WEDNESDAY, Sept. 3 (HealthDay News) -- Hydrating kidney disease patients with sodium bicarbonate during coronary angiography is no more effective in reducing the risk of serious kidney disease than hydration with sodium chloride, researchers say.

Nephropathy is a serious kidney disorder and a known complication of exposure to the iodine in the contrast agent used during angiography. The risk of nephropathy related to contrast agents ranges from 2 percent in low-risk people to 50 percent in those who are at high-risk.

Previous animal studies and one randomized clinical trial have suggested that hydration with sodium bicarbonate may be effective in preventing contrast-induced nephropathy.

A new study in the Sept. 3 Journal of the American Medical Association looked at 353 people with moderate to severe kidney disease who were undergoing coronary angiography. The researchers randomly assigned the patients to receive either sodium chloride or sodium bicarbonate before, during, and after their angiography.

Overall, 13.9 percent of the patients developed contrast-induced nephropathy.

There was no difference between the sodium chloride and the sodium bicarbonate groups in terms of developing nephropathy. Nor were there differences between the groups in the rates of death, dialysis, heart attack, and cerebrovascular events.

These findings suggest that hydration with sodium bicarbonate is not superior to hydration with sodium chloride in kidney disease patients who are undergoing coronary angiography, say the researchers.

"Any true difference between the hydration strategies is likely to be small and not clinically significant," the study's authors wrote.

More information

The National Heart, Lung, and Blood Institute has more about coronary angiography.