Antidementia medication may improve survival in Alzheimer’s disease

Dr Christoph Mueller is an Academic Clinical Lecturer at the Department of Old Age Psychiatry at King’s College London. He and his co-authors published a paper on the influence of antidementia medication on survival in Alzheimer’s disease in Age and Ageing. He tweets at @DrChrisMueller

At present Acetylcholinesterase inhibitors, as Donepezil or Rivastigmine, are the only medications available for treatment of the early stages of Alzheimer’s disease. They can slow down the progression of the illness and alleviate distressing symptoms. However, their benefits are modest and they can have side effects, such as a slow heartbeat, indigestion, weight loss or an increased risk of falls. Moreover, dementia and Alzheimer’s disease is the leading cause of death for men and women 80 years or older in England and Wales. We investigated whether being prescribed antidementia medication was associated with survival in patients with Alzheimer’s disease.

We looked back at the anonymised electronic health records of 2,464 patients diagnosed with Alzheimer’s disease in South East London between 2008-2012 using the South London and Maudsley Clinical Record Interactive Search (CRIS) system. These records contain information on a wide range of patient characteristics and are linked to national data on hospital admissions and mortality.  Through this linkage we could establish whether the included patients were admitted to a general hospital in the year before dementia diagnosis and the reasons for admission.  We attempted to account for the fact that clinicians are more likely to prescribe Acetylcholinesterase inhibitors to healthier patients by including a so-called ‘propensity score’ into our analysis. For each patient included, this score represents the likelihood of being treated with the antidementia medication.

We found that about half of the patients with Alzheimer’s disease were prescribed an Acetylcholinesterase inhibitor. Less likely to receive this medication were patients who were older, unmarried, with worse memory, physical or mental wellbeing, functioning, or those living in more deprived areas. When taking all of these factors into consideration, our analysis showed that patients prescribed Acetylcholinesterase inhibitors had a 23% reduced risk of dying compared to those who were not prescribed the medication.

From this type of study, we cannot say with certainty that this risk reduction is caused by the antidementia medication itself. It might also be, at least partly, explained by another factor related to being prescribed the drug which we were not able to measure.

However, good reasons why Acetylcholinesterase inhibitors could prolong life are reported in the literature. As mentioned before, they slow down memory decline and loss of independence. Some studies also report that these medications have positive effects on heart failure and coronary heart disease which could lead to better survival.

In conclusion, Acetylcholinesterase inhibitors are not only helpful for memory, psychiatric symptoms and functioning, but may also improve survival.  They should be strongly considered in every patient diagnosed with Alzheimer’s disease.