[3] There are multiple risk factors of contrast-induced nephropathy, whereof a 2016 review emphasized chronic kidney disease, diabetes mellitus, high blood pressure, reduced intravascular volume, and old age.
[4] European guidelines classify a pre-existing decreased kidney function to be a risk factor of contrast-induced nephropathy in the following cases:[5] To calculate estimated GFR (a measure of kidney function) from creatinine, European guidelines use the CKD-EPI formula in adults ≥ 18 years, and the revised Schwartz formula in children.
[5] The Mehran score is a clinical prediction rule to estimate probability of CIN which includes the following risk factors: systolic blood pressure <80 mm Hg for at least one hour requiring inotropic support, intra-aortic balloon pump, congestive heart failure with New York Heart Association Functional Classification class III or worse, history of pulmonary edema, age >75 years, hematocrit level <39% for men and <35% for women, diabetes mellitus, contrast media volume, decreased kidney function (serum creatinine level >1.5 g/dL or decreased estimated glomerular filtration rate).
[6][7] European guidelines include the following procedure-related risk factors:[5] Swedish guidelines list the following additional risk factors:[5] The main alternatives in people with a risk of contrast-induced nephropathy are:[citation needed] According to European guidelines, the ratio of the contrast dose (in grams of iodine) divided by the absolute estimated glomerular filtration rate (GFR) should be less than 1.1 g/(ml/min) for intra-arterial contrast medium administration with first-pass renal exposure (not passing lungs or peripheral tissue before reaching the kidneys).
[5] Swedish guidelines are more restrictive, recommending a ratio of less than 0.5 g/(ml/min) in patients with risk factors and irrespective of route of administration, and even more caution in first-pass renal exposure.
Several studies have shown that intravenous contrast material administration was not associated with excess risk of acute kidney injury, dialysis, or death, even among patients with comorbidities reported to predispose them to nephrotoxicity.