Oldest Old Patients Should be Recruited More in Clinical Trials of Dementia.

Life expectancy is expected to increase in industrialized countries. It was reported recently that Korea might be the first country where life expectancy could exceed 90 years in 2030.1 Considering that the prevalence of dementia increases rapidly from the age of 65, doubling every 5.8 years,2 dementia in very old people might be a serious medical issue in the near future. Of people who have Alzheimer's dementia, 38% were age 85 or older in 2010, whereas 51% are estimated to be 85 or older in 2050.3 The clinical presentation, neuropathological and imaging features, risk factors, and treatment responses of dementia in patients aged 85 or older is known to be different from patients aged 85 or younger.4 However, most of the clinical studies investigated the effectiveness and safety of cognitive enhancers on the market for treating dementia in patients less than 85 years of age.5

In the current issue of Journal of Korean Medical Science, Lim et al.6 reported that the adverse effects of anti-dementia agents, such as cholinesterase inhibitors and memantine, were observed in 26 (33.8%) of the 77 oldest old (age 85 or more) patients and in 26 (33.3%) of the 78 younger old (age less than 85) patients, retrospectively. The change during the first year of treatment in cognitive impairment which was measured with Mini-Mental State Examination, as well as in functional impairment which was measured with clinical dementia rating and instrumental activities of daily living, was also not different between the two groups. Although the study has a relatively small sample size and was conducted by retrospective chart review in a single center, it confirmed the safety and efficacy of anti-dementia agents which were delivered to the oldest old patients with dementia in the setting of clinical practice.

Many new medications, including anti-amyloid agents increasing beta-amyloid clearance or reducing beta-amyloid production, are currently undergoing clinical trials for dementia treatment.7 These therapies are expected to prevent, defer, or slow the decline of dementia. However, it was reported that only 8% of participants of recent clinical trials in dementia were 85 years or older.8 The age gap between participants in clinical trials and patients who could benefit from the medications studied is fairly substantial. Clinical trials in the future should not overlook the fact that the majority of dementia patients are likely to be 85 or older.