Improved cost-effectiveness and efficiency with a slower shockwave delivery rate

OBJECTIVE To determine the benefits of a slower shockwave (SW) delivery rate of 70 shocks/min on the treatment efficiency and cost-effectiveness of extracorporeal SW lithotripsy (ESWL). PATIENTS AND METHODS Patients who had ESWL for their upper urinary tract radio-opaque calculi were categorized into two groups: slow (70 SW/min) and fast (100 SW/min) delivery rate. All treatment was carried out using a lithotripter (Model S, Dornier MedTech, Wessling, Germany) as an outpatient procedure with no anaesthesia or sedation. The groups were followed for >= 6 months. The primary outcomes compared were the stone-free rate, re-treatment rate, additional procedure rate, perceived cost and actual cost. Clinical success was defined as stone-free status or asymptomatic insignificant residual fragments of < 3 mm. Perceived cost was defined as the cost of ESWL alone, and actual cost included the cost of additional procedures and overhead costs to result in clinical success. RESULTS In all, the study included 102 patients, categorized into the fast (51) and slow (51) rate groups. The groups were comparable in terms of sex, age, body mass index, stone size and stone location. The slow group had a significantly better stone-free rate (67% vs 25.5%, P = 0.002, chi-square), fewer mean shocks to clinical success (3045 vs 4414, P < 0.001, U-test), lower re-treatment rate (22% vs 45% P = 0.013, chi -square), a lower additional procedure rate (12% vs 29%, P = 0.02, chi-square), greater efficiency quotient (0.51 vs 0.16) than the fast group. The mean perceived cost of ESWL (GB pound 297 vs 394 pound, P = 0.013, U-test) and the mean actual cost of the slow group were significantly less (496 pound vs 1002 pound, P = 0.001, U-test). CONCLUSION Slowing the SW delivery rate to 70/min significantly reduced the actual cost by half and improved treatment efficiency.