Impact of Recurrent Acute Kidney Injury on Patient Outcomes

Background/aims: Recurrent acute kidney injury (AKI) is common among patients after a first hospitalized AKI. However, little is known about the prognosis of recurrent AKI episodes in chronic kidney disease (CKD) development, cardiovascular events and mortality.

Methods: A retrospective study included patients admitted to our Hospital from 2000 to 2010. AKI was defined according to the Acute Dialysis Quality Initiative criteria. In the follow-up period after the first AKI episode, clinical, laboratory data and the number of repeated AKI episodes, etiology and severity were recorded.

Results: Among the 359 AKI survivor patients included, 250 new AKI episodes were observed in 122 patients (34%). Variables independently associated to new episodes were: type 2 DM [OR 1.2, 95%CI 1.2-3.8, p=0.001], ischemic heart disease [OR 1.9; 95%CI 1.1-3.6, p=0.012], and SCr at the first AKI event>2,6 mg/dl [OR 1.2; 95%CI 1.03-1.42, p=0.02]. Development of CKD during four years follow-up was more frequent in patients with recurrent AKI, HR [2.2 (95% CI: 1.09-4.3, p=0.003)] and 44% of recurrent AKI patients who developed CKD occurred during the first 6 months after the initial event. Cardiovascular events were more frequent among patients with recurrent AKI patients than in those with one AKI episode (47.2% vs 24%, p=0.001). Mortality at 4 years was higher in the patient subgroup with several episodes of AKI as compared with those with a single episode [HR: 4.5 (95% CI 2.7-7.5) p<0.001].

Conclusion: Episodes of recurrent AKI have a high potential to be associated with relevant complications such as cardiovascular events, mortality and CKD development.