Patterns of multimorbidity, multimorbidity clusters and associations with mortality in patients with intellectual disabilities in the UK.

Date of Approval
Application Number
Technical Summary

The management of multimorbidity (two or more long-term physical and/or mental health conditions) has risks of disease-disease interactions, drug-disease interactions and drug-drug interactions. It is increasingly recognised that diseases tend to occur together, which has led to an emerging interest in the natural clustering of diseases in the adult general population. Understanding and treating multimorbidity is also a major policy priority in the UK. Adults with intellectual disabilities (requiring support for daily activities, with onset before adulthood) have a point prevalence of mental ill-health of 41%, and 99% have multiple physical and/or mental health conditions (multimorbidity). However, no previous studies have investigated patterns of natural clustering of diseases in adults with intellectual disabilities who experience different health conditions to those seen in the general population.

The aim of the proposed study is to describe the extent of multimorbidity in adults with intellectual disabilities compared to the general population, and investigate characteristics, service use, and mortality in clusters of multi-morbid diseases. For this population-based study, we will use primary care records, derived from general practice information systems, linked anonymously with secondary care data from Hospital Episode Statistics Admitted Patient Care, Outpatient and A&E data, the Mental Health Services Data Set, and ONS Death Registration Data. We plan to use the linkage of these data provided by the Clinical Practice Research Datalink Gold and Aurum datasets.

This research will include a cross-sectional, descriptive study of the prevalence of multimorbidity in patients with and without intellectual disabilities, and a retrospective cohort analysis investigating the relationship between multimorbidity, health service utilisation and mortality. We will describe the prevalence of multimorbidity and will investigate patterns of the most common comorbidities using latent class analysis. We will use regression models to examine how health service utilisation and mortality may differ according to the presence of multimorbidity.

Health Outcomes to be Measured

Primary Outcomes
Prevalence of long-term physical and mental health conditions and those occurring together for different age groups (18-44, 45-64, 65-84, and 85+ years of age); Pairs of any two separate morbidities from the designated list of 43 long-term conditions (Appendix 1)

Secondary Outcomes
Number of primary care consultations (in-person or by phone); Number of repeat prescriptions (at least four times in a year by counting the unique British National Formulary (BNF) codes) per patient; Number of hospital admissions (defined by discharge dates); Mortality at two and five years after first record of both diseases


Deborah Kinnear - Chief Investigator - University of Glasgow
Kirsty Dunn - Corresponding Applicant - University of Glasgow
Angela Henderson - Collaborator - University of Glasgow
Barbara Nicholl - Collaborator - University of Glasgow
Daniel Mackay - Collaborator - University of Glasgow
Duncan Edwards - Collaborator - University of Cambridge
Kate O'Donnell - Collaborator - University of Glasgow
Rupert Payne - Collaborator - University of Bristol


2011 Rural-Urban Classification at LSOA level;HES Admitted Patient Care;Mental Health Services Data Set (MHSDS);ONS Death Registration Data;Patient Level Index of Multiple Deprivation Domains