Primary Care Diabetes Management May Also Reduce Risk of Dementia

New research has strengthened the association between glycemic control and dementia incidence among individuals with type 2 diabetes (T2D).

The study, published in JAMA Network Open, found that patients with T2D who participated in a diabetes primary care management program experienced a 28% reduction in the risk of developing all-cause dementia, compared with those who did not attend the program and received standard care.

Diabetes management may reduce dementia risk | Image credit: Dragana Gordic – stock.adobe.com

While poorly controlled T2D has been linked to an increased risk of dementia, there is limited research exploring how interventions for diabetes management might influence dementia incidence. This retrospective matched cohort study aimed to investigate the impact of a multidisciplinary diabetes management program, known as the Risk Assessment and Management Program-Diabetes Mellitus (RAMP-DM), on the incidence of dementia among patients with T2D. Utilizing electronic health care records from over 8 years of follow-up, the study focused on patients receiving public health care services in Hong Kong between 2011 and 2019. Participants with T2D managed in primary care settings were included, with 27,809 patients enrolled in RAMP-DM matched in a 1:1 ratio with patients receiving standard care.

The analysis assessed the incidence of all-cause dementia and dementia subtypes, comparing outcomes between RAMP-DM participants and those receiving usual care, while adjusting for baseline characteristics, biomarkers, and medication history. This was determined using ICD-10 codes or ICPC-2 codes indicating a diagnosis of dementia, along with prescriptions for dementia medications. Pre-existing dementia was also identified using these criteria, and participants with dementia due to alcohol, drugs, or infectious agents were excluded. Secondary outcomes measured hemoglobin A_1C (HbA_1C) levels to explore associations between glycemic control and dementia incidence.

Among the 55,618 total matched participants—with a mean (SD) age of 62.28 (11.9) years and including 51.4% women—patients had an average T2D diagnosis duration of 5.90 years. Over a median follow-up of 8.4 years, 6.97% of patients in the RAMP-DM group and 9.81% in the usual care group received a dementia diagnosis.

Participants from RAMP-DM exhibited reduced risks of developing:

• All-cause dementia by 28% (adjusted HR [aHR], 0.72; 95% CI, 0.68-0.77; P < .001)
• Alzheimer disease by 15% (aHR, 0.85; 95% CI, 0.76-0.96; P = .009)
• Vascular dementia by 39% (aHR, 0.61; 95% CI, 0.51-0.73; P < .001)
• Other or unspecified dementia by 29% (aHR, 0.71; 95% CI, 0.66-0.77; P < .001)

Further, compared with patients with a mean HbA_1C level between 6.5% and 7.5% during the first 3 years after cohort entry, those with higher HbA_1C levels had a 17% to 54% elevated risk of dementia incidence.

This study had several notable limitations. First, there is inherent selection bias typical of studies using electronic health record data, compounded by the exclusion of private sector health care records, potentially leading to an incomplete representation of patients' diabetes management. Although propensity score matching was employed to mitigate bias, differences in health consciousness between the RAMP-DM and usual care groups may still exist, influencing dementia incidence. Additionally, unmeasured baseline characteristics such as health literacy and attitudes towards glycemic control were not accounted for, possibly affecting the estimated association between RAMP-DM use and dementia incidence. Sensitivity analysis aimed at reducing reverse causality may not have fully addressed this issue, according to the authors.

Second, information biases, including undiagnosed and unspecified dementia types, might have underestimated dementia incidence rates, and limited data on RAMP-DM program participation duration and referrals to specialized health care services in Hong Kong further restricted comprehensive analysis. Third, smoking status was not consistently available in the database, potentially confounding the association between RAMP-DM and dementia incidence, although efforts were made to control for related characteristics. Lastly, while an HbA_1C level of 6.5% to 7.5% appeared associated with lower dementia incidence, the authors said this should not be interpreted as an optimal glycemic control threshold, especially considering variations across age groups and the observational nature of the study, which precludes causal inference.

According to the authors, future research should employ prospective cohorts or randomized controlled trials to confirm the efficacy of similar diabetes management interventions in reducing dementia risks and explore their underlying biological mechanisms, and assessing the cost-effectiveness of such programs in mitigating the incidence of dementia warrants further investigation.

Reference

Wang K, Zhao S, Lee EKP, Y SZM, Eu Y, Hung CT, Yeoh EK. Risk of dementia among patients with diabetes in a multidisciplinary, primary care management program. JAMA Netw Open. 2024;7(2):e2355733. doi:10.1001/jamanetworkopen.2023.55733