Incidence and prognosis of acute kidney injury versus acute kidney disease among 71 041 inpatients

BACKGROUND: Acute kidney disease (AKD) defines patients with acute kidney injury (AKI) or subacute loss of kidney function lasting for >7 days. Little is known about the prognosis of AKD in hospitalized patients. The aim of this study was to investigate the risk factors and prognosis of AKD and to compare different types of acute/subacute renal impairment among Chinese inpatients. METHODS: Complete data were available for 71 041 patients for a range of 5–63 months. AKI and AKD were diagnosed based on the Acute Disease Quality Initiative criteria of 2017. RESULTS: Of 71 041 inpatients, 16 098 (22.7%) patients developed AKI or AKD; 5895 (8.3%) AKI patients recovered within 7 days, 5623 (7.9%) AKI patients developed AKD and 4580 (6.4%) patients developed AKD without AKI. Mortality was proportional to stages of AKI and AKD (P < .05), while AKI followed by AKD was associated with a higher risk of long-term mortality [hazard ratio (HR) 4.51] as compared with AKD without AKI (HR 2.25) and recovery from AKI (HR 1.18). The AKD criteria were robustly associated with overall survival [area under the receiver operating characteristic curve (AUROC) 0.71] and de novo CKD (AUROC 0.71), while the AKI criteria showed a relatively lower ability to fit the risk of overall survival (AUROC 0.65) and CKD (AUROC 0.63). CONCLUSIONS: AKD and AKD stages are useful clinical definitions for clinical practice, as they predict unfortunate clinical outcomes such as overall long-term mortality and CKD. Research activities should focus on AKD.