The Impact of Dementia on Diabetes Control: An Evaluation of HbA Trajectories and Care Outcomes in Linked Primary and Specialist Care Data.

Objectives: Diabetes self-care may become increasingly challenging as cognition declines. We sought to characterize glycated hemoglobin A (HbA) trajectories, markers of diabetes-related management, health care utilization, and mortality in people with preexisting type 2 diabetes (T2D) with and without dementia and based on the extent of cognitive impairment at the time of dementia diagnosis.

Design: Retrospective matched cohort study.

Setting And Participants: Using a linkage between a primary care (Lambeth DataNet) and a secondary mental healthcare database, up to 5 individuals aged ≥65 y with preexisting T2D without dementia were matched to each individual with dementia based on age, sex, and general practice.

Methods: Comparisons were made for HbA trajectories (linear mixed effects models), markers of diabetes-related management and severity at dementia diagnosis (logistic regression), mortality (Cox regression), and health care utilization (multilevel mixed effects binomial regression).

Results: In 725 incident dementia and 3154 matched comparators, HbA trajectories differed by dementia status; HbA increased over time for mild dementia and non-dementia, but the increase was greater in the mild dementia group; for those with moderate-severe dementia, HbA decreased over time. Despite individuals with dementia having increased health care utilization around the time of dementia diagnosis, they were less likely to have had routine diabetes-related management. Patients with dementia had a higher prevalence of macrovascular complications and diabetes foot morbidity at dementia diagnosis and a higher mortality risk than those without dementia; these relationships were most marked in those with moderate-severe dementia.

Conclusions And Implications: Our study has highlighted important differences in the monitoring, management, and control of diabetes in people with dementia. The effects of frailty and the extent of cognitive impairment on the ability to self-manage diabetes and on glycemic control may need to be considered in treatment guidelines and by primary care.