MP43-16 RISK FACTORS FOR LOSS TO FOLLOW-UP IN PATIENTS WITH UPPER URINARY TRACT STONES AFTER SURGICAL TREATMENT

INTRODUCTION AND OBJECTIVE: After surgical treatment for urolithiasis, regular follow-up is critical in preventing and monitoring stone growth or new stone formation. The aim of the present study was to investigate risk factors for loss to follow-up in patients with upper urinary tract stones after surgical treatment. METHODS: We retrospectively identified 287 consecutive patients treated with extracorporeal shock wave lithotripsy (SWL), ureteroscopy (URS) or percutaneous nephrolithotomy (PNL) between January 2010 and December 2013. Kaplan-Meier estimates were calculated for probability of loss to follow-up. In cases where physician did not make a follow-up appointment or patient did not come on the appointment day, the date taken for the event was the date of the last visit. Data were censored on the day of last visit for patients who were referred to another urology clinics. Cox proportional hazard models were utilized to identify risk factors for loss to follow-up. Characteristics considered included age, gender, number of stone episodes (first time or recurrent), number of stones (single or multiple), stone location (kidney or ureter), stone size, type of surgery, number of surgical procedure, residual stones, type of outpatient clinic (general or specialized stone clinic). RESULTS: Overall, 91 patients were lost to follow-up with a median follow up of 632 days (range 2-1968 days). Of these, 53 events (58.2%) were due to patient behavior, while 38 events (41.8%) were attributed to physician. One-, 2- and 3-year probability of loss to follow-up were 23.6%, 29.1% and 35.4%, respectively. Independent and significant risk factors for loss to follow-up identified in Cox proportional hazard models were age ≤ 60 years, ureteral stone, SWL, single surgical procedure and general clinic (Table). CONCLUSIONS: Our findings will help physicians recognize patients who require additional support by stone specialist for retention in follow-up program, including younger patients, those with ureteral stones and those who underwent less invasive or single surgical procedure.Source of Funding: none