Clinical Predictors of Cognitive Impairment in a Cohort of Patients with Older Age Bipolar Disorder

Background: An increased risk of cognitive decline has been reported in patients with older age bipolar disorder (OABD); however, the underlying factors contributing to this association remain unclear. This cross-sectional study aims to identify the clinical features associated with cognitive impairment in OABD. Methods: A total of 152 participants, aged at least 50 years and diagnosed with bipolar disorder (BD) and related disorders in agreement with the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision criteria, were included in the study and divided into two subgroups based on the presence/absence of cognitive impairment, defined as a diagnosis of Mild Neurocognitive Disorder or Major Neurocognitive Disorder. Univariate comparisons and multivariate logistic regression models were performed to investigate the associations between clinical variables and cognitive impairment. Results: Cognitively impaired patients had a higher prevalence of otherwise specified BD/cyclothymic disorder, while BD type 2 was more common in the cognitively unimpaired group. Additionally, the cognitively impaired group had a later onset of major mood episodes (p < 0.05), fewer lifetime depressive episodes (p = 0.006), a higher prevalence of vascular leukoencephalopathy (p = 0.022) and dyslipidemia (p = 0.043), a lower prevalence of agoraphobia (p = 0.040), worse global functioning (p < 0.001), and higher psychopathology severity (p < 0.001). Late onset, vascular leukoencephalopathy, and dyslipidemia were all independently associated with cognitive impairment. Conclusions: Atypical BD, late onset of mood episodes, and somatic comorbidities like vascular leukoencephalopathy and dyslipidemia are associated with a higher risk of developing cognitive impairment and neurodegenerative disorders in OABD patients.