Economic burden associated with ESBL-producing Escherichia coli infections in Laos: econometric modeling using evidence from a prospective cost-of-illness study

Introduction: Antimicrobial resistance poses a major global health threat, yet evidence on its economic impact in low- and middle-income countries remains limited. This study estimated the economic burden of infections caused by ESBL-producing Escherichia coli (E. coli), a key resistant pathogen, in Laos. Methods: A prospective cost-of-illness study was conducted among patients with laboratory-confirmed infections in Setthathirath hospital in Vientiane, Laos, collecting cost data through repeated interviews and medical records. Descriptive analyses and econometric modeling approaches, including inverse probability weighting (IPW) and instrumental variable (IV) analyses, were used to estimate out-of-pocket expenditures, public expenditures, total cost of illness, and length of stay, accounting for potential confounding. Results: ESBL-producing E. coli was consistently associated with higher economic burden across all analyses. The unadjusted per-patient cost was US$ 689.0 for ESBL-producing E. coli, compared with US$ 489.4 for non-ESBL-producing E. coli and US$ 537.6 for non-E. coli. The association remained statistically significant for out-of-pocket cost after IPW-adjustment (US$156.2; 95% CI, 14.3 to 298.1; P = 0.03), while other outcomes were not statistically significant. Instrumental variable analyses showed consistent directional effects but with wide confidence intervals and no statistically significant differences. Conclusions: Findings suggest that ESBL-producing E. coli may be associated with increased economic burden in Laos; however, this association was not consistently statistically robust across analytical approaches. These findings suggest a potential economic impact of ESBL infection, although uncertainty remains regarding the magnitude of the effect. Strengthening antimicrobial stewardship, infection prevention and control, and improved diagnostic capacity remain essential to mitigate the potential AMR burden.