To follow up the long-term prognosis of acute kidney injury (AKI) patients with normal basic renal function, and to further identify the clinical features as well as risk factors associated with the prognosis of AKI patients.

Clinical date of 166 patients who occurred AKI episode during hospitalization from Jan 1 2011 to Dec 31 2014 in The First Affiliated Hospital of Fujian Medical University were retrospectively analyzed. All these patients had normal basic renal function and had follow-up of more than two years after discharge. According to their renal function after two years, patients were divided into recover and non-recover group. The clinical features and risk factors associated with the prognosis of AKI patients were identified using multivariate logistic regression, and the proportion of renal function progression was calculated during follow-up period.

One hundred and sixty-six patients were enrolled in this observational study, including 114 male, 52 female with an average age of 58.1±16.6. Eighty-seven patients were AKI stage 1, 39 AKI stage 2, and 40 AKI stage 3. Thirty-seven patients were caused by pre-renal factors, 113 patients by renal causes and 16 patients by post-renal causes. Renal function when discharged (P=0.002, OR=2.980) and infection (P=0.003, OR=2.786) were the risk factors of failing to restore after two years. Eighty-four patients' renal function returned to normal when discharged, but the number of patients whose renal function progressed to CKD 3 stage and even worse 1 year and two years later were 12 (14.3%) and 20 (23.8%) respectively. Fifty-four patients were diagnosed as partial recovery and 28 patients as non-recovery when discharged. One year later 22 (40.7%) and 12 (42.9%) patients' renal function progressed to CKD 3 stage and more, while those numbers became 28 (51.9%) and 16 (57.1%) two years later.

The risk factors of AKI long-term outcome include unrecovered renal function when discharged and infection. After AKI episode, even with fully recovered renal function, patients are still possible to progress to CKD, highlighting the importance of follow-up observation.

Acute kidney injury; Prognosis; Renal insufficiency, chronic; Risk factors