Mild Cognitive Dysfunction and DM Control in Elderly Adults
Mild Cognitive Dysfunction and DM Control in Elderly Adults
Neither executive dysfunction nor memory dysfunction in the mild range were independently associated with diabetes mellitus control in longitudinal analyses in this sample of older adults with diabetes mellitus.
These results both conflict and agree with the results of prior research. A cross-sectional study of older African Americans with diabetes mellitus found that HbA1c values were 0.23 units lower for each unit increase in higher executive function score. Another cross-sectional study of older adults reported that global cognitive dysfunction was inversely correlated with HbA1c. In comparison, a small study of older adult men found no correlation between executive dysfunction and HbA1c, lipid levels, or blood pressure. Differences in findings may be due to heterogeneity in study populations but may also be due to the cognitive measures selected. The findings with the Color Trails Test, an executive functioning task, and SRT, a verbal test of memory, were similar. Most prior studies of cognitive dysfunction and metabolic control have examined only executive dysfunction as it relates to metabolic control. Diabetes mellitus self-management requires complex thought processing with mental flexibility, which is an attribute of executive functioning. Memory may also be important for diabetes mellitus self-management, specifically for tasks related to meal preparation, medication adherence, and administration of diabetes mellitus medications, and should be examined. Appropriate self-management of diabetes mellitus is important for the prevention of diabetes mellitus–related complications and adverse outcomes, such as micro- and macrovascular disease and death. Mild dysfunction in executive functioning and memory did not seem to affect self-management of diabetes mellitus in this sample of older adults.
Several limitations should be considered. First, the examination of cognition relied on a discrete number of tests, particularly for executive dysfunction, which is complex and difficult to measure. It is possible that a more-comprehensive battery would have found that cognition affects diabetes mellitus control, but the current authors found that ever having cognitive dysfunction was not associated with diabetes mellitus control. Second, the sampling frame for this study was participants in a randomized controlled trial (RCT), and the potential for selection bias in RCTs is high, with the healthiest and most educated individuals likely to enroll. It is possible that the results are not generalizable to clinic-based samples. It is also possible that the minority sample with a relatively low educational achievement was somewhat homogeneous from diabetes mellitus control and cognitive performance standpoints, explaining the null findings. Third, data were not available to estimate change in diabetes mellitus medication use to account for the possible confounding by indication, with individuals who control their diabetes mellitus with insulin being observed to have greater baseline executive dysfunction. Last, it is possible that the Medicare recipients with diabetes mellitus in the sample received assistance from formal (e.g., nurses) or informal (e.g., relatives) caregivers, but related data were not collected, so this could not be taken into account. Participants with cognitive impairment could have overcome its effects on diabetes mellitus control through the assistance of formal or informal caregivers. Collection of these data was not part of the original design of the study, although mild cognitive dysfunction of any type was not associated with diabetes mellitus self-care activities or self-efficacy. If third-party assistance explained the null findings, one would expect to find a relationship between cognitive dysfunction and these self-care variables but not between cognitive dysfunction and direct measures of diabetes mellitus control. Nonetheless, it would be useful to collect data on third-party assistance in relation to cognitive dysfunction in diabetes mellitus. Significant strengths of the study include the large sample size and detailed longitudinal data on cognition and diabetes mellitus control parameters. More-severe cognitive dysfunction (e.g., dementia) could affect diabetes mellitus control, but this study addressed mild dysfunction, which is the most common in clinical practice.
Diabetes mellitus is a complex disease that requires a substantial amount of self-management. Identifying what factors may inhibit ideal self-management is important so that it may be addressed in the clinical setting, where the provider can provided targeted education. Mild cognitive dysfunction was not related to diabetes mellitus control in this sample of elderly diabetics. Future studies need to explore whether assistance prompted by cognitive dysfunction, which could not be addressed, could explain these null findings.
Discussion
Neither executive dysfunction nor memory dysfunction in the mild range were independently associated with diabetes mellitus control in longitudinal analyses in this sample of older adults with diabetes mellitus.
These results both conflict and agree with the results of prior research. A cross-sectional study of older African Americans with diabetes mellitus found that HbA1c values were 0.23 units lower for each unit increase in higher executive function score. Another cross-sectional study of older adults reported that global cognitive dysfunction was inversely correlated with HbA1c. In comparison, a small study of older adult men found no correlation between executive dysfunction and HbA1c, lipid levels, or blood pressure. Differences in findings may be due to heterogeneity in study populations but may also be due to the cognitive measures selected. The findings with the Color Trails Test, an executive functioning task, and SRT, a verbal test of memory, were similar. Most prior studies of cognitive dysfunction and metabolic control have examined only executive dysfunction as it relates to metabolic control. Diabetes mellitus self-management requires complex thought processing with mental flexibility, which is an attribute of executive functioning. Memory may also be important for diabetes mellitus self-management, specifically for tasks related to meal preparation, medication adherence, and administration of diabetes mellitus medications, and should be examined. Appropriate self-management of diabetes mellitus is important for the prevention of diabetes mellitus–related complications and adverse outcomes, such as micro- and macrovascular disease and death. Mild dysfunction in executive functioning and memory did not seem to affect self-management of diabetes mellitus in this sample of older adults.
Several limitations should be considered. First, the examination of cognition relied on a discrete number of tests, particularly for executive dysfunction, which is complex and difficult to measure. It is possible that a more-comprehensive battery would have found that cognition affects diabetes mellitus control, but the current authors found that ever having cognitive dysfunction was not associated with diabetes mellitus control. Second, the sampling frame for this study was participants in a randomized controlled trial (RCT), and the potential for selection bias in RCTs is high, with the healthiest and most educated individuals likely to enroll. It is possible that the results are not generalizable to clinic-based samples. It is also possible that the minority sample with a relatively low educational achievement was somewhat homogeneous from diabetes mellitus control and cognitive performance standpoints, explaining the null findings. Third, data were not available to estimate change in diabetes mellitus medication use to account for the possible confounding by indication, with individuals who control their diabetes mellitus with insulin being observed to have greater baseline executive dysfunction. Last, it is possible that the Medicare recipients with diabetes mellitus in the sample received assistance from formal (e.g., nurses) or informal (e.g., relatives) caregivers, but related data were not collected, so this could not be taken into account. Participants with cognitive impairment could have overcome its effects on diabetes mellitus control through the assistance of formal or informal caregivers. Collection of these data was not part of the original design of the study, although mild cognitive dysfunction of any type was not associated with diabetes mellitus self-care activities or self-efficacy. If third-party assistance explained the null findings, one would expect to find a relationship between cognitive dysfunction and these self-care variables but not between cognitive dysfunction and direct measures of diabetes mellitus control. Nonetheless, it would be useful to collect data on third-party assistance in relation to cognitive dysfunction in diabetes mellitus. Significant strengths of the study include the large sample size and detailed longitudinal data on cognition and diabetes mellitus control parameters. More-severe cognitive dysfunction (e.g., dementia) could affect diabetes mellitus control, but this study addressed mild dysfunction, which is the most common in clinical practice.
Diabetes mellitus is a complex disease that requires a substantial amount of self-management. Identifying what factors may inhibit ideal self-management is important so that it may be addressed in the clinical setting, where the provider can provided targeted education. Mild cognitive dysfunction was not related to diabetes mellitus control in this sample of elderly diabetics. Future studies need to explore whether assistance prompted by cognitive dysfunction, which could not be addressed, could explain these null findings.
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