Frequency of new asymptomatic MRI lesions during attacks and follow-up of patients with NMOSD in a real-world setting.

BACKGROUND: We aimed to assess the frequency of new asymptomatic lesions on brain and spinal imaging (magnetic resonance imaging (MRI)) and their association with subsequent relapses in a large cohort of neuromyelitis optica spectrum disorder (NMOSD) patients in Argentina. METHODS: We retrospectively reviewed 675 MRI (225 performed during an attack and 450 during the relapse-free period (performed at least 3 months from the last attack)) of NMOSD patients who had at least 2 years of clinical and MRI follow-up since disease onset. Kaplan-Meier (KM) curves were used for depicting time from remission MRI to subsequent relapse. RESULTS: We included 135 NMOSD patients (64.4% were aquaporin-4-immunoglobulin G (AQP4-IgG)-positive). We found that 26 (19.26%) and 66 (48.88%) of patients experienced at least one new asymptomatic MRI lesion during both the relapse-free period and attacks, respectively. The most frequent asymptomatic MRI lesions were optic nerves followed by short-segment myelitis during the relapse-free period and attacks. KM curves did not show differences in the time taken to develop a new relapse. CONCLUSION: Our findings showed that new asymptomatic lesions are relatively frequent. However, the presence of new asymptomatic MRI lesions during the relapse-free period and at relapses was not associated with a shorter time to developing subsequent relapses.

Argentinean consensus recommendations for the use of telemedicine in clinical practice in adult people with multiple sclerosis.

BACKGROUND: The use of telemedicine has quickly increased during of the COVID-19 pandemic. Given that unmet needs and barriers to multiple sclerosis (MS) care have been reported, telemedicine has become an interesting option to the care of these patients. The objective of these consensus recommendations was to elaborate a guideline for the management of people with MS using telemedicine in order to contribute to an effective and high-quality healthcare. METHODS: A panel of Argentinean neurologist's experts in neuroimmunological diseases and dedicated to the diagnosis, management,and care of MS patients gathered virtually during 2021 and 2022 to conduct a consensus recommendation on the use of telemedicine in clinical practice in adult people with MS. To reach consensus, the methodology of "formal consensus RAND/UCLA Appropriateness method" was used. RESULTS: Recommendations were established based on relevant published evidence and expert opinion focusing on definitions, general characteristics and ethical standards, diagnosis of MS, follow-up (evaluation of disability and relapses of MS), identification and treatment of relapses, and finally disease-modifying treatments using telemedicine. CONCLUSION: The recommendations of this consensus would provide a useful guide for the proper use of telemedicine for the assessment, follow-up, management, and treatment of people with MS. We suggest the use of these guidelines to all the Argentine neurologists committed to the care of people with MS.

Disability outcomes in NMOSD and MOGAD patients: data from a nationwide registry in Argentina.

The objective was to evaluate time to reach an EDSS of 4, 6, and 7 in NMOSD and MOGAD patients included in the Argentinean MS and NMOSD registry (RelevarEM, NCT 03,375,177). METHODS: NMOSD patients diagnosed according to 2015 criteria and with MOGAD were identified. Patients with at least 3 years of follow-up and periodic clinical evaluations with EDSS outcomes were included. AQP4-antibody and MOG-antibody status was recorded, and patients were stratified as seropositive and seronegative for AQP4-antibody. EDSS of 4, 6, and 7 were defined as dependent variables. Log rank test was used to identify differences between groups. RESULTS: Registry data was provided for a total of 137 patients. Of these, seventy-five presented AQP4-ab-positive NMOSD, 45 AQP4-ab-negative NMOSD, and 11 MOGAD. AQP4-ab status was determined by cell-based assay (CBA) in 72% of NMOSD patients. MOG-ab status was tested by CBA in all cases. Mean time to EDSS of 4 was 53.6 ± 24.5 vs. 63.1 ± 32.2 vs. 44.7 ± 32 months in seropositive, seronegative NMOSD, and MOGAD, respectively (p = 0.76). Mean time to EDSS of 6 was 79.2 ± 44.3 vs. 75.7 ± 48.6 vs. 54.7 ± 50 months in seropositive, seronegative NMOSD, and MOGAD (p = 0.23), while mean time to EDSS of 7 was 86.8 ± 54 vs. 80.4 ± 51 vs. 58.5 ± 47 months in seropositive, seronegative NMOSD, and MOGAD (p = 0.39). CONCLUSION: No differences were observed between NMOSD (seropositive and seronegative) and MOGAD in survival curves.

