Time Trends in Incidence of Motor Neuron Diseases in France: A Comprehensive 14-Year Nationwide Study (2010-2023).

BACKGROUND

Changes over time in the incidence of Motor Neuron Disease (MND) remain uncertain. We aimed to examine time trends in the incidence and survival of MND over 14 years using the Système National des Données de Santé, a nationwide French administrative database.

METHODS

We utilized a published algorithm that integrates riluzole prescriptions and hospital discharge to identify incident MND cases from January 1, 2010, to December 31, 2023. Crude and standardized incidences were calculated per 100,000 person-years. Multivariate Poisson regression models determined time trends in MND incidence by age and sex. Survival was analyzed using Kaplan-Meier methods and Cox proportional hazards models to calculate adjusted hazard ratios for different time periods.

RESULTS

A total of 30,028 incident cases were identified. Crude incidence rose from 2.99 to 3.49 cases per 100,000 person-years between 2010 and 2019, reflecting an annual increase of 1.7% (IRR 1.017, 95% CI 1.012-1.021). After accounting for population aging, there was still an annual increase of 0.7% (IRR: 1.007 [95% CI 1.002-1.012]) between 2010 and 2019. From 2020 to 2023, observed incidence rates deviated from the expected trend, particularly in 2022, which showed a 15% decrease. The median survival time after diagnosis was 18.1 months (2010), 17.8 months (2015), and 15.6 months (2019).

CONCLUSIONS

Although population aging explains much of the rise in case numbers, it does not fully account for the increase. Mortality rates remained stable between 2010 and 2015, but the COVID-19 pandemic had a notable impact, leading to reduced incidence and survival rates.