Multiple physical and mental health comorbidity in adults with intellectual disabilities: population-based cross-sectional analysis

Cooper et al. BMC Family Practice (2015) 16:110 DOI 10.1186/s12875-015-0329-3 RESEARCH ARTICLE Open Access Multiple physical and mental health comorbidity in adults with intellectual disabilities: population-based cross-sectional analysis Sally-Ann Cooper1*, Gary McLean2, Bruce Guthrie3, Alex McConnachie4, Stewart Mercer2, Frank Sullivan5 and Jill Morrison2 Abstract Background: Adults with intellectual disabilities have increased early mortality compared with the general population. However, their extent of multimorbidity (two or more additional conditions) compared with the general population is unknown, particularly with regards to physical ill-health, as are associations between comorbidities, neighbourhood deprivation, and age. Methods: We analysed primary health-care data on 1,424,378 adults registered with 314 representative Scottish practices. Data on intellectual disabilities, 32 physical, and six mental health conditions were extracted. We generated standardised prevalence rates by age-groups, gender, and neighbourhood deprivation, then calculated odds ratio (OR) and 95 % confidence intervals (95 % CI) for adults with intellectual disabilities compared to those without, for the prevalence, and number of condition. Results: Eight thousand fourteen (0.56 %) had intellectual disabilities, of whom only 31.8 % had no other conditions compared to 51.6 % without intellectual disabilities (OR 0.26, 95 % 0.25–0.27). The intellectual disabilities group were significantly more likely to have more conditions, with the biggest difference found for three conditions (10.9 % versus 6.8 %; OR 2.28, 95 % CI 2.10–2.46). Fourteen physical conditions were significantly more prevalent, and four cardiovascular conditions occurred less frequently, as did any cancers, and chronic obstructive pulmonary diseases. Five of the six mental health conditions were significantly more prevalent. For the adults with intellectual disabilities, no gradient was seen in extent of multimorbidity with increasing neighbourhood deprivation; indeed findings were similar in the most affluent and most deprived areas. Co-morbidity increased with age but is highly prevalent at all ages, being similar at age 20–25 to 50–54 year olds in the general population. Conclusions: Multi-morbidity burden is greater, occurs at much earlier age, and the profile of health conditions differs, for adults with intellectual disabilities compared with the general population. There is no association with neighbourhood deprivation; people with intellectual disabilities need focussed services irrespective of where they live, and at a much earlier age than the general population. They require specific initiatives to reduce inequalities. Keywords: Intellectual disabilities, Mental retardation, Multi-morbidity, Physical health, Mental health, Inequalities, Deprivation * Correspondence: 1 Mental Health and Wellbeing group, Institute of Health and Wellbeing, University of Glasgow, Administrative Building, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow G12 0XH, UK Full list of author information is available at the end of the article © 2015 Cooper et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Cooper et al. BMC Family Practice (2015) 16:110 Page 2 of 11 Background Adults with intellectual disabilities are thought to experience health inequalities and earlier age of death compared with the general population [1]. However, there is little reported information on their wider experience of multimorbidity/comorbidity (two or more conditions additional to the intellectual disabilities) in this population across the adult lifespan. Comorbidity is clinically important, as it may require a different management approach to the care of an individual disease, and may introduce pharmacological contraindications. There is increasing awareness of its clinical importance, due to the relatively recent studies of multi-morbidity in the general population showing that it starts to become more common over the age of 50 and increases in the elderly [2]. In people with intellectual disabilities, rates of individual disorders have been previously reported, for example, a point-prevalence of 40 % for additional mental ill-health [3], 30 % for epilepsy [4], and 50 % for gastro-oesophageal reflux disorder [5]. This might suggest that multi-morbidity would be a particular problem for this population, but we have only been able to find two previous studies on the topic, both of which were focussed only on older people with intellectual disabilities [6, 7]. Both reported high rates of multimorbidity/ comorbidity; 71 % in 695 older persons with intellectual disabilities [6], and 80 % in 1047 older persons receiving paid support [7]. These studies did not drawn direct comparisons with rates in the general population living in the same areas, nor at the same age. The extent of multimorbidity is higher in the general population living in more deprived neighbourhoods [2]. It is therefore important to examine if this is also true for people with intellectual disabilities, since this would indicate higher needs in this population which may need specific organisation to meet. Both children and adults with intellectual disabilities are more likely to live in more deprived areas [8–11]. However, the impact this has on their health and health care has been little studied [10]. This study was undertaken to quantify the extent of recorded ill-health and comorbidity experienced by adults with intellectual disabilities compared with the general population, and to measure the associations between neighbourhood deprivation, age, and comorbidity in adults with intellectual disabilities. age, sex, and socioeconomic deprivation, with a more detailed explanation available elsewhere [2]. Data on the presence of intellectual disabilities, 32 common chronic physical health conditions and six mental health conditions were extracted (definitions are provided in Additional file 1: Appendix 1). We defined intellectual disabilities using a set of Read Codes based on definitions used by NHS Scotland Information Services and from the Quality & Outcomes Framework (Additional file 1: Appendix 2). Neighbourhood deprivation was measured using the Carstairs deprivation score divided into quintiles (from most affluent to most deprived) [13]. The Carstairs score is based on postcode of residence and is widely used in healthcare research as a (...truncated)