Radiologically isolated syndrome: from biological bases to practical management.

BACKGROUND: Technological advances and greater availability of magnetic resonance imaging have prompted an increment on incidental and unexpected findings within the central nervous system. The concept of radiologically isolated syndrome characterizes a group of subjects with images suggestive of demyelinating disease in the absence of a clinical episode compatible with multiple sclerosis. Since the description of this entity, many questions have arisen; some have received responses but others remain unanswered. A panel of experts met with the objective of performing a critical review of the currently available evidence. Definition, prevalence, biological bases, published evidence, and implications on patient management were reviewed. Thirty to 50% of subjects with radiologically isolated syndrome will progress to multiple sclerosis in 5 years. Male sex, age < 37 years old, and spinal lesions increase the risk. These subjects should be evaluated by a multiple sclerosis specialist, carefully excluding alternative diagnosis. An initial evaluation should include a brain and complete spine magnetic resonance, visual evoked potentials, and identification of oligoclonal bands in cerebrospinal fluid. Disease-modifying therapies could be considered when oligoclonal bands or radiological progression is present. CONCLUSION: At present time, radiologically isolated syndrome cannot be considered a part of the multiple sclerosis spectrum. However, a proportion of patients may evolve to multiple sclerosis, meaning it represents much more than just a radiological finding.

Clinical and demographic characteristics of primary progressive multiple sclerosis in Argentina: Argentinean registry cohort study (RelevarEM).

BACKGROUND: Primary progressive multiple sclerosis (PPMS) is an infrequent clinical form of multiple sclerosis (MS). Scarce information is available about PPMS in Latin America. The aim of this work is to describe the clinical and demographic characteristics of PPMS patients in Argentina. MATERIAL AND METHODS: RelevarEM is a longitudinal, strictly observational registry in Argentina. Clinical and epidemiological data from PPMS patients were described. RESULTS: There were 144 cases of PPMS. They represented 7% of MS patients. The mean age was 44.1 years. The female:male ratio was 1.08. The mean Expanded Disability Status Scale (EDSS) score was 5.5 and the mean disease evolution time was 10.6 years. Oligoclonal bands were found in 72.9%. At the time of diagnosis, magnetic resonance imaging showed spinal cord lesions in 82.6% and contrast-enhancing brain lesions in 18.1% of patients. Almost one third of patients were treated with a disease-modifying drug, and ocrelizumab was the most frequently used (55.8%). CONCLUSIONS: PPMS is an infrequent subtype of MS and its recognition is of the highest importance as it has its own evolution, treatment, and prognosis. The importance of our research resides in providing local data and contributing to a better understanding of PPMS and its treatment in Latin America.

Multiple sclerosis and neuromyelitis optica spectrum disorders in Argentina: comparing baseline data from the Argentinean MS Registry (RelevarEM).

