Abstract
Background
Older adults with multimorbidity experience fragmentation of care. Ensuring optimal use of healthcare services requires stratifying their need for integrated care. We aimed to map existing stratification tools for assessing older adults with multimorbidity in an integrated care context.
Methods
We searched MEDLINE, Embase, PsycINFO, Cochrane Library, and CINAHL, and extracted definitions of population, concept, and context following the JBI Framework for Scoping Reviews.
Results
We identified 17,689 articles of which 11 articles were included. Few stratification tools for this population exist and differ on scoring methods, domains and settings of use. Stratification is used for identifying older adults with multimorbidity to multidisciplinary teams or to case managers. Future research should develop stratification tools across sectors focused on the common risk factors of multimorbidity in older adults.
Background
The global prevalence of multimorbidity—defined as the co-occurrence of multiple chronic diseases—is rising1,2 and is associated with increased use of healthcare resources and polypharmacy.2,3 Increasingly common with older age, multimorbidity is highly heterogeneous due to differences in the diseases present and their severity, often visualised by disease clusters with similar aetiology.2,4,5 Complex multimorbidity is often defined as a severe form of multimorbidity, 6 reflected in differences in prognosis and improvements following healthcare interventions. For example, life expectancy in older adults with mental–physical multimorbidity is 10–20 years shorter compared to the general population.7–9 In addition, extremely poor health-related quality of life is observed in older adults with complex cardiometabolic and respiratory disease clusters. 10 Healthcare use, length of stay, and bed rest days increase linearly with the number of chronic conditions, 3 further adding to the complexity of multimorbidity in older adults.
Treatment of multimorbidity remains fragmented, despite emerging knowledge about disease clusters. Older adults experience higher rates of care transitions across healthcare sectors, 11 influenced by factors such as educational attainment and poor health literacy.12–14 Mortality in older adults with multimorbidity also exhibits an occupational gradient, with lower socioeconomic status associated with a greater 10-year mortality risk. 15 This complex interplay between biological, psychological, and sociological factors necessitates integrated care approaches that ensure all aspects of treatment are incorporated into an individualised and patient-centred plan. 16
Integrated care refers to care models that adopt a holistic approach to treatment, often comprising flexible, person-centred care plans with an emphasis on coordination and collaboration between healthcare professionals and across healthcare sectors. 17 However, definitions of integrated care vary between healthcare systems and also lack a standardised measure for integrated care quality. 18 Providing integrated care requires the allocation of time and resources that extends beyond usual care and demands precise identification of older adults with the greatest need for integrated care. 16
As a result, there is a growing demand for effective tools capable of identifying the need for integrated care among older adults with multimorbidity, with the aim of improving care and health outcomes through integrated care approaches. However, it remains unknown which stratification tools are available for identifying the need for integrated care in older adults with multimorbidity, and whether such tools are used within an integrated care context. Therefore, the aim of this scoping review is to map the existing literature on stratification tools for older adults with multimorbidity in an integrated care context.
Methods
Protocol and registration
Development of the protocol was informed using the Joanna Briggs Institute Guidelines 19 and reported using the PRISMA Guidelines for Scoping Reviews. 20 The protocol was made publicly available at the Open Science Framework Registry (https://doi.org/10.17605/OSF.IO/8H3DT).
Consultation with knowledge users
We conducted consultations with knowledge users during the development of the review, following the guidelines by Pollock and colleagues (2022) to ensure the clinical relevance of the scoping review. In short, consultation exercises with knowledge users refer to the ways in which they may be involved in conducting systematic and scoping reviews. 21
We recruited knowledge users through gatekeepers in hospitals and primary care settings. Knowledge users were selected on the basis that each represented an area of knowledge and expertise within and across the healthcare system. The JBI four-stage guidance 19 was used to prepare for the involvement of knowledge users. Consultations employed participatory design through interviews and workshops. We consulted multiple knowledge users before, during, and after the review process. Knowledge users included healthcare professionals from psychiatric and somatic departments across Næstved-Slagelse-Ringsted Hospitals (n = 7), general practitioners (n = 2), healthcare professionals from the municipality (n = 8), one patient with multimorbidity and their relative in a patient organisation (n = 2), and researchers (the authors of this article). Knowledge users participated in workshops that informed the authors about the need for stratification tools and the description of the population, concept, and context. We used this information to define our eligibility criteria and ensure the relevance of our aim.
