Long-term impact of competitive biddings and an antimicrobial stewardship program in a general hospital in Chile

Background: The long-term effect of an antimicrobial stewardship program (ASP) and its integrated impact with competitive biddings have been seldom reported. Aim: To evaluate the long-term effect of an ASP on antimicrobial consumption, expenditure, antimicrobial resistance and hospital mortality. To estimate the contribution of competitive biddings on cost-savings. Material and Methods: A comparison of periods prior (2005-2008) and posterior to ASP initiation (2009 and 2015) was done. An estimation of cost savings attributable to ASP and to competitive biddings was also performed. Results: Basal median antimicrobial consumption decreased from 221.3 to 170 daily defined doses/100 beds after the start of the ASP. At the last year, global antimicrobial consumption declined by 28%. Median antimicrobial expenditure per bed (initially US$ 13) declined to US$ 10 at the first year (-28%) and to US$ 6 the last year (-57%). As the reduction in consumption was lower than the reduction in expenditure during the last year, we assumed that only 48.4% of savings were attributable to the ASP. According to antimicrobial charges per bed from prior and after ASP implementation, we estimated global savings of US$ 393072 and US$ 190000 directly attributable to the ASP, difference explained by parallel competitive biddings. Drug resistance among nosocomial bacterial isolates did not show significant changes. Global and infectious disease-associated mortality per 1000 discharges significantly decreased during the study period (p < 0.05). Conclusions: The ASP had a favorable impact on antimicrobial consumption, savings and mortality rates but did not have effect on antimicrobial resistance in selected bacterial strains.