Incidence of acute kidney injury in cancer patients: a Danish population-based cohort study.

Cancer patients may be at increased risk of acute kidney injury, but evidence is limited. We assembled a cohort of incident cancer patients diagnosed within a population-based hospital setting in Northern Denmark (population:~1.2 million) between 1999 and 2006. Patients were followed up to five years for acute kidney injury, identified using creatinine measurements recorded in a laboratory database covering the study area. Acute kidney injury was defined according to recent consensus criteria as a 50% increase in creatinine level. We computed incidence rate, 1-year, and 5-year risks of acute kidney injury, accounting for competing risk from death. Acute kidney injury incidence was compared between cancers using a Cox regression model adjusted for important confounders. Among 37,267 incident cancer patients with a creatinine measurement, 9613 (25.8%) developed acute kidney injury during 77,376 person-years. The incidence was 258 (95%CI: 252-264) per 1000 person-years the first year after cancer diagnosis decreasing to 43 (95%CI: 41-44) thereafter. The 1-year risk was 17.5% (95%CI: 17.1-17.9%), and the 5-year risk was 27.0% (95%CI: 26.5-27.5%). We observed the highest 1-year risk in patients with kidney cancer [44.0% (95%CI: 40.5-47.5)], liver cancer [33.0% (95%CI: 28.2-37.8%)], or multiple myeloma [31.8% (95%CI: 27.3-36.3%)]. Similar results were observed after adjustment for confounders. Both overall and for most specific cancer sites, risks were higher among patients with distant metastases at cancer diagnosis. Acute kidney injury is a common complication in cancer patients, particularly in patients with kidney cancer, liver cancer, or multiple myeloma. Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.