Marieke van Rosmalen

Clinical outcomes in MMN 29 2 the obtained p values for multiple testing using the Benjamini-Hochberg method. Multiple linear regression analysis was used with backward elimination based on p value selection to predict the MRC sum score 2015 – 2016 based on sex, symptom onset in a leg, presence of anti-GM1 IgM antibodies, FSS (0 – 63), duration of treatment in months (log-transformed), months untreated (log- transformed) and age at onset of symptoms in years). Longitudinal follow-up data The mean yearly rate of decline of each outcome measure was estimated between visit 1 (2007) and visit 2 (2015 – 2016) and tested using a one sample t test (i.e. assessing whether the yearly rate of decline is other than zero). Multiple linear regression analysis was performed with backward elimination based on p value selection to predict the yearly rate of decline in MRC sum score based on sex, presence of anti-GM1 IgM antibodies, symptom onset in leg, months untreated (log- transformed), age at onset of symptoms in years, ODSS (0 – 8), MRC sum score (0 – 180) and sum score of reflexes (0 – 8). The last three variables were analysed with data of the first visit (2007). Patients were asked to describe their disease course as stable, gradually but slowly progressive, gradually progressive, stepwise progressive or gradually improving. RESULTS Patients We identified a total of 142 patients with MMN. Hundred patients (70.4%) agreed to participate of whom 60 patients previously participated in a nationwide cross sectional cohort study in 2007. 11 Reasons for not participating are shown in Figure 2.1 . Clinical characteristics Patient characteristics (sex, age at onset of symptoms, MMN diagnosis according to EFNS/PNS criteria and additional investigations i.e. NCS, MRI brachial plexus, CSF protein and presence of anti-GM1 IgM antibodies) between participants (n = 100) and non-participants (n = 42), were not significantly different, except for the onset of muscle weakness ( p = 0.04). Median age at onset of symptoms and age of diagnosis were significantly higher in patients diagnosed after 2007 ( p < 0.01 and p = 0.02; Table 2.1 ). We performed univariate linear regression analysis with year of diagnosis as independent variable. Both median age at onset of symptoms and median age of diagnosis significantly increased over time (both p < 0.01) ( Figure 2.2 ). Median time from symptom onset to diagnosis (i.e. diagnostic delay) decreased over time (6.4 years (range 1 – 27) in period 1996 to 2000; 1.8 years (range 1 – 29) in period 2011 – 2015) but was significantly longer for patients with onset of symptoms in a leg and for patients with higher age at diagnosis ( p = 0.01 and p < 0.01). We use a starting dose of 0.4 g/kg immunoglobulins per 3-4 weeks and then tailor the dose (if needed up to 1 g/kg) until patients remain stable during the treatment interval. 2 The starting dose