Eligibility criteria
Eligibility criteria used in selection of evidence.
Search strategy
We conducted a systematic search in Embase, MEDLINE, Cochrane Library, PsycINFO, and CINAHL from January 2007 to May 2025. This period was chosen to ensure that the available literature was up to date. One author (VZ) evaluated the initial search strategy in PsycINFO, MEDLINE and Embase. The search matrix included subject indexing terms and free-text terms for title, abstract, and keyword searching. One author (VZ) conducted the initial search in collaboration with a research librarian. We extracted and imported all articles into EndNote X8 for data management and later into Covidence (https://www.covidence.org) for screening. Covidence automatically removed any remaining duplicates. Search matrices and search results can be found as Supplemental Material for all databases.
Selection of sources of evidence
Four authors (JAC, MM, DH, LB) pilot-tested the eligibility criteria on 50 articles. Two authors (JAC, MM) independently screened titles, abstracts, and full-text articles in accordance with our pre-specified eligibility criteria. Any conflicts were resolved by two senior authors (DH, LB). We adjusted our eligibility criteria following the initial screening, as recommended in the literature.19,22,23
Data charting process
All authors reviewed and updated the data extraction form through an iterative process. JAC and MM independently extracted data from the included articles. Inconsistencies in data extraction were resolved through consensus discussions held in online meetings between the two authors (JAC and MM).
Data items
We extracted data on study characteristics (e.g. title, authors, year, and country); characteristics of the included articles (e.g. study aim, design, study setting/context); participant characteristics (description of the population, eligibility criteria, type of recruitment method, total number of participants, male-to-female sex ratio, and chronic diseases); outcome characteristics (description of stratification tools and assessment methods, description of primary and secondary outcomes); and any reported adverse events. We mapped the key findings of the included articles and presented them narratively.
Results
Selection of sources of evidence
We identified 21,345 articles. After removing duplicates, we screened 17,698 articles and selected 69 for full-text review. Eleven articles met the eligibility criteria for inclusion in our analysis (Figure 1). Articles were excluded for the following reasons: no use of stratification tools to identify population of interest (n=8); patients not being older adults with multimorbidity (n=15); stratification not conducted in an integrated care context (n=11); language other than English, Danish, Swedish and/or Norwegian (n=3), and source not a peer-reviewed study (n=21). PRISMA flowchart of selection process.
Characteristics of sources of evidence
Characteristics of included studies.
aHigh risk was defined as having a 30% probability of readmission to the emergency department within 28 days following discharge.
bThe risk nomogram used was a previously validated tool developed by Arendts and colleagues in 2015 (doi: 10.1007/s11739-015-1219-3).
cThe number of female participants (counts and percentages) was extracted and calculated from tables within the articles.
dComplex social needs were not defined in the study.
eThe study was included based on the complex group meeting the mean age inclusion criteria.
fThe mean age in all groups was ≥65 years, and the study was therefore included in our analysis.
Synthesis of results
All articles used stratification tools for assessing the need for integrated care, but differed in the specific tools employed. For example, a validated risk-prediction nomogram was used to predict emergency department readmission. 24 Risk nomograms are tools used to assess the likelihood of specific clinical outcomes (e.g., mortality, readmission, falls), and have been extensively applied to differentiate and prioritise individuals during treatment and interventional work. The Comprehensive Geriatric Assessment (CGA) was widely used in multiple studies to provide a comprehensive evaluation of risk factors and treatment needs, although the scoring methods, assessment domains, and settings of use varied across the included studies.25–27 The CGA is a common multidimensional screening tool for assessment of geriatric patients.28,29 One study included a comprehensive assessment of patients across domains such as function, nutrition, and medical history, but did not explicitly define this approach as CGA, 30 while another study used the CGA as one component of a broader assessment procedure. 31 The Adjusted Clinical Groups (ACG) system was used in a single study, 32 while others varied in the domains assessed and the scoring methods applied.33–35 Not all scoring methods were clearly described. Stratification was primarily conducted either in hospital or clinic settings (n=6), or in general practice (n=5).
All participants were older adults with multimorbidity but differed in their medical histories and comorbidities. Interestingly, most participants were not explicitly defined as multimorbid but were often characterized as ‘frail’, ‘geriatric’ or ‘complex’. The mean age across most groups was >75 years, with the highest being 89.0 years, 25 indicating a very old population. Patients were most often recruited from hospitals or general practices, as recruitment to integrated care involved assessing and stratifying patients on their risk of a clinical outcome and/or treatment needs.
