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Urinary angiotensinogen predicts adverse outcomes among acute kidney injury patients in the intensive care unit.

Alge JL, Karakala N, Neely BA, Janech MG, Velez JC, Arthur JM, SAKInet Investigato - Crit Care (2013)

Bottom Line: The uAnCR of patients with pre-renal AKI was lower compared to patients with AKI of other causes (median uAnCR 11.3 vs 80.2 ng/mg; P=0.02).Elevated urinary angiotensinogen is associated with adverse events in AKI patients in the ICU.It could be used to identify high risk patients who would benefit from timely intervention that could improve their outcomes.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: Acute kidney injury (AKI) is commonly observed in the intensive care unit (ICU), where it can be caused by a variety of factors. The objective of this study was to evaluate the prognostic value of urinary angiotensinogen, a candidate prognostic AKI biomarker identified in post-cardiac surgery patients, in this heterogeneous population.

Methods: Urinary angiotensinogen was measured by ELISA and corrected for urine creatinine in 45 patients who developed AKI in the ICU. Patients were grouped by AKI etiology, and the angiotensinogen-to-creatinine ratio (uAnCR) was compared among the groups using the Kruskal-Wallis test. The ability of uAnCR to predict the following endpoints was tested using the area under the ROC curve (AUC): the need for renal replacement therapy (RRT) or death, increased length of stay (defined as hospital discharge>7 days or death≤7 days from sample collection), and worsening AKI (defined as an increase in serum creatinine>0.3 mg/dL after sample collection or RRT).

Results: uAnCR was significantly elevated in patients who met the composite outcome RRT or death (89.4 vs 25.4 ng/mg; P=0.01), and it was a strong predictor of this outcome (AUC=0.73). Patients with uAnCR values above the median for the cohort (55.21 ng/mg) had increased length of stay compared to patients with uAnCR≤55.21 ng/mg (22 days vs 7 days after sample collection; P=0.01). uAnCR was predictive of the outcome increased length of stay (AUC=0.77). uAnCR was also a strong predictor of worsening of AKI (AUC=0.77). The uAnCR of patients with pre-renal AKI was lower compared to patients with AKI of other causes (median uAnCR 11.3 vs 80.2 ng/mg; P=0.02).

Conclusions: Elevated urinary angiotensinogen is associated with adverse events in AKI patients in the ICU. It could be used to identify high risk patients who would benefit from timely intervention that could improve their outcomes.

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Urinary angiotensinogen-to-creatinine ratio and length of stay. (A) Patients were stratified into groups by urinary angiotensinogen-to-creatinine ratio (uAnCR). Patients with uAnCR > the median for the cohort were classified as high (red line), whereas patients with uAnCR ≤ the median were classified as low (black line). Patients who died were censored. The median times to discharge (defined as days after sample collection) were 22 and 7 days for the high and low uAnCR groups, respectively. (B) Receiver operator characteristic (ROC) curve analysis was performed to evaluate the ability of uAnCR to predict the composite outcome discharge > 7 days after sample collection or death ≤ 7 days from sample collection. AUC, area under the curve.
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Figure 2: Urinary angiotensinogen-to-creatinine ratio and length of stay. (A) Patients were stratified into groups by urinary angiotensinogen-to-creatinine ratio (uAnCR). Patients with uAnCR > the median for the cohort were classified as high (red line), whereas patients with uAnCR ≤ the median were classified as low (black line). Patients who died were censored. The median times to discharge (defined as days after sample collection) were 22 and 7 days for the high and low uAnCR groups, respectively. (B) Receiver operator characteristic (ROC) curve analysis was performed to evaluate the ability of uAnCR to predict the composite outcome discharge > 7 days after sample collection or death ≤ 7 days from sample collection. AUC, area under the curve.

Mentions: Among patients who survived to discharge (n = 26), uAnCR was correlated with days to hospital discharge (r = 0.57, P = 0.002). Patients who had high uAnCR values (defined as > 55.21 ng/mg, the median value) had an increased (LOS) compared to patients who had low uAnCR (≤ 55.21 ng/mg). The median LOS (defined as days after the time of sample collection) for these groups was 22 days and 7 days, respectively (P = 0.01) (Figure 2A), and the AKIN stage-adjusted hazard ratio for discharge was 0.367 (95% CI 0.17, 0.91) for patients with high uAnCR compared to those with low uAnCR, indicating that uAnCR affects LOS independently of changes in sCr. Elevated uAnCR was strongly associated with an increased risk of the composite outcome discharge > 7 days from the time of sample collection or death ≤ 7 days from collection. The multiplicative OR for one SD increase in uAnCR was 3.31 (95% CI 1.36, 8.04). ROC curve analysis demonstrated that uAnCR was a strong predictor of this outcome (AUC = 0.77) (Figure 2B). At the optimal cutoff, 59.61 ng/mg, the sensitivity and specificity of the prediction of prolonged hospital stay was 60.6% and 83.3%, respectively. The cutoff at which the test had the highest positive likelihood ratio (LR+ = 5.5) was 123.5 ng/mg. Sixteen patients were above this cutoff, of which fifteen met the outcome. At this cutoff, the sensitivity and specificity of the test was 43.5% and 95.5%, respectively. Similarly, the lowest negative likelihood ratio of the test was achieved at a cutoff of 3.31 ng/mg (LR- = 0.12). Four patients had uAnCR values ≤ 3.31 ng/mg; three of these did not meet the outcome. The test had a sensitivity and specificity of 97.1% and 25.0%, respectively at this cutoff.


