Study finds patients with diabetes, liver disease at high risk for nephropathy

The factors associated with clinically significant contrast-induced nephropathy are a low estimated glomerular filtration rate (<40 mL/min/1.73 m²), inpatient status, liver disease, use of loop diuretics, and diabetes, according to a May 19 presentation at the 2009 International Symposium on Multidetector-Row CT.

Symposium codirector Dr. Geoffrey D. Rubin gave the presentation for Dr. Steven D. Weisbord, a nephrologist with the VA Pittsburgh Healthcare System, who was unable to attend. Patients who fall into the above categories are those most at risk of developing contrast-induced nephropathy, Weisbord's PowerPoint presentation concludes.

A low glomerular filtration rate signals reduced kidney function, which, in turn, puts a patient at higher risk for contrast-induced nephropathy (CIN).

It should be noted the presence of CIN does not imply clinical significance, Rubin said on Weisbord's behalf. Often CIN resolves on its own, and the condition is relatively uncommon, occurring in approximately 2% of patients.

Despite its low occurrence, CIN does happen, and the best way to prevent the reaction is to identify patients who are at risk, according to Weisbord.

While determining which patients are at high risk, it is also important to choose the right intravenous fluid for contrast administration. Weisbord concludes that isotonic IV fluids are more effective than hypotonic fluids in preventing CIN and data are insufficient to support using sodium bicarbonate over sodium chloride. It is important to note, however, overall incidence of clinically significant CIN is low and intravenous fluids should be used only for high-risk patients.

The presentation was based on a study by Weisbord and colleagues published in the Clinical Journal of the American Society of Nephrology involving 421 patients (2008;3:1274-1281). In it the researchers found CIN in 6.5% of their patients and clinically significant CIN in only 2%. The odds ratio for inpatient versus outpatient status was 5.4. It was 5.5 for liver disease and 4 for use of loop diuretics.