Received January 23, 2009
Accepted on April 28, 2009

ORIGINAL ARTICLES

Contrast-Induced Nephropathy and Long-Term Adverse Events: Cause and Effect?

Richard J. Solomon ^*1, Roxana Mehran , Madhu K. Natarajan , Serge Doucet , Richard E. Katholi ^||, Cezar S. Staniloae ^¶, Samin K. Sharma ^**, Marino Labinaz , Joseph L. Gelormini , and Brendan J. Barrett

*Department of Renal Services, Fletcher Allen Health Care, Burlington, Vermont; Center for Interventional Vascular Therapy, New York-Presbyterian Hospital/Columbia University Medical Center, New York, New York; Division of Cardiology, Hamilton Health Sciences, Hamilton, Ontario, Canada; Montreal Heart Institute, University of Montreal, Montreal, Quebec, Canada; ||Department of Medicine, Prairie Educational and Research Cooperative, St. John’s Hospital, Springfield, Illinois; ¶Comprehensive Cardiovascular Center, St. Vincent’s Hospital Manhattan and Medical Center, New York, New York; **Cardiovascular Institute, Mount Sinai Medical Center, New York, New York; Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada; Interventional Cardiology, Buffalo Heart Group, Buffalo, New York; and Patient Research Centre, Health Science Center, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada

¹ To whom correspondence should be addressed. E-mail: richard.solomon{at}vtmednet.org.

	Abstract

Background and objectives: The relationship of contrast-induced nephropathy (CIN) to long-term adverse events (AEs) is controversial. Although an association with AEs has been previously reported, it is unclear whether CIN is causally related to these AEs.

Design, setting, participants, & measurements: We obtained long-term (1 yr) follow-up on 294 patients who participated in a randomized, double-blind comparison of two prevention strategies for CIN (iopamidol versus iodixanol). A difference in the incidence of AEs between patients who had developed CIN and those who had not was performed using a ² test and Poisson regression analysis. A similar statistical approach was used for the differences in AEs between those who received iopamidol or iodixanol. Multiple definitions of CIN were used to strengthen and validate the results and conclusions.

Results: The rate of long-term AEs was higher in individuals with CIN (all definitions of CIN). After adjustment for baseline comorbidities and risk factors, the adjusted incidence rate ratio for AEs was twice as high in those with CIN. Randomization to iopamidol reduced both the incidence of CIN and AEs.

Conclusions: The parallel decrease in the incidence of CIN and AEs in one arm of this randomized trial supports a causal role for CIN.