Hydration with sodium bicarbonate for the prevention of contrast-induced nephropathy: a meta-analysis of randomized controlled trials.

BACKGROUND: Whether hydration with sodium bicarbonate is beneficial for the prevention of contrast-induced nephropathy is uncertain.
METHODS: We conducted a meta-analysis of trials to evaluate the benefit of sodium bicarbonate solutions for the prevention of contrast-induced nephropathy. Our pre-specified criteria were; 1) adult subjects; 2) English literature 3) randomized trials of individuals assigned to a bicarbonate-containing intravenous solution versus an alternate solution; 4) an end-point that included the incidence of contrast-induced nephropathy 5) a uniform contrast agent. Trials in which certain additional prophylactic agents were allowed or administered in a non-standardized, non-stratified manner were ineligible.
RESULTS: Ten randomized comparisons of sodium bicarbonate versus sodium chloride satisfied study criteria (total n = 1,090). The majority of studies involved subjects undergoing cardiac angiography and a nonionic low osmolar contrast agent was used in most instances. Woolf's test showed no evidence of heterogeneity (p = 0.10; I2 = 39%) and there was no publication bias (p = 0.34). The effect size using the exact Mantel-Haenszel-test revealed an odds ratio (OR) of 0.57 (95% CI: 0.38 - 0.85) for the occurrence of contrast-induced nephropathy with the use of sodium bicarbonate. An analysis restricted to studies that employed hydration without additional prophylactic agents favored sodium bicarbonate to a greater extent (OR 0.33:95% CI: 0.17 - 0.62). However, many trials in this arena may not be considered high-quality studies.
CONCLUSION: Though inference should be tempered by trial quality issues, given lack of heterogeneity or publication bias the summary effect of randomized trials balanced in important characteristics favors hydration with sodium bicarbonate for the prevention of contrast-induced nephropathy.