'Middle-age' frailty and multimorbidity in diabetes: Why does it matter?

Our new paper shows that among people aged between 40 and 70 living with type 2 diabetes, frailty and multimorbidity are both common and linked with a range of adverse consequences. Here we explore what this means and why it matters.

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Type 2 diabetes is a common and important long-term condition. An estimated 462 million people worldwide are living with type 2 diabetes, including 15% of all people aged between 50 and 70. The impact of type 2 diabetes on the individual can be improved through clinical management of the condition, however, there is no 'one-size fits all' approach to diabetes care. Many factors influence how care should be individualised. Among the most important are frailty and multimorbidity. 

Frailty is a state of reduced reserve, meaning people living with frailty are at greater risk of adverse health outcomes in response to stressors. Multimorbidity, on the other hand, describes the combination of multiple long-term conditions in an individual. There is huge variation, however, in how frailty and multimorbidity are measured. Both frailty and multimorbidity are common in people with type 2 diabetes.

Clinical guidelines for managing type 2 diabetes recommend that older people with frailty or multimorbidity be managed differently. Clinicians are recommended to consider higher targets for blood sugar control. However, we know that frailty and multimorbidity affect people at a wide range of ages, including 'middle-aged' people under the age of 65 years. At these younger ages, it is less clear if and how frailty and multimorbidity should inform our management of people with type 2 diabetes. Our paper, therefore, attempts to unpick some of the implications of frailty and multimorbidity for people with type 2 diabetes.

Why study frailty and multimorbidity in younger people?

Frailty and multimorbidity both become more common as people age. Frailty, in particular, has mostly been studies in people aged 65 years or older. However, there is growing interest in the implications of frailty and multimorbidity in younger populations. We previously studied the prevalence and impact of frailty in the UK Biobank research cohort, which includes half a million people aged between 37 and 73 years old. We found that frailty was common, particularly in people with multiple long-term conditions, and was associated with double the risk of mortality. Many questions remain, however, about the more nuanced implications of frailty and multimorbidity in younger people. In particular, it is not clear if frailty or multimorbidity are the most appropriate "lens" with which to view people with long-term conditions, such as type 2 diabetes, when informing clinical decisions. 

Figure taken from Hanlon et al, Frailty and pre-frailty in middle-aged and older adults and its association with multimorbidity and mortality: a prospective analysis of 493 737 UK Biobank participants, Lancet Public Health, 2018. 

Frailty in people with type 2 diabetes

The importance of frailty in people with type 2 diabetes is increasingly recognised, and has informed international clinical guidelines. Less strict control of blood sugar is generally recommended, partly based on limited life expectancy and higher risk of hypoglycaemia in people living with frailty. We recently completed a systematic review of observational studies of frailty in people with diabetes. Despite guidelines recommendations based on the risk of hypoglycaemia in people living with frailty, we only identified one study which had assessed this outcome. Also, while frailty certainly carried increased mortality risk in type 2 diabetes, few of these studies have assessed people aged under 65 years. The implications of frailty in 'middle-aged' people with type 2 diabetes, is therefore not clear.

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Figure taken from Hanlon et al, Frailty measurement, prevalence, incidence, and clinical implications in people with diabetes: a systematic review and study-level meta-analysis, Lancet Healthy Longevity, 2020

What our study adds

Our study, recently published in Communications Medicine, compares two different measures of frailty (frailty phenotype and frailty index) and two measures of multimorbidity (Charlson comorbidity index and a numerical count of 42 long-term conditions) in UK Biobank participants with type 2 diabetes (aged between 40 and 72 years).

We found that regardless of measure, both frailty and multimorbidity were common in middle-aged as well as older people. However, there was little overlap in the people identified by each measure: 42% were identified by at least one measure, but only 2.2% by all four. This suggests that it may be unhelpful to focus on a single narrow definition when attempting to identify individuals at higher risk who may be in need of individualised care and clinical management. 

Despite this lack of overlap, each measure was associated with mortality, heart attacks and strokes, falls and fractures, and hospitalisation with hypoglycaemia. However, for each measure, age remained an important prognostic factor. Younger people with an equivalent level of frailty had a considerably lower absolute risk of adverse outcomes than older people with a similar degree of frailty. 

5-year risk of all-cause mortality with frailty or multimorbidity

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Our findings support calls to embed identification of both multimorbidity and frailty within routine diabetic reviews, including for middle aged people. However care should be taken to assess risk and appropriate treatment targets at an individual level. This assessment should reflect patients’ age, as well as other other risk factors. 

Frailty and multimorbidity are clinically important concepts across a range of ages, including people under 65 years who have not traditionally been the focus of frailty research. However, as our findings highlight, we must be careful of extrapolating recommendations based on older populations to younger people who may meet criteria for frailty or multimorbidity. Frailty and multimorbidity may not be the most appropriate lens to inform target blood sugar control in younger people with type 2 diabetes - as the assumptions around life expectancy informing some guideline recommendations do not hold to the same degree. However, these tools may help identify people at higher risk for whom treatment may be optimised. As with any translation of population-based measures to clinical practice, our understanding of frailty and multimorbidity should inform and support, rather than dictate, clinical decisions.

Peter Hanlon

Clinical Research Fellow, Dr. Peter Hanlon