Examining variation in the measurement of multimorbidity in research: a systematic review of 566 studies

Iris Iris Szu-Szu Ho, Amaya Azcoaga-Lorenzo, Ashley Akbari, Corri Black, Jim Davies, Peter Hodgins, Kamlesh Khunti, Umesh T. Kadam, Ronan A. Lyons, Colin McCowan, Stewart W. Mercer, Krishnarajah Nirantharakumar, Bruce Guthrie* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Background: There is a lack of systematic understanding of how multimorbidity has been constructed and measured. This review aims to examine multimorbidity definition and measurement in research.

Methods: Systematic review registered with PROSPERO (CRD420201724090), with searches in nine bibliographic databases, from inception to 21/01/20. Reference lists of retrieved articles were hand-searched. Eligible studies measured multimorbidity for any purpose in primary care, community or hospital populations. Two reviewers independently reviewed the retrieved
studies. We used descriptive analyses to understand characteristics and patterns of multimorbidity measures.

Findings: In total, 566 studies were included in this review. 36% of studies did not explicitly report how they defined multimorbidity and 13% did not report the conditions their measure included. The number of conditions included in measures ranged from 2 to 285 (median 17, interquartile range 11-23). 98% of measures included at least one cardiovascular condition, compared to at least one metabolic and endocrine (97%), respiratory (93%), musculoskeletal
(88%) and mental health (79%) condition, whereas chronic infections (27%), haematological (24%), ENT (24%), skin (16%) and oral (4%) conditions were uncommonly included. Only eight individual conditions were included by more than half of studies (diabetes, stroke, cancer, COPD, hypertension, coronary heart disease, chronic kidney disease and heart failure), none of which were mental health conditions.

Interpretation: Measurement of multimorbidity is poorly reported and very variable. Consistent reporting of measure definitions should be required by journals, and consensus studies are needed to define core and optional conditions to include.
Original languageEnglish
Pages (from-to)e587-e597
Number of pages11
JournalThe Lancet Public Health
Issue number8
Early online date22 Jun 2021
Publication statusPublished - Aug 2021

Bibliographical note

Funding: Health Data Research UK (CFC0110)
This project was funded by HDR UK (CFC0110). We would like to express our appreciation to the wider HDR UK National Multimorbidity Resource for support.

Data Availability Statement

Study data are available on request to the corresponding author.


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