Demographic, disease factors linked to MS progression risk
Men, smokers among groups at higher risk, meta-analysis shows
Factors including being male, smoking, and having more frequent relapses are linked to significantly increased risk of disease progression in multiple sclerosis (MS), according to a meta-analysis of several published studies.
Other variables linked to disease progression included disability score and the use of disease-modifying therapies (DMTs). “Hence, particular attention should be given to these risk factors when assessing MS deterioration,” the study’s author, Yun Huang of the First People’s Hospital of Yibin in Sichuan, China, wrote.
The study, “Predictive factors for the progression of multiple sclerosis: a meta-analysis,” was published in Neurological Sciences.
MS is caused when the immune system mistakenly attacks myelin, the protective fatty layer surrounding nerve fibers that ensures efficient communication between nerve cells. As the disease advances, continued myelin damage disrupts nerve signaling, leading to worsening MS symptoms and increasing disability. While the exact drivers of disease progression remain unclear, factors such as patient demographics, clinical characteristics, and treatment strategies are thought to be involved.
“Identifying predictors of disability worsening is critical for improving management and outcomes in these patients,” Huang wrote.
Pooled data covers thousands of patients
The study analyzed data pooled from 14 published articles on MS disease progression. All participants had been evaluated using the Expanded Disability Status Scale (EDSS), a standard measure of disability in MS in which higher scores reflect greater impairment and disease progression. To ensure relevance, Huang included only studies that assessed at least one potential predictor of MS progression of interest for the analysis.
In total, the studies covered 42,630 participants. All were cohort studies, meaning they followed a group of individuals over time without a specific intervention.
Men had a significantly higher risk of progression than women. Also, “current or former smokers had nearly twice the risk of disease worsening compared to non-smokers,” Huang wrote.
Certain features of the disease also predicted the risk of progression. These included the number of relapses, with each relapse increasing the chance of disease worsening by 5%.
“We believe that the number of relapses serves as a predictor of short-term MS progression but has limited value in long-term prognosis,” Huang wrote, referencing findings from a previous study that showed weakening correlations between relapse frequency and disease progression over time. Higher EDSS scores were also a significant predictor of disease progression.
But “patients who received DMTs had a 62% lower risk of disease worsening compared to those who did not receive DMTs,” Huang wrote. This is in line with the intended purpose of DMTs, which aim to stop or slow progression of symptoms.
Early, or prodromal, MS symptoms may include mental health problems like anxiety, depression, and emotional stability. Whether individuals exhibited these symptoms did not, however, influence worsening disability.
Age at disease onset and duration of the disease also did not seem to significantly affect progression. This is at odds with previous work, which has consistently linked these factors to accumulation of disability. According to Huang, it’s possible that the relatively short follow-up period of the included studies influenced these findings.
“Geographic and population variations could also play a role, as genetic, environmental, and lifestyle factors vary widely across regions and may affect disease presentation and progression,” Huang noted. Additionally, the analysis did not stratify by disease subtype (relapsing-remitting MS or progressive MS), which may have affected results.
Identifying sex, smoking, relapse frequency, EDSS score, and DMT use as risk factors influencing disease progression may help clinicians and scientists efficiently assess worsening disability, according to Huang. “These risk factors should be prioritized when assessing when evaluating MS progression,” Huang wrote.
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