Predictors of High Relapse Activity in Patients with MS

Cincinnati—Worse clinical outcomes can be expected in patients with multiple sclerosis (MS) who have high relapse activity (HRA) due to faster disability progression. Understanding the factors that can predict HRA can help clinicians identify patients who are at risk for HRA and who may benefit from the most from highly effective MS treatment.

Noting that there are limited data evaluating predictors of HRA in an MS population, researchers recently conducted a retrospective longitudinal study to identify HRA predictors using a claims database. They reported study results during a poster session at the AMCP meeting. The poster was titled Predictors of High Relapse Activity in a Multiple Sclerosis Population Using US Medical and Pharmacy Claims Database.

Inclusion criteria included at least one International Classification of Diseases, Ninth Revision code for MS in 2009 and at least one in 2005-2008, being ≥18 years of age in 2009, and continuous enrollment for 60 months in 2005-2009. HRA was defined as having ≥2 relapses in 2009.

Bivariate analyses were conducted to compare patients with HRA with other MS patients in terms of patient characteristics, treatment patterns, and disease activity in previous years. The researchers also conducted logistic regression to identify predictors of HRA based on demographics, comorbidities, MS symptoms as defined by the National MS Society, treatment patterns, and prior disease activity in the 4 years prior to the index date.

After applying inclusion criteria, the final study sample included 13,344 patients. Of those, 4.7% (n=622) had HRA and 95.3% (n=12,722) did not. Those with HRA were younger (53 vs 55 years; P<.001) and less likely to be employed (52.7% vs 57.2%; P=.03) compared with participants without HRA. Mean Charlson Comorbidity Index score was 0.7 for those with HRA compared with 0.6 for those without in 2009 (P<.02).

In 2009, patients with HRA were more likely to report MS symptoms compared with MS patients without HRA (83.0% vs 69.4%; P<.001). Patients with HRA experienced more MS relapses in 2007 (1.3 vs 0.2; P<.001) and 2008 (1.6 vs 0.2; P<.0001), respectively, compared with those without HRA. Finally, the number of disease-modifying therapies (DMTs) used was higher for patients with HRA compared with those without HRA in 2009 (1.2 vs 0.9; P<.0001).

Patients who had MS symptoms in 2008 were more likely to have HRA compared to not having MS symptoms (odds ratio [OR], 1.86; 95% confidence interval [CI], 1.46-2.36; P<.0001). The number of relapses increased the likelihood of HRA with ORs of 1.39 (95% CI, 1.28-1.51) and 2.40 (95% CI, 1.14-1.46) for 2008 and 2009, respectively; P<.0001. The number of DMTs used from 2005 to 2008 was associated with an increased likelihood of HRA (OR, 1.29; 95% CI, 1.14-1.46; P<.001).

In conclusion, the researchers said, “A number of MS-related factors including the number of relapses and the presence of MS-related symptoms in previous years were associated with HRA. These factors may assist in the early identification of patients with more aggressive MS, so that highly effective MS therapies can be started earlier, potentially mitigating the long-term course of disease. Future research should focus on identifying additional predictors of HRA.”

This study was supported by Novartis Pharmaceuticals Inc.