Among patients first hospitalized for ischemic stroke, family history of short ischemic stroke survival of less than 4 years in siblings is a predictor for overall mortality, especially in younger men. These study findings were published in Stroke.
The study utilized data from Swedish national registers and included patients hospitalized with ischemic stroke for the first time between 1991 and 2010. Eligible participants also had 1 sibling who had been hospitalized for ischemic stroke for the first time between 1991 and 2010.
Survival time of the patient’s sibling after first hospitalization for ischemic stroke in 1991 to 2010 was the predictor variable, allowing for a minimum of 5 years at the end of follow-up on December 31, 2015. Survival was dichotomized as <1 year or longer (≥1 years), <2 years or longer (≥2 years), <3 years or longer (≥3 years), <4 years or longer (≥4 years), and <5 years or longer (≥5 years).
Among 2760 eligible participants from 1380 full sibling pairs with ischemic stroke (mean [SD] age, 62  years), 1070 (38.8%) deaths occurred. The overall mean and median follow-up time was 9.49 and 8.87 years, respectively.
Regarding sibling ischemic stroke survival at 4 years or longer, shorter sibling ischemic stroke survival (<4 years) was associated with an increased risk of death in the crude model (familial hazard ratio [FHR], 1.26 [95% CI, 1.03-1.54]), adjusted model (FHR, 1.24 [95% CI, 1.02-1.51]), and fully adjusted model (FHR, 1.24 [95% CI, 1.02-1.51]). Older age at onset, longer hospitalization time, coronary heart disease, diabetes, dementia, heart failure, obesity, and alcohol use disorder were also associated with shorter survival in the fully adjusted model.
In younger participants (aged <62 years), survival of a sibling between less than 2 and less than 4 years after ischemic stroke was a significant predictor. The highest FHR occurred in participants with siblings with ischemic stroke survival of less than 4 years (FHR 1.42 [95% CI, 1.08-1.88]). No significant associations were found in patients aged 62 years or older.
Among participants who had a sibling with survival less than 3 or less than 4 years, no significant associations were found in women. In men, associations were found only in young men with an FHR of 1.62 (95% CI, 1.18-2.24) and 1.80 (95% CI, 1.33-2.46) for sibling survival of less than 3 years and less than 4 years, respectively.
Study limitations included the absence of molecular genetic data and information about other variable parameters, including stroke severity and smoking. In addition, the number of sibling pairs with 2 affected siblings was relatively few and limited to those from Sweden.
“The present study suggests that genetic study of prognostic familial factors in stroke might be worthwhile,” wrote the researchers. “Careful monitoring may also be considered for ischemic stroke patients with a history of poor familial ischemic stroke survival among males and young subjects.”
Zöller B, Pirouzifard M, Lindgren MP, Sundquist J, Sundquist K. Familial mortality risks in patients with ischemic stroke: a Swedish sibling study. Stroke. Published online February 2, 2022. doi: 10.1161/STROKEAHA.121.035669