Incidence, prevalence and disability associated with neurological disorders in Italy between 1990 and 2019: an analysis based on the Global Burden of Disease Study 2019

DOI: https://doi.org/10.1007/s00415- 021- 10774- 5

Abstract-Summary Neurological conditions are highly prevalent and disabling, in particular in the elderly.

The Italian population has witnessed sharp ageing and we can thus expect a ris-

ing trend in the incidence, prevalence and disability of these conditions.

We relied on the Global Burden of Disease 2019 study to extract Italian data on incidence, prevalence and years lived with a disability (YLDs) referred to a broad set of neurological disorders including, brain and nervous system cancers, stroke, encephalitis, meningitis, tetanus, traumatic brain injury, and spinal cord injury.

The most prevalent conditions were tension-type headache, migraine, and dementias, whereas the most disabling were migraine, dementias and traumatic brain injury.

YLDs associated with neurological conditions increased by 22.5%, but decreased

by 2.3% in age-standardized rates.

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Epidemiology

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The increase in YLDs associated with neurological conditions is mostly due to population ageing and growth: nevertheless, lived disability and, as a consequence, impact on health systems has increased.

Extended: The Italian population comprised 60.6 million in 2019, with a life expectancy at birth of 83.1 years (ranking third at European level) and 71.0 years of healthy life expectancy years (ranking sixth at European level) [12].

The most prevalent conditions in 2019 were migraine and TTH, with 12.5 and 23.2 million prevalent cases (28.5 million cases when combined), and an increase of 8.2% and 12.8% compared to 1990.

Introduction The authors of this manuscript evidenced a consistently increasing trend for number of prevalent cases and disability, in addition to burden, for the selected neurological diseases, and hypothesized that the same indices are reasonably expected to further on increase in reason of population ageing and growth: however, no direct informa- tion was referred to YLDs associated with neurological disease by country.

The aims of this article are, therefore, the following: to describe the incidence, prevalence and YLDs associated with a broad group of neurological disorders in Italy, and their variation between 1990 and 2019; to address the trends for those NCDs with typical onset in young to adult age (e.g. headache disorders) and for those with typical onset in old age (e.g. Alzheimer’s disease and other demen- tias), as well as for neurological injuries and for communicable neurological dis- eases; to compare estimates referred to Italy to those of other Western Europe countries.

Methods This broad group of neurological conditions included both level 3 and level 4 condi- tions as presented in the GBD, specifically as follows: (a) A set of level 3 NCDs, namely Alzheimer’s disease and other dementias, brain and nervous system cancers, epilepsy, MND, MS, PD and stroke, as well as two level-4 ones, namely migraine and TTH.

Non-fatal outcomes for the individual disorders included in this residual cate- gory need to be approximated by assuming the same YLDs/YLLs ratios estimated for the main fatal neurological disorders, which can be a precise approach for those conditions associated to relevant mortality (e.g. Huntington’s disease), but not for those associated to little or no mortality (e.g. myasthenia gravis).

Changes over the period were also analysed at the group level, i.e. young to adult-age onset NCDs, older age onset NCDs, neurological injuries, and communi- cable neurological diseases.

Results With regard to incidence, a consistent decrease both for counts and age- standardized rates was observed for stroke, meningitis, tetanus and TBI, whereas a consistent increase both for counts and age-standardized rates was observed for TTH, MS, dementias and MND.

As for prevalence, a consistent decrease both for counts and age-standardized rates was observed for meningitis and tetanus, whereas a consistent increase both

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for counts and age-standardized rates was observed for migraine, TTH, MS and MND.

For PD, stroke, TBI and SCI the trend was increasing when counts were taken into account, and decreasing in age-standardized rates; for migraine, TTH and dementias and brain and nervous system cancers the trend was increasing when counts were taken into account, and stable in age-standardized rates; finally, for encephalitis, the trend was decreasing in age-standardized rates, and stable in counts.

Discussion There has been a dramatic increase in the counts and age-standardized rates of inci- dence and prevalence of some conditions with typical onset in old age, in particular for Alzheimer disease and other dementias, brain and nervous system cancers and MND.

The increase in YLDs was due to a clear epidemiological change mostly for young to adult-onset conditions, for which age-standardized YLD rates increased by 5.0%, whereas for old-age onset disease the variation herein observed was mostly an effect of population ageing and growth as age-standardized YLDs rates decreased by 13.7%.

Incidence, prevalence and YLDs associated with Alzheimer’s disease and other dementias have more than doubled in Italy over the 1990–2019 period, but not in terms of age-standardized rates, where only for incidence a minor increase was found, suggesting that such an increase is a consequence of population ageing.

Conclusions We reported information on incidence, prevalence and disability associated with neurological disorders in Italy relying on the GBD 2019 estimates.

Our results show that headache disorders are still the most prevalent and dis- abling conditions, and that epidemiological patterns have changed between 1990 and 2019.

Our work pinpoints a worrisome rise in incidence and prevalence for conditions with typical onset in older ages, particularly dementias and PD as an effect of popu- lation ageing; for MND, on the contrary, estimates suggest a consistent increase which cannot be explained by population ageing only, but also as an effect of pro- longed survival.

The increase is mostly due to population ageing and growth, with the only excep- tions of MND and MS (for which classification changes and the inclusion of less severe varieties can be also implicated), and points out the increased survival for many of these conditions.

Acknowledgement A machine generated summary based on the work of Raggi, Alberto; Monasta, Lorenzo; Beghi, Ettore; Caso, Valeria; Castelpietra, Giulio; Mondello, Stefania; Giussani, Giorgia; Logroscino, Giancarlo; Magnani, Francesca Giulia; Piccininni, Marco; Pupillo, Elisabetta; Ricci, Stefano; Ronfani, Luca; Santalucia, Paola; Sattin, Davide; Schiavolin, Silvia; Toppo, Claudia; Traini, Eugenio; Steinmetz, Jaimie; Nichols, Emma; Ma, Rui; Vos, Theo; Feigin, Valery; Leonardi, Matilde. 2021 in Journal of Neurology.

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Epidemiology

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