Risk of hospital readmission and associated factors after a positive sample for a multidrug-resistant microorganism.

Background: To determine the risk of hospital readmission and associated factors in patients with a positive sample for multidrug-resistant microorganisms (MRM) and to analyze whether there is a higher risk of hospital readmission with some of the more common MRM.

Methods: Retrospective cohort study (2012-16) performed in a tertiary-care teaching hospital in Barcelona. Patients were divided into two groups, depending on the presence or absence of an MRM-positive sample during hospital admission. Logistic regression models were used to estimate the risk of hospital readmission in the first 30 and 90 days, and the first year for patients with an MRM-positive sample compared with those without. The models were stratified by the presence or absence of an MRM-positive sample and by grouped Charlson comorbidity index.

Results: We included 983 patients with an MRM-positive sample and 39 323 patients without. The risk of hospital readmission in the first 30 days was 41% higher in admitted patients with an MRM-positive sample (95%CI=1.17 to 1.69) than in those without. Stratified models showed similar results to the overall results for all Charlson comorbidity index groups. When the models were stratified by the presence of an MRM-positive sample, methicillin-resistant Staphylococcus aureus showed the highest risk of readmissions within the more common MRM [103% (95%CI=1.10 to 3.75)].

Conclusions: MRMs seem to be an important risk factor for hospital readmissions both among patients with and without comorbidities. Specific types of MRM may represent a higher risk for hospital readmissions than other MRMs, depending on the particular environment or hospital.