Global Burden of Neurologic Disorders

By Tasha Welch, MD
Assistant Professor, Department of Anesthesiology and Perioperative Medicine
Mayo Clinic College of Medicine, Rochester, MN

Tasha Welch, MD

The Global Burden of Disease study in 1990 was the first to assess disease burden by examining not only mortality, but also the disability from major diseases and disorders.   As physicians caring for patients with neurologic diseases and disorders, it is important for us to recognize the global burden of neurologic disorders.  Millions of people are affected by neurologic diseases worldwide, and as the population ages and medical advancement continues to increase life expectancy, the burden of neurologic disease is only likely to grow.

In 2017, the Neurological Disorders Collaborator Group reported on the neurologic diseases classified in the Global Burden of Disease Study 2015 data. In this study, neurological disorders compromised 9.4 million deaths or 16.8% of global deaths, second only behind cardiovascular diseases.  While neurological disorders were the second leading cause of death, they were the largest cause of disability-adjusted life years (calculated as the sum of the estimated years of life lost and years of life with disability related to neurologic disease). 

Compared to the first study in 1990, the 2015 study found the overall fraction that neurologic diseases contributed to disability-adjusted life years surprisingly decreased by 30% and the overall rate of death caused by neurologic disease decreased by 26%.  However, the absolute number of disability-adjusted life years and deaths from all neurological disorders combined over 1990-2015 increased by 7.4% and 36.7% respectively. 

In 2015, stroke, migraine, meningitis, dementia, and epilepsy each caused more than 10 million disability-adjusted life years. Of these, stroke (both ischemic and hemorrhagic) accounted for the largest number of disability-adjusted life years (47% among all neurologic diseases) and deaths (67% among all neurologic disease).  After stroke, the largest contributors to disability-adjusted life years were migraines (13%), meningitis (10%), and Alzheimer’s disease and other dementias (9%).  The largest causes of death after stroke were Alzheimer’s disease and other dementias (20%), meningitis (4.0%), and central nervous system cancer (2.4%).

The concept of global burden of disease may become a measure by which disease and disorders are addressed in healthcare.  In other words, those diseases and disorders with a higher burden may become a priority in allocating already limited healthcare resources. Because neurological diseases and disorders are a large contributor to global disease burden, physicians who care for these patients may find a shift in health systems aiming to prioritize care and resources for these patients.  As physicians who work with this patient population, it is important for us to recognize that these diseases and disorders have an impact that goes far beyond the care received within the acute clinical care setting.  Perhaps insight into the global burden of disease will provide an opportunity for us as physicians to improve patient lives not only in the operating room or intensive care unit, but in their lives at home as well.

References:

1. Global Burden of Diseases Study Collaborators. Global, regional, and national disability-adjusted life-years (DALYs) for 315 diseases and injuries and healthy life expectancy (HALE), 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015. Lancet 2016;388: 1603-58.
2. Global Burden of Disease Study Collaborators. Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015. Lancet 2016;388: 1545-1602.
3. Global Burden of Diseases Neurological Disorders Collaborator Group. Global, regional, and national burden of neurological disorders during 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015. Lancet Neurol 2017;16: 877-97.