Characteristics of included stratification tools.
Discussion
To our knowledge, this is the first scoping review to map the existing literature on stratification tools for older adults with multimorbidity in an integrated care context. Despite a large number of articles, we identified 11 studies that stratified older adults with multimorbidity within such a context. The tools identified often involved comprehensive assessments of physical, psychological, or social dimensions of health, and frequently incorporated widely used instruments—such as the Comprehensive Geriatric Assessment (CGA)—to identify appropriate patients and determine their need for integrated care approaches. However, the tools varied considerably in terms of the assessment domains included and the scoring methods used for stratification, combining objective measures, questionnaires, and qualitative assessment methods. All studies included participants characterised by multimorbidity, although not all explicitly defined their populations as such. In most cases, stratification was used to identify the need for a multidisciplinary team to collaborate on treatment planning, or to determine the need for a case manager responsible for coordinating referrals and serving as the patient’s primary point of contact.
Stratification tools must be used to differentiate subpopulations into strata based on the risk of a particular outcome occurring, and represent a valid method for guiding treatment decisions. 37 Our results show that, while stratification tools are employed to identify patients for integrated care approaches, the properties, domains, and scoring systems used are largely heterogeneous across studies. Indeed, considerable variability in the risk factors included for stratification is common when attempting to identify patients with multimorbidity, making it difficult to draw generalised conclusions or make comparisons across tools. 38 The heterogeneity in both stratification domains and outcomes may be attributed to the lack of consensus on a meaningful definition of multimorbidity, particularly regarding which risk factors are most relevant when identifying older adults at highest risk of adverse clinical outcomes.39,40 Although efforts have been made to refine the concept of multimorbidity—such as through the introduction of terms like complex multimorbidity and mental–physical multimorbidity—these approaches have not yet proven effective in identifying the key risk factors needed for stratification. 6
Most of the included studies used the Comprehensive Geriatric Assessment (CGA) to assess patients. While the CGA has been validated across various settings in older adults, it has not been externally validated specifically for older adults with multimorbidity. This omission may result in important risk factors being overlooked when stratifying this population, potentially contributing to poor quality of life and increased mortality risk. More broadly, many new models are rarely externally validated and often lack clinical utility. 41 It may be argued that, given the high prevalence of multimorbidity among older adults, the use of tools such as the CGA to identify their needs is unproblematic. However, multimorbidity is highly heterogeneous across age groups due to differences in disease clusters and socioeconomic status.4,12 This suggests that the risk factors relevant for determining the need for integrated care—and therefore those that clinicians should stratify on—vary significantly even within seemingly similar populations, such as older adults. The absence of a meaningful definition for differentiating risk profiles in older adults with multimorbidity may explain why no tools identified in this review were specifically developed and validated for this population. Instead, most tools adopt a comprehensive and holistic approach, incorporating multiple domains to identify appropriate patients for integrated care. This highlights a persistent knowledge gap in the development and validation of stratification tools tailored to older adults with multimorbidity in integrated care contexts.
The heterogeneity of sample populations, outcome measures, and risk factors not only complicates comparisons across stratification tools but also presents a significant challenge to their implementation within broader healthcare systems. Our findings indicate that stratification tools for older adults with multimorbidity are primarily used to identify at-risk patients, but their application is limited to clinical settings such as hospitals, outpatient clinics, and general practice. This limited use may be attributed to the considerable difficulty in developing, validating, and implementing stratification tools that are suitable for use across multiple sectors. These challenges arise from differences in the populations served by each sector, the resources available for stratification, and variations in clinical workflows and needs. 42 Furthermore, stratification is part of the evolving landscape of precision medicine and individualised risk profiling, which has yet to be fully adopted across the healthcare sector. This slow adoption is partly due to unresolved ethical challenges surrounding healthcare data sharing. 43
A recent systematic review also revealed that risk stratification tools designed to predict healthcare utilisation are widely implemented in primary care, but often lack external validation and have been associated with either no change or increased healthcare utilisation when used to identify at-risk patients. 42 This suggests potential issues with the routine use and implementation of such tools across healthcare sectors. In our review, the Comprehensive Geriatric Assessment (CGA) emerged as the most frequently used tool for identifying patients for integrated care. This may be due to the CGA already being routinely implemented across many healthcare sectors, where older adults with multimorbidity are likely to present for assessment. 44 In addition, the CGA is not solely a tool for patient identification; it also functions as a multicomponent integrated care approach, 45 which may make it more practical to implement compared to separating risk stratification and integrated care into two distinct processes
The development, validation, and implementation of stratification tools require significant time and resources, and their utility depends on clinicians perceiving them as necessary and feasible within their daily routines. For example, the implementation of risk stratification in primary care is influenced by a facility’s technological capabilities, staffing levels, and resource availability. Risk stratification has been reported as time-consuming and difficult to integrate into existing workflows, 46 which may help explain the knowledge gap identified in this review. This may also account for why none of the identified tools were used across multiple sectors. Tools intended for cross-sector use would likely require even more advanced technological infrastructure, greater staffing capacity, enhanced communication, and a more integrated healthcare service framework to support their implementation.
