We sought to develop a simple risk score of contrast-induced nephropathy (CIN) after
percutaneous coronary intervention (PCI).
Although several risk factors for CIN have been identified, the cumulative risk rendered
by their combination is unknown.
A total of 8,357 patients were randomly assigned to a development and a validation
dataset. The baseline clinical and procedural characteristics of the 5,571 patients
in the development dataset were considered as candidate univariate predictors of CIN
(increase >or=25% and/or >or=0.5 mg/dl in serum creatinine at 48 h after PCI vs. baseline).
Multivariate logistic regression was then used to identify independent predictors
of CIN with a p value <0.0001. Based on the odds ratio, eight identified variables
(hypotension, intra-aortic balloon pump, congestive heart failure, chronic kidney
disease, diabetes, age >75 years, anemia, and volume of contrast) were assigned a
weighted integer; the sum of the integers was a total risk score for each patient.
The overall occurrence of CIN in the development set was 13.1% (range 7.5% to 57.3%
for a low [<or=5] and high [>or=16] risk score, respectively); the rate of CIN increased
exponentially with increasing risk score (Cochran Armitage chi-square, p < 0.0001).
In the 2,786 patients of the validation dataset, the model demonstrated good discriminative
power (c statistic = 0.67); the increasing risk score was again strongly associated
with CIN (range 8.4% to 55.9% for a low and high risk score, respectively).
The risk of CIN after PCI can be simply assessed using readily available information.
This risk score can be used for both clinical and investigational purposes.