Functional limitations and health care resource utilization for individuals with cognitive impairment without dementia: Findings from a United States population-based survey

Abstract

Introduction: Little is known about functional limitations and health care resource utilization of people with cognitive impairment with no dementia (CIND).

Methods: Respondents with stable or progressive cognitive impairment (CI) after the first (index) indication of CIND in 2000-2010 were identified from the Health and Retirement Study (HRS). Respondents never exhibiting CI were identified as potential controls. Propensity score-based optimal matching was used to adjust for differences in demographics and history of stroke. Differences between cohorts were assessed accounting for HRS survey design.

Results: After matching, CIND respondents had more functional limitations (difficulty with ≥1 activities of daily living: 24% vs. 15%; ≥1 instrumental activities of daily living: 20% vs. 11%) and hospital stays (37% vs. 27%) than respondents with no CI (all P < .001). Seventy five percent of CIND respondents developed dementia in the observable follow-up (median time: ∼6 years).

Discussion: Even before dementia onset, CI is associated with increased likelihood of functional limitations and greater health care resource use.

Keywords: Burden; CIND; Dementia; Functional limitations; Health care resource use.

Fig. 1

Sample selection and resulting patient counts. The HRS data include 36,986 unique respondents, of whom 1979 do not have valid cognitive assessment data. These respondents were excluded from the analysis. Additionally, for 2518 patients, the first observed indication of cognitive impairment was dementia rather than CIND; these respondents were also excluded from the analysis. Respondents in the CIND cohort were excluded if they had a wave indicating no CI at any point following the index wave. Respondents were weighted using person-level weights (provided by the HRS) from 2004. Respondents without a positive weight in 2004 were excluded from the analysis. Abbreviations: CI, cognitive impairment; CIND, cognitive impairment with no dementia.

Fig. 2

Difference in health care resource use among matched CIND and no CI cohorts—during the index wave. *P < .05; †P < .1. Relative difference in rates was calculated by dividing the difference between proportions of CIND respondents with a given health care resource use and corresponding proportions among matched no CI respondents by corresponding proportions among matched no CI respondents. Respondents with CIND were matched 1:1 to those with no CI using propensity score–based optimal matching techniques. Propensity scores were calculated using logistic regression models that estimated the probability of having CIND as a function of age, gender, race, region, years of education, marital status, year of index wave, and presence of stroke/TIA. P-values were calculated using logistic regression models to account for complex survey design elements and correlation between matched pairs. Abbreviations: CI, cognitive impairment; CIND, cognitive impairment with no dementia.

Fig. 3

Kaplan-Meier analyses of progression from CIND to dementia. The index wave for respondents with CIND was defined as the wave with first indication of CIND. For respondents with gaps in cognitive assessment data, the last observed cognitive status was carried forward. Respondents who did not transition to dementia after the index wave were right-censored at the last wave with valid cognitive assessment data. Respondents were weighted using person-level weights (provided by the HRS) from 2004. Respondents without a positive weight in 2004 were excluded from the analysis. Abbreviations: CIND, cognitive impairment no dementia; HRS, Health and Retirement Study.