The objective of this study was to describe and compare the baseline epidemiological data of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) patients included in RelevarEM (Clinical Trials registry number NCT03375177). METHODS: RelevarEM is a longitudinal, strictly observational MS and NMOSD registry in Argentina. Epidemiological and comorbidity data from MS and NMOSD patients were described and compared. For comorbidities, the Charlson comorbidity index (CCI) was used to calculate the burden at entry. CCI was stratified in 0 and ≥ 1 and described for the entire cohort. RESULTS: A total of 1588 and 75 MS and NMOSD patients (respectively) were included. For MS patients, the mean age was 42 ± 7 years, female sex 65.3%, mean EDSS 2, and mean disease duration 8 ± 6 years. In NMOSD, the mean age was 40 ± 7 years, female sex 78.7%, mean disease duration 5 ± 3.5 years, and mean EDSS 2.5. The most frequent MS phenotype was RRMS in 82.4%. In MS, the CCI was 0 in 85.8.2% while ≥ 1 was in 14.2% of patients. Regarding phenotype stratification, CCI ≥ 1 was 3.9% in CIS, 13.5% in RRMS, 28.7% in SPMS, and 17.4% in PPMS (p < 0.001 between groups). In NMOSD, the CCI was 0 in 64% while ≥ 1 was in 36%. The MS/NMOSD ratio found was 21/1. CONCLUSIONS: This is the first analysis of the longitudinal Argentinean registry of MS and NMOSD describing and comparing conditions that contributes to provide reliable real-world data in the country.

It is time to rethink clinical trials on Bruton's tyrosine kinase inhibitors in multiple sclerosis.

The EVOLUTION trials comparing evobrutinib and teriflunomide in multiple sclerosis revealed unexpected negative results, challenging the choice of the annualized relapse rate (ARR) as the primary outcome. While monoclonal antibodies effectively control inflammation, the focus on ARR may not capture the long-term disability progression addressed by Bruton's tyrosine kinase inhibitors (BTKi). This letter questions the suitability of teriflunomide as a comparator due to low relapse rates in the control group, possibly stemming from patient selection bias. The author advocates for a reevaluation of study design, outcomes, and comparators in multiple sclerosis research, emphasizing the need for new approaches to address disease activity and disability progression. It is time to rethink clinical trials on Bruton's tyrosine kinase inhibitors in multiple sclerosis.

Clinical characterization of long-term multiple sclerosis (COLuMbus) patients in Argentina: A cross-sectional non-interventional study.

BACKGROUND: Most Multiple Sclerosis (MS) clinical trials fail to assess the long-term effects of disease-modifying therapies (DMT) or disability. METHODS: COLuMbus was a single-visit, cross-sectional study in Argentina in adult patients with ≥10 years of MS since first diagnosis. The primary endpoint was to determine patient disability using the Expanded Disability Status Scale (EDSS). The secondary endpoints were to evaluate the distribution of diagnoses between relapsing-remitting MS (RRMS) and secondary progressive MS (SPMS), patient demographics, disease history, and the risk of disability progression. The relationship between baseline characteristics and the current disability state and the risk of disability progression was assessed. RESULTS: Out of the 210 patients included, 76.7 % had a diagnosis of RRMS and 23.3 % had been diagnosed with SPMS, with a mean disease duration of 17.9 years and 20.5 years, respectively. The mean delay in the initial MS diagnosis was 2.6 years for the RRMS subgroup and 2.8 years for the SPMS subgroups. At the time of cut-off (28May2020), 90.1 % (RRMS) and 75.5 % (SPMS) of patients were receiving a DMT, with a mean of 1.5 and 2.0 prior DMTs, respectively. The median EDSS scores were 2.5 (RRMS) and 6.5 (SPMS). In the RRMS and SPMS subgroups, 23 % and 95.9 % of patients were at high risk of disability, respectively; the time since first diagnosis showed a significant correlation with the degree of disability. CONCLUSIONS: This is the first local real-world study in patients with long-term MS that highlights the importance of recognizing early disease progression to treat the disease on time and delay disability.

Treatment strategies and responses for attacks of neuromyelitis optica spectrum disorder: A real-world retrospective cohort study.

