Quality improvement of surgical prophylaxis in Dutch hospitals: evaluation of a multi-site intervention by time series analysis

Objectives:Misuseofantibiotics insurgical prophylaxisis stillquitecommon.Theobjectivesofthis study were to reduce the quantity and improve the quality of surgical prophylaxis and to reduce costs. Methods: Prospective multi-site study of elective procedures in 13 Dutch hospitals. The quality of prophylaxiswasauditedbeforeandafteraninterventionconsistingofperformancefeedbackandimplementation of national clinical practice guidelines. Process outcome parameters were antibiotic choice, duration, timing, antibiotic volume and costs. Segmented regression analysis was used to estimate the effect sizeoftheintervention.Patientoutcomewasdocumentedbytheincidenceofsurgicalsiteinfections(SSI). Results: Before the intervention, 1763 procedures were recorded and 2050 thereafter. Antimicrobial use decreased from 121 to 79 DDD (defined daily doses)/100 procedures and costs reduced by 25% per procedure. After the intervention, antibiotic choice was inappropriate in only 37.5% of the cases instead of in 93.5% expected cases had the intervention not occurred. Prolonged prophylaxis was observed in 31.4% instead of 46.8% expected cases and inappropriate timing in 39.4% instead of the expected 51.8%. Time seriesanalysisshowedthatallimprovementswerestatisticallysignificant (P<0.01)andthattheycouldbe fullyattributedtotheintervention.TheoverallSSIratesbeforeandafterinterventionwere5.4%(95%CI:4.3– 6.5) and 4.6% (95% CI: 3.6–5.4), respectively. Conclusions: The intervention led to improved quality of surgical prophylaxis and to reduced antibiotic use and costs without impairment of patient outcome.