-Original-

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

Taeko Saito¹, Takehisa Yamada², Yasushi Miyauchi³, Naoya Emoto^4,5 and Fumitaka Okajima⁴

¹Department of Nursing, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
²Department of Nephrology, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
³Department of Cardiovascular Medicine, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
⁴Department of Diabetes, Endocrinology and Metabolism, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
⁵Diabetes & Thyroid Clinic, Sakura Chuo Hospital, Chiba, Japan

Background: The number of people diagnosed with dementia worldwide is set to increase significantly. Patients with dementia often have comorbidities, particularly diabetes, and patients with type 2 diabetes mellitus (T2DM) have a high risk of cognitive decline. This study investigated whether older people with T2DM have disease-specific cognitive deficits.
Methods: The Montreal Cognitive Assessment is a well-known tool for examining mild cognitive impairment, and the modified Japanese version (MoCA-J) has been confirmed as effective. Using the MoCA-J, we assessed the cognitive function of Japanese adults aged ≥75 years with and without T2DM and analyzed the results.
Results: Thirty-three patients with T2DM and 23 non-DM patients completed the examination, and MoCA-J total scores differed between these groups (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 had scores ≥26, which is the cutoff point for mild cognitive impairment, although all patients were capable of self-care. Additionally, delayed recall scores were significantly lower for the older patients with T2DM had for the non-DM group.
Conclusions: Patients aged ≥75 years with T2DM might have worse cognition than those without T2DM; the inability to perform delayed recall in T2DM patients suggests a decline in cognitive function. Therefore, patients aged ≥75 years with T2DM should receive explanations of their care that are individualized in relation to their cognitive status.

J Nippon Med Sch 2022; 89: 196-202

Keywords
Montreal Cognitive Assessment, elderly, type 2 diabetes mellitus

Correspondence to
Taeko Saito, Department of Nursing, Nippon Medical School Chiba Hokusoh Hospital, 1715 Kamagari, Inzai, Chiba 270-1694, Japan
taeko-saito@nms.ac.jp

Received, January 5, 2021
Accepted, June 11, 2021