MP38-03 EFFECT OF STEP-WISE VOLTAGE RAMPING ON RENAL DAMAGE AND TREATMENT OUTCOME FOLLOWING EXTRACORPOREAL SHOCKWAVE LITHOTRIPSY (ESWL) OF KIDNEY STONES: RESULTS OF A PROSPECTIVE RANDOMIZED TRIAL.

Abstract

INTRODUCTION AND OBJECTIVES: To estimate costs and outcomes of immediate ureteroscopic management compared to serial ureteral stenting for symptomatic urolithiasis during pregnancy. METHODS: We built a decision analytic model of pregnant women diagnosed with symptomatic ureteral calculi treated with either serial stenting or immediate ureteroscopy (URS). All outcomes were derived from the literature and included stent infection, migration, and spontaneous stone passage with stent placement. Outcomes for URS included ureteral injury, failed URS, postoperative infection, premature delivery, and anesthetic complications. We assumed stent replacement every four weeks during pregnancy, use of intravenous sedation for stent replacement, and spinal anesthetic for URS. Using direct costs and quality-adjusted life years (QALYs), we reported the costs, effectiveness, and net monetary benefit of URS and serial stenting based on gestational age (GA) at stone diagnosis, with separate analyses conducted for stones diagnosed at 12, 20, 32, and 36 weeks GA. We performed one-way and Monte-Carlo sensitivity analyses to assess the strength of the model. RESULTS: URS was less costly and more effective for ureteral stone treatment, irrespective of GA at diagnosis and demonstrated the greatest cost-effectiveness for stones treated earlier during pregnancy. URS was $67,706 less costly than serial stenting for a stone diagnosed at 12 weeks, and $10,051 less costly for a stone diagnosed at 36 weeks (Fig. A). Incremental effectiveness decreased from 0.586 to 0.111 QALYs across those same time points (Fig. B). Accordingly, the net monetary benefit of URS was greatest for a stone diagnosed at 12 weeks, compared to one diagnosed and treated at 36 weeks ($97,005 vs. $15,601). The model was robust to all variables during sensitivity analyses. CONCLUSIONS: Immediate URS is more cost effective than serial stenting for treatment of ureteral calculi, regardless of the GA at diagnosis and is most beneficial for women diagnosed and treated earlier during pregnancy. Source of Funding: None