Cesar Augusto Lam MD, Presenter: Nothing to Disclose

Christina Eldredge MD, MS, Abstract Co-Author: Nothing to Disclose

Glenn Bushee, Abstract Co-Author: Nothing to Disclose

Rahul N. Sawlani MD, Abstract Co-Author: Nothing to Disclose

Bradley W. Taylor BS, Abstract Co-Author: Nothing to Disclose

Charles E. Kahn MD, MS, Abstract Co-Author: Shareholder, Hotlight Inc Officer, Hotlight Inc

Whether contrast-induced nephropathy (CIN) is a real disorder or an artifact of prior studies is controversial. We sought to explore the effect of IV contrast on kidney function. We applied an i2b2 (Informatics for Integrating Biology and the Bedside) platform – an open-source, scalable framework to link biomedical research datasets to clinical record systems – to query a large, de-identified patient population to examine the validity of CIN.

A 3-year retrospective review of a large academic medical center’s electronic medical record system was performed using i2b2 software. CT exams (with or without IV contrast) with associated serum creatinine (SCr) results (within 24 hours before and within 72 hours after the exam) were obtained.

We reviewed 25,202 CT examinations of 18,384 patients. Of these, 17,718 exams (72.9%) and 12,673 patients (70.3%) received IV contrast.  Both groups (contrast enhanced and Non contrast enhanced) demonstrated a statistically significant decrease in SCr with a P<0.0001 for both groups. For the non-contrast group, the SCr mean (Std) before exam 1.76(+/- 1.73) and after exam 1.57(+/- 1.56) for a mean (Std) difference of -0.19 (+/- 0.91) [CI -0.21,-0.17; P<0.0001]. For the contrast group, the SCr mean (Std) before exam 1.10 (+/- 1.30) and after 1.04 (+/- 1.24) revealed a mean (Std) difference of -0.06 (+/- 0.54); [CI -0.07, -0.05: P<0.0001]. The incidence of CIN (defined by a 25% or 0.5 mg/dL increase in SCr) in a subset of patients in the contrast group with a baseline (pre-exam) SCr >1.3 SCr (n=1941) was statistically significant (p<0.001) with an absolute risk of 3.5 (1.6-5.5%) and relative risk 1.28 (1.12-1.47).

The existence of contrast induced nephropathy is controversial. Our preliminary results indicate that the average creatinine value decreased after the CT exam in both contrast enhanced and non-contrast enhanced groups, although the incidence of CIN increased in patient’s with an increased SCr at baseline. We are in the process of further stratifying additional data points (GFR, age, gender, and hospital setting [ER, inpatient, or outpatient]) to establish their significance.

Several recent large scale retrospective articles have suggested that contrast induced nephropathy (CIN) may not exist when comparing contrast enhanced CT’s to non-contrast CT control groups.

Lam, C, Eldredge, C, Bushee, G, Sawlani, R, Taylor, B, Kahn, C, Assessing the Validity of Contrast Induced Nephropathy Using the i2b2 Informatics Framework: A Retrospective 3-year Electronic Medical Record Review.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018500.html