DALYs

Neurological diseases have a very different frequency. Neurological practice and brain research need to have this in mind. The global burden of disease study has shown that neurologic diseases are the leading cause group of disability-adjusted life years (DALYs) of all medical disease groups in 2015 with 10.2% of global DALYs. Table 1 shows the age-standardized rates of DALYs, deaths and the prevalence of the different neurologic diseases.1 In this schematic rare neurological diseases are mostly covered within the category ‘other neurological diseases’. The prevalence cannot be estimated based on the available data. However, the number of existing rare neurological diseases is very large. The current website of the NIH lists 1244 neurologic rare diseases which is the largest number among all rare disease groups and covers approximately 60% of rare diseases.2 These more than 1200 diseases produce more than 0.9% of the neurological DALYs world-wide which seems at first glance to be relatively small.

It is not new that human disease is imposing a burden on the sufferers and a challenge for the physician. While neurologists are having the privilege being physicians and have the single patient in our focus of attention, health economists take a different view. Their thinking is focusing on the burden of disease for the society and its economic implications. They look at the costs of disease in different terms. The classical measures for the burden of disease are the costs in terms of disability-adjusted life years (DALYs) which are defined as the sum of years of life lost due to the disease (YLLs) and years lived with the disease (YLDs) accounting for reduced life time with good quality of life due to the disability. Another important measure is the Socio-demographic Index (SDI) reflecting economic and educational development. There is big science behind all these calculations which I will not go into detail here.