Review ArticleSystematic Review

Measures of Multimorbidity and Morbidity Burden for Use in Primary Care and Community Settings: A Systematic Review and Guide

Alyson L. Huntley, Rachel Johnson, Sarah Purdy, Jose M. Valderas and Chris Salisbury
The Annals of Family Medicine March 2012, 10 (2) 134-141; DOI: https://doi.org/10.1370/afm.1363

Article Figures & Data

Tables

  • Table 1

    Characteristics and Application of the Most Commonly Studied Multimorbidity Measures in Outpatient Settings

    MeasureOriginal Derivation/Validation PopulationsInformation NeededOriginal Purpose of ScoreHow Information Is UsedComments
    Disease countNot applicable (varies for different studies)Clinician-rated disease counts derived from medical records or clinician diagnosis
    Self-reported disease counts based on questionnaires or interviews    		Not applicable (varies for different studies)Single diseases added to give a total number of diseases/conditions per individualNo weighting of diseases regarding severity or prognosis
    Chronic Disease Score (CDS)/RxRisk Model15–17Original CDS15: adult HMO enrollees from a single US HMO
    Revised CDS16 derived and validated in 254,694 adult members of a US HMO.
    RxRisk17 derived and validated in large samples of US HMO enrollees    		Automated pharmacy data during a 1-year periodTo develop a stable measure of chronic disease status using routine pharmacy data rather than chart reviewOriginal CDS considered 17 disease states, weighted by an expert panel
    Score based on history of dispensed drugs for 1 year, adjusted for age and sex
    Subsequent versions used empirically derived weights and expanded number of diseases16,17    		Limited number of disease states
    Weighting of original CDS based on consensus rather than empirical data (addressed by subsequent versions)
    Charlson Index18Derived in 559 US medical inpatients
    Validated in 685 women receiving treatment for breast cancer    		Various versions are available; 17 to 22 disease categories, including age
    In different forms, can be administered by a health professional on paper or electronically or self-completed as a questionnaire
    Free    		To predict 1-year mortality among patients admitted to hospital
    Later adapted to predict costs19    		Each disease is given a weighting of 1 to 6 and weighted scores are summated; this score can also be combined with age
    Variations have been developed to use ICD-9 data, namely, Romano et al (Dartmouth- Manitoba score),20 Deyo et al,21 D’Hoore et al,22 Ghali et al,23 Rius et al24    		Limited number of diseases
    Prognoses vary between cancers yet have similar rating
    Needs information about severity of some conditions
    Prognosis for some conditions has improved since index developed
    Adjusted Clinical Groups (ACG) System25Derived and validated in US using large HMO databases
    Validation sample also included 30,000 Medicaid recipients    		Age, sex, and diagnosis codes from medical records or insurance claims coded using the ICD or Read code systems
    Data entered into ACG System software available at cost under license    		Originally devised to predict morbidity burden and use of health care resources
    System developed to provide a number of tools with different purposes    		Collapsed into Initial Diagnosis Codes then to calculate ADGs (32); CADGs (12); MACs (26); ACGs (102). Each ACG includes individuals with a similar pattern of morbidity and similar expected resource useNeed to purchase bespoke software
    Based on records or claims data so dependent on reliability of those data
    Cumulative Index Illness Rating Scale (CIRS)26,27Hospitalized men in the United States26 and subsequently older adults in ambulatory settings27A rating scale consisting of 14 body systems categories that can be filled in by trained assessors directly during clinical consultation or from medical records.
    Free access    		To assess the medical burden of chronic illnessEach body system has a severity rating of 0 to 4, which are summated to create a total score (0–56), or presented as an index based on the number of categories scoring 2 or more.
    Several variations exist    		Requires training based on a manual. Broad body system groups
    Prognoses vary among types of condition and may have improved since index was devised
    (Duke Severity Illness Check-list (DUSOI) index28–30Developed in 249 adult patients attending a family practice in the United StatesSeverity of illness checklist for measuring a person’s illness severity
    Can be filled in during clinical consultation or from medical records
    Available from author    		To quantify the burden of illness as measured by the physicianEach diagnosis is rated on 4 levels: symptom, complication, prognosis without treatment, prognosis with treatment
    Various severity scores are calculated using the ratings (from 0 to 4) for each parameter of every diagnosis    		Subjective judgment is required on the part of the assessor
    Requires training

    • ADGs=Adjusted Diagnosis Groups; CADGS = collapsed Aggregated Diagnosis Groups; HMO=health maintenance organization, ICD=International Classification of Diseases; MACs=major Adjusted Categories.

  • Appendix

    Measures of Multimorbidity Identified

    Diagnosis Based MeasuresMedication Based Measures
    Adjusted Clinical Groups (ACG) System version25Chronic Disease Score (CDS)/Rx-Risk15–17
    Charlson index18Simple count of drug types prescribed43
    Cumulative Index Illness Rating Scale (CIRS)26,27Morbidity Drug Burden Index (MDBI)44,45
    Disease countNursing home multimorbidity matrix46
    Duke Severity of Illness Checklist (DUSOI )28
    Elixhauser index31
    Functional Comorbidity Index (FCI)32–34
    Geriatric Index of Comorbidity (GIC)35
    Hierarchical Coexisting Conditions (HCCs)36
    Index of Co-Existent Disease (ICED)37
    Seattle Index of Comorbidity (SIC)38,39
    Self-Administered Comorbidity Questionnaire (SCQ)40
    Disease Burden (Bayliss)41,42

    • Note: Only key references given in this table.

Additional Files

  • The Article in Brief

    Measures of Multimorbidity and Morbidity Burden for Use in Primary Care and Community Settings: A Systematic Review and Guide

    Chris Salisbury , and colleagues

    Background Many primary care patients have multiple medical conditions (multimorbidity). To assess the impact of muilitmorbidity, it is necessary to measure it. This analysis of existing research identifies measures of multimorbidity and morbidity (illness) burden suitable for use in research in primary care and community populations and investigates their validity.

    What This Study Found This systematic review identifies 17 different measures. The measures most commonly used in primary care, and for which there is greatest evidence of validity, are disease counts, the Charlson index, and the Adjusted Clinical Groups (ACG) System. Different measures are most appropriate according to the outcome being studied and the type of data available. For example, researchers interested in the relationship between multimorbidity and health care utilization will find most evidence for the validity of the Charlson Index, the ACG System and disease counts, but evidence is strongest for the ACG System in relation to costs, for Charlson index in relation to mortality, and for disease counts or Charlson index in relation to quality of life. Other measures, such as the Cumulative Index Illness Rating Scale and Duke Severity of Illness Checklist, are more complex to administer and their advantages over easier methods have not been well established.

    Implications

    • Research is needed to directly compare the performance of different measures.

  • Supplemental Appendix, Tables, & Figure

    Supplemental Appendix. Multimorbidity in the Primary Care Setting Search Strategy; Supplemental Table 1. Index of Studies With Demonstrated Associations Between Patient Sociodemographic Characteristics and Multimorbidity or Morbidity Burden Using Different Measures; Supplemental Table 2. Index of Studies Which Have Demonstrated Relationships Between Multimorbidity or Morbidity Burden and Cost or Process of Care Using Different Measures; Supplemental Table 3. Index of Studies Which Have Demonstrated Relationships Between Multimorbidity or Morbidity Burden and Patient Health Outcomes Using Different Measures; Supplemental Figure 1. PRISMA diagram

    Files in this Data Supplement:
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