P1‐083: Association between direct medical costs and reduced cognitive function within categories of normal cognition and mild cognitive impairment

Abstract

We previously observed increased medical costs for persons with either dementia or MCI relative to persons with normal cognition. Whether costs increase as impairment increases within normal and MCI categories is unknown. Subjects were a subset of the Mayo Clinic Study of Aging (MCSA). MCSA used unique Rochester Epidemiology Project (REP) resources to construct a sampling frame of all Olmsted County, MN residents, age 70–89 years. A stratified random sample (n = 6,682) was selected and evaluated for eligibility. Persons who met criteria for prevalent dementia following neurologist's review of all medical records, were terminally ill, or could not be contacted were excluded. Remaining subjects were invited to participate in sequential evaluations that included comprehensive clinical and neuropsychological assessments. This study is limited to participants who, at their initial in-person assessment, met criteria for normal cognition or MCI. We obtained informant responses to the Functional Activities Questionnaire (FAQ), a 10-question survey related to daily cognitive functioning (e.g., “write checks, pay bills, balance checkbook”; “play a game of skill or work on a hobby”; etc.). Total scores range from 0 (no difficulty on any question) through 30 (completely dependent on every question). Based on FAQ definitions and distributions (see Figure), we categorized MCI subjects as 0 (n = 148), 1–10 (i.e., an average over all questions of no need for assistance but performs with difficulty) (n = 204), or >10 (i.e., an average over all questions of needing assistance) (n = 31) and normal subjects as 0 (n = 1,505) or >0 (n = 489). Using REP provider-linked line-item billing data, we obtained all costs for goods and services 1 year before first assessment. Total costs were computed and assigned nationally standardized wage- and inflation-adjusted dollar estimates. Within normal and MCI categories, associations between costs and FAQ categories were assessed using generalized linear models, accounting for skewed costs and adjusting for age and sex. Distribution of FAQ Scores and Cut-points For Persons Categorized as Normal and MCI Within normal and MCI subjects, those with any difficulty exhibited higher costs versus those with no difficulty (See Table). In general, medical costs increase as cognitive functioning declines, even within categories of normal and MCI. The contribution of comorbidity to cost differences will be assessed.