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As diabetes care continues to grow and evolve, understanding of comorbidity patterns can help inform the design of future health services.
Although there have been considerable improvements in diabetes care in Australia in recent years, the prevalence of significant comorbid conditions in older people with diabetes can add to the complexity of care needed.
The prevalence of diabetes (type 1, type 2 and other diabetes, excluding gestational diabetes) in Australia is estimated to be around 5%. In 2021, diabetes contributed to 11.2% of all deaths in Australia and was among the ten leading causes of death. Mortality rates for diabetes have also been reported to be higher in people aged 85 years and over compared with younger populations.
The prevalence of diabetes increases with age, with about 20% of Australians aged 80–84 years living with diabetes.
In a recent research prioritisation exercise, Diabetes UK identified certain areas of focus to improve the care of older people. Among them was a better understanding of characteristics such as comorbid conditions of older people with diabetes.
In a 2020 review, a panel of multidisciplinary experts who were part of the International Geriatric Diabetes workshop highlighted the lack of inclusion of older people in diabetes research compared with younger population. Recommendations were made also for the development and establishment of patient classification systems based on comorbidity patterns. This would help guide treatment allocation and better use of limited health care resources.
Older people with diabetes have varied backgrounds and medical profiles, and a better understanding of comorbidity patterns can help in the development of targeted care.
The patterns of comorbid conditions in older people
For our analysis, we focused on older people aged over 65 years with type 2 diabetes mellitus where all of their comorbid conditions were recorded by the general practitioner. We conducted descriptive analyses and explanatory factor analyses to identify comorbidity patterns of older people with type 2 diabetes mellitus.
We found that 19% of patients aged 65 years or older at GP encounters had a diagnosis of type 2 diabetes mellitus. Patients aged 65–84 years had a higher type 2 diabetes mellitus prevalence than those aged 85 years or over (20% v 14%). Patients from a non-English speaking background were more likely to have type 2 diabetes mellitus (31%) compared with those from an English-speaking background (18%). The majority of patients with type 2 diabetes mellitus (95%) had at least one comorbid condition, and almost two-thirds (68%) had three or more comorbid conditions.
We identified a high prevalence of cardiovascular-related comorbid conditions such as hypertension (71%), hyperlipidaemia (48%) and ischaemic heart disease (28%) in our dataset. We also identified two distinct patterns of comorbid conditions among older people with type 2 diabetes mellitus: a pattern that associates psychological and musculoskeletal conditions, and another pattern linking cardiovascular conditions with chronic renal failure. The psychological and musculoskeletal conditions frequently occurring together comprised depression, insomnia, anxiety, arthritis, chronic back pain and gastro-oesophageal reflux disease. The cardiovascular conditions that co-occurred together included ischaemic heart disease, congestive heart failure, peripheral vascular disease, atrial fibrillation and chronic renal failure.
Our study had some limitations, including the cross-sectional design. We were not able to explore the influence and impact of comorbid conditions over time. Future longitudinal studies examining the impact of comorbid conditions among older people with type 2 diabetes mellitus could address this.
The challenges of mental health and linguistic diversity
The presence of non-cardiovascular-related comorbid conditions highlights the heterogeneity of older people with type 2 diabetes mellitus.
Older people with type 2 diabetes mellitus are not exempt from the ongoing mental health crisis. A recent report from Bartholomaeus and colleagues showed an increasing rate of utilisation by older Australians of primary care mental health services from 2009 to 2019. If we consider mental health and its implications for diabetes, there is growing evidence of an association between mental disorders such as depression and anxiety, poor glycaemic control, diabetes-related complications and mortality. The Royal Australian College of General Practitioners (RACGP) have resources on mental health and type 2 diabetes mellitus that could be used accordingly.
In our study sample, the prevalence of type 2 diabetes mellitus was much higher in people with non-English speaking background (31%) compared with people with English-speaking background (18%). A recent review on access to health services among culturally and linguistically diverse populations in Australia highlighted the different challenges, one of them being inadequate interpreter services and its link to low levels of health literacy. However, another study reported that some GPs felt that an interpreter was not needed due to the GPs being multilingual. In managing type 2 diabetes mellitus, patients may require other health services apart from their GPs, and considerations should be made to ensure more members of the health care team have the necessary communication support.
As diabetes care continues to grow and evolve, understanding of comorbidity patterns can help inform the design of future health services. Our analysis of patients attending GPs in our studied population showed many older patients with type 2 diabetes mellitus (two-thirds) have several comorbid conditions. This shows the continuing need to strengthen primary health care in Australia, led by GPs, ensuring continuity of care. Given their complex needs, it is essential to maintain continuity of care beyond their GPs to prevent the fragmentation of treatment for older patients with diabetes.
Wei Jin Wong is a pharmacist and a PhD candidate at the Faculty of Medicine and Health, the University of Sydney.
Tu Nguyen is a Research Fellow at the George Institute for Global Health and Honorary Senior Lecturer at Sydney School of Public Health, the University of Sydney. She is a geriatrician by training.
Christopher Harrison is a Senior Lecturer at the Sydney School of Public Health, the University of Sydney. He is the data custodian of the BEACH data and the co-lead of the OCEAN project.
The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.
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