Prescription Drug Use in NMOSD: A Population-Based Study in Greece with Estimation of National Disease Administrative Prevalence

<b>Background/Objectives</b>: Neuromyelitis Optica Spectrum disorder (NMOSD) is a rare, autoimmune disease of the central nervous system with a globally heterogeneous prevalence/ To estimate the prescription-based prevalence of NMOSD in Greece and determine the use of long-term immunotherapies and concomitant medications in these patients. <b>Methods</b>: We analyzed anonymized prescription records from the national prescription database, dating from 1 January 2017 to 1 May 2024. The administrative point prevalence of NMOSD in Greece on 1 January 2022 was calculated according to the national census conducted in late 2021. <b>Results</b>: We identified 219 cases of NMOSD and a 1:6.8 male-to-female ratio. The point prevalence on 1 January 2022 was 1.97 per 100,000, with the highest detected in the region of Crete, and the lowest in the regions of Eastern Macedonia and Thrace. The mean age of people with NMOSD on that date was 51.3 years old. Azathioprine was the most frequently prescribed maintenance immunotherapy, while antidepressants were the most common concomitant medications prescribed. Polypharmacy was observed in 28.9% of the identified cases. <b>Conclusions</b>: We hereby present the prescription drug use of people with NMOSD in Greece in the era just before the introduction of NMOSD-specific immunotherapy in Greece.