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Kidney Week

Abstract: FR-PO114

Point-of-Care Ultrasonography for the Diagnosis of Hydronephrosis: A Systematic Review and Meta-Analysis

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Wang, Dominic, The University of British Columbia Faculty of Medicine, Vancouver, British Columbia, Canada
  • Wang, Michael Ke, McMaster University, Hamilton, Ontario, Canada
Background

Hydronephrosis is a common sign of urinary tract obstruction detected on imaging. The diagnostic test accuracy of point-of-care ultrasound (POCUS) for hydronephrosis is uncertain.

Methods

We searched MEDLINE, EMBASE, and CENTRAL for observational studies and randomized controlled trials without language restrictions from inception until April 2024. We included studies reporting the diagnostic accuracy of POCUS for hydronephrosis compared to formal radiographic imaging as the reference standard (i.e., ultrasound, computed tomography, and/or intravenous pyelogram performed by a radiology technician or radiologist). We pooled sensitivity and specificity using random-effects models and reported their corresponding 95% confidence intervals (CIs).

Results

We included 22 observational studies (n=4893). The pooled population included patients presenting with flank pain (13 studies), acute kidney injury (AKI) (2 studies), either flank pain or AKI (2 studies), or were unspecified (5 studies). Twenty studies were conducted in the emergency department, 1 study was conducted in hospital wards, and the remaining study was conducted in both an intensive care unit and hospital wards. POCUS had a pooled sensitivity of 0.83 (95% CI 0.79-0.87) and specificity of 0.80 (95% CI 0.74-0.86) for the diagnosis of hydronephrosis when compared to formal imaging. In a subgroup analysis of 3 studies (n=1078), the diagnosis of any severity of hydronephrosis on formal imaging based on moderate to severe hydronephrosis on POCUS demonstrated a pooled sensitivity of 0.32 (95% CI 0.28-0.37) and specificity of 0.96 (95% CI 0.93-0.98).

Conclusion

POCUS has moderate sensitivity and specificity for hydronephrosis and may be used to rule out urinary tract obstruction in patients with a low pre-test probability. Moderate to severe hydronephrosis on POCUS is highly specific for hydronephrosis detected on formal imaging.

Sensitivity and specificity forest plot