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Harvard University. Harvard Medical School

PIRA Outcome Measure Identifies Disability Accumulation Not Related to Relapse in MS Patients

Strategic Insights

— 1 min read

Progression Independent of Relapse Activity (PIRA) has emerged as a vital outcome measure in multiple sclerosis (MS) clinical studies, allowing researchers to identify disability accumulation that is not related to relapses. A recent study conducted at Harvard Medical School's Brigham Multiple Sclerosis Center aimed to assess changes in fatigue and cognitive functioning in the absence of PIRA. The study's findings suggest that participants without PIRA still experience cognitive worsening and fatigue worsening, at a similar rate to those with PIRA.

Key Takeaways:

  • The study involved 479 participants who completed a measure of fatigue (modified fatigue impact scale (MFIS)) and a brief cognitive screening measure (symbol digit modalities test (SDMT)) yearly, with a complete clinical exam including a measurement of the Expanded Disability Status Scale (EDSS) every six months.
  • Among participants with no PIRA, 8.8% had decreases in SDMT of at least 8 points after 2 years, and 31.1% had increases in MFIS of at least 4 points.
  • The study found limited differences in the change in MFIS or SDMT between participants with PIRA and those with no PIRA at any time interval.
  • The study concluded that participants with no PIRA are still experiencing cognitive worsening and fatigue worsening, at a similar rate to those with PIRA.
  • The research was led by Tanuja Chitnis, Department of Neurology, Harvard Medical School, Boston, MA, United States, with additional authors Bonnie I. Glanz, Howard L. Weiner, and Brian C. Healy.

Statistics:

  • 479 participants contributed to the analysis.
  • 8.8% of participants with no PIRA had decreases in SDMT of at least 8 points after 2 years.
  • 31.1% of participants with no PIRA had increases in MFIS of at least 4 points.
  • The study found limited differences in the change in MFIS or SDMT between participants with PIRA and those with no PIRA at any time interval.

Sources:

  • Chitnis, T., Glanz, B. I., Weiner, H. L., Healy, B. C. (2025). Assessment of changes in fatigue and cognitive functioning in the absence of progression independent of relapse activity. Multiple Sclerosis and Related Disorders, 104, 106786.
  • NewsRx. (2025, October 31). Researchers from Harvard Medical School Provide Details of New Studies and Findings in the Area of Science (Assessment of changes in fatigue and cognitive functioning in the absence of progression independent of relapse activity). Health & Medicine Week, p 6527.

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