Comorbidity Control Might Slow MS Activity

COPENHAGEN — The largest and perhaps most rigorous study to demonstrate an association between the presence of comorbidities and accelerated progression of multiple sclerosis (MS) is sufficiently compelling that both the study author and an independent expert maintained clinical practice should be adjusted.

Even while acknowledging that “it is hard to make causative statements” on the basis of these types of data, the findings are sufficiently compelling to suggest that comorbidities “should be a pressing concern” in MS management, according to Amber Salter, PhD, an associate professor of biostatistics at the University of Texas Southwestern Medical School, Dallas.

The strong association in this meta-analysis, presented at the 2024 ECTRIMS annual meeting, were drawn from 15 multicenter phase 3 treatment trials with 16,794 participants followed for at least 2 years, Dr Salter reported. Her data were published simultaneously in JAMA Neurology.

“One of the strengths of this study is that the data on comorbidities were collected prospectively as part of these trials,” explained Mark S. Freedman, MD, director of the Multiple Sclerosis Research Center at The Ottawa Hospital in Canada. He agreed with Dr Salter that it is reasonable to apply these findings to clinical practice given their consistency with numerous other studies and the value of what he termed as “a holistic approach” to improving outcomes in MS.

Meta-Analysis Avoids Weaknesses of Previous Data

There are many potential weaknesses of past observational studies that the authors of this meta-analysis hoped to avoid. These include the possibility that MS patients with comorbidities might be less likely to take or adhere to disease-modifying therapies (DMT) or that comorbidity burden might masquerade or be misinterpreted as MS progression. By employing data from phase 3 DMT trials, Dr Salter maintained that prospectively collected data monitored carefully over an extended follow-up allows the impact of comorbidities on outcome to be evaluated in a more controlled fashion.

Dr Freedman liked the design of this study, but he admitted that he was surprised by the result.

“Phase 3 trials typically include exclusion criteria for significant comorbidities, so I did not think they would be able to show any meaningful differences,” Dr Freedman said in an interview.

For the main outcome of evidence of disease activity (EDA), defined as confirmed disability worsening measured with the Expanded Disability Status Scale (EDSS), relapse activity, or any new or enlarging lesions on MRI, the differences reached significance even after adjustments for multiple potentially confounding factors.

MS Activity Increases Significantly With More Comorbidities

Compared with no comorbidity, the presence of three or more comorbidities were associated with a significant 14% increase in the adjusted hazard ratio (aHR) of EDA (aHR, 1.14; 95% CI, 1.02-1.28), Dr Salter reported. If there were two or more cardiometabolic comorbidities, the risk of EDA was increased 21% (aHR, 1.21; 95% CI, 1.08-1.37).

The list of comorbidities considered in this study was drawn from the International Advisory Committee on Clinical Trials in MS. It included numerous cardiometabolic comorbidities, such as hypertension, hyperlipidemia, diabetes, ischemic heart disease, cerebrovascular disease, and peripheral vascular disease. It also included chronic lung diseases, such as asthma and chronic obstructive pulmonary disease; psychiatric diseases, such as depression and anxiety; and miscellaneous autoimmune conditions.

The number of comorbidities was categorized for analysis as zero, one, two, or three or more. However, Dr Salter acknowledged that these phase 3 trials did include comorbidity exclusion criteria. In fact, severe forms of most of these comorbidities were exclusion criteria in at least some studies. Yet, the prevalence of one or more comorbidities was still 45.4% in the total population from this meta-analysis.

By themselves alone, ischemic heart disease (aHR, 1.63), cerebrovascular disease (aHR, 1.70), and at least one psychiatric disorder (aHR, 1.14) were all significant for increased MS activity at the end of 2 years by a 95% CI that did not cross the line of unity.

When the EDA endpoints were evaluated individually, not even three or more comorbidities was associated with an increased rate of active lesions on MRI at the end of follow-up, but two or more and three or more comorbidities were associated with a significantly increased risk of disability worsening (aHR, 1.16 and aHR, 1.31, respectively) and relapse (aHR, 1.16 for both).

An Underestimation of Associations?

Prospective trials are still needed to show that treating comorbidities improves outcome in MS, but randomization will be problematic if it means withholding treatment for conditions with risks independent of MS, Dr Salter said. Although the data from this analysis did not permit an analysis of how relative severity of comorbidities affected MS outcome, she reiterated that most patients with severe comorbidities were likely excluded from inclusion in the studies anyway.

“We think that we are probably seeing an underestimation of an associations between comorbidity and increased MS activity,” Dr Salter said. While she reported that confounding cannot be ruled out, the robust associations identified in a meta-analysis “limit the possibility of bias or chance findings.”

Asked if the message that clinicians should treat comorbidities to reduce MS activity is a reasonable conclusion in the absence of proof that treatment is beneficial, Dr Freedman looked both to the body of evidence and to the common sense behind the recommendation.

Basically, Dr Freedman believes that comorbidities should be addressed routinely and rigorously even if there was no evidence that they improve MS outcome. These data provide just one other source of support for a practice that should be conducted anyway.

Dr Salter reported financial relationships with Abata Therapeutics, Gryphon Bio, and Owl Therapeutics. Dr Freedman reported financial relationships with more than 10 pharmaceutical companies. 

This article originally appeared on MDedge.com, part of the Medscape Professional Network.