Analysis of diffusion tensor parameters in spinocerebellar ataxia type 3 and type 10 patients.

INTRODUCTION: There is a dearth of studies of spinocerebellar ataxias (SCAs) and diffusion tensor magnetic resonance imaging (DTI). OBJECTIVE: To analyze changes observed in DTI parameters and correlate these to clinical findings in SCA3 and SCA10 patients. METHODS: SCA3 (n = 19) and SCA10 (n = 18) patients were compared with a similar number of controls and assessed clinically and with the scale for the assessment and rating of ataxia (SARA) before undergoing the same MRI protocol. TRACULA (TRActs Constrained by UnderLying Anatomy) software was used to analyze the DTI metrics FA, AD, RD and MD. RESULTS: More white matter fiber tracts with changes in diffusivity were found in SCA3 patients than in SCA10 patients. There was a reduction in AD in altered fiber tracts in SCA3 and a greater increase in RD in SCA10. In the SCA3 patients, FA was reduced in the corticospinal tract (CST) and inferior longitudinal fasciculus (ILF), but this was not observed in the SCA10 patients. SARA score was correlated with DTI findings in SCA3 but not in SCA10. CONCLUSION: Changes were observed in DTI for both SCA3 and SCA10 but were more widespread in SCA3. Our finding of myelin-sheath changes in SCA10 and secondary axonal changes in SCA3 may reflect the more rapid, aggressive clinical course of SCA3.

Volumetric MRI Changes in Spinocerebellar Ataxia (SCA3 and SCA10) Patients.

Spinocerebellar ataxias type 3 (SCA3) and type 10 (SCA10) are the most prevalent in southern Brazil. To analyze the relationships between volumetric MRI changes and clinical and genetic findings in SCA3 and SCA10 patients. All patients in the study had a confirmed genetic diagnosis. Demographic data, ataxia severity (SARA score), and the size of the expanded alleles were evaluated. Nineteen SCA3 and 18 SCA10 patients were selected and compared with a similar number of healthy controls. Patient and control groups underwent the same MRI protocol. The standard FreeSurfer pipeline was used for the morphometric data. Our results show more affected brain structures (volume reductions) in SCA3 patients than in SCA10 patients (15 vs. 5 structures). Volume reductions in brain structures were also greater in the former. The main areas with significant volumetric reductions in the former were the cerebellum, basal ganglia, brain stem, and diencephalon, whereas in the latter, significant volume reductions were observed in the cerebellum and pallidum. While SARA scores and disease duration were more correlated with volume reduction in SCA10, in SCA3, the expansion length (CAGn) correlated positively with cerebellar WM, thalamus, brain stem, and total GM volumes. There was no correlation between expansion length (ATTCTn) and neuroimaging findings in SCA10. Neuroimaging results differed significantly between SCA3 and SCA10 patients and were compatible with the differences in clinical presentation, disease progression, and molecular findings.

Neuroradiological Findings in the Spinocerebellar Ataxias.

Background: The spinocerebellar ataxias (SCAs) are a group of autosomal dominant degenerative diseases characterized by cerebellar ataxia. Classified according to gene discovery, specific features of the SCAs - clinical, laboratorial, and neuroradiological (NR) - can facilitate establishing the diagnosis. The purpose of this study was to review the particular NR abnormalities in the main SCAs. Methods: We conducted a literature search on this topic. Results: The main NR characteristics of brain imaging (magnetic resonance imaging or computerized tomography) in SCAs were: (1) pure cerebellar atrophy; (2) cerebellar atrophy with other findings (e.g., pontine, olivopontocerebellar, spinal, cortical, or subcortical atrophy; "hot cross bun sign", and demyelinating lesions); (3) selective cerebellar atrophy; (4) no cerebellar atrophy. Discussion: The main NR abnormalities in the commonest SCAs, are not pathognomonic of any specific genotype, but can be helpful in limiting the diagnostic options. We are progressing to a better understanding of the SCAs, not only genetically, but also pathologically; NR is helpful in the challenge of diagnosing the specific genotype of SCA.

Alternative option for osteogenesis imperfecta and trigeminal neuralgia.