We aimed to assess the treatment strategies utilized in patients with neuromyelitis optica spectrum disorder (NMOSD) experiencing relapses, including their frequency, types, and response after 6 months based on the Expanded Disability Status Scale (EDSS) score. METHODS: We conducted a retrospective study involving NMOSD patients from the Argentinean MS and NMOSD registry (RelevarEM, NCT03375177). Treatment response at 6 months was categorized as "good" if the EDSS score decreased by ≥1 point after a nadir EDSS score ≤ 3, or by ≥2 points after a nadir EDSS score > 3, "poor" if the EDSS score decrease was slighter, and as "absent" if the EDSS score remained unchanged or worsened. RESULTS: We included 120 NMOSD patients (seropositive N = 75), who experienced 250 NMOSD-related relapses and received 248 treatments. At 6 months, complete recovery was achieved in 70/98 (71.4%) and 15/19 (79%) patients, respectively. Predictors of a "good" response in our regression model were a younger age at disease onset (OR:3.54, CI95% 2.45-5.01, p < 0.0001) and a short delay from onset of relapse to treatment initiation (OR:1.56, CI95% 1.22-2.13, p = 0.004). CONCLUSIONS: Approximately two-thirds of patients experienced complete recovery, and younger age and a short delay to start treatment were independent predictors of a "good" response.

Traditional first-line treatment failure rates in neuromyelitis optica spectrum disorder patients included in the Argentinean registry (RelevarEM).

BACKGROUND: Immunosuppressive therapies as azathioprine (AZA), mycophenolate mofetil (MMF) and rituximab (RTX) are widely prescribed as first-line treatment to prevent relapses in NMOSD. However, the rate of response to these traditional therapies is unknown in Argentina. We aimed to describe and compare treatment failure rates in NMOSD patients included in the Argentinean MS and NMOSD registry (RelevarEM, NCT03375177). METHODS: A retrospective cohort study was conducted in NMOSD patients included in RelevarEM (a nationwide, longitudinal, observational, non-mandatory registry of MS and NMOSD in Argentina). NMOSD patients were defined based on validate diagnostic criteria. Only NMOSD patients who received AZA or MMF for at least 6 months or RTX for at least 1 month were included. Patients who were receiving AZA, MMF, or RTX and then switched to another 1 of these 3 therapies were included if the above-mentioned criteria for each drug were fulfilled. Data on patient demographics, clinical, neuroradiological findings, and treatments administered were collected. Treatment failure was defined as any new attack/relapse that occurred despite immunosuppressive treatment. RESULTS: We included 139 NMOSD patients who were receiving AZA (n = 105), MMF (n = 5) or RTX (n = 29) with a mean follow-up time of 41.3 ± 11.4 months and median of EDSS at treatment initiation of 3. We observed a reduction in the annualized relapse rate from pre-treatment to post-treatment of 51.1 %, 48.4 %, and 79.1 % respectively with a Hazard Risk relative to RTX (95 % CI) of 1.67 (1.34-3.54, p = 0.01) for AZA and 2.01 (1.86-4.43, p = 0.008) for MMF. AZA, MMF and RTX failure was observed in 45/105 (42.8 %), 2/5 (40 %) and 3/29 (10.3 %) patients, respectively. CONCLUSIONS: Treatment failure rates were higher for AZA and MMF than RTX in Argentinean NMOSD patients in a real-world setting. High-efficacy treatment increases the opportunity to prevent attacks of NMOSD.

Selection of disease modifying therapies in multiple sclerosis based on patient's age and disease activity: Data from a nationwide registry.

BACKGROUND: Knowledge of the safety and efficacy of disease-modifying therapies (DMTs) in older patients with Multiple Sclerosis (pwMS) is limited due to their exclusion from clinical trials. Our purpose is to evaluate the choice of DMTs in pwMS older than 50 years old in a real-world setting. METHODS: Cross-sectional study of pwMS from the Argentine MS and NMOSD Registry. We included patients under 35 and above 50 years old prescribed DMTs. Disease activity was categorized as highly active (HA) or not highly active (NHA), and DMTs were classified as low efficacy therapies (LET) or high efficacy therapies (HET). RESULTS: 1460 patients (65% females) were enrolled. The HA group comprised 241 patients, 198 young (82.2%) and 43 older (17.8%). The NHA group included 1219 patients, 893 young (73%) and 326 older (27%). In the NHA group, older patients received LET more frequently than younger patients (66% versus 44%; p < 0.01). In the HA group, older patients received LET in 61% of cases, whereas younger patients received HET in 71% (p = 0.01). CONCLUSION: The study shows the preference of LET in older patients regardless of disease activity. However it does not demonstrate a difference in disability in older patients based on low vs high efficacy DMTs used, probably due to the design of the study. Further longitudinal studies are warranted to address this issue.

