Predictors of Renal Recovery among Patients of Obstructive Urolithiasis with Renal FailureA Prospective Observational Study

Abstract

Introduction: Timely intervention in patients of obstructive uropathy secondary to renal and /or ureteric stones can reduce the morbidity and mortality in such patients. Aim: To determine the factors predicting recovery in patients of urinary stones and obstructive uropathy. Materials and Methods: This prospective observational study was conducted at Shri Mahant Inderesh Hospital, Dehradun, Uttrakhand, India, between December 2018 and June 2020. All patients with renal failure (serum creatinine >1.5 mg/dL) secondary to urinary stones presenting to the Emergency Department were included in the study. Baseline demographic data, clinical, haematological, biochemical and microbiological parameters were recorded at presentation and after Double J Stent (DJS) insertion at postintervention day 1, 3 and 7. Total 40 patients were divided into two groups i.e, recovered (n=25) and non recovered (n=15) groups. Receiver Operating Characteristic (ROC) curves was used to obtain optimal threshold duration of illness, the values of serum creatinine, serum urea, haemoglobin and serum potassium, and time to nadir creatinine for predicting renal recovery. The graphs were made using both Microsoft excel and SPSS software. Results: Out of total 40 pateints, 29 were males and 11 were females. The mean duration of symptoms in the recovered and non recovered groups was 4.64 and 15.53 days, respectively (p-value=0.001). Thirteen out of 15 patients (86.6%) in the non recovered group and 10 out of 25 (40%) in the recovered group had pre-existing co-morbidities (p-value=0.004). Postobstructive diuresis was present in 84% patients in the recovered and 46.6% in the non recovered group (p-value=0.016). The nadir serum creatinine level was 1.26 mg/dL in recovered as compared to 6.08 mg/dL in the non recovered patients (p-value=0.001). The ROC curves were plotted for various parameters in order to find the prognostic accuracy in predicting recovery. The best criteria were symptom duration ≤6 days, serum creatinine at presentation ≤6.2 mg/dL, serum potassium ≤5.5 mg/dL, and haemoglobin level >9.4 gm/dL. Conclusion: Short duration of symptoms (≤6 days), lower serum creatinine levels (≤6.2 mg/dL), lower serum potassium levels (≤5.5 mg/dL), and higher haemoglobin level (>9.4 gm/dL) were found to predict a greater chance of recovery. These factors can help in formulating treatment protocols for early intervention leading to a better prognosis in this subgroup of patients.