Patients with late-onset neuromyelitis optica spectrum disorder (NMOSD) exhibited more severe disabilities than patients with early-onset NMOSD, according to new findings published in Frontiers in Neurology.
Researchers conducted a retrospective study of 71 patients diagnosed for at least 3 years with NMOSD in central China between January 2012 and January 2021. In 39 patients, late-onset NMOSD occurred after 40 years of age, and in 32 patients, early-onset NMOSD occurred prior to or at 40 years of age.
The investigators compared early- vs late-onset disease characteristics and prognostic factors and determined the severity of NMOSD-related disability by calculating the expanded disability status scale (EDSS) at baseline, 3 months, 1 year, 3 years, and final follow-up.
Patients with late-onset NMOSD consistently scored higher on the EDSS than those with early-onset at each time point, reflecting more severe disability throughout the course of the disease. The early-onset group scored higher on the EDSS at disease onset through the third month (4.0 vs 2.5; P =.001), whereas the late-onset group scored higher later in the course of their disease around 1 year (4.0 vs 2.5; P =.003).
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EDSS scores indicating visual dysfunction were significantly higher in the late-onset group than in the early-onset group at the time of final follow-up (3.0 vs 2.0; P =.038). The researchers also observed that the risk of requiring a cane to assist with ambulation increased by 65% with each 10-year increase in the age of disease onset.
Spinal cord lesions also occurred more frequently in the cervical region in patients with early-onset NMOSD (P=.032), and they demonstrated optic neuritis more frequently compared to the late-onset group (43.8% vs. 30.8%). The early-onset group had a significantly higher likelihood of initially exhibiting area postrema syndrome compared to the late-onset group (18.8% vs 2.6%; P =.04).
Conversely, patients with late-onset NMOSD exhibited transverse myelitis more frequently than patients with early-onset NMOSD (48.7% vs 25.0%, P =.041).
Age of onset and annualized relapse rate comprised the 2 main prognostic factors predicting patient outcomes. For every 10-year increase in age of onset, the probability of an EDSS score of 4.0 increased by 51.9% (P =.004). Patients with late-onset NMOSD were 3 times more likely to achieve EDSS scores of 6.0 (P =.049), and the annual relapse rate significantly predicted worse outcomes (P =.027).
“Patients with [late-onset NMOSD] developed more severe disabilities than patients with [early-onset]-NMOSD,” the authors said. “All of the patients may experience recurrent aggravated symptoms after their first year, with only patients with [early-onset NMOD] partly recovering from the 3rd year.”
Yu J, Yan S, Niu P, Teng J. Relatively early and late-onset neuromyelitis optica spectrum disorder in central China: clinical characteristics and prognostic features. Front Neurol. 2022;13:859276. doi:10.3389/fneur.2022.859276