Abstract P507: Pre-Statistical Harmonization of Cognitive Measures Across Eight Population-Based NIH Cohorts in the Collaborative Cohort of Cohorts for COVID-19 Research (C4R)

Introduction: Long-term neurological consequences (eg, stroke, impaired cognition) have been linked to SARS-CoV-2 infection and severity. There are limited data from studies with racial, ethnic, socioeconomic, and geographic diversity. C4R is a prospective study of adults from 14 cohorts that aims to link pre-COVID phenotyping, including cognition (8 studies), to COVID related illness and sequelae. We aimed to conduct pre-statistical harmonization of cognitive tests administered in English and Spanish from 8 cohorts: ARIC, CARDIA, FHS, HCHS/SOL-INCA, MESA, NOMAS, REGARDS, and SHS (Table). Methods: We conducted extensive item-level review of administration, scoring, and coding procedures and score distributions for 84 tests administered in English (all studies) and Spanish (NOMAS, MESA, HCHS/SOL-INCA). Results: Orientation to time and 3-word registration and recall spanned all studies and both languages. Word list recall and verbal fluency (animal; letter) spanned 7 studies (Table). There was variability in the structure, content, administration, scoring, and data coding procedures for items across cohorts and between Spanish and English. Word lists varied by number of words (9-16) and learning trials (3-5). Animal naming varied by time (30 vs. 60 seconds), animal type (4-legged vs. any animal), and scoring (allowing mythical/imaginary animals). Letter fluency varied by whether both Spanish and English words were permitted. Other tests differed by version, study-specific adaptations, prompts/cues, and specificity of scoring rules across cohorts. Conclusions: Cognitive test harmonization requires detailed review of administration, scoring, coding, translation, and procedural differences. Accounting for this variability is essential to cognitive data interpretation. Our pre-statistical harmonization will inform data augmentation and formal harmonization to yield harmonized measures of cognition to clarify population-level differences in cognitive outcomes linked to SARS-CoV-2 infection.