[Prevention of contrast-induced nephropathy: time for nuance and a new guideline].

Contrast-induced nephropathy (CIN) is defined as an increase in serum creatinine following intravascular administration of iodinated contrast media. Patients with pre-existing kidney disease therefore receive intravenous periprocedural hydration, as recommended by guidelines. The costs for preventive hydration are high, EUR 56.6 million annually in the Netherlands alone. However, evidence on the efficacy of this preventive measure is scarce. There are only two randomized placebo-controlled trials on the efficacy of hydration. Hard evidence proving a causal relationship between CIN and morbidity or mortality is lacking, although some associations have been found. In the vast majority of CIN patients, renal function recovers within weeks or months. Research is needed to study whether patients with mild chronic kidney disease truly benefit from preventive hydration.