Countries’ treatment strategies for RRMS affect disability outcomes

Researchers found an association between differences in treatment strategies for relapsing-remitting MS and disability outcomes at a national level, according to results of a cohort study published in JAMA Neurology.

The study compared treatment strategies between Denmark, which recommended teriflunomide as first-line treatment of patients with RRMS with mild to moderate disease activity between 2013 and 2019, and Sweden, where teriflunomide treatment received initial approval only for patients with RRMS whose treatment with interferon beta failed, with full indication for RRMS not granted until 2016. Further, Sweden has increasingly used rituximab as off-label treatment for MS, and it has become the most frequently used disease-modifying treatment (DMT).

“While both countries have similar socioeconomic standards and health care systems, the choice of DMT and the treatment strategy for RRMS demonstrate significant differences,” Tim Spelman, PhD, MD, of the department of clinical neuroscience at Karolinska Institute in Sweden, and colleagues wrote. “The objective of this retrospective cohort study, based on data obtained from the Swedish and Danish MS registries, was to investigate whether national treatment recommendations and clinical practice are associated with disability outcomes after 3 to 7 years of follow-up.”

The researchers analyzed data of 4,861 patients included in the Danish and Swedish national MS registries from the date of index DMT initiation, which occurred between January 2013 and December 2016, until the last recorded visit at time of data extraction on Oct. 2, 2019. They included all MS-specific DMTs initiated during the observation period. Time to 24-week confirmed disability worsening served as the primary outcome. Secondary outcomes included 24-week confirmed disability improvement, milestone Expanded Disability Status Scale scores of three and four, annualized relapse rate, time to first relapse and treatment switching. Spelman and colleagues conducted the analysis via inverse probability of treatment weighting-based models that used a propensity score to account for the imbalance of confounders noted at baseline between the two countries.

The researchers included Swedish MS registry data of 2,700 patients (69.2% women; mean age, 36.1 years) and Danish MS registry data of 2,161 patients (68.1% women; mean age, 37.3 years) who started a first DMT between 2013 and 2016 and were observed for a mean of 4.1 years. Results showed 92.3% of Danish patients initiated a low to moderately effective DMT, of which 42% initiated teriflunomide, and 7.6% initiated a highly effective DMT. Among Swedish patients, 65.5% initiated a low to moderately effective DMT, of which 2.4% initiated teriflunomide, and 34.5% initiated a highly effective DMT. The researchers noted a 29% reduction in the rate of postbaseline 24-week confirmed disability worsening associated with the Swedish treatment strategy vs. the Danish treatment strategy (HR = 0.71; 95% CI, 0.57-0.9). Moreover, they observed an association between the Swedish treatment strategy and a 24% reduction in the rate of reaching an expanded disability status scale score of three (HR = 0.76; 95% CI, 0.6-0.97) and a 25% reduction in the rate of reaching an expanded disability status scale score of four (HR = 0.75; 95% CI, 0.61-0.96) compared with Danish patients.

“Starting with a more effective therapy and switching to a more effective DMT at treatment discontinuation irrespective of reason seemed to be superior to commencing a conventional first-line DMT and escalation,” Spelman and colleagues wrote.