Burden of multimorbidity and verbal phonemic fluency in cognitively healthy and mildly impaired older adults: findings from a real-world study

Objective: To examine the association between burden of multimorbidity and cognitive function in older adults with normal cognition or mild cognitive impairment (MCI). Methods: Data from electronic health records of 898 individuals cognitively healthy or with MCI were included. Burden of multimorbidity was assessed using Cumulative Illness Rating Scale-Geriatrics (CIRS-G) total score, while cognitive function was evaluated using a comprehensive battery of neuropsychological tests. Age, sex, education, basic activities of daily living and instrumental activities of daily living scores, and total number of current medications were covariates. Spearmen's correlations and multivariate regression models investigated the cross-sectional association between burden of multimorbidity and cognitive function. Results: At a first exploratory analysis, higher CIRS-G score was significantly and negatively correlated with Addenbrooke's Cognitive Examination Revised (ACE-R) total score, ACE-R Fluency Score, ACE-R Visual-spatial score, Digit Span Test Forward, Verbal Fluency Test, Visual Search Test and Coloured Progressive Matrices, while it was positively correlated with Trail Making Test A. Fitting fully-adjusted models and independent of all covariates, the inverse association between CIRS-G score and Verbal Fluency Test was confirmed (P <.001), while no significant association was found with other cognitive tests. Noteworthy, we excluded that specific disease categories could have driven the association. Conclusions: The burden of multimorbidity is associated with impaired verbal phonemic fluency in individuals with normal cognition or MCI. Although further studies are required to confirm it, impaired verbal phonemic fluency may be an early sign of cognitive decline in older adults with multimorbidity, with potential implications for prevention strategies.