Use of the Japanese Version of the Montreal Cognitive Assessment to Estimate Cognitive Decline in Patients Aged 75 Years or Older with and without Type 2 Diabetes Mellitus

Background The number of people diagnosed with dementia worldwide is set to increase significantly. While patients with dementia often have comorbidities, particularly diabetes, patients with type 2 diabetes mellitus (T2DM) have a high risk of cognitive decline. This study aimed to determine whether older people with T2DM exhibit specificity in cognitive function. Methods The Montreal Cognitive Assessment (MoCA) is a well-known tool for examining mild cognitive impairment. The modified Japanese version (MoCA-J) has been confirmed as effective. We conducted an investigative survey to assess the cognitive function of Japanese individuals aged ≥75 years with and without T2DM, using the MoCA-J, and analyzed the results. Results Thirty-three patients with T2DM and 23 non-DM patients completed the examination. Between both groups, a significant difference in the MoCA-J total scores was found. (T2DM mean, 21.4 ± 3.5; non-DM mean, 23.5 ± 3.6). Only 9% of patients with T2DM and 39% of those with non-DM showed scores ≥26, which is the cutoff point for mild cognitive impairment, whereas all patients had the ability of self-care. Additionally, older patients with T2DM had significantly lower delayed recall scores than the non-DM group. Conclusions Patients aged ≥75 years with T2DM might have lower cognition than those without T2DM; the inability to perform delayed recall in T2DM patients might denote a cognitive function decline.Therefore, compared with other patients, patients aged ≥75 years with T2DM need to receive individually tailored explanations about their care, based on their cognition.