Global and regional burden of ischemic stroke associated with atrial fibrillation, 2009-2019

The extent of the preventable burden of ischaemic stroke associated with atrial fibrillation (AF) remains uncertain to date. To address this knowledge gap, we utilised the comparative risk assessment methodology to estimate the burden of ischaemic stroke associated with AF at both global and regional levels. The population attributable fraction for ischaemic stroke and AF was obtained from published literature, while data on the prevalence, incidence, deaths, and disability-adjusted life years (DALY) associated with ischaemic stroke were sourced from the Global Burden of Disease study database. Our analysis revealed that in 2019, globally, there were an estimated 0.7 (95% uncertainty interval [UI] of 0.55 to 0.83) million incident cases, 6.9 (5.81 to 8.12) million prevalence cases, 0.3 0.25 to 0.34) million deaths and 5.7 (4.91 to 6.57) million DALY resulting from ischaemic stroke associated with AF. The age-standardised death and DALY rates declined between 2009 and 2019 in all regions to varying degrees. Conversely, the age-standardised incidence and prevalence rates reduced only in high-income countries, Central Europe, Eastern Europe and Central Asia and Latin America and Caribbean regions. It is likely that our findings under-estimated the true burden of ischaemic stroke associated with AF due to limitations such as the use of a fixed population attributable fraction and poor quality of data. Nevertheless, we believe that our estimates provide valuable insights and highlight the urgent need for optimised management of AF through the implementation of efficacious interventions. Such efforts can help reduce the occurrence of preventable ischaemic strokes.

Global, regional, and national burden of heart failure associated with atrial fibrillation

BACKGROUND

Heart failure is a leading cause of mortality and morbidity worldwide, and Atrial fibrillation (AF) is among many modifiable risk factors for heart failure. No estimates are available on the magnitude of the burden of heart failure associated with AF, and this study estimated the global, regional, and national burdens associated with AF.

METHODS

We used the comparative risk assessment method to estimate the disease burden in terms of prevalence and years lived with disability (YLD). The population-attributable fraction for heart failure and AF was calculated from prevalence estimates of AF and the recalculated relative risks of heart failure associated with AF from a systematic review summarising the longitudinal association between AF and outcomes. The burden of heart failure was retrieved from the Global Burden of Disease database.

RESULTS

Globally, 2.6% (95% uncertainty interval 1.3 to 4.7%) of the burden of heart failure is associated with AF. This was 1.5 (95% UI 0.6 to 3.2) million people in 2019, a 49.8% increase from 1990. The highest prevalence was from South-East Asia, East Asia and Oceania. The highest YLD was estimated for Central Europe, Eastern Europe and Central Asia. High-income countries showed a sharp decline in the age standardised prevalence and YLD rates from 1990 to 2019.

CONCLUSION

The burden of heart failure associated with AF has increased substantially over the past two decades despite the advances in AF management. However, falling prevalence and YLD rates of heart failure associated with AF in high-income countries over time indicate that reducing this burden is possible.

A Regional Burden of Sequence-Level Variation in the 22q11.2 Region Influences Schizophrenia Risk and Educational Attainment

BACKGROUND

Genomic loci where recurrent pathogenic copy number variants are associated with psychiatric phenotypes in the population may also be sensitive to the collective impact of multiple functional low-frequency single nucleotide variants (SNVs).

METHODS

We examined the cumulative impact of low-frequency, functional SNVs within the 22q11.2 region on schizophrenia risk in a discovery cohort and an independent replication cohort (N = 1933 and N = 11,128, respectively), as well as the impact on educational attainment (EA) in a third, independent, general population cohort (N = 2081). In the discovery and EA cohorts, SNVs were identified using genotyping arrays; in the replication cohort, whole-exome sequencing was available. For verification, we compared the regional SNV count for schizophrenia cases in the discovery cohort with a normative count distribution derived from a large population dataset (N = 26,500) using bootstrap procedures.

RESULTS

In both schizophrenia cohorts, an increased regional SNV burden (≥4 low-frequency SNVs) in the 22q11.2 region was associated with schizophrenia (discovery cohort: odds ratio = 7.48, p = .039; replication cohort: odds ratio = 1.92, p = .004). In the EA cohort, an increased regional SNV burden at 22q11.2 was associated with decreased EA (odds ratio = 4.65, p = .049). Comparing the SNV count for schizophrenia cases with a normative distribution confirmed the unique nature of the distribution for schizophrenia cases (p = .002).

CONCLUSIONS

In the general population, an increased burden of low-frequency, functional SNVs in the 22q11.2 region is associated with schizophrenia risk and a decrease in EA. These findings suggest that in addition to structural variation, a cumulative regional burden of low-frequency, functional SNVs in the 22q11.2 region can also have a relevant phenotypic impact.