Aim: To assess the relationship between type of contrast media (CM), iso-osmolar contrast media (IOCM) or low-osmolar contrast media (LOCM), and major adverse renal and cardiovascular events (MARCE). Materials & methods: Coronary or peripheral angioplasty visits were stratified into CM cohorts: IOCM or LOCM. Multivariable regression analysis used hospital fixed effects to assess the relationship between MARCE events and type of CM. Results: Among 333,533 visits (357 hospitals), the incidence of MARCE was 7.41%. After controlling for observable and unobservable time invariant within-hospital characteristics, administration of IOCM versus LOCM was associated with a 0.69% absolute and 9.32% relative risk reduction in MARCE rate. Conclusion: Our study indicates that as compared with LOCM, IOCM may be associated with reduction of MARCE events in coronary or peripheral angioplasty patients. Arterial angiography and percutaneous intervention require administration of iodinated contrast media (CM) to render the blood vessels radiographically opaque. Contrast-induced acute kidney injury (CI-AKI) is one of the major adverse events associated with administration of iodinated CM [1,2]. The most common definition of CI-AKI is a rise in serum creatinine levels by ≥0.3 mg/dl within 48 h of contrast administration. CI-AKI has been associated with progression to advanced stages of chronic kidney disease (CKD) and with increased risk for major adverse cardiac events (MACE) [3,4].CI-AKI is the third most common cause of hospital-acquired renal failure and is associated with increased morbidity, prolonged hospitalization and higher rates of in-hospital and long-term mortality [5,6]. The incidence of CI-AKI varies from 2% in the general population to over 50% in high-risk groups [7]. In studies of the impact of the osmolality of iodinated CM, the use of low-osmolar contrast media (LOCM) has been shown to substantially reduce the risk of nephropathy when compared with high-osmolar CM [8][9][10][11].In several studies, iodixanol, iso-osmolar contrast media (IOCM) have been associated with lower risk for CI-AKI when compared with LOCM [12][13][14][15][16]. In a meta-analysis of 16 randomized controlled trials, McCullough et al. found that CI-AKI occurred less frequently for all patients in the iodixanol group when compared with the LOCM group [15]. Similar findings were reported for the subgroup of patients with CKD and for patients with CKD and diabetes mellitus. More recent meta-analysis concluded that iodixanol use was associated with less nephrotoxicity compared with LOCM and that use of iodixanol was associated with significantly fewer contrast-induced nephropathy events compared with LOCM [12]. Both meta-analyses concluded that intra-arterial