Impact of cognitive impairment and systemic vascular comorbidities on risk of all-cause and cardiovascular mortality: National Health and Nutrition Examination Survey 1999 to 2002.

OBJECTIVES

To evaluate impacts of cognitive impairment and systemic vascular comorbidities on hazards of all-cause and cardiovascular mortality in a representative United States population.

METHODS

Subjects aged ≥60 years from two waves of National Health and Nutrition Examination Survey were analyzed. Cognitive function was evaluated by Digit Symbol Substitution Test. Systemic vascular comorbidities included diabetes mellitus (DM), chronic kidney disease (CKD), high blood pressure (HBP) and hypotension. Hazards of all-cause and cardiovascular mortality were estimated with Cox proportional hazard regression models.

RESULTS

After a median follow-up of 9.83 years, 937 (35.6%) and 247 (8.6%) deaths caused by all causes and cardiovascular diseases, respectively. After adjusting for confounders, cognitive impairment predicted a higher risk of all-cause mortality (Hazard Ratios (HR), 2.00; 95% confidence interval (CI), 1.62-2.46) and cardiovascular mortality (HR, 1.79; 95% CI, 1.27-2.53). Risk of all-cause mortality was further increased among those with cognitive impairment concomitant with DM (HR, 2.24; 95% CI, 1.61-3.13), CKD (HR, 2.56; 95% CI, 1.77-3.67), HBP (HR, 2.57; 95% CI, 1.73-3.84) or hypotension (HR, 2.38; 95% CI, 1.78-3.18). Co-presence of cognitive impairment with DM (HR, 2.30; 95% CI, 1.25-4.26), CKD (HR, 2.56; 95% CI, 1.35-4.88), HBP (HR, 4.65; 95% CI, 2.28-9.46) or hypotension (HR, 2.69; 95% CI, 1.67-4.31) also posed a significant higher risk of cardiovascular mortality than participants with neither condition.

INTERPRETATION: Cognitive impairment concomitant with other systemic vascular comorbidities predicted further increased risks of mortality. More extensive assessments and management of cognitive function and systemic vascular comorbidities are warranted.