Risk factors for readmission after sepsis and its association with mortality.

Background: Sepsis is associated with an approximately 20 % 30-day readmission rate and with subsequent mortality.

Objectives: To determine the demographics, comorbidities that had been documented prior to sepsis onset, processes of care, commonly administered laboratory tests measured near discharge, and post-sepsis infections that may be associated with readmission and, secondarily, whether readmission is an independent risk factor for 90-day mortality.

Methods: Using a database of patients who met Sepsis-3 criteria divided into Construction and Validation groups, we used logistic regression to estimate the factors independently associated with readmission within 30 days after discharge and proportional hazard regression to estimate the factors independently associated with 90-day mortality.

Results: Of the 30,798 patients ≥ 18 years at our combined referral and community hospital and were discharged alive who met Sepsis-3 criteria between July 10, 2009 and September 7, 2019, 5943 (19 %) were readmitted within 30 days. Thirteen thousand, four hundred forty-four (44 %) of the patients were female, 25,293 (82 %) White, 3523 (11 %) Black, and the mean age was 59 ± 17 years. Among the readmitted patients, 894 (15 %) died within 90 days from the original discharge compared to 11 % (p < 0.001) who had not been readmitted. Seven comorbidities, five processes of care (presepsis platelet transfusion, postsepsis platelet transfusion, operation, ICU length of stay, and hospital length of stay), five culture results, two discharge laboratory values, and discharge location were associated with readmission. The model had good discrimination, 0.770 ± 0.004 (Construction Group) and 0.748 ± 0.006 (Validation Group) and good relevancy (area under the precision recall curve), 0.390 ± 0.004 (Construction group) and 0.476 ± 0.005 (Validation group). Readmission within 30 days was independently associated with a 56 % higher risk of death (HR=1.562, 95 % CI=1.434, 1.703, p < 0.001) within 90 days from discharge.

Conclusions: Comorbidities, abnormal laboratory values, processes of care, and post-sepsis onset culture results, but not demographic characteristics, were associated with 30-day readmission. Readmission was associated with 90-day mortality.