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Review Article
Assessment of Comorbidity Burden and its Association With Functional Rehabilitation Outcome After Stroke or Hip Fracture: A Systematic Review and Meta-Analysis

https://doi.org/10.1016/j.jamda.2016.07.028Get rights and content

Abstract

Background

A well-grounded functional prognosis during triage for rehabilitation is important, especially in older patients who experience the burden of comorbidity. However, it remains unclear what impact comorbidity has on functional outcome after rehabilitation.

Aim

To investigate the associations between comorbidity indexes and functional outcome after inpatient stroke or hip fracture rehabilitation. Furthermore, to identify which method of comorbidity assessment best reveals this relationship.

Design

Systematic review and meta-analysis.

Methods

An extensive search in PubMed, EMBASE, COCHRANE, Web of Science, and CINAHL of cited references and gray literature was carried out on March 4, 2016. This meta-analysis was conducted in agreement with the guidelines for Preferred Reporting Items for Systematic reviews and Meta-Analyses. Studies were included if participants were adult patients with a stroke or hip fracture, participants received inpatient rehabilitation, comorbidity was assessed with a valid index, and functional status was an outcome measure. Two reviewers independently extracted data; according to the predefined data extraction plan, included studies were independently evaluated on risk of bias.

Results

Twenty studies were eligible for review, and 7 studies were included in the meta-analysis. The pooled correlation between comorbidity and functional status at discharge was −0.43 [−0.69; −0.06]. Presence and strength of correlations differed between comorbidity indexes. Charlson index: range = 0.0 to −0.88 and 0%–1% explained variance (%var). Cumulative illness rating scale (CIRS) total or cumulative: range = −0.02 to −0.34 and unknown %var. CIRS-severity index: range = −0.25 to −0.40 and 12–16 %var. Comorbidity-severity index: range = −0.39 and −0.47 and 5 %var. Liu index: range = −0.28 to −0.50 and 4–7 %var. When the index contained a severity weighting, the associations were more evident.

Conclusions

An association between comorbidity burden and functional outcome exists, albeit modest. Assessment of severity weighted comorbidity is preferred for estimating the functional prognosis after stroke and hip fracture rehabilitation.

Section snippets

Search Strategy

This meta-analysis was conducted following A Measurement Tool to Assess Systematic Reviews and Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) (Appendices A and B).15, 16, 17 A systematic search of publications was carried out in the following electronic databases: PubMed (Medline), Embase, The Cochrane Library (CENTRAL), Web of Science, and CINAHL from the earliest record to March 4, 2016. The search strategy was designed under the supervision of an experienced

Study Selection

The database search identified 2910 articles, and 1514 articles were identified by using other sources. After removing the duplicates, 2551 articles were screened for eligibility of which 20 met all criteria. Reasons for exclusion are reported in the PRISMA flowchart (Appendix E).

Studies that assessed comorbidity using the Tier ranking system were excluded after discussion with 2 other reviewers (W.A. and R.vB.).20, 21 This system was developed by the Centers for Medicare and Medicaid Services

Main Findings

This review supports the hypothesis that preexisting comorbidity is negatively associated with functional rehabilitation outcome. This relation becomes more evident when comorbidity is assessed by indicating the severity of present comorbidities.

In the studied patient populations, we detected 4 comorbidity indexes: the CharlsonCI, the LiuCI, the COM-SI, and the CIRS(G) scored as total, cumulative, or severity index. The LiuCI and COM-SI were specifically designed for use in a rehabilitation

Conclusions

There seems to be insufficient evidence that assessing comorbidity helps predicting the functional prognosis if current comorbidity indexes are used. This review adds new insights in emphasizing the severity of comorbidity to assist in estimating their functional prognosis after acute illnesses such as stroke or hip fracture. More research is needed to investigate whether a brief and practical index that captures individual impact of comorbidity, is feasible, reliable, and valid for use in

Acknowledgments

The authors thank J.W. Schoones, medical information specialist from the Leiden University Medical Center (LUMC) for his supervision regarding the design of the search strategy. The corresponding author (AK) had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

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    This work was supported by Laurens, nursing care organization in Rotterdam.

    The authors declare no conflicts of interest.

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