Impaired Cognition and Illness Beliefs in Breast Cancer Survivors Comorbid With Diabetes.

Abstract

Background: Breast cancer survivors (BCS) are at greater risk for cognitive impairment due to their cancer status, treatment history, and frequent comorbid illnesses such as diabetes (DM). Given the critical role of cognition in illness beliefs, cognitive impairments can contribute to inaccurate risk perceptions, misunderstanding of information, and limited symptom awareness, which have significant implications for disease self-management. In a cohort of BCS with DM, we investigated the relationship between cognitive impairments and illness beliefs about DM.

Methods: We measured illness beliefs in our cohort of BCS with DM using the Illness Perception Questionnaire (IPQ). Cognition was assessed utilizing a well-validated neuropsychological battery (i.e., WAIS-IV, Trail Making Test-A&B, Hopkins Verbal Learning Test) measuring attention, working memory, executive functioning, processing speed, and learning and memory. Cognitive impairment was classified as z-scores ≤ -1.5 standard deviations below the normative mean adjusting for age, sex, and education. Wilcoxon tests assessed the associations between cognitive impairments and illness beliefs, subsequently adjusted for age, race, and breast cancer stage using multivariable regression models.

Results: Of the 244 BCS with DM [mean (SD) age: 66.5 (7) years], 26.3% had impairments in attention, 19.1% in working memory, 24.1% in executive functioning, 9.9% in processing speed, 26.9% in memory recall, and 17.5% in memory retention. Impairments in attention, working memory, or executive functioning were associated with greater belief that DM is episodic (p = 0.003, 0.01, 0.003), short-term (p = 0.04, 0.04, 0.009), and less controllable (p = 0.006, < 0.001, 0.03). Impairments in attention and working memory were also linked to stronger beliefs that DM was due to chance (p = 0.003, 0.02). Those with processing speed impairments more often believed DM was episodic (p = 0.003) and less controllable (p = 0.004). Memory retention impairments were similarly associated with lower perceived control (p = 0.03), and memory recall impairments with the belief that DM is short-term (p = 0.01). All associations remained significant after adjustment for age, race, and breast cancer stage.

Conclusions: BCS with DM and impairments in cognition, particularly in attention, working memory, and executive functioning, are more likely to hold suboptimal beliefs about their DM. These findings highlight the importance of screening for cognitive impairments in these patients in order to identify those at risk for poor disease self-management and outcomes. Future studies should explore interventions or compensatory strategies to best support BCS with DM and cognitive impairments.