Readmission to hospital of medical patients – A cohort study

Introduction The incidence of acute readmissions is higher among elderly medical patients than in the general population. Risk factor identification is needed in order to prevent readmissions. Objective To estimate the incidence of acute readmissions among medical patients ≥ 65 years discharged from departments of internal medicine and to identify risk factors associated with readmissions. Material and methods We included patients discharged between 1st of January 2011 and 1st of December 2014 and collected data regarding primary diagnosis and comorbidities. The primary outcome was acute readmission within 30 days of discharge. We determined risk factors using a multivariable Cox proportional hazards model. Results Out of 21,634 discharged patients, 3432 (15.9%) patients had an acute readmission. Risk factors were: age per decade (HR: 1.06, 95%CI: 1.02–1.11), male sex (HR: 1.07, 95%CI: 1.00–1.15), receiving home care service (personal care) (HR: 1.33, 95%CI: 1.15–1.55), nursing home residency (HR: 1.30, 95%CI: 1.14–1.48), a previous admission within six months (HR: 1.59, 95%CI: 1.48–1.72), increased length of index admission (HR: 1.14, 95%CI: 1.11–1.17), and moderate or high level of comorbidities (HR: 1.22, 95%CI: 1.13–1.32, HR: 1.52, 95%CI: 1.38–1.67, respectively). Conclusion Around one in six patients had an acute readmission and we identified several risk factors. The risk factors a previous hospital admission within six months, a long or very long length of index admission and a high level of comorbidities were strong risk factors for an acute readmission.