title: Predictors of renal recovery in renal failure secondary to bilateral obstructive urolithiasis.
abstract: OBJECTIVE
  To identify factors predicting renal recovery in patients presenting with renal failure secondary to bilateral obstructing urolithiasis.
  
  
  METHODS
  Data from electronic records of consecutive adult patients presenting with bilateral obstructing urolithiasis between January 2007 and April 2011 were retrieved. Ultrasonography of the abdomen, and kidney, ureter, bladder (KUB study) X-ray or abdominal non-contrast computed tomography confirmed the diagnosis. Interventional radiologists placed bilateral nephrostomies. Definitive intervention was planned after reaching nadir creatinine. Renal recovery was defined as nadir creatinine of ⩽2 mg/dL.
  
  
  RESULTS
  In all, 53 patients were assessed, 50 (94.3%) were male, and 18 (33.9%) were aged ⩽40 years. Renal recovery was achieved in 20 patients (37.7%). A symptom duration of ⩽25 days (P< 0.01), absence of hypertension (P= 0.018), maximum renal parenchymal thickness of >16.5 mm (P= 0.001), and haemoglobin >9.85 g/dL (P< 0.01) were significant on unadjusted analysis. Symptom duration of ⩽25 days alone remained significant after adjusted analysis. Symptom duration of ⩽25 days (hazard ratio (HR) 13.83, 95% confidence interval (CI) 4.52-42.26;P< 0.01), parenchymal thickness of ⩾16.5 mm (HR 5.91, 95% CI 1.94-17.99;P= 0.002), and absence of hypertension (HR 9.99, CI 95% 1.32-75.37;P= 0.026) were significantly related to time to nadir creatinine. Symptom duration of ⩽25 days (HR 17.44, 95% CI 2.48-122.79;P= 0.004) alone remained significant after adjusted analysis. A symptom duration of ⩽25 days (P= 0.007) was 22-times more likely to indicate renal recovery.
  
  
  CONCLUSIONS
  Shorter symptom duration (⩽25 days) is predictive of renal recovery in renal failure secondary to bilateral obstructive urolithiasis.
authors.affiliation: Department of Urology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
authors.forename: Muthukrishna P
authors.initials: MP
authors.lastname: Rajadoss
authors.affiliation: Department of Urology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
authors.forename: Chandrasingh Jeyachandra
authors.initials: CJ
authors.lastname: Berry
authors.affiliation: Department of Biostatistics, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
authors.forename: Grace J
authors.initials: GJ
authors.lastname: Rebekah
authors.affiliation: Department of Radiology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
authors.forename: Vinu
authors.initials: V
authors.lastname: Moses
authors.affiliation: Department of Radiology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
authors.forename: Shyamkumar N
authors.initials: SN
authors.lastname: Keshava
authors.affiliation: Department of Psychiatry, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
authors.forename: Kuruthukulangara S
authors.initials: KS
authors.lastname: Jacob
authors.affiliation: Department of Urology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
authors.forename: Santosh
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Urology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
authors.forename: Nitin
authors.initials: N
authors.lastname: Kekre
authors.affiliation: Department of Urology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India.
authors.forename: Antony
authors.initials: A
authors.lastname: Devasia
keywords: AUC, area under the ROC curve; CKD, chronic kidney disease; Calculus anuria; HR, hazard ratio; KUB, kidney, ureter, bladder; Obstructive urolithiasis; PCN, percutaneous nephrostomy; ROC, receiver operating characteristic; Renal failure; US, ultrasonography