SAN DIEGO—A new statistical model may be able to estimate a patient’s current risk of progressing from relapsing-remitting multiple sclerosis (MS) to secondary progressive MS. If future investigations prove the model robust, it eventually may help select high-risk patients for clinical trials and aid in the design of trials in which secondary progressive MS is an outcome, said Helen Tedeholm, MSci, a doctoral student at the University of Gothenburg in Sweden.
At the 65th Annual Meeting of the American Academy of Neurology, Ms. Tedeholm and colleagues presented their study of 157 untreated patients diagnosed with relapsing-remitting MS according to the Poser criteria. All patients had had a distinct second relapse of the disease and were followed up for more than 45 years.
The researchers created Poisson regression models with secondary progressive MS as an outcome using previously validated clinical characteristics as variables. The variables were confirmed for each patient as they arose at any time during the course of relapsing-remitting MS.
Of the original cohort, 118 patients developed secondary progressive MS. The risk of secondary progressive MS peaked when the patients were approximately age 30. Three of the variables that the investigators tested—current age, severity of the last relapse, and time since the last relapse—were independently significant predictors of transition to secondary progressive MS.
Ms. Tedeholm and colleagues developed a statistical model that included information from the second relapse onward, as well as the time and clinical characteristics of relapses. The risk of transition to secondary progressive MS increased sharply with a relapse with a high severity score, but it decreased with a relapse with a low severity score.
By applying the model to individual patients, the researchers calculated their current risk of developing secondary progressive MS. Among the study participants, 40 had the highest risk of progressive MS (greater than 0.14 events/year), and 41 had the lowest risk (less than 0.015 events/year).
—Erik Greb
Senior Associate Editor
Suggested Reading
Martinelli-Boneschi F, Esposito F, Brambilla P, et al. A genome-wide association study in progressive multiple sclerosis. Mult Scler. 2012;18(10):1384-1394. Roudbari SA, Ansar MM, Yousefzad A. Smoking as a risk factor for development of secondary progressive multiple sclerosis: A study in IRAN, Guilan. J Neurol Sci. 2013 Apr 26 [Epub ahead of print].