Effects of Allostatic Load on Long-Term Survival After Stroke.

BACKGROUND

Allostatic load index (ALI) is often utilized to quantify the physiological response to stress. This study assesses the relationship between ALI and its impact on all-cause, cardiovascular, and stroke mortality in individuals with a self-reported history of stroke and within the general National Health and Nutritional Examination Survey sampled population.

METHODS

Using data from the National Health and Nutritional Examination Survey (III, 1988-1994) and the 2015 Linked Mortality File, we selected adults aged ≥25 years with self-reported stroke. We computed the weighted prevalence of each ALI category to obtain nationally representative estimates with higher ALI corresponding to a higher stress burden. We evaluated the relationship between ALI category and mortality outcomes using the Cox proportional hazard model, considering the survey design variables and adjusting for age, sex, race/ethnicity, education, marital status, income, drinking, and smoking status.

RESULTS

Of 17 284 people screened in the National Health and Nutritional Examination Survey sample population, 15 567 individuals were included in the study. The ALI distribution was 48.3% ALI ≤1, 21.7% ALI=2, and 30% ALI ≥3. Of 414 individuals with a reported history of stroke, there were 11.8% ALI ≤1, 22.1% ALI=2, and 66.1% ALI ≥3. There was an association between a higher ALI and older age, Black and Mexican American race, and >1 comorbidity in the overall sampled population. In the population with prior stroke, those with ALI ≥3 had 2.7× higher adjusted all-cause mortality (hazard ratio, 2.7 [CI, 1.5-4.9]) and 4.5× higher adjusted cardiovascular mortality (hazard ratio, 4.5 [CI, 1.4-14.3]) compared with those with ALI ≤1. In the general sampled National Health and Nutritional Examination Survey population, the ALI ≥3 group had 1.8× higher adjusted stroke mortality (hazard ratio, 1.8 [CI, 1.1-3.1]).

CONCLUSIONS

Baseline higher ALI is associated with greater all-cause and cardiovascular mortality in stroke survivors and greater stroke mortality in the overall sampled National Health and Nutritional Examination Survey population.