Based on our findings, we recommend that the development of future risk stratification tools for older adults with multimorbidity in an integrated care context should include: (a) a development phase that identifies risk factors related to the need for integrated care in older adults with multimorbidity, in collaboration with stakeholders from all sectors, to identify commonly presenting risk factors; (b) the development of causal loop diagrams, systems maps, and the use of exploratory machine learning on existing data to uncover additional risk factors not identified by stakeholders; (c) internal and external validation of the tools on populations across sectors, with training of the risk stratification models on multiple data types (e.g., qualitative interviews, patient-reported outcome measures, objective measures) and across various settings (e.g., primary care, clinics, municipalities); and (d) collaboration on the implementation of the tools in practice across diverse healthcare sectors. Interventions that involve the development and use of stratification tools could benefit from established frameworks for complex interventions, such as the Medical Research Council (MRC) Framework, which encompasses all phases from development to implementation. 47
While our study benefited from stakeholder involvement and a thorough, inclusive search strategy, it also had several limitations. These include the exclusion of specific search terms due to the varying definitions of integrated care and multimorbidity. Furthermore, our findings were limited by the inclusion of only peer-reviewed articles, which may have excluded relevant grey literature or unpublished studies.
Conclusion
We identified several knowledge gaps related to stratification tools for older adults with multimorbidity in an integrated care context. Our findings revealed that risk stratification is underdeveloped and suffers from heterogeneity in scoring methods, items, and measurement domains. We observed that stratification was primarily used to identify older adults with multimorbidity for referral to multidisciplinary teams or to assign a care manager. Notably, the most widely used tools were not originally designed with multimorbidity in mind, despite the fact that multimorbidity is highly heterogeneous even among older adults. Many of the tools identified, such as the Comprehensive Geriatric Assessment, are already implemented in clinical practice, which may explain their widespread use. Future development of risk stratification tools should be carried out in collaboration across healthcare sectors. Implementation efforts must consider the technological capabilities, staffing levels, and resource availability within the intended setting. To ensure successful adoption in clinical practice, tools must be easy to use, straightforward, and not impose significant time or resource burdens.
Supplemental Material
Supplemental Material - Stratification tools for assessing older adults with multimorbidity in an integrated care context: A scoping review
Supplemental Material for Stratification tools for assessing older adults with multimorbidity in an integrated care context: A scoping review by Jon André Christensen, Michael Marcussen, Vicki Zabell, Bettan Bagger, Ditte Høgsgaard, Sanne Lundstrøm, Barbara Ann Barrett, Anne Frølich, Søren Thorgaard Skou and Lene Lauge Berring in Journal of Multimorbidity and Comorbidity
Footnotes
Acknowledgements
The authors would like to graciously thank Anja Mortensen for her contributions in refining the manuscript and providing feedback. Moreover, we would like to thank research librarian Vibeke Grünbaum for her help in refining the search matrix and providing support through the review process.
Ethical considerations
There are no human participants in this article and informed consent is not required.
Author’s contributions
All authors contributed to conceptualization. JAC, MM, VZ, DH and LLB contributed to formal analysis, investigation and methodology. JAC wrote the original draft in collaboration with MM, DH and LLB, and all authors contributed to the review, editing and final approval of the manuscript.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Novo Nordisk Fonden, 0077572 and Region Sjælland, R24 A2069, R24-A1828, Sla-2024-1. None of the funders were involved in the development, analysis or interpretation of the research findings.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data Availability Statement
All search matrices are included in the Supplemental Material. Data from Covidence can be retrieved upon request to corresponding author(s).
Supplemental Material
Supplemental material for this article is available online.
References
Supplementary Material
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