Date of Award

January 2013

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)



First Advisor

Steven Coca

Subject Area(s)



Few studies have examined the ability of urinary biomarkers to associate with recovery from acute kidney injury (AKI), a common complication for hospitalized patients that is independently associated with severe morbidity and mortality. We hypothesized that urinary biomarkers of kidney injury (NGAL, IL-18) or repair (YKL-40) would be associated with renal recovery in patients with severe AKI.

We prospectively enrolled 48 patients admitted at Yale New Haven Hospital with severe AKI (AKIN Stage 3). Daily morning urine samples were collected (until recovery up to max of 9 days). Levels of urinary YKL-40, NGAL, and IL-18 were measured. The primary exposures were the concentrations of the biomarkers on the first, last, and average daily values of the biomarker during enrollment. The primary outcome was renal recovery at discharge and was classified as "complete" if SCr ≤1.4 mg/dL, "partial" if SCr >1.4 and lower than peak SCr reached, and "non-recovery" if SCr > 4mg/dL or death.

Fifteen patients recovered completely, 17 recovered partially, and 16 did not recover (11 due to death). Mean time to partial recovery from the first sample collection was 2.47 ± 1.92 days and mean time to complete recovery was 6.60 ± 4.03 days. Median values of the day 1, average, last NGAL (p= 0.01, p=0.01, and p <0.01) and last YKL-40 (p=0.02) were significantly higher in patients that did not recover from AKI, compared to those that experienced partial or complete recovery. The AUCs for non-recovery for day 1, average, and last NGAL were 0.76, 0.77, and 0.81, for YKL-40 0.58, 0.66, and 0.75, and for IL-18 0.54, 0.55, and 0.59 respectively.

In conclusion, high values of YKL-40 and NGAL appear to be associated with non-recovery from severe while IL-18 did not discriminate between recovery and non-recovery in this cohort of patients. Larger studies will need to confirm these findings.