In patients in the earlier stages of MS, an accelerated rate of spinal cord atrophy can indicate “silent progression,” worsening disability in the absence of relapses, and a faster advancement toward secondary progressive multiple sclerosis (SPMS), according to findings shared at the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2022.
Antje Bischof, MD, and colleagues investigated spinal cord and brain atrophy as predictors of silent clinical progression by capturing upper cervical cord area from brain MRI scans. The data analyzed 360 patients with MS, as well as 80 matched healthy controls. Participants were followed for 12 years. Most participants were female, with an average age in the early 40s.
Silent Progression Evident “Quite Early” in Disease Progression
“We know that there are some patients who, very early on in the disease, already demonstrate disability worsening [in the absence of relapses],” said Dr. Bischof and colleagues. “We thought it would be important to look into whether spinal cord atrophy would be a predictor of progression” in MS.
Silent progression was evident in 159 patients with MS after an average of about 3.3 years in the study, which is “quite early” in the disease’s progression, according to Dr. Bischof. She noted that patients with silent progression had significantly lower median Expanded Disability Status Scale (EDSS) scores at baseline than those who did not (scores of 1.5 vs 2), indicating these patients tended to start with less severe disability.
Spinal Cord Atrophy Greatest Predictor of Silent Progression
“Spinal cord atrophy was the strongest predictor of silent clinical progression,” Dr. Bischof and colleagues wrote. “A 1% faster spinal cord atrophy rate was associated with 69% shorter time to silent clinical progression. Ventricular enlargement was the second strongest MRI metric and the strongest brain measure to predict silent progression, with each 1% enlargement of the lateral ventricles being associated with a 16% shorter time to silent clinical progression.”
The investigators observed that silent clinical progression is predominantly linked with cervical cord atrophy. “This atrophy is often present from the earliest disease stages and predicts the speed of silent progression,” they wrote. Patients with silent progression also had a larger rate of ventricular enlargement (3.57% vs 3.12%), they noted, referring to an increase in the size of fluid-filled spaces (ventricles) in the brain. This link is “probably a proxy of brain atrophy,” Dr. Bischof explained.
No association was observed between spinal cord atrophy and relapse rates, treatments, or lesions, the study team added.