Barriers to access and unmet needs to neuromyelitis optica spectrum disorders care in an Argentinean cohort.

INTRODUCTION: Neuromyelitis optica spectrum disorder (NMOSD) is a rare but severe neuroimmunological condition associated with a significant financial burden. NMOSD is also associated with increased health care utilization, including neurology outpatient visits, magnetic resonance imaging (MRI) use, long-term medication, among others. We aimed to evaluate real-world patient experiences in access to care and NMOSD burden in an Argentinean cohort. METHODS: This cross-sectional study used a self-administered survey and was conducted in Argentina (2022). Patients with NMOSD were divided into three groups: private health insurance (PHI), social health insurance (SHI), and public health insurance (PHI, Ministry of Public Health). Differences in access and health care barriers were assessed. RESULTS: One hundred patients with NMOSD (74 women) with a mean age at diagnosis of 38.7 years were included. Their EDSS was 2.8 and they were followed for 5.2 years. Of them, 51%, 11%, and 13% were employed (full-time: 57.5%), currently unemployed and retired by NMOSD, respectively. 55% of them visited between 2-3 specialists before NMOSD diagnosis. Aquaporin-4-antibody and/or myelin oligodendrocyte glycoprotein-antibody testing was requested in 91% (health insurance covered this partially in 15.3% and 32.9% of the time the test was entirely paid by patient/family). Patients with NMOSD receiving private medical care reported greater access to MRI, outpatient visits, and fewer issues to obtain NMOSD medications compared to those treated at public institutions. A longer mean time to MRI and neurology visit was found in the PHI group when compared with the other two subgroups. Regression analysis showed that private insurance (OR=3.84, p=0.01) was the only independent factor associated with appropriate access to NMOSD medications in Argentina. CONCLUSION: These findings suggest that barriers to access and utilization of NMOSD care services in Argentina are common. NMOSD patients experienced problems to receive NMOSD medication properly, especially those from the public sector.

Neuro rehabilitation effectiveness based on virtual reality and tele rehabilitation in people with multiple sclerosis in Argentina: Reavitelem study.

Virtual Reality (VR) has emerged as a new treatment approach in neurorehabilitation (NR). REAVITELEM Study is a specific NR intervention program based on VR at center (VRC) and tele-rehabilitation (TR) in Argentina. Methods First national multicenter study with a 12-week program intervention of VRC and TR. Participants were assessed at baseline, at 6th and 12th week. Phase I: recruitment and gather of 5 NR Centers from Argentina by the coordinator center (INEBA) to unify evaluation and intervention criteria. Phase II, all centers completed VRC an TR programs. Intervention was 30-minute session, twice a week for 12 weeks. Outcome measures: Expanded Disability Status Scale (EDSS), Fist and Key Pinch Dynamometry, Beck Depression Inventory-Fast Screen, Fatigue Severity Scale, Functional Independence Measure (FIM), International Questionnaire investigating Quality of life in MS (MusiQol) and a Visual Analogue Scale (VAS) of satisfaction after treatment. Results A total of 54 PWMS (23 males) were recruited for VRC. Afterwards, 14 completed TR. The mean age for VRC was 44.72 (SD ± 13.74) and 41.71 (SD ± 10.5) for TR. The median EDSS was 4, 75 for VR. At VRC, 42 have RRMS, 8 have SPMS and 4 PPMS. At TR, 13 have RRMS and 1 have SPMS. The VAS reported an excellent level of satisfaction after treatment with an average of 9, 02 (SD±1.35) in VRC and 9.42 (SD±0.66) in TR. There were significant differences for MusiQol, which improved from baseline to the post-intervention assessment at VRC (p=<0.001) and at TR (p = 0.004) as well as FIM post-intervention assessment at VCR (p = 0.02) and TR (p = 0.04). Conclusion this study suggest that the NR treatment based on VR in MS in Argentina, is an additional effective tool, which favors improvements in the level of functioning in activities of daily living, quality of life, mood, and satisfaction with the treatment.

