Role of Demographic Factors in Stone-Free Rates After Extracorporeal Shockwave Lithotripsy: A Multicentric Study from JPMC Karachi and IKD Peshawar

Background: Extracorporeal shock wave lithotripsy (ESWL) is a well-established, non-invasive treatment for renal stones, but stone-free rates (SFR) can differ based on stone size, location, and patient demographics. This study aimed to evaluate the SFR after ESWL in relation to demographic and geographic factors across two major centers in Pakistan. Methods: A prospective, multicentric cohort study was carried out from February to April 2022 at the Department of Urology and Transplantation, JPMC Karachi, and the Institute of Kidney Diseases, Hayatabad Peshawar. A total of 300 patients of either gender were enrolled using non-probability consecutive sampling. Prophylactic antibiotics were administered to all participants, and ketorolac 30 mg IV was given as analgesia before the procedure. Data were analyzed using SPSS software. Means were reported for continuous variables and frequencies for categorical variables. Results: Of the 300 patients, 150 were treated at JPMC and 150 at IKD. The mean age was 39 years in the JPMC group and 34 years in the IKD group. Males constituted 62.66% (n=94) of the JPMC group and 73.33% (n=110) of the IKD group. Mean stone size was 15.3 mm at JPMC and 14.7 mm at IKD (p>0.05). Mean stone density was 690 ± 120 HU at JPMC and 750 ± 105 HU at IKD, with no significant difference. At six weeks, complete stone clearance was seen in 229 patients (76.3%) with an average of 1.5 ESWL sessions. The SFR was significantly higher at IKD (82%, n=124) compared to JPMC (70%, n=105) (p<0.05). Better fragmentation was observed in patients from areas supplied by the Indus River system. Gender did not influence fragmentation rates. Partial clearance after three sessions was recorded in 71 patients. Conclusion: ESWL achieved complete stone clearance in 76% of patients across both centers. Outcomes were better among patients from urban populations with Indus River water supply. Lower calyceal stones were an independent risk factor for partial clearance.