Background and aims: Both vascular disease and diabetes type 2 (DM2) decrease cognitive functioning in elderly people. It is uncertain if DM2 affects cognition independent of vascular disease. In patients with symptomatic arterial disease, we studied the effect of DM2 on cognition and identified clinical and radiological determinants for impaired cognition in patients with DM2.
Methods: 766 patients (mean age 58.8+/-9.5 years; 108 DM2) with symptomatic arterial disease underwent neuropsychological testing. In 542 patients (77 DM2), volumes of brain tissue, ventricles and white matter lesions were obtained by segmentation of brain MR images. Infarcts were distinguished into small (lacunar) or large (cortical or subcortical).
Results: Patients with arterial disease and DM2 performed worse on neuropsychological tests compared to similar patients without DM2 (adjusted composite z-score: beta -0.14 [-0.25 to -0.02]). Insulin treatment, systolic and diastolic blood pressures were significantly associated with cognition in patients with DM2. Large infarcts, global and cortical atrophy on MRI were independently associated with cognition in patients with DM2.
Conclusion: The presence of DM2 in patients with symptomatic arterial disease is associated with decreased cognitive functioning. Insulin treatment, high blood pressure, brain atrophy and large infarcts were determinants for cognitive dysfunction in patients with DM2 and arterial disease.