Systematic oral hydration with water is similar to parenteral hydration for prevention of contrast-induced nephropathy: an updated meta-analysis of randomised clinical data

Abstract

Background: Contrast-induced nephropathy (CIN) is the third most common cause of hospital-acquired kidney injury and is related to increased long-term morbidity and mortality. Adequate intravenous (IV) hydration has been demonstrated to lessen its occurrence. Oral (PO) hydration with water is inexpensive and readily available but its role for CIN prevention is yet to be determined.

Methods: PubMed, EMBASE and the Cochrane Central register of controlled trials (CENTRAL) databases were searched until April 2015 and studies were selected using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. All randomised clinical trials with head-to-head comparison between PO and IV hydration were included.

Results: A total of 5 studies with 477 patients were included in the analysis, 255 of those receiving PO water. The incidence of CIN was statistically similar in the IV and PO arms (7.7% and 8.2%, respectively; relative risk 0.97; 95% CI 0.36 to 2.94; p=0.95). The incidence of CIN was statistically similar in the IV and PO arms in patients with chronic kidney disease and with normal renal function. Rise in creatinine at 48-72 h was lower in the PO hydration group compared with IV hydration (pooled standard mean difference 0.04; 95% CI 0.03 to 0.06; p<0.001; I(2)=62%).

Conclusions: Our meta-analysis shows that systematic PO hydration with water is at least as effective as IV hydration with saline to prevent CIN. PO hydration is cheaper and more easily administered than IV hydration, thus making it more attractive and just as effective.

Figures

Figure 1

Risk of bias assessments for included studies. This is the risk of bias assessment based on author assessment according to the Cochrane Risk of Bias Assessment Tool. A notation of ‘+’ suggests a low risk of bias; a ‘−’ notation suggests a high risk of bias and a ‘?’ notation suggests an uncertain risk of bias.

Figure 2

Funnel plot analysis of included trials. Circles indicate studies with patients with CKD. Diamonds indicate studies with patients with normal kidney function (CKD, chronic kidney disease; RD, risk difference).

Figure 3

Flow chart for the selection of studies. Flow diagram representing the number of studies screened, reviewed and included in analysis.

Figure 4

Incidence of contrast-induced nephropathy in patients with CKD, normal kidney function and all patients. The boxes and lines indicate the RRs and their CIs. Weights are from random-effects analysis. The size of the box indicates the relative weight of each estimate. Diamonds indicate the combined RRs (CKD, chronic kidney disease; IV, intravenous; PO, oral; RRs, relative risks).

Figure 5

Standard mean difference of change in creatinine between the intravenous (IV) versus oral (PO) arm. The boxes and lines indicate the relative risks (RRs) and their CIs. Weights are from random-effects analysis. The size of the box indicates the relative weight of each estimate. Diamonds indicate the combined RRs.