Objective: We investigated: (i) the cognitive performance of type 2 diabetes mellitus (T2DM) patients compared to healthy control participants and (ii) the Health-related Quality of life (HRQOL) of type 2 diabetics with neuropsychological deficits.
Method: We conducted a prospective study in (N = 44) T2DM patients and (N = 28) demographically matched healthy controls. All participants were assessed with a flexible comprehensive neuropsychological battery of tests that have been standardized in Greece and found to be sensitive in detecting cognitive deficits in type 2 diabetics. They were additionally assessed on measures of general intelligence, general mental state, and depression. They were also administered the WHO QOL-BREF self-report questionnaire to evaluate perceived health-related quality of life.
Results: Groups were well matched on baseline demographic characteristics and estimated premorbid intelligence. The groups did not differ on general mental state but varied in the encoding of verbal material, total verbal learning, delayed recall of verbal information, mental information processing speed, phonological and semantic verbal fluency and executive functions, set-shifting. Glycosylated hemoglobin levels and an interaction of age, education, and premorbid intelligence were the most important predictors of domain-specific neuropsychological performance. T2DM patients with deficits in verbal learning, executive functions, set-shifting, and semantic verbal fluency, had significantly lower QOL in the domains of psychological and environmental health, social relationships, and general health, respectively.
Conclusion: T2DM patients have cognitive deficits on several domains compared to healthy participants. Domain specific neuropsychological deficits in middle aged T2DM patients have a significant impact on HRQOL.
Keywords: Cognitive performance; Health Related quality of Life (HRQOL); Neuropsychological Deficits; Type 2 Diabetes Mellitus (T2DM).