External validation of risk stratification strategy in the use of renal ultrasonography in the evaluation of acute kidney injury

Abstract

BACKGROUND Per the American College of Radiology Appropriateness Criteria, renal ultrasound is the most appropriate imaging examination to evaluate patients with acute kidney injury. However, recent studies suggest that renal ultrasound may be more selectively performed, which could lead to reductions in the use of medical imaging. OBJECTIVE Evaluate a published risk stratification prediction model (the Licurse model) for using renal ultrasound in hospitalized patients with acute kidney injury. DESIGN Prospective, observational cohort study. SETTING A 793‐bed, quaternary care, academic hospital. PATIENTS All adult hospitalized patients who underwent renal ultrasound for the indication of acute kidney injury. INTERVENTION/EXPOSURE None. MEASUREMENTS Primary outcome was rate of hydronephrosis diagnosed on ultrasound. Secondary outcome was rate of hydronephrosis resulting in urologic intervention. RESULTS Of 778 patients who underwent renal ultrasonography to evaluate acute kidney injury, hydronephrosis was present in 106 (13.6%); urologic intervention was performed in 23 patients (3.0%). The Licurse model had sensitivity of 91.3% (95% confidence interval [CI]: 73.2%‐97.6%) for urologic intervention and 93.4% (95% CI: 87.2%‐96.8%) for hydronephrosis, respectively. Specificity was low for urologic intervention (23.0% [95% CI: 20.2‐26.2]) and hydronephrosis (25.1% [95% CI: 22.0‐28.6]). We estimated that for 22.6% of patients, hydronephrosis could be ruled out based on clinical predictors. CONCLUSIONS We found that the Licurse renal ultrasonography risk stratification model was sufficiently accurate in classifying patients at risk for ureteral obstruction among hospitalized patients with acute kidney injury. Journal of Hospital Medicine 2016;11:763–767. © 2016 Society of Hospital Medicine

Risk Stratification for Renal Ultrasonography in the Evaluation of Acute Kidney Injury

“…Our analysis extends previous work by evaluating the role of nephrology consultation. 13 We found that risk stratification outperforms consultant recommendation, predicting 86% compared to 56% of hydronephrosis episodes. Previous analyses have found that appropriateness of certain diagnostic testing in AKI may increase when recommended by nephrology consultation rather than the primary team, however our findings did not support this for RUS.…”

“…We found that using a risk stratification framework to guide RUS ordering for hospitalized patients with AKI predicted 86% of episodes of hydronephrosis. 9,13 The majority (60%) of RUS were ordered on medium-or low-risk patients, while only 3% of these patients were found to have hydronephrosis.…”

“…7,8,11,12 A risk stratification framework to identify patients who are high-vs. low-risk for hydronephrosis have been described and validated, however is not widely used by primary teams or nephrology consultants. 9,13 Several factors may account for this: lack of knowledge of the framework, lack of workflow integration, and lack of assessment of harms of unnecessary imaging.…”

Risk Stratification for Hydronephrosis in the Evaluation of Acute Kidney Injury

“…We found that a risk strati cation framework predicted 86% ofepisodes of hydronephrosis in hospitalized patients with AKI whohad obtained a RUS. 11,12 The majority (60%) of RUS wereordered on medium-or low-risk patients, while only 3% of thesepatients were found to have hydronephrosis. Previous analyses havefound that appropriateness of certain diagnostic testing in AKI mayincrease when recommended by nephrology consultation, and ouranalysis extends previous validations by evaluating the role ofnephrology consultation in RUS ordering.…”

“…1,[3][4][5][6][7][8][9][10] A risk strati cation framework to identify patients who arehigh-risk for having hydronephrosis has been previously describedand validated, but is currently underutilized. 11,12 Several factors may account for this: lack of knowledge of theframework, lack of work ow integration, and lack of assessment ofcosts of unnecessary imaging. Recommendations from nephrologistsalso inform RUS ordering for hospitalized patients with AKI,however the relationship between the risk strati cation frameworkand nephrologist recommendations is unclear.…”