Estimating baseline kidney function in hospitalized patients with impaired kidney function

Defining measures of kidney function in observational studies using routine health care data: methodological and reporting considerations

“…Researchers are then left with the option of applying different windows to identify prior serum creatinine measurements to define as to who had AKI. 62,[86][87][88][89] Nevertheless, for a proportion of patients, a creatinine test within the specified period will be lacking.…”