Geographic variation of prevalence of Alzheimer’s Disease and related dementias in the Central Appalachian region of the United States

Abstract

AbstractBackgroundAreas within the Appalachian region may have a greater burden of under diagnosed Alzheimer’s disease and related dementias (ADRD). As rural areas have lower reported ADRD prevalence compared to urban areas in spite of lower educational attainment (which should lead to higher ADRD prevalence) this argues that the true burden of ADRD is likely underestimated in areas without adequate detection resources. There is need to understand if ADRD prevalence is truly lower in rural areas, or if this is a disease detection difference. The objective of this proposal is to assess the burden of ADRD in Central Appalachia.MethodsCenters for Medicare and Medicaid Services Public Use Files from 2015‐2018 were used to estimate county‐level ADRD prevalence among all fee‐for‐service beneficiaries in Central Appalachia (Kentucky, North Carolina, Ohio, Tennessee, Virginia, and West Virginia). Negative binomial regression was used to estimate prevalence overall, by Appalachian Regional Commission’s Appalachian/non‐Appalachian designation, and by rural/urban (Rural‐Urban Continuum Codes) classification. Models were then adjusted for county‐level demographics including age, gender, Medicaid eligibility, and comorbidities (atrial fibrillation, chronic kidney disease, depression, diabetes, heart failure, hyperlipidemia, hypertension, ischemic heart disease, schizophrenia/other psychotic disorders, and stroke).ResultsThe prevalence of ADRD did not vary over the time period but was higher for Appalachian counties both overall (12.0% vs. 11.6%; p = 0.001; Figure 1) and among both urban (p<0.001) and rural counties (p = 0.024; Figure 2). Urban Appalachian counties had 2‐4% higher prevalence compared to urban non‐Appalachian counties with this difference reaching statistical significance in 2017 and 2018. While a similar trend was observed in rural counties (Appalachian counties having 1‐3% higher prevalence), these yearly ratios did not reach statistical significance. After adjustment, the associations attenuated in urban counties, but over the entire study period, rural Appalachian counties had 2.2% higher prevalence than rural non‐Appalachian counties (Figure 3).ConclusionThere is a consistent difference between Appalachian and non‐Appalachian counties, demonstrated overall and by rural status, with Appalachian counties having ADRD prevalence in the range of 1.0‐4.5% higher than non‐Appalachian counties. However, while county‐level demographics and comorbidities explained the difference in urban counties, the elevated prevalence in rural‐Appalachian counties persisted.