Why is bicarbonate therapy a controversial prevention method for contrast-induced nephropathy (CIN)?

Updated: Feb 21, 2020
  • Author: Anita Basu, MD, FACP; Chief Editor: Vecihi Batuman, MD, FASN  more...
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A 2008 retrospective cohort study at the Mayo Clinic assessed the risk of CIN associated with the use of sodium bicarbonate, NAC, and the combination of sodium bicarbonate with NAC and found that, compared with no treatment, sodium bicarbonate used alone was associated with an increased risk of CIN. NAC alone or in combination with sodium bicarbonate did not significantly affect the incidence of CIN. The results were obtained after adjusting for confounding factors, including total volume of hydration, medications, baseline creatinine, and contrast iodine load. [45] Given the above information, further evaluation of the use of sodium bicarbonate to prevent CIN was recommended.

Subsequently, a prospective, double-blind, multicenter randomized clinical trial in 391 patients with an estimated glomerular filtration rate (eGFR) < 45 ml/min/1.73 m2 undergoing elective coronary or peripheral angiography found no statistically significant difference between sodium bicarbonate and sodium chloride in terms of the incidence of the composite of death, dialysis, or sustained 6-month reduction in eGFR or contrast-induced acute kidney injury. This trial used a high dose of isotonic sodium bicarbonate (target 2.0 mEq/kg) or a similar molar amount of isotonic sodium chloride. [46]

Furthermore, a meta-analysis and systematic review of 29 studies concluded that overall, hydration with sodium bicarbonate could significantly reduce CIN and the length of hospital stay compared with sodium chloride and that the addition of NAC as a supplement to sodium bicarbonate could increase prophylactic effects against nephropathy. In addition, hydration with sodium bicarbonate was found to be more effective in emergency coronary imaging and high-risk patients than in elective coronary imaging. [47]

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