Meta-analysis Shows No Relationship Between CIN and Permanent Renal Failure
While there are safety guidelines in place protecting patients from experiencing contrast induced nephropathy (CIN) as a result of undergoing intravenous contrast enhanced CT (CECT), Shira Moos, M.D., and colleagues were interested in finding out how serious a problem CIN actually is in these cases.
By Mike Bassett
In research presented Monday at RSNA 2014, Dr. Moos, of the Department of Radiology, Academic Medical Center, University of Amsterdam, the Netherlands, sought to determine exactly how many patients developed CIN after receiving CECT. "And more importantly," she said, "what were the real consequences" of CIN as it relates to long-term adverse events, such as permanent renal failure, renal replacement therapy, and death.
Dr. Moos and her colleagues performed a systematic review and meta-analysis of relevant literature and identified 15 studies covering 4,455 patients. Of those patients, 8.2 percent developed CIN—a figure that may be on the high side considering that other studies have shown that lower percentages of patients develop CIN, she said.
For purposes of the study, Dr. Moos and her colleagues defined CIN as either a 25% increase in serum creatinine from a baseline measure or 0.5 mg/dL (44 µmol/L) increase in absolute value, within two to five days of intravenous contrast administration.
Of the patients in the study population who developed CIN, the incidence of permanent renal failure, renal replacement therapy, and death was 13.28 percent, 0.5 percent, and 13.46 percent, respectively. Dr. Moos and her colleagues calculated that the risk difference for permanent renal failure was 0.07 between CIN patients and patients without CIN, 0.05 for renal replacement therapy, and 0.15 for death.
Consequently, Dr. Moos said, the researchers found no relationship between CIN and permanent renal failure. "Which means that most patients who developed CIN had their kidney function normalize within a week," she said. "And patients didn't see any increase in kidney disease if they already had it, and if they had normal kidney function their kidney values returned to normal."
In addition, the researchers found no relationship between CIN and the need for renal replacement therapy. "Based on our research, it is safe to say that patients who develop CIN don't really have a higher risk of developing permanent renal failure or needing renal replacement therapy," she said.
However, Dr. Moos said the results suggested that individuals who developed CIN had a higher risk of death. "Which was surprising, because the factors that we expected to increase the risk of death were permanent renal failure and the need for renal replacement therapy," she said. "But the incidence in the population of those two things were lower than the risk of death. So we see there is some kind of relationship there, but we really couldn't figure it out from the data."
Dr. Moos said that despite the apparent association between CIN and death, it is possible that death is less a consequence of CIN and more the result of a pre-existing co-morbidity.
Dr. Moos said a randomized control trial is needed to further study what the long-term outcomes are in patients after the administration of iodinated contrast.