• To investigate the etiology and epidemiology of acute kidney injury (AKI).
• To find out risk factors associated with the occurence of AKI.
• To find out risk factors related to the prognosis of AKI,focusing on uremic toxins, inflammation, oxidative stress and nutritional status.
• To study on the relationship between gene polymorphism and prognosis of acute kidney injury.

1. To investigate the relationship between preexisting protein-energy wasting (PEW) and adverse outcomes in patients with AKI.
2. To evaluate the association of serum nutritional variables and prognosis of AKI.
3. Given the different half-lives of serum nutritional markers, we hypothesized that the utility of serum nutritional variables as prognostic predictors may differ in early death (<7 days) and late death (>7 days, <28 days) patients.
4. To investigate the various kinds of uremic toxins in AKI, furthermore, to evaluate the relationship between uremic toxins, especially protein bound toxins, and short- or long-term mortality in AKI patients.
5. To investigate the mineral bone disorders in AKI,and to evaluate whether these markers would role as prognostic predictors of AKI.
6. Several risk factors of mortality in AKI,such as markers of PEW, inflammation and serum creatinine,have been used; however, no single indicator is considered to be a "gold standard."

Inclusion Criteria:

• age >=18 years and <= 88 years
• clinically diagnosed with acute kidney injury, according KDIGO criteria.

Exclusion Criteria:

• preexisting chronic kidney failure (defined as an eGFR <60 ml/min per 1.73 m2)
• post-renal obstruction or rapid progressive glomerulonephritis as the main cause of AKI
• known acute renal dysfunction
• hospital stays <24 hours
• malignancy

adult patients aged >18 years, with hospital-acquired acute kidney injury, from a university-affiliated hospital in Shanghai, China.