Urinary angiotensinogen predicts adverse outcomes among acute kidney injury patients in the intensive care unit.

Alge JL, Karakala N, Neely BA, Janech MG, Velez JC, Arthur JM, SAKInet Investigato - Crit Care (2013)

Urinary angiotensinogen-to-creatinine ratio and length of stay. (A) Patients were stratified into groups by urinary angiotensinogen-to-creatinine ratio (uAnCR). Patients with uAnCR > the median for the cohort were classified as high (red line), whereas patients with uAnCR ≤ the median were classified as low (black line). Patients who died were censored. The median times to discharge (defined as days after sample collection) were 22 and 7 days for the high and low uAnCR groups, respectively. (B) Receiver operator characteristic (ROC) curve analysis was performed to evaluate the ability of uAnCR to predict the composite outcome discharge > 7 days after sample collection or death ≤ 7 days from sample collection. AUC, area under the curve.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672721&req=5

Figure 2: Urinary angiotensinogen-to-creatinine ratio and length of stay. (A) Patients were stratified into groups by urinary angiotensinogen-to-creatinine ratio (uAnCR). Patients with uAnCR > the median for the cohort were classified as high (red line), whereas patients with uAnCR ≤ the median were classified as low (black line). Patients who died were censored. The median times to discharge (defined as days after sample collection) were 22 and 7 days for the high and low uAnCR groups, respectively. (B) Receiver operator characteristic (ROC) curve analysis was performed to evaluate the ability of uAnCR to predict the composite outcome discharge > 7 days after sample collection or death ≤ 7 days from sample collection. AUC, area under the curve.
Mentions: Among patients who survived to discharge (n = 26), uAnCR was correlated with days to hospital discharge (r = 0.57, P = 0.002). Patients who had high uAnCR values (defined as > 55.21 ng/mg, the median value) had an increased (LOS) compared to patients who had low uAnCR (≤ 55.21 ng/mg). The median LOS (defined as days after the time of sample collection) for these groups was 22 days and 7 days, respectively (P = 0.01) (Figure 2A), and the AKIN stage-adjusted hazard ratio for discharge was 0.367 (95% CI 0.17, 0.91) for patients with high uAnCR compared to those with low uAnCR, indicating that uAnCR affects LOS independently of changes in sCr. Elevated uAnCR was strongly associated with an increased risk of the composite outcome discharge > 7 days from the time of sample collection or death ≤ 7 days from collection. The multiplicative OR for one SD increase in uAnCR was 3.31 (95% CI 1.36, 8.04). ROC curve analysis demonstrated that uAnCR was a strong predictor of this outcome (AUC = 0.77) (Figure 2B). At the optimal cutoff, 59.61 ng/mg, the sensitivity and specificity of the prediction of prolonged hospital stay was 60.6% and 83.3%, respectively. The cutoff at which the test had the highest positive likelihood ratio (LR+ = 5.5) was 123.5 ng/mg. Sixteen patients were above this cutoff, of which fifteen met the outcome. At this cutoff, the sensitivity and specificity of the test was 43.5% and 95.5%, respectively. Similarly, the lowest negative likelihood ratio of the test was achieved at a cutoff of 3.31 ng/mg (LR- = 0.12). Four patients had uAnCR values ≤ 3.31 ng/mg; three of these did not meet the outcome. The test had a sensitivity and specificity of 97.1% and 25.0%, respectively at this cutoff.

Bottom Line: The uAnCR of patients with pre-renal AKI was lower compared to patients with AKI of other causes (median uAnCR 11.3 vs 80.2 ng/mg; P=0.02).Elevated urinary angiotensinogen is associated with adverse events in AKI patients in the ICU.It could be used to identify high risk patients who would benefit from timely intervention that could improve their outcomes.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: Acute kidney injury (AKI) is commonly observed in the intensive care unit (ICU), where it can be caused by a variety of factors. The objective of this study was to evaluate the prognostic value of urinary angiotensinogen, a candidate prognostic AKI biomarker identified in post-cardiac surgery patients, in this heterogeneous population.

Methods: Urinary angiotensinogen was measured by ELISA and corrected for urine creatinine in 45 patients who developed AKI in the ICU. Patients were grouped by AKI etiology, and the angiotensinogen-to-creatinine ratio (uAnCR) was compared among the groups using the Kruskal-Wallis test. The ability of uAnCR to predict the following endpoints was tested using the area under the ROC curve (AUC): the need for renal replacement therapy (RRT) or death, increased length of stay (defined as hospital discharge>7 days or death≤7 days from sample collection), and worsening AKI (defined as an increase in serum creatinine>0.3 mg/dL after sample collection or RRT).

Results: uAnCR was significantly elevated in patients who met the composite outcome RRT or death (89.4 vs 25.4 ng/mg; P=0.01), and it was a strong predictor of this outcome (AUC=0.73). Patients with uAnCR values above the median for the cohort (55.21 ng/mg) had increased length of stay compared to patients with uAnCR≤55.21 ng/mg (22 days vs 7 days after sample collection; P=0.01). uAnCR was predictive of the outcome increased length of stay (AUC=0.77). uAnCR was also a strong predictor of worsening of AKI (AUC=0.77). The uAnCR of patients with pre-renal AKI was lower compared to patients with AKI of other causes (median uAnCR 11.3 vs 80.2 ng/mg; P=0.02).

Conclusions: Elevated urinary angiotensinogen is associated with adverse events in AKI patients in the ICU. It could be used to identify high risk patients who would benefit from timely intervention that could improve their outcomes.

Show MeSH
Related in: MedlinePlus