The attributable mortality, length of stay, and health care costs of methicillin-resistant infections in Singapore.

Objectives: We used a multi-state model, which mitigates time-dependent bias, to estimate the mortality, length of stay (LOS), and costs of methicillin-resistant (MRSA) infections in Singapore.

Methods: We conducted a retrospective study in a hospital in Singapore from 2018 to 2022. Patients with MRSA infections were matched 1:1:3 to patients with MRSA colonization and patients without MRSA by age, gender, specialty, and intensive care admission, respectively. A multi-state model was used to derive excess LOS and mortality hazard ratios. The attributable cost of infections was estimated in 2022 Singapore dollars (SGDs) from the health care perspective.

Results: We matched 536 patients with MRSA infections to 536 patients with MRSA colonization, and to 1608 patients without MRSA. The excess LOS due to MRSA infection was 2.11 (95% confidence interval [CI] 2.05-2.17) days compared with MRSA colonization and 3.75 (95% CI 3.69-3.80) days compared with no MRSA, which translated to an excess cost of SGD $1825 and SGD $3238, respectively. Of the different MRSA infection types, pneumonia had the highest mortality risk (hazard ratio 4.13; 95% CI 2.28-7.50) compared with patients without MRSA.

Conclusions: MRSA infections increased hospital LOS and health care costs in Singapore. Our estimates can inform future economic analyses of management strategies against MRSA.