What Is the Appropriate Use of Renal Sonography in an Inner-City Population With New-Onset Acute Kidney Injury?
Academic Article
Overview
abstract
OBJECTIVES: We aimed to determine the prevalence of hydronephrosis in patients who underwent renal sonography for new-onset acute kidney injury (AKI) and to identify clinical factors predictive of hydronephrosis. In patients with hydronephrosis, we sought to investigate how routine renal sonography affects patient treatment, including performance of interventional procedures. METHODS: A retrospective chart review identified 274 adults with AKI who underwent renal sonography at an urban teaching hospital from January through July 2011. The prevalence of hydronephrosis was determined. Electronic medical records were reviewed for comorbidities, including risk factors for hydronephrosis such as a pelvic mass, prior renal or pelvic surgery, and neurogenic bladder, and for subsequent interventions and outcomes. RESULTS: Sonography showed hydronephrosis in 28 patients (10%); 5 (18%) had subsequent interventions. In a multivariable logistic regression model with the outcome being hydronephrosis, all considered risk factors (pelvic mass, prior renal or pelvic surgery, and neurogenic bladder) were significantly associated with hydronephrosis (odds ratio, 6.4; 95% confidence interval, 2.7-15.4; P < .001) when adjusting for age and diabetes mellitus. Diabetes had a negative predictive value for hydronephrosis. No diabetic patients younger than 85 years and without clinical risk factors had hydronephrosis. CONCLUSIONS: Hydronephrosis is infrequently seen on sonograms in hospitalized patients with AKI who lack risk factors for urinary tract obstruction. Deferral of sonography pending a trial of medical treatment is safe and will reduce medical costs. Adoption of clinical guidelines to assess patients' risk levels for hydronephrosis is critical to avoid unnecessary imaging.
