of CIN was 24.8%.

Adverse events were significantly increased in the CIN group (42% vs. 26%, p = 0.02). After adjustment for baseline factors that might contribute to long-term adverse events, the incidence rate ratio for CIN was 2.0 (p = 0.0291).

Furthermore, Dr. Solomon and associates report,