Two‐year longitudinal outcomes of subjective cognitive decline in Hispanics compared to non‐Hispanic Whites.

Background: Hispanics are at higher risk for Alzheimer disease (AD) than non‐Hispanic Whites (NHW), motivating further study of differences and risk factors at the preclinical level. Subjective cognitive decline (SCD) is considered a preclinical AD stage, but its features and outcomes in Hispanics are less studied. We investigated the differences in longitudinal change in SCD phenotype, cognition, and function among Hispanics compared to NHW. Method: Longitudinal analyses were performed on consecutive participants with SCD who were evaluated at the NYU Alzheimer's Disease Research Center. Inclusion criteria were self‐identification as Hispanic (n = 23) or NWH (n = 165) and a 2‐year follow‐up visit. Demographics, conversion rate to mild cognitive impairment (MCI), SCD characteristics, and psychometric performance were analyzed by t‐test, multiple linear regression models, or Cox models as appropriate. Models were adjusted for age, sex, education, depression, and baseline values. Result: Hispanics were at higher risk for conversion to MCI (HR: 6.57, 95% CI 1.25‐34.47, p = 0.02596). Hispanic ethnicity was associated with increased SCD severity in time as measured via the total Brief Cognitive Rating Scale (BCRS) score (OR: 4.28, 95% CI 1.42‐12.83, p = 0.0094), and in specific BCRS domains: mood and behavior (OR: 0.18, 95% CI 0.03‐0.89, p = 0.0355) and calculation (OR: 29.68, 95% CI 4.02‐219.18, p = 0.0009). Global cognitive function by Mini‐Mental State Examination had a higher risk of declining in time in Hispanics (HR: 2.83, CI 1.09‐7.35, p = 0.0320). Likelihood of decline in domain‐specific tests associated with Hispanic ethnicity for Trails A (HR: 4.05, 95% CI 1.93‐8.47, p = 0.0002), Trails B (HR: 3.16, 95% CI 1.62‐6.14, p = 0.0007), and delayed paragraph recall (HR: 2.08, 95% CI 1.01‐4.24, p = 0.0444). Conclusion: Hispanics present a higher risk of conversion from SCD to MCI than NHW. Apart from stage conversion, subjective and objective measure of cognition worsen more in Hispanics, but in a domain‐specific manner. These findings suggests that Hispanics not only decline at a faster rate, but that this decline is expressed with a different phenotype. This should be considered when studying this population in preclinical investigations. [ABSTRACT FROM AUTHOR]