Atrial fibrillation and cognitive decline: a longitudinal cohort study

Abstract

Objective: We sought to determine whether in the absence of clinical stroke, people with atrial fibrillation experience faster cognitive decline than people without atrial fibrillation.

Methods: We conducted a longitudinal analysis in the Cardiovascular Health Study, a community-based study of 5,888 men and women aged 65 years and older, enrolled in 1989/1990 or 1992/1993. Participants did not have atrial fibrillation or a history of stroke at baseline. Participants were censored when they experienced incident clinical stroke. Incident atrial fibrillation was identified by hospital discharge diagnosis codes and annual study ECGs. The main outcome was rate of decline in mean scores on the 100-point Modified Mini-Mental State Examination (3MSE), administered annually up to 9 times.

Results: Analyses included 5,150 participants, of whom 552 (10.7%) developed incident atrial fibrillation during a mean of 7 years of follow-up. Mean 3MSE scores declined faster after incident atrial fibrillation compared with no prior atrial fibrillation. For example, the predicted 5-year decline in mean 3MSE score from age 80 to age 85 was -6.4 points (95% confidence interval [CI]: -7.0, -5.9) for participants without a history of atrial fibrillation, but was -10.3 points (95% CI: -11.8, -8.9) for participants experiencing incident atrial fibrillation at age 80, a 5-year difference of -3.9 points (95% CI: -5.3, -2.5).

Conclusions: In the absence of clinical stroke, people with incident atrial fibrillation are likely to reach thresholds of cognitive impairment or dementia at earlier ages than people with no history of atrial fibrillation.

Figure 1. Model-predicted mean 3MSE score trajectories

Blue line represents 3MSE trajectory without a history of AF. Four red lines represent 3MSE trajectories after incident AF identified at ages 70, 75, 80, and 85 years. Shading represents 95% confidence intervals. The model included 5,150 participants and was adjusted for birth year, sex, race, education, cigarette smoking, alcohol use, diabetes, hypertension, systolic blood pressure, coronary heart disease, and heart failure, all assessed at baseline, and the interaction of age with each covariate except birth year. AF = atrial fibrillation; 3MSE = Modified Mini-Mental State Examination.

Figure 2. Model-predicted mean DSST score trajectories

Blue line represents DSST trajectory without a history of AF. Four red lines represent DSST trajectories after incident AF identified at ages 70, 75, 80, and 85 years. Shading represents 95% confidence intervals. The model included 5,279 participants and was adjusted for birth year, sex, race, education, cigarette smoking, alcohol use, diabetes, hypertension, systolic blood pressure, coronary heart disease, and heart failure, all assessed at baseline, and the interaction of age with each covariate except birth year. AF = atrial fibrillation; DSST = Digit Symbol Substitution Test.