PhD defence Onno Groeneveld 21 January 2020

Summary

In ageing populations, there is an increased co-occurrence of type 2 diabetes mellitus (T2DM) and dementia. Moreover, T2DM increases the risk of mild cognitive impairment (MCI) and dementia. We studied to what extent clinicians at memory clinics should take into account the presence of T2DM.

T2DM patients had a diffuse profile of objective cognitive impairment, with marked interindividual variation. Cognitive profiles of memory clinic patients with and without T2DM were similar. At the memory clinic, a standard neuropsychological assessment is appropriate for T2DM patients. Any objective cognitive impairment is relevant, as it can affect diabetes self-management.

Patterns of brain injury were largely similar between patients with and without T2DM, with MCI or dementia. Our results and the literature combined suggest that non-AD-related neurodegeneration may contribute to MCI and dementia in patients with T2DM. At the memory clinic, establishing an etiological diagnosis does not need adjustment in T2DM patients.

Presence of T2DM was not associated with a worse clinical outcome in patients with MCI or dementia during two years follow-up. At the memory clinic, patients with or without T2DM can be informed about their prognosis similarly.

We reviewed experimental rodent studies, showing that glucose-lowering drugs improve cognitive functioning through pleiotrophic effects on the brain. Whether these promising results also translate into improved cognitive outcomes for T2DM patients has yet to be established.

In conclusion, establishing a diagnosis and prognosis at the memory clinic in T2DM patients can be carried out according to standard practice, without T2DM-specific adjustments.