Risk factors for 90-day readmission of sepsis patients.

Background: Sepsis readmissions are common and a substantial burden to society and can have severe consequences to the patient with physical, cognitive and psychiatric impairment or death. Research in readmission after sepsis is sparse. The primary objective of our study was to examine risk factors for readmission in emergency department (ED) patients with sepsis.

Method: A single-center observational population-based cohort study among all adult (≥18 years) patients with infectious diseases admitted to the emergency department of Slagelse Hospital during 1.10.2017-31.03.2018. Sepsis was defined as an increase in the sequential organ failure assessment (SOFA) score of ≥ 2. The primary outcome was 90-day readmission. We used Cox regression to estimate adjusted hazard ratios (aHRs) with 95% confidence intervals (CI) to compare the risk of readmission. We followed patients from the date of discharge from the index admission until the end of the follow-up period or until the time of readmission to hospital or death. Patients who died during the follow-up period without being readmitted, were censored at the time of death. The potential confounders were chosen a priory on existing knowledge of the association between the variables and readmission or if the variables in the crude analyses were associated with increased risk of readmission.

Results: A total of 2,110 patient were admitted with infections and 714 (33.8%) suffered sepsis. A total of 52 patients had died during admission and were excluded leaving 662 patients (44.1% female) with a median age of 74.8 (interquartile range: 66.0-84.2) years for further analysis. A total of 237 (35,8%; 95% CI 32.1-39.6) patients were readmitted within 90 days. After adjustment for potential confounding we found that a history of malignant disease (aHR 1,75; 95% CI 1.27-2.41), if previously admitted with sepsis within one year before the index admission (aHR; 1.47; 95% CI 1.13-1.93), and treatment with diuretics (aHR 1.47; 95% CI 1.47; 1.14-1.90) were independent risk factors for readmission. aHR for diuretic treatment was consistent in a stratified analysis without heart failure patients.

Discussion and Conclusions: To the authors knowledge this is the first study to examine 90-day readmission in patients with sepsis identified by the SOFA criteria. More than one third of the patients were readmitted. A history of malignant disease, if previously admitted with sepsis, and diuretic treatment were independent risk factors for 90-day readmmission. Our results can be helpful in discharge planning and in future research of interventions to reduce potentially avoidable readmissions