Rates and Reasons for Readmission after Hospitalisation on the Acute Medical Unit.

Abstract

Introduction: Readmission after hospital discharge is an ongoing challenge that healthcare systems face worldwide, with multimorbidity increasing the readmission risk significantly. Identifying higher risk groups of patients allows for safety netting at discharge to be implemented to prevent harm. The aim of this study was to compare readmission rates and reasons across common diagnostic groups presenting to the acute medical unit.

Method: A retrospective analysis was performed on an anonymous dataset extracted from Salford Royal Hospital from 2014 - 2022 covering all non-elective inpatient admissions to AMU or medical same day emergency care where the patient survived to discharge. Episodes were grouped according to ICD-10 diagnostic codes, with readmission rates and reasons at 30 and 90 day calculated and compared using descriptive statistics. Further subgroups were evaluated according to demographic and co-morbid features.

Results: There were 89,897 admissions to AMU and SDEC where patients survived to discharge: age 68±19 years, 53% female. 5,880 episodes were excluded due to inpatient death. The most common first admission reasons were pneumonia (n=9,121), COPD (4,800) and sepsis (3,440). The overall 30 day readmission rate was 12.3%, with the highest rates being found where first admission episode was due to liver disease (21.9%), chronic obstructive pulmonary disease (COPD, 21.1%), and falls (17.9%). 6% of all patients were readmitted within 30 days due to recurrence of the primary presenting illness, representing 49% of all readmissions. After primary illness recurrence, pneumonia was the second most common readmission reason in 17 of 22 diagnostic groups and accounted for 25% of all readmissions excluding primary illness recurrence. Overall 90 day readmission rate was 24.2% with the same 3 most common diagnostic groups (liver disease 44%, COPD 39% and falls 34%). For 90 day readmission reasons according to specified comorbidities, the highest rates were seen in heart failures (34.1%) and COPD (33.1%). The highest readmission reason in the diagnostic groups was 41.4% of heart failure patients being readmitted with respiratory causes. Heart failure was the most impactful co-morbid factor associated with higher likelihood of 90 day readmission in other disease presentations (34.4% with heart failure, 22.8% without).

Discussion: Readmission rates vary significantly between diagnostic and co-morbid groups meaning that targeting high risk groups for safety netting may be possible using only simple admission details.