Mortality of neuromyelitis optica spectrum disorder patients in an Argentinean population: A study from the RelevarEM registry.

We aimed to evaluate mortality and causes of death among Argentinean neuromyelitis optica spectrum disorder (NMOSD) patients and identify predictors of death. Retrospective study included 158 NMOSD patients and 11 (7%) patients died after 11 years of follow-up for a total exposure time of 53,345 days with an overall incidence density of 2.06 × 10.000 patients/day (95% CI 1.75-2.68). Extensive cervical myelitis with respiratory failure (45%) was the most frequent cause of death. Older age (HR = 2.05, p = 0.002) and higher disability score (HR = 2.30, p < 0.001) at disease onset were independent predictors of death. We found an 11-year mortality rate of 7% in Argentinean NMOSD patients.

Evaluation of the times of disability progression and related factors in patients with primary progressive multiple sclerosis from Argentina.

Background PPMS (primary progressive multiple sclerosis) patients represent less than 10% of MS patients in Argentina, men and women were similarly affected and most of them had a severe functional impairment. More rapid progression has been reported in males, but this is not the case in all datasets. The main objective of our study was to determine the time to EDSS (Expanded disability Status Scale) 4, 6 and 7 in PPMS patients. We also compared the times to reach these EDSS in men and women and aimed to identify factors associated with the disability progression. Method This cohort of patients with diagnosis of PPMS (n = 253) was selected from follow-up recorded in the RelevarEM registry database. Result The median times to EDSS 4, 6 and 7 were 24 (IQR 12-48), 72 (IQR 36-96) and 96 (IQR 60-120) months, respectively. Comparison of the survival curves to EDSS 4, 6 and 7 according to gender did not show significant differences (p = 0.33, p = 0.55 and p = 0.59). There is no evidence of an association between the clinical adjustment variables (sex, age >40 years at diagnosis, EDSS > 3 at onset and multifocal MS symptoms at disease onset) and the time of arrival at the EDSS 4, 6 and 7. Conclusion Severe disability was observed six years after the onset of symptoms. No association was found between the studied factors and the time to arrival to severe disability.

Rebound activity after fingolimod cessation: A case - control study.

BACKGROUND: There has been an increase in the number of reports of multiple sclerosis (MS) rebound activity (RA), which is usually defined as a severe disease reactivation after natalizumab or fingolimod withdrawal that exceeds pre-treatment baseline inflammatory activity. The frequency and risk factors that could predict RA remain unknown. Fingolimod is currently the most frequently prescribed disease modifying therapy for MS in Argentina, so that there is a need to determine possible predictors of RA. OBJECTIVES: To identify risk factors for developing RA after fingolimod cessation; to describe RA characteristics, management and evolution. METHODS: The study was a multicenter, retrospective, case-control study of patients with MS who had discontinued fingolimod and were followed up to nine months after discontinuation. Demographic, clinical and paraclinical data was extracted, including age, gender, MS phenotype, reason for discontinuation, number of relapses during the year prior to suspension, time treated with fingolimod, EDSS before, during and after rebound, MRI findings. RESULTS: 26 cases of RA were matched 1:1 with patients without RA. The median time elapsed to RA was 50 days. 68% showed worsening of the EDSS in the evaluation at 3 months of RA. When compared with the control group, no difference was found in terms of age, gender, phenotype, EDSS at the moment of suspension, reason for discontinuation, number of relapses in the previous year, and time on therapy. CONCLUSION: In this case-controlled study, no risk factors could be identified to predict RA after fingolimod cessation. Further controlled, prospective, better powered studies are needed to confirm these findings.

