A. Manouchehrinia
Karolinska Institutet Centre for Molecular Medicine (CMM), Department of Clinical NeurosciencesAuthor Of 2 Presentations
HT04.03 - Presentation 03 - Cortical atrophy in multiple sclerosis may start at puberty
Abstract
Background
Decreased gray matter (GM) volumes have been shown at the diagnosis of multiple sclerosis (MS), suggestive of early neurodegeneration processes preceding clinical symptoms. The onset and progression rate of atrophy in early stages and across large time spans in MS is still, however, uncertain.
Objectives
To analyze cortical atrophy rates in relation to the patient age vs. disease duration, to find a possible impact of age-at-onset on atrophy progression and to retropolate the time of the brain atrophy onset, based on the progression rate and trajectories.
Methods
Standardized high-resolution brain volumetric imaging was performed in the Stockholm Prospective Assessment of MS (StopMS) study. A total of 1085 MS patients (age: 11-79 years, disease duration: 0-48 years) were included and 3642 brain MRI scans were performed. FSL-SIENAX was used to evaluate the normalized cortical GM volume and further analyzed using R-libraries. Cortical atrophy rates were assessed in relation to age and disease duration respectively and stratified into five age-at-onset subgroups: <20, 20-30, 30-40, 40-50, >50 years. Locally estimated scatterplot smoothing - LOESS and linear regressions were used to calculate atrophy rates for each subgroup for the first, last and all MRI scans performed per patient (range 1-14 scans per person, median 3 scans) between the ages 17 and 60 years, and duration 0-40 years. Demographic and clinical data were available from the Swedish MS Registry.
Results
Cortical atrophy had a clearly linear progression with patient age. At the group level, the normalized cortical GM volume decreased by 3.1 ml/year. The corresponding annual cortical atrophy rates were 0.43% at age 17 and 0.53% at age 60. Patients with later onset started with lower cortical volume, following a similar linear age trajectory as patients with earlier onset. Similar findings were found for both sexes and all MS subtypes. Primary progressive MS patients, older at diagnosis, had the correspondingly lower cortical volume at their time of diagnosis. Retropolation of cortical atrophy trajectory along the linear age-related slopes to normative values suggested that MS atrophy can possibly start as early as at the age of 13 (time of puberty). Similar GM volume analyses vs. disease duration (instead of age) showed separate atrophy trajectories, where each age-at-onset subgroup started with 350 ml difference in volume at the time of onset and followed its own quasi-linear trajectory. Early age-at-onset subgroups had a higher atrophy rate with disease duration and a late age-at-onset subgroups had the lower rates.
Conclusions
Cortical atrophy progresses linearly from around the time of puberty, i.e. typically before the first reported MS symptom and appears largely independent of reported time of MS onset, diagnosis, or a subtype. Assessments of neurodegeneration in MS should preferably be analyzed in relation to the patient's age rather than the disease duration.
PS05.04 - Ongoing disease modifying treatment associated with mis-classification of secondary progressive as relapsing-remitting multiple sclerosis
Abstract
Background
Until recently, disease modifying treatment options for MS patients with a secondary progressive course (SPMS) were limited, leading to the common practice of off-label treatment with drugs approved for relapsing-remitting MS. We previously showed that applying objective algorithms tend to increase the proportion of SPMS in MS registries, suggesting that SPMS is under-diagnosed in clinical practice, possibly related to available treatment options.
Objectives
To compare characteristics of patients clinically assigned an RRMS course that are re-classified when an algorithm-based SPMS assignment method is applied.
Methods
Data from MS registries in the Czech Republic (11,336 patients), Denmark (10,255 patients), Germany (23,185 patients), Sweden (11,247 patients) and the United Kingdom (5,086 patients) were used. Inclusion criteria were patients with relapsing remitting (RR)MS or SPMS with age ≥ 18 years at the beginning of the study period (1 January 2017 – 31 December 2019). In addition to clinically assigned SPMS a data-driven assignment method was applied in the form of a decision tree classifier based on age and last EDSS (Ramanujam, R. et al., 2020. medRxiv, 2020.07.09.20149674).
Results
Across the five registries 8,372 RRMS patients were re-assigned as SPMS (Denmark: n=1,566, Czech Republic: n=1,958, Germany: n=2,906, Sweden: n=648, United Kingdom: n=1,294) increasing the overall SPMS proportion from 17% to 31%. Re-assigned patients tended be younger, were older at onset and had experienced a quicker progression to SPMS. The overall proportion of clinically assigned SPMS patients on disease modifying treatments (DMTs) was 36% but varied greatly between registries (Czech Republic: 18%, Denmark: 35%, Germany: 50%, Sweden: 40%, and the United Kingdom: 12%) whereas a higher proportion of 69% (OR=4.0, P<0.00004) were on DMTs among RRMS patients re-assigned as SPMS (Czech Republic: 71%, Denmark: 68%, Germany: 78%, Sweden: 80%, and the United Kingdom 40%).
Conclusions
SPMS patients on DMTs may be clinically mis-classified as RRMS, most likely by not being re-assigned to SPMS after conversion has occurred. This challenges the use of time to SPMS conversion as an outcome in comparative effectiveness studies using real world evidence data and argues for the use of objective classification tools in the analysis of MS patient populations.