Contrast-induced nephropathy and long-term adverse events: cause and effect?
OBJECTIVE
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.


METHODS
We obtained long-term (> or =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 chi(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.
Solomon
Richard J
RJ
Department of Renal Services, Fletcher Allen Health Care, Burlington, VT 05401, USA. richard.solomon@vtmednet.org
Mehran
Roxana
R
Natarajan
Madhu K
MK
Doucet
Serge
S
Katholi
Richard E
RE
Staniloae
Cezar S
CS
Sharma
Samin K
SK
Labinaz
Marino
M
Gelormini
Joseph L
JL
Barrett
Brendan J
BJ
D058186:Acute Kidney Injury / Q000139:chemically induced* / Q000453:epidemiology / Q000517:prevention & control*; D000293:Adolescent; D000328:Adult; D000368:Aged; D015897:Comorbidity; D003287:Contrast Media / Q000009:adverse effects*; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006331:Heart Diseases / Q000000981:diagnostic imaging*; D006801:Humans; D015994:Incidence; D007479:Iopamidol / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012307:Risk Factors; D013997:Time Factors; D014283:Triiodobenzoic Acids / Q000009:adverse effects*; D055815:Young Adult
C525030:CST3 protein, human; D003287:Contrast Media; D055316:Cystatin C; D014283:Triiodobenzoic Acids; D003404:Creatinine; C044834:iodixanol; D007479:Iopamidol