Impact of Renal Stone Clearance in Patients of Chronic Kidney Disease: A Prospective Observational Study from a Tertiary Care Centre

Introduction: Varying degrees of renal insufficiency is associated with renal stone disease. The incidence of Chronic Kidney Disease (CKD) in renal stone is around 0.8 to 17.5%. There is limited data on the outcomes of Percutaneous Nephrolithotomy (PCNL) in CKD patients like improvement in Glomerular Filtration Rate (GFR), Effective Renal Plasma Flow (ERPF), postoperative complications, morbidity like dialysis dependence and mortality and various other factors. Aim: To study the impact of PCNL in patients of urolithiasis with CKD. Materials and Methods: A prospective observational study was conducted on 100 patients of chronic kidney disease seeking operative treatment during June 2017 to September 2019 in the Department of Urology, Superspeciality Hospital and Government Medical College (GMC), Nagpur, Maharashtra, India. All suspected patients underwent a plain Computed Tomography (CT) scan. Patients were classified into three groups; group 1 included stage III, group 2 included stage IV and group 3 included stage V CKD patient. Patients with Acute Kidney Injury (AKI) underwent urine diversion first. Both short term impact like hospital stay, need for blood transfusion, AKI, sepsis, fever and long term impact like change in renal function, stage migration were studied. Statistical analysis was done using Kruskal Wallis Test (age distribution); Chi-squared test (gender and AKI); Fisher’s exact test (stone Composition and transfusion); Kruskal Wallis Test {Body Mass Index (BMI), hospital stay, Effective Renal Plasma Flow (ERPF) and Estimated Glomerular Filtration Rate (eGFR)}. Results: A total of 55 patients were of Grade III CKD, 31 were of Grade IV CKD and 14 patients were of stage V CKD and classified into groups 1, 2 and 3, respectively. Age and gender distribution were not significantly different among various groups. There was no significant difference in BMI (Kg/m2) or diabetes in the groups. The most common stone composition was calcium oxalate dihydrate (53%). Among 100 patients, urine culture was sterile in 77 patients. No significant difference was found in the incidence of urinary tract infection (p-value=0.629). Group 3 presented with significantly higher incidence of AKI (p-value=0.001). Stone free rate was not significantly different among groups (p-value=0.252). Blood transfusion rates was not statistically different in these groups (p-value=0.066). Mean hospital stay was significantly higher with higher stages of CKD (p-value <0.001). Change in renal function was evaluated by change ERPF and eGFR. ERPF significantly increased by 1.96±4.87 (p-value=0.001) after surgery. Similarly, there was significant increase in eGFR over time (p-value=0.037). Conclusion: PCNL in patients of chronic kidney disease has a minor but significant improvement in GFR with good clearance rates.