Seasonal variation in attacks of neuromyelitis optica spectrum disorders and multiple sclerosis: Evaluation of 794 attacks from a nationwide registry in Argentina.

BACKGROUND: Identification of triggers that potentially instigate attacks in neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) has remained challenging. We aimed to analyze the seasonality of NMOSD and MS attacks in an Argentinean cohort seeking differences between the two disorders. METHODS: A retrospective study was conducted in a cohort of NMOSD and MS patients followed in specialized centers from Argentina and enrolled in RelevarEM, a nationwide, longitudinal, observational, non-mandatory registry of MS/NMOSD patients. Patients with complete relapse data (date, month and year) at onset and during follow-up were included. Attack counts were analyzed by month using a Poisson regression model with the median monthly attack count used as reference. RESULTS: A total of 551 patients (431 MS and 120 NMOSD), experiencing 236 NMOSD-related attacks and 558 MS-related attacks were enrolled. The mean age at disease onset in NMOSD was 39.5 ± 5.8 vs. 31.2 ± 9.6 years in MS (p < 0.01). Mean follow-up time was 6.1 ± 3.0 vs. 7.4 ± 2.4 years (p < 0.01), respectively. Most of the included patients were female in both groups (79% vs. 60%, p < 0.01). We found a peak of number of attacks in June (NMOSD: 28 attacks (11.8%) vs MS: 33 attacks (5.9%), incidence rate ratio 1.82, 95%CI 1.15-2.12, p = 0.03), but no differences were found across the months in both disorders when evaluated separately. Strikingly, we observed a significant difference in the incidence rate ratio of attacks during the winter season when comparing NMOSD vs. MS (NMOSD: 75 attacks (31.7%) vs MS: 96 attacks (17.2%), incidence rate ratio 1.82, 95%CI 1.21-2.01, p = 0.02) after applying Poisson regression model. Similar results were observed when comparing the seropositive NMOSD (n = 75) subgroup vs. MS. CONCLUSIONS: Lack of seasonal variation in MS and NMOSD attacks was observed when evaluated separately. Future epidemiological studies about the effect of different environmental factors on MS and NMOSD attacks should be evaluated prospectively in Latin America population.

Accumulative risk of clinical event in high-risk radiologically isolated syndrome in Argentina: data from the nationwide registry RelevarEM.

INTRODUCTION: We aimed to analyze the accumulative risk of MRI and OB factors for evolution from RIS to MS in subjects included in the Argentinean MS registry (NCT03375177). METHODS: RIS subjects were identified according to RIS diagnosis criteria. Subjects were longitudinally followed with clinical and MRI at intervals of 6 months. Time from RIS identification to the first clinical event was estimated using Kaplan-Meier. Multivariable Cox regression models were created to assess the independent predictive value of demographic characteristics, as well as clinical, OB and MRI data on time to the first clinical event. The single and increased risk factor of evolution of RIS was quantified. RESULTS: A total of 88 RIS subjects, mean follow-up time 42 ± 4 months were included. 39 (44.3%) and 23 (26.1%) had a new MRI lesion or a clinical event, respectively, during the follow-up. OB (HR 5.9, 95% CI 1.29-10.1, p = 0.004), infratentorial lesions (HR 3.7, 95% CI 1.09-7.5) and spinal cord lesions (HR 5.3, 95% CI 1.4-8.2, p = 0.01) at RIS identification were independent predictors associated with a subsequent clinical event. The accumulative risk showed that when two of the three factors (OB, infratentorial or spinal cord lesions) were present the HR was 10.4, 95% CI 4.4-22, p < 0.001, and when three factors were present, it was HR 15.6, 95% CI 5.7-28, p < 0.001 for a relapse. CONCLUSION: The presence of three factors significantly increased the risk of clinical event; high-risk subjects should probably be managed by a different approach than those used for individuals without high-risk factors.