Objective:

This study aimed to understand the incidence of acute kidney injury in cancer patients, to figure out which clinical factors could increase the risks of acute kidney injury, and then to assess the effect of acute kidney injury on in-hospital mortality, length of stay, and hospital cost.

Methods:

This study was designed as a retrospective cohort study based on the hospital inpatient database in Zhongshan Hospital, Shanghai, China. Patients with malignancy and admitted to the hospital between 1 October 2014 and 30 September 2015 were recruited. Data on demographics, comorbidities, and clinical records were exported for analysis. Acute kidney injury was diagnosed using KDIGO (Kidney Disease: Improving Global Outcomes) criteria and stratified into community-acquired and hospital-acquired acute kidney injury. Multivariate model and survival analysis were applied to discover the influencing factors of acute kidney injury among cancer patients.

Results:

Of the 26,914 eligible cancer admissions, 3326 acute kidney injury cases were identified with an incidence of 12.4%. Of them, 2961 patients located in acute kidney injury stage 1 and another 365 cases developed to stage 2–3. The highest rates were localized to renal cancer (27.3%), multiple myeloma (24.1%), and leukemia (23.9%). Patients with older age and hematologic cancer shared a higher acute kidney injury incidence. Pre-existing chronic kidney disease (adjusted odds ratio = 7.14), heart failure (adjusted odds ratio = 4.20), surgery/chemotherapy (adjusted odds ratio = 0.99/2.28), hyponatremia (adjusted odds ratio = 2.84), hypokalemia (adjusted odds ratio = 2.42), and hyperuricemia (adjusted odds ratio = 2.62) were the major factors associated with acute kidney injury. In-hospital mortality for acute kidney injury patients was 5.1% as compared with those without acute kidney injury (0.8%). Survival analysis reveals that the risk of death was higher among patients with hospital-acquired acute kidney injury (adjusted hazard ratio = 4.50) and severe acute kidney injury stage (adjusted hazard ratio = 2.68/3.91). Furthermore, the length of stay (13.5 days) and hospital cost (45,066 CNY) were significantly greater in patients with community-acquired acute kidney injury.

Conclusion:

Acute kidney injury was common in cancer patients and associated with an ominous outcome. Pre-existing comorbidities, electrolyte disturbances, and abnormal biochemical were the predicting factors for acute kidney injury incidence. Better monitoring of electrolytes, identification of high-risk patients, and early acute kidney injury diagnosis should be considered as a priority during anti-cancer treatment.