ANTIMICROBIAL PROPHYLAXIS PRIOR TO SHOCK-WAVE LITHOTRIPSY IN PATIENTSWITH STERILE URINE BEFORE TREATMENT - A METAANALYSIS AND COST-EFFECTIVENESS ANALYSIS

Objectives. To determine the efficacy and cost-effectiveness of routin e antimicrobial prophylaxis prior to shock wave lithotripsy (SWL) in p atients with a sterile pretreatment urine culture. Methods. A structur ed MedLine search revealed eight prospective, randomized, controlled t rials (RCTs) of active treatment versus placebo or no treatment (n = 8 85) and six clinical series (non-RCTs; n = 597) addressing the use of antimicrobial prophylaxis for SWL. A meta-analysis was performed on th e eight RCTs, with the primary outcome being the diagnosis of a urinar y tract infection (UTI) post-SWL. A cost analysis was performed compar ing a prophylactic strategy (prophylaxis for every patient and treatme nt for post-SWL UTIs) with a treatment-only strategy for post-SWL UTIs using various antimicrobial combinations and the median probability o f post-SWL UTIs determined by meta-analysis. Results. The incidence of post-SWL UTIs ranged from 0% to 28% in the control group and from 0% to 7.7% in the patients who underwent prophylaxis. Combining the place bo/no-drug treatment arms in the six RCTs by meta-analysis (Bayesian a nalysis) resulted in a median probability of a post-SWL UTI of 5.7% (9 5% confidence interval [CI] 5.8% to 8.4%). For the drug treatment arms , the median probability of a UTI was 2.1% (95% CI 0.9% to 3.6%). Rela tive risk (RR) analysis resulted in an overall RR of post-SWL UTls wit h prophylaxis versus without prophylaxis of 0.45 (95% CI 0.22 to 0.93) (P = 0.0005). Depending on the antimicrobial regimen used for prophyl axis and treatment, a prophylactic strategy added minimally to the ove rall treatment cost of SWL, and proved cost beneficial when taking int o consideration serious UTIs requiring inpatient treatment. Conclusion s. A policy of antibiotic prophylaxis prior to SWL in patients with st erile pretreatment urine cultures is efficacious in reducing the rate of post-SWL UTIs. Discounting inpatient episodes for sepsis and acute pyelonephritis, however, the strategy is not cost-effective. In contra st, using literature-derived incidence estimates for post-SWL urosepsi s or pyelonephritis necessitating inpatient treatment, prophylaxis bec omes both efficacious and cost-effective, and thus constitutes a domin ant strategy. (C) 1997, Elsevier Science Inc.