OBJECTIVES : No studies have evaluated the effect of metabolic syndromes (MetS) on the risk of Alzheimer’s diseases and related dementia (ADRD) and its subtypes among the elderly Medicare population. The objective of this study was to determine the effect of MetS on the risk of ADHD and its subtypes among the elderly Medicare population.

METHODS : This study was designed as a cross-sectional study among the elderly Medicare population in 2016. MetS is a summary of diabetes/prediabetes, hyperlipidemia, hypertension, and obesity based on the NIH definition. MetS was measured based on relevant ICD-10 codes from Medicare claims. Univariate and bivariate analyses were conducted to determine the data distribution and potential confounding factors. Multivariable logistic regressions were implemented to determine the effect of MetS on the risk of ADRD, with weighted associations for nationally representative data.

RESULTS : In the study population, 33.71% had diabetes/prediabetes, 54.73% had hyperlipidemia, 60.79% had hypertension, and 11.40% had obesity. Based on the NIH definition, 27.29% of Medicare beneficiaries had MetS. This study identified 8.06% of patients with ADRD, including 3.03% of Alzheimer's disease and 5.03% of related dementias. Higher percentage of ADRD was found in individuals with MetS (9.01% vs. 2.85%, p<0.0001). After controlling for covariates, individual with MetS were more like to have ADRD (OR: 2.36; 95% CI: 1.66-3.35), Alzheimer's disease (OR: 1.64; 95% CI: 1.05-2.57), and related dementias (OR: 3.08; 95% CI: 1.92-4.94). In addition, diabetes/prediabetes (OR: 1.22; 95% CI: 1.02-1.47) and hypertension (OR: 2.13; 95% CI: 1.65-2.75) were associated with the increased risk of ADRD.

CONCLUSIONS : Our study showed that MetS are a common condition, and are a strong predictor for the risk of ADRD and its subtypes among the elderly Medicare population. Compared to its previous versions, using ICD-10 codes to capture ADRD may be easier, more accurate and more comprehensive in Medicare claims data.