Newer MS diagnostic criteria show ‘prognostic improvement’

Researchers observed a continuous decrease in the time to MS diagnosis and treatment initiation across diagnostic criteria periods during the past 25 years, according to results of a retrospective study published in Neurology.

“The establishment of different MS criteria over the last decades has enabled diagnosing patients in earlier stages of the disease, thereby offering these patients more opportunities to benefit from disease-modifying drugs at an earlier time, which could imply a better disease control in terms of disability,” Mar Tintore, MD, PhD, of the department of neurology/neuroimmunology at the Vall d'Hebron University Hospital in Spain, and colleagues wrote.

“Although a recent study has shown a decrease in the risk of reaching disability milestones in recent years, others did not find this shifting trajectory over time,” the authors continued. “Furthermore, information in previous studies was collected at the time of MS diagnosis but not at the time of the first episode, the so-called clinically isolated syndrome (CIS).”

Investigators sought to determine whether the course of MS had changed in the past several decades by analyzing prospectively collected data from 1,174 individuals included in the Barcelona-CIS cohort between 1994 and 2020. They classified patients into the following five periods based on different MS diagnostic criteria established over time: 1994 to 2000 (Poser period); 2001 to 2004 (McDonald 2001 period); 2005 to 2009 (McDonald 2005 period); 2010 to 2016 (McDonald 2010 period); and 2017 to March 2020 (McDonald 2017 period). They then evaluated the time to MS diagnosis and treatment initiation.

Using Cox regression analysis according to diagnostic criteria periods, Tintore and colleagues assessed the age at which patients with MS reached an expanded disability status scale (EDSS) score of three or more. To remove possible bias derived from the use of different diagnostic criteria over time, or the so-called “Will Rogers” phenomenon, they applied 2017 McDonald criteria and used Cox regression for assessment of EDSS scores of three or more.

Results showed reductions of 77% and 82% in median time from CIS to MS diagnosis and from CIS to treatment initiation, respectively, between the Poser to the McDonald 2017 diagnostic criteria periods.

Patients of a given age diagnosed during more recent periods were less likely to reach EDSS scores of three or more vs. patients of the same age diagnosed during earlier periods. With the Poser period as the reference category, researchers noted adjusted HRs of 0.47 (95% CI, 0.24-0.9) for McDonald 2001; 0.25 (95% CI, 0.12-0.54) for McDonald 2005; 0.3 (95% CI, 0.12-0.75) for McDonald 2010 and 0.07 (95% CI, 0.01-0.45) for McDonald 2017. Early treatment periods showed an aHR of 0.53 (95% CI, 0.33-0.85) for reaching age at EDSS of three or more compared with late treatment.

“Overall, patients diagnosed in more recent diagnostic criteria periods displayed a lower risk of reaching disability,” Tintore and colleagues wrote. “Importantly, the prognostic improvement is maintained after discarding the ‘Will Rogers’ phenomenon, and early treatment appears to be the most likely contributing factor.”