Risk factors for acute care hospital readmission in older persons in Western countries: a systematic review
Authors: Pedersen Mona Kyndi , Meyer Gabriele , Uhrenfeldt Lisbeth 
Published: November 2019

EXECUTIVE SUMMARY

Background
Hospital readmission in older persons is common and reported as a post-discharge adverse outcome from hospitalization. Readmission relates to a mix of factors associated with increasing age, living conditions, progression of disease as well as factors related to the processes of care. To allow health professionals to focus more intensively on patients at risk of readmission, there is a need to identify the characteristics of those patients.

Objectives
To identify and synthesize the best available evidence on risk factors for acute care hospital readmission within one month of discharge in older persons in Western countries.

Inclusion criteria Types of participants
Participants were older persons from Western countries, hospitalized and discharged home or to residential care facilities.

Types of intervention(s)/phenomena of interest
The factors of interest considered generic factors related to socio-demographics, health characteristics and clinical and organizational factors related to the care pathway.

Types of studies
The current review considered analytical and descriptive epidemiological study designs that evaluated risk factors for acute care hospital readmission.

Outcomes
The outcome was readmission to an acute care hospital within one month of discharge.

Search strategy
A three-step search was utilized to find published and unpublished studies in English, French, German, Norwegian, Swedish or Danish. Five electronic databases were searched from 2004 to 2013, followed by a manual search for additional studies.

Methodological quality
Methodological quality was assessed independently by two reviewers, using the standardized Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) critical appraisal tool.

Data extraction
Data were extracted verbatim using a data extraction form, which identified the components from the standardized JBI data extraction tool from JBI-MAStARI and was adapted to the needs of the present review.

Data synthesis
Due to the clinical and methodological heterogeneity of the studies included, a narrative summary and metasynthesis of the quantitative findings was conducted.

Results
Based on a review of nine studies from ten Western countries, we found several significant risk factors pertaining to readmission to an acute care hospital within one month of discharge in persons aged 65 years and over. Factors associated with higher risk of hospital readmission covered socio-demographics such as higher age, male gender, ethnicity, living conditions, health characteristics such as poor overall condition and functional disability as well as prior admissions. Organizational factors including length of hospital stay, method of referral and discharge destination were associated with increased risk of acute care hospital readmission.

Conclusion
We found several significant, but inconsistent, associations between readmission to an acute care hospital within one month of discharge in persons aged 65 years and over. These associations involved a mix of socio-demographic factors, factors related to health and illness, previous hospitalizations, length of stay as well as clinical and organizational determinants related to the index admission. Although more studies concluded that certain diagnoses or comorbid conditions affected the risk of readmission, they did not agree on any disease in particular.
Due to the breadth and diversity of variables examined and the lack of comparability of findings, the impact of these varying factors and their value as risk adjusters and application in different settings and populations are limited.