No IV hydration vs IV hydration in prevention of contrast-induced nephropathy: meta-analysis of randomized controlled trials

Abstract

Abstract Background Iodinated contrast is commonly utilized in modern medicine. However, it does not come free of risks. Incidence of contrast induced nephropathy is estimated to be 1% to 6% and can be as high as 50% in patients at high risk. IV hydration is routinely used to prevent Contrast-Induced Nephropathy (CIN). Recent randomized controlled trials (RCTs) suggested that no hydration is not inferior to hydration in prevention of CIN. Objective To evaluate the risk of forgoing IV hydration in patients undergoing procedures utilizing iodinated IV contrast. Methods We searched MEDLINE, COCHRANE, EMBASE databases for RCTs comparing no IV hydration to IV hydration in patients undergoing procedures utilizing IV iodinated contrast such as CT contrast and coronary interventions. Studies comparing any preventive measure to IV hydration were excluded. 6 RCTs were extracted that match our search criteria (1–6). 3 RCTs included patients undergoing percutaneous coronary intervention and 3 RCTs included patients with CKD stage III undergoing contrast CT. Outcome evaluated was the risk of Contrast-Induced Nephropathy in no IV hydration group compared to IV hydration group. Analysis was conducted initially using all 6 RCTs. Additional analysis was conducted using studies limited to contrast CT in patients with stage III chronic kidney disease (CKD) (3,5,6). Results A total of 1938 patients (972 in no IV hydration group vs 966 in IV hydration group) were analyzed from 6 RCTs. CIN occurred in 111 (11.4%) in no IV hydration group and in 62 (6.4%) in IV hydration group. Relative risk of CIN in no IV hydration group was 1.75 [95% CI 1.31–2.33, P=0.0001, I2=0%] (Figure 1). In our analysis utilizing trials limited to contrast CT in patients with CKD stage III, a total of 1261 patients (634 in no hydration group vs 627 in IV hydration group) were analyzed from 3 RCTs. 2 trials utilized IV sodium bicarbonate and 1 used IV normal saline in IV hydration arm. CIN occurred in 21 (3.3%) who did not receive prophylactic IV hydration and in 17 (2.7%) received IV hydration. There was no increased risk of CIN in patients who did not receive IV hydration in patients with CKD stage III underwent contrast CT. Relative risk was 1.24 [95% CI 0.66–2.32, P=0.51, I2=0%] (Figure 2). Conclusion In patients with CKD stage III undergoing IV contrast CT scans, withholding IV hydration is not associated with increased risk of CIN compared to IV hydration. Nevertheless, this conclusion does not apply to patients undergoing coronary intervention. The difference in outcome could be explained by the population undergoing coronary interventions which is typically higher risk, and the dose of contrast which is typically higher in coronary interventions than in contrast CT. Funding Acknowledgement Type of funding sources: None. Figure 1Figure 2