Prevalence of many diseases increases with age so many older people have more than one illness (comorbidity). Progressive diseases like cancer, organ or system failure (e.g. chronic heart failure, chronic obstructive pulmonary disease) and neurological conditions can interfere substantially with life for older adults. In the case of frailty and comorbidities, knowing exactly when death will occur is often difficult to predict and can impact on timely and person-centred palliative care.
This evidence summary aims to discuss the implications of comorbidity and frailty in prognostication and management of older adults, and subsequently provision of palliative care services.
More than 50% of older adults have three or more chronic diseases, the presentation and severity of symptoms will be heterogeneous, but produce cumulative effects for each individual. [1,7] Comorbidity is associated with poorer quality of life and increased risk of frailty and morbidity.  While evidence based guidelines exist for the management of a single disease, few address comorbidities particularly in a palliative care context where polypharmacy is inevitable.  In addition there is a low inclusion rate of older adults in comorbidity randomised clinical trials and therefore reinforces the difficulty in creating appropriate clinical protocols for their management. 
Clinicians may need to pursue more flexible approaches to care of older adults with comorbidities in a palliative care context where the medical goals are to provide comfort and quality of life. [6,7]
Clinical goals may vary according to prognosis, however prognostication is additionally difficult for those with the frailty of old age and no overriding diagnosis but multiple comorbidities or ‘multimorbidity’ and often a degree of cognitive impairment. [2,4,5] Clinicians often find discussing end-of-life preferences and advance care planning more difficult where prognostication is not clear-cut and as a result older adults may be subjected to unnecessary treatment and side effects. [2,8,9]
Prioritising treatments requires an assessment across all health issues. Identifying patient priorities and preferences for care is important in providing patient-centred care over time in the context of polypharmacy and multimorbidity.  Older adults with comorbidities are at particular risk of adverse reactions from polypharmacy and in the case of symptom review and setting health priorities, some medications may be therapeutically omitted where burden outweighs benefits. [6-9] Currently there is insufficient evidence or guidelines to facilitate prognostication, appropriate polypharmacy and symptom management for older adults with multimorbidity.
Older adults with comorbidity of cognitive impairment may be under-prescribed as a result of the difficulties in assessing symptoms and pain.  Development of tools or decision-making guides is being conducted but as yet only single-disease-specific guidance exists. [2,4,6]
Overall the quality of the evidence was acceptable – high, [1,2,4,6,9-11] although four studies scored poorly [3,5,8,12] due to the lack of reporting on methodology and quality of included studies. These papers were still included in this review due to their relevancy to the topic.
Page updated 24 May 2017