Sodium Bicarbonate Reduces Incidence of Contrast-Induced Nephropathy

A new study shows that shown that preprocedural treatment with sodium bicarbonate based hydration is the optimal treatment strategy to prevent contrast-induced nephropathy (CIN) during radiologic procedures.

Researchers from the University of Michigan (UMICH, Ann Arbor, MI, USA) worked with a team of international researchers to study the results of 17 randomized controlled trials, featuring a total of 2,633 subjects, to assess the effectiveness of saline versus sodium bicarbonate for the prevention of CIN. The researchers searched MEDLINE, EMBASE, The Cochrane library databases, the International Pharmaceutical Abstracts database, the ISI Web of Science, and conference proceedings. Random-effects models were used to calculate summary odds ratios. The researchers found that CIN occurred in 109 of the 1,327 patients treated with sodium bicarbonate, and in 175 of the 1306 patients who received normal saline. The researchers concluded that reprocedural hydration with sodium bicarbonate was associated with a significant decrease in the rate of CIN; no significant difference in the rates of postprocedure hemodialysis or death was observed. The researchers hypothesized that--while the exact mechanism of CIN is still unknown--sodium bicarbonate might prevent CIN by increasing the alkalinity of urinary tubular fluid, creating an environment less amenable to free radical production. The study was published on May 13, 2009 in the open access journal BMC Medicine, a publication of BioMed Central.

"Contrast agents are administered in millions of procedures annually worldwide. In the USA and Europe, contrast-induced nephropathy (CIN) is the third leading cause of acute renal failure in hospitalized patients, accounting for about 10% of hospital-acquired renal failure," said lead author Hitinder Gurm, M.D. "Although CIN is generally limited to a transient decline of renal function, it cannot be regarded as a benign complication; as many as 30% of cases result in lasting kidney damage."

CIN is defined as either a greater than 25% increase of serum creatinine or an absolute increase in serum creatinine of 0.5 mg/dL. Three factors have been associated with an increased risk of contrast-induced nephropathy: preexisting renal insufficiency, preexisting diabetes, and reduced intravascular volume. Patients should be properly hydrated, preferably via intravenous (IV) means, both before and after contrast administration.

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