SARS-CoV-2 Susceptibility and COVID-19 Mortality Among Older Adults With Cognitive Impairment: Cross-Sectional Analysis From Hospital Records in a Diverse US Metropolitan Area

Abstract

Introduction: Persistent knowledge gaps exist as to the extent that preexisting cognitive impairment is a risk factor for susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and mortality from the coronavirus disease 2019 (COVID-19). Methods: We conducted a cross-sectional analysis of adults tested for SARS-CoV-2 at a tertiary healthcare system. Cognitive impairment was identified utilizing diagnosis codes (mild cognitive impairment, Alzheimer's disease, vascular, and other dementias) or cognitive impairment-specific medication use. Propensity score (PS) matched analyses were utilized to report odds ratios (OR) and 95% confidence intervals (CI) for association of cognitive impairment with SARS-CoV-2 susceptibility and COVID-19 mortality. Results: Between March-3rd and December-11th, 2020, 179,979 adults were tested, of whom 21,607 (12.0%) tested positive. We identified 6,364 individuals with preexisting cognitive impairment (mean age: 78.5 years, 56.8% females), among whom 843 (13.2%) tested positive and 139 (19.5%) of those hospitalized died. In the pre-PS matched cohort, cognitive impairment was significantly associated with increased SARS-CoV-2 susceptibility (OR, CI: 1.12, 1.04-1.21) and COVID-19 mortality (OR, CI: 2.54, 2.07-3.12). One-to-one matches were identified for 6,192 of 6,364 (97.3%) individuals with prior cognitive impairment and 687 of 712 (96.5%) hospitalized patients with prior cognitive impairment. In the fully balanced post-matched cohort, preexisting cognitive impairment was significantly associated with higher likelihood of SARS-CoV-2 infection (OR, CI: 1.51, 1.35-1.70); however, cognitive impairment did not confer higher risk of COVID-19 mortality (OR, CI: 0.96, 0.73-1.25). Discussion: To mitigate the effects of healthcare catastrophes such as the COVID-19 pandemic, strategies for targeted prevention and risk-stratified comorbidity management are warranted among the vulnerable sub-population living with cognitive impairment.

Keywords: Alzheimer's disease; COVID-19; SARS-CoV-2; cognitive impairment; dementia; patient registries; propensity score matching.

Figure 1

SARS-CoV-2 testing characteristics and hospital outcomes among the study population at Houston Methodist (HM), stratified by preexisting cognitive impairment status. Post-propensity score matched odds ratios (ORs) and 95% confidence intervals (95% CI) for SARS-CoV-2 susceptibility and in-hospital mortality among the cognitively impaired (vs. no cognitive impairment) population presented.

Figure 2

Covariate and propensity score balance for SARS-CoV-2 susceptibility analyses. Pre- and post-matched standardized mean differences (SMD) are presented, using a SMD threshold of 0.1. Cohorts matched on age, sex, race, ethnicity, marital status, insurance coverage, area deprivation index (ADI), obesity, diabetes, hypertension, and overall Charlson Comorbidity Index (CCI).

Figure 3

Covariate and propensity score balance for COVID-19 mortality analyses. Pre- and post-matched standardized mean differences (SMD) are presented, using a SMD threshold of 0.1. Cohorts matched on age, sex, race, ethnicity, marital status, insurance coverage, area deprivation index (ADI), obesity, diabetes, hypertension, overall Charlson Comorbidity Index (CCI), mean systolic and diastolic blood pressure (SBP/DBP) at admission, elevated respiratory rate at admission, elevated temperature at admission, low oxygen saturation (O2) at admission, intensive care unit (ICU) stay, and mechanical ventilation utilization.

Figure 4

Pre- and post-matched distribution of individual propensity scores among SARS-CoV-2 tested individuals, by preexisting cognitive impairment status. Cohort proportions (Y-axis) by propensity score (X-axis) are presented. Cohorts matched on age, sex, race, ethnicity, marital status, insurance coverage, area deprivation index (ADI), obesity, diabetes, hypertension, and overall Charlson Comorbidity Index (CCI).

Figure 5

Pre- and post-matched distribution of individual propensity scores among COVID-19 hospitalized patients, by preexisting cognitive impairment status. Cohort proportions (Y-axis) by propensity score (X-axis) are presented. Cohorts matched on age, sex, race, ethnicity, marital status, insurance coverage, area deprivation index (ADI), obesity, diabetes, hypertension, overall Charlson Comorbidity Index (CCI), mean systolic and diastolic blood pressure (SBP/DBP) at admission, elevated respiratory rate at admission, elevated temperature at admission, low oxygen saturation (O2) at admission, intensive care unit (ICU) stay, and mechanical ventilation utilization.