Open Access

Svenja Leonie Klinsing, Yavor Vasilev Yalachkov, Christian Förch

• Background and purpose: The transition from relapsing–remitting to secondary progressive multiple sclerosis (SPMS) is not well defined. Different definitions and tools to identify SPMS have been proposed. Meanwhile, early diagnosis of “active” SPMS is getting progressively more important as pharmaceutical treatment options are developed. In this study, we compared different classification methods regarding their accuracy to reliably identify “active SPMS.” Methods: Independent from previous diagnostic classification, we descriptively analyzed the disease course (regarding relapses, progression, and magnetic resonance imaging activity) in 208 consecutive multiple sclerosis (MS) patients treated in our MS outpatient clinic in 2018. Patients were reclassified according to different SPMS criteria and tools. Diagnostic accuracy in identifying patients with “active SPMS” was determined. Results: Comparing the tools to each other, significant variability in the number of patients identified as having SPMS as well as in the proportion of these patients having “active SPMS” was noted. Applying both diagnostic criteria “SPMS” and “active disease” reduced the sensitivity in identifying patients with active progressive disease in all approaches. Conclusions: We propose lessening the emphasis on the label “SPMS” in favor of the more open term “active progressive disease” to simplify the process of identifying patients who may benefit from immune therapy.