BACKGROUND/AIMS: We attempted to define possible subgroups of Alzheimer's disease (AD) associated with diabetes mellitus (DM) based on brain imaging. METHODS: We classified 175 patients with clinically diagnosed AD and type 2 DM into 4 subgroups on the basis of the presence or absence of cerebrovascular disease (CVD) on MRI (CVD or no CVD) and posterior cerebral hypoperfusion on SPECT (AD pattern or no AD pattern). Differences in the clinical characteristics among the subgroups were examined. RESULTS: The subgroup showing neither a CVD pattern nor an AD pattern had significantly older age, higher hemoglobin A1c level, longer duration of diabetes, higher frequency of insulin therapy, lower frequency of apolipoprotein E4 carriers, less severe medial temporal lobe atrophy, more impaired attention, less impaired word recall, and slower progression of cognitive impairment than the subgroup showing an AD pattern. We found no characteristic features of other subgroups. CONCLUSION: The clinical features of subjects with AD associated with DM may differ depending on brain imaging patterns. Among them, there may be a dementia subgroup with characteristics predominantly associated with DM-related metabolic abnormalities.
BACKGROUND/AIMS: We attempted to define possible subgroups of Alzheimer's disease (AD) associated with diabetes mellitus (DM) based on brain imaging. METHODS: We classified 175 patients with clinically diagnosed AD and type 2 DM into 4 subgroups on the basis of the presence or absence of cerebrovascular disease (CVD) on MRI (CVD or no CVD) and posterior cerebral hypoperfusion on SPECT (AD pattern or no AD pattern). Differences in the clinical characteristics among the subgroups were examined. RESULTS: The subgroup showing neither a CVD pattern nor an AD pattern had significantly older age, higher hemoglobin A1c level, longer duration of diabetes, higher frequency of insulin therapy, lower frequency of apolipoprotein E4 carriers, less severe medial temporal lobe atrophy, more impaired attention, less impaired word recall, and slower progression of cognitive impairment than the subgroup showing an AD pattern. We found no characteristic features of other subgroups. CONCLUSION: The clinical features of subjects with AD associated with DM may differ depending on brain imaging patterns. Among them, there may be a dementia subgroup with characteristics predominantly associated with DM-related metabolic abnormalities.