Meta-analysis finds no link between stroke and sickle cell trait

A meta-analysis of four large population-based studies has produced no evidence that sickle cell trait (SCT) in African Americans is associated with risk of stroke, investigators reported in JAMA Neurology.

Those findings contrast with an earlier longitudinal study that found a 1.4-fold risk of ischemic stroke in SCT carriers, the authors noted.

In their study, neither crude stroke incidence rates nor regression analysis indicated a link between SCT and stroke, said first author Hyacinth I. Hyacinth, MD, PhD, MPH, of the Aflac Cancer and Blood Disorder Center, Emory University, Atlanta, and his coauthors.

“The absence of an association between SCT and risk of ischemic stroke was consistent among the cohorts, and suggests that SCT is not an independent genetic risk factor for ischemic stroke among African Americans,” Dr. Hyacinth and his coauthors wrote.

The results may have implications for patient care. In particular, a more thorough evaluation of stroke in a patient with SCT may be warranted, instead of assuming that the SCT is an underlying cause of the stroke, they said.

The meta-analysis included a total of 19,464 subjects from four large, prospective, population-based studies with African American cohorts.

Results of the meta-analysis show that crude incidence of stroke was similar for individuals with SCT, at 2.9 per 1,000 person-years (95% confidence interval, 2.2-4.0), and for those with no SCT, at 3.2 per 1,000 person-years (95% CI, 2.7-3.8).

After adjusting for stroke risk factors, the hazard ratio of stroke independently associated with SCT was 0.80 (95% CI, 0.47-1.35; P = 0.82), results further show.

It’s unclear why this study found no association between SCT and stroke when the earlier population-based study suggested a link between the two. Dr. Hyacinth and his coauthors suggested differences in study methods or proportion of individuals at risk for stroke may account for the divergent findings. They also controlled for left ventricular hypertrophy, while the previous study did not.

“However, in our analysis, adjusting for left ventricular hypertrophy did not change the direction of estimate effects,” they said in the report.

Further study is needed to determine whether or not SCT may be linked to a particular type of stroke. “We were unable to test the association of SCT with ischemic stroke subtypes,” the authors noted.

Dr. Hyacinth and his coauthors reported no conflicts of interest related to the study.

SOURCE: Hyacinth HI et al. JAMA Neurol. 2018 Apr 23. doi:10.1001/jamaneurol.2018.0571

A meta-analysis of four large population-based studies has produced no evidence that sickle cell trait (SCT) in African Americans is associated with risk of stroke, investigators reported in JAMA Neurology.

Those findings contrast with an earlier longitudinal study that found a 1.4-fold risk of ischemic stroke in SCT carriers, the authors noted.

In their study, neither crude stroke incidence rates nor regression analysis indicated a link between SCT and stroke, said first author Hyacinth I. Hyacinth, MD, PhD, MPH, of the Aflac Cancer and Blood Disorder Center, Emory University, Atlanta, and his coauthors.

“The absence of an association between SCT and risk of ischemic stroke was consistent among the cohorts, and suggests that SCT is not an independent genetic risk factor for ischemic stroke among African Americans,” Dr. Hyacinth and his coauthors wrote.

The results may have implications for patient care. In particular, a more thorough evaluation of stroke in a patient with SCT may be warranted, instead of assuming that the SCT is an underlying cause of the stroke, they said.

The meta-analysis included a total of 19,464 subjects from four large, prospective, population-based studies with African American cohorts.

Results of the meta-analysis show that crude incidence of stroke was similar for individuals with SCT, at 2.9 per 1,000 person-years (95% confidence interval, 2.2-4.0), and for those with no SCT, at 3.2 per 1,000 person-years (95% CI, 2.7-3.8).

After adjusting for stroke risk factors, the hazard ratio of stroke independently associated with SCT was 0.80 (95% CI, 0.47-1.35; P = 0.82), results further show.

It’s unclear why this study found no association between SCT and stroke when the earlier population-based study suggested a link between the two. Dr. Hyacinth and his coauthors suggested differences in study methods or proportion of individuals at risk for stroke may account for the divergent findings. They also controlled for left ventricular hypertrophy, while the previous study did not.

“However, in our analysis, adjusting for left ventricular hypertrophy did not change the direction of estimate effects,” they said in the report.

Further study is needed to determine whether or not SCT may be linked to a particular type of stroke. “We were unable to test the association of SCT with ischemic stroke subtypes,” the authors noted.

Dr. Hyacinth and his coauthors reported no conflicts of interest related to the study.

SOURCE: Hyacinth HI et al. JAMA Neurol. 2018 Apr 23. doi:10.1001/jamaneurol.2018.0571

A meta-analysis of four large population-based studies has produced no evidence that sickle cell trait (SCT) in African Americans is associated with risk of stroke, investigators reported in JAMA Neurology.

Those findings contrast with an earlier longitudinal study that found a 1.4-fold risk of ischemic stroke in SCT carriers, the authors noted.

In their study, neither crude stroke incidence rates nor regression analysis indicated a link between SCT and stroke, said first author Hyacinth I. Hyacinth, MD, PhD, MPH, of the Aflac Cancer and Blood Disorder Center, Emory University, Atlanta, and his coauthors.

“The absence of an association between SCT and risk of ischemic stroke was consistent among the cohorts, and suggests that SCT is not an independent genetic risk factor for ischemic stroke among African Americans,” Dr. Hyacinth and his coauthors wrote.

The results may have implications for patient care. In particular, a more thorough evaluation of stroke in a patient with SCT may be warranted, instead of assuming that the SCT is an underlying cause of the stroke, they said.

The meta-analysis included a total of 19,464 subjects from four large, prospective, population-based studies with African American cohorts.

Results of the meta-analysis show that crude incidence of stroke was similar for individuals with SCT, at 2.9 per 1,000 person-years (95% confidence interval, 2.2-4.0), and for those with no SCT, at 3.2 per 1,000 person-years (95% CI, 2.7-3.8).

After adjusting for stroke risk factors, the hazard ratio of stroke independently associated with SCT was 0.80 (95% CI, 0.47-1.35; P = 0.82), results further show.

It’s unclear why this study found no association between SCT and stroke when the earlier population-based study suggested a link between the two. Dr. Hyacinth and his coauthors suggested differences in study methods or proportion of individuals at risk for stroke may account for the divergent findings. They also controlled for left ventricular hypertrophy, while the previous study did not.

“However, in our analysis, adjusting for left ventricular hypertrophy did not change the direction of estimate effects,” they said in the report.

Further study is needed to determine whether or not SCT may be linked to a particular type of stroke. “We were unable to test the association of SCT with ischemic stroke subtypes,” the authors noted.

Dr. Hyacinth and his coauthors reported no conflicts of interest related to the study.

SOURCE: Hyacinth HI et al. JAMA Neurol. 2018 Apr 23. doi:10.1001/jamaneurol.2018.0571