Aging of the patients with neuromyelitis optica spectrum disorder in the Noto Peninsula, Japan.

INTRODUCTION: Reports of late onset neuromyelitis optica spectrum disorder (NMOSD) cases have been accumulating. The Noto Peninsula areas exhibit a considerably higher aging rate compared to urban centers, potentially serving as an early example of aging-related challenges in NMOSD care in Japan. This study aimed to elucidate the demographic and clinical characteristics associated with aging in NMOSD patients in the Noto Peninsula areas. METHODS: A retrospective, single-center analysis was conducted on patients diagnosed with NMOSD and treated at Kanazawa Medical University Hospital between January 2009 and December 2024. RESULTS: The mean age at onset among patients residing in the Noto Peninsula areas (n=10) was 63.0 years, significantly higher than the 41.9 years observed in patients from the Kanazawa City and surrounding areas (n=8, p=0.034). Moreover, age at onset showed a significant upward trend over the years (03c1;=0.636, p=0.005). At the final observation, vascular risk factors were identified in 11.1-38.9% of patients, with hypertension notably prevalent among those with onset at age 70 years or older (75%, p=0.028). The mean number of medications at last follow-up was 7.9 (4 - 11), with no significant difference across age-at-onset groups. CONCLUSIONS: The age at NMOSD onset has exhibited a progressive increase over recent years, most markedly within the Noto Peninsula areas, likely reflecting demographic shifts such as declining birthrates and population aging. Advances in immunotherapeutic regimens have extended patient longevity, thereby contributing to an aging NMOSD cohort. Consequently, age-associated complications, including vascular risk factors and polypharmacy, are becoming increasingly prevalent.