Abstract
Background: In clinical practice, the diagnosis of secondary progressive multiple sclerosis (SPMS) is often delayed, retrospective and non-reproducible, as there are no consensus criteria that define the advent of SPMS. Early identification of SPMS is essential to improve patient care. Methods: Eight regional board meetings in France involving 56 multiple sclerosis (MS) experts (neurologists) were convened to discuss diagnostic criteria for SPMS. Subsequently, a national board meeting of 13 neurologists (with an expert representing each geographical region) was held to review points of convergence or divergence between regions and to develop a national consensus document. Results: Based on the discussions from the regional boards, the MS experts at the national board retained the worsening of the EDSS score, with compatible clinical features, as the only consensus criterion for the diagnosis of SPMS in clinical practice. The patient should have experienced during at least the previous 6 months and in the absence of any relapse, a worsening in the EDSS score of +1.0 point (if the previous EDSS was ≤ 5.0) or of +0.5 point (if the previous EDSS was ≥ 5.5), with a pyramidal or cerebellar functional system score ≥ 2 and without setting a minimum EDSS score; or, in case of a stable EDSS score ≥ 4.0, a worsening of a functional score. This worsening should be confirmed within 3 to 6 months. According to the MS experts, the patient's age, duration of illness and a minimal threshold EDSS score are only risk factors for transition to SPMS. Patient reports during consultation and cognitive impairment are important warning signs, which should trigger an objective assessment with specific tests or closer monitoring. Clinical relapse and/or MRI activities are non-discriminatory for making the diagnosis of SPMS. Conclusions: The experts defined precise diagnostic criteria adapted to clinical practice for earlier identification of SPMS, paving the way for better management of this stage of the disease.