A timely diagnosis of Alzheimer’s disease

Dementia is now the leading cause of mortality in England and Wales. And the current trajectory predicts that the number of people over 60 living with dementia in the UK is expected to double in the next 25 years to reach 2 million by 2050 ( Alzheimer's Research UK ).

Dementia is an umbrella term encompassing a range of cognitive (e.g. memory impairment) and psychological (e.g. depression, anxiety, paranoia) symptoms that arise after substantial loss of brain cells. It is a late presentation of a number of different neurodegenerative diseases such as Parkinson’s, Huntington’s and Alzheimer’s; the latter being responsible for the majority (~60-70%) of cases ( World Health Organization 2022).

Alzheimer’s is a disease close to my heart. My grandfather passed away in 1995 from what was diagnosed as probable-Alzheimer’s disease based on his symptoms. ‘Probable’, because in the 90’s definitive diagnosis was only possible at autopsy. My family still vividly remembers the painful decline of a good-humoured, intelligent and much-loved father and grandfather. Sadly, stories like this are all too abundant.

A timely diagnosis

The definition of a timely diagnosis varies, but perhaps the broadest is ‘one made at the right time for the individual patient, irrespective of the disease stage’ (Dubois 2015). Currently diagnosis is most commonly made at the dementia stage, once a person can no longer continue to live their normal life. It’s hard to imagine how this can be the ‘right time’ for patients and their families.

Due to advances in science we now have the ability to accurately identify the protein signatures of Alzheimer’s (beta-amyloid and tau) during life by scans (amyloid-PET) or analysis of cerebrospinal fluid (CSF); a simple blood test is even on the horizon. Astonishingly, these biomarkers can actually be detected decades before the symptoms of dementia become apparent. This has led researchers to conclude that Alzheimer’s is in fact a disorder of middle age rather than old age (Ritchie et al 2015). This discovery offers a range of exciting opportunities for patients, families and our NHS.

The potential benefits of an early diagnosis include: 

• Risk reduction: healthy living (regular exercise, Mediterranean diet, moderate alcohol consumption etc.) might help reduce the risk of developing dementia ( World Health Organization Guidelines 2019). 
• Appropriate and early management of symptoms: use of biomarkers at early stages changed diagnosis by ~30% and management by 46% (Cognat et al 2019).
• Stay at home for longer: early diagnosis of Alzheimer’s dementia has been shown to delay time to institutionalisation by an average of 9 months (Littlewood et al 2010)
• Clinical trial access: many current drug trials are recruiting at an early stage (pre-clinical and mild cognitive impairment) and require biomarker evidence of Alzheimer’s (Cummings et al 2021).
• Reduce time to diagnosis: the time from referral to diagnosis has been shown to be as much as 2 years in some cases (National Audit of Dementia 2021)
• Societal benefit: early diagnosis and intervention might achieve savings from reducing the need for care and institutionalisation (Rasmussen et al 2019)
• The value of diagnostic information (Wurcel et al 2019): patient and carer empowerment e.g. many carers of dementia patients feel that diagnosis would have been more useful if it had been made earlier (Woods et al 2018)

I’m not sure what my grandfather would have made of these advances in diagnosis and if, given the opportunity, he would have wished to know his risk whilst he was still fit and healthy, after all it remains a personal choice. However, a recent survey of the UK population found that the vast majority (74%) of people would want to know their diagnosis before they had symptoms of dementia ( Alzheimer's Research UK 2019). In any event, if we are going to realise the goal of making dementia a ‘very rare condition’ ( Craig Ritchie 2022), early diagnosis will definitely have a big part to play.