21 st century: an aging world We live in an aging world. It is estimated that by 2030 1 in 6 people in the world will be aged 60 years or over and the number of people aged 80 years or older is expected to triple between 2020 and 2050, reaching 426 million worldwide. It is also important to note that while population ageing started in high-income countries, low- and middle-income countries are now seeing the same shift, which will result in global issues as populations age and new needs arise.

This new scenario showcases the importance of deep changes in healthcare systems. The current approach to disease in Europe is single-disease oriented, so patients with two or more co-existing chronic conditions (a phenomenon known as multimorbidity) lack a specific management and therefore become more vulnerable to adverse events. Older adults have a high prevalence of multimorbidity, with data showing that more than 50% of older adults between 60-69 years old are multimorbid, and this percentage soars up to 70% in people aged 70 years and above.

Dementia and multimorbidity: coexisting entities

Among all conditions that can present in older adults, dementia is one of the most debilitating chronic conditions and leads to high impact healthcare needs. According to Columbia University (The 2016 Health and Retirement Study Harmonized Cognitive Assessment Protocol Project), almost 10% of adults ages 65 and older have dementia, and another 22% have mild cognitive impairment (MCI). Furthermore, on average, dementia patients have more than 4 additional chronic diseases such as diabetes, chronic kidney disease or cardiovascular diseases. When dementia and multimorbidity coexist, adverse outcomes such as increased mortality, disability and frailty, increased risk of drug interactions and adverse drug effects, and increased healthcare costs a are more frequent.

If older adults are commonly multimorbid and dementia is highly prevalent, these two factors will coexist quite frequently. Although this is our current reality, the truth is that guidelines that asses both multimorbidity and dementia are nonexistent, leaving a wide gap in knowledge that needs to be addressed. Treatments for diseases like diabetes, which is highly prevalent in older adults, may be different in older patients with MCI/mild dementia than in general populations, yet there are no clinical guidelines or randomized clinical trials on this matter.

Clinical guidelines: how things stand

The available clinical guidelines are hardly ever stratified by age, less than 35% tackle older adults and populations over 80 years old are widely underrepresented. The lack of specific evidence for old patients causes, in the best-case scenario, a reduced ability to implement recommendations on them; worst-case scenario, they could even cause a harmful effect when treatments for multiple diseases are initiated at the same time according to different guidelines, without taking a holistic approach and prioritizing those conditions that affect quality of life, disability, mortality, morbidity, hospitalization, burden of care, and healthcare costs. This highlights the need for modified guidelines and a more integral management in multimorbid older adults with MCI or mild dementia.

Regarding multimorbidity, only 27% of clinical guidelines address this factor. Drug recommendations in these patients are poorly outlined, even though multimorbid older adults with dementia are prone to adverse effects and the risk of drug interactions is remarkably high due to increased polypharmacy rates. Furthermore, the absence of consideration of multimorbidity in guidelines may result in futile treatments, such as initiating a cholinesterase inhibitor in a patient who is also taking a drug with anticholinergic activity, resulting in pharmacological antagonism. There is also evidence that hospitalized older adults with dementia are less likely to be well managed in comparison to patients admitted for the same disease with no prior history of dementia.

Conclusions

The development of clinical guidelines that address both MCI/mild dementia and multimorbidity should be a priority. Our aging society will only increase its pressure on health systems, and the management of elderly adults with both dementia and multimorbidity will provide a great challenge. New evidence is needed to cement a better care for older adults.