Association between cognitive capacity and metabolic indices in patients with neuropsychiatric disorders

Although previous studies suggested the relationship between metabolic indices and cognitive capacity, results have been conflicting. The prevalence of metabolic and cognitive disorders is high in patients with neuropsychiatric disorders. We aimed to assess the relationship between laboratory metabolic indices and specific areas of cognitive capacity.

This was a retrospective review of the medical records of 423 from 452 patients with neuropsychiatric disorders who were admitted to the neuropsychiatry unit, Ayatollah Kashani Hospital, Isfahan, Iran, from September 1, 2018, to September 30, 2022. We extracted demographic factors, laboratory metabolic indices, and scores of the Neuropsychiatry Unit Cognitive Assessment tool (NUCOG). We utilized a generalized linear model (GLM) to demonstrate the effect of metabolic indices on the risk of reduction in cognitive domains. Due to the presence of missing data in the metabolic indices, we used the multiple imputation method.

The regression coefficient of NUCOG total score and subscale scores for metabolic indices using GLM after multiple imputation method demonstrated that among the metabolic indicators, fasting blood sugar (FBS) had the reverse relationship with the total score of NUCOG (β = -.05). Among the NUCOG subscales, executive functioning had the strongest relationship with FBS (β = -.01). Also, there was a negative relationship between patients' age and the total score of NUCOG (β = -.38). Educational level had a positive relationship with the total NUCOG score (β =10.2).

The main metabolic factors that might reduce cognitive capacity were higher FBS.