Contrast-induced nephropathy: what are the true clinical consequences?

BACKGROUND AND OBJECTIVES Observational studies have demonstrated that short- and long-term mortality is increased in patients who develop contrast-induced nephropathy (CIN). The more clinically relevant questions, and the objectives of this review, are whether CIN is causally related to mortality, and to what extent could mortality in patients undergoing contrast procedures be reduced by preventing CIN. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A literature review was conducted, focusing on observational studies that assessed factors associated with mortality in patients with CIN. RESULTS The deaths of some patients with CIN are complicated by factors that cannot be directly related to CIN, such as liver disease, sepsis, respiratory failure, bleeding, etc. However, it is plausible that CIN contributes to cardiovascular causes of death in patients with CIN. CONCLUSIONS At the very least, CIN is a marker for increased mortality. More carefully designed prospective studies are needed to fully elucidate the relationship between CIN and death. In the absence of data disproving a causal relationship between CIN and death in all subgroups, reducing its incidence should remain a goal in clinical practice as well as a target for future research.