Osteogenesis imperfecta (OI) is a bone disorder that can lead to skull base deformities such as basilar invagination, which can cause compression of cranial nerves, including the trigeminal nerve. Trigeminal neuralgia in such cases remains a challenge, given distorted anatomy and deformities. We present an alternative option, consisting in cannulation of the foramen ovale and classical percutaneous treatment. Percutaneous balloon microcompression was performed in a 28 year-old woman with OI and severe trigeminal neuralgia using computed tomography (CT) and radiographic-guided cannulation of the Gasserian ganglion without neuronavigation or stereotactic devices. The patient developed hypoesthesia on the left V1, V2 and V3 segments with good pain control. This alternative technique with a CT-guided puncture, using angiosuite without the need of any Mayfield clamp, neuronavigation systems, frame or frameless stereotactic devices can be a useful, safe and efficient alternative for patients with trigeminal neuralgia with other bone deforming diseases that severely affect the skull base.

Alternative option for osteogenesis imperfecta and trigeminal neuralgia / Opção alternativa em tratamento da neuralgia do trigêmeo com osteogênese imperfeita

Summary Osteogenesis imperfecta (OI) is a bone disorder that can lead to skull base deformities such as basilar invagination, which can cause compression of cranial nerves, including the trigeminal nerve. Trigeminal neuralgia in such cases remains a challenge, given distorted anatomy and deformities. We present an alternative option, consisting in cannulation of the foramen ovale and classical percutaneous treatment. Percutaneous balloon microcompression was performed in a 28 year-old woman with OI and severe trigeminal neuralgia using computed tomography (CT) and radiographic-guided cannulation of the Gasserian ganglion without neuronavigation or stereotactic devices. The patient developed hypoesthesia on the left V1, V2 and V3 segments with good pain control. This alternative technique with a CT-guided puncture, using angiosuite without the need of any Mayfield clamp, neuronavigation systems, frame or frameless stereotactic devices can be a useful, safe and efficient alternative for patients with trigeminal neuralgia with other bone deforming diseases that severely affect the skull base.

Resumo Osteogênese imperfeita (OI) é uma doença óssea que pode levar a deformidades de base de crânio, como invaginação basilar que pode provocar compressão de nervo craniano, incluindo o nervo trigêmeo. Nestes casos, a neuralgia do trigêmeo permanece como um desafio, pela anatomia distorcida e pelas deformidades. Apresentamos uma alternativa que consiste na canulação do forame oval e no tratamento percutâneo clássico. A microcompressão percutânea por balão foi realizada em uma paciente de 28 anos apresentando OI e grave neuralgia do trigêmeo, sendo realizadas tomografia computadorizada (CT) e canulação guiadas do gânglio gasseriano sem neuronavegação ou dispositivos estereotáxicos. A paciente apresentou hipoestesia à esquerda dos segmentos V1, V2 e V3, com bom controle da dor. Essa técnica alternativa com punção orientada por CT utilizando o angiosuite sem a necessidade de qualquer grampo de Mayfield, sistemas de neuronavegação, ou dispositivos com ou sem arcos estereotáxicos, pode ser uma opção útil, segura e eficiente para pacientes com neuralgia do trigêmeo cursando com outras doenças deformativas que afetem a base craniana de modo grave.

No correlation was observed between vitamin D levels and disability of patients with multiple sclerosis between latitudes 18° and 30° South.

Objective: Vitamin D has taken center stage in research and treatment of multiple sclerosis (MS). The objective of the present study was to assess the serum vitamin D levels of a large population of patients with MS and controls living in a restricted tropical area. Methods: Data from 535 patients with MS and 350 control subjects were obtained from 14 cities around the Tropic of Capricorn. Results: The mean serum 25-OH vitamin D level was 26.07 ± 10.27 ng/mL for the control subjects, and 28.03 ± 12.19 ng/mL for patients with MS. No correlation was observed between vitamin D levels and the disability of patients over the disease duration. Conclusion: At least for the region around the Tropic of Capricorn, serum levels of vitamin D typically are within the range of 20 to 30 ng/mL for controls and patients with MS.

No correlation was observed between vitamin D levels and disability of patients with multiple sclerosis between latitudes 18° and 30° South / Não foi observada correlação entre os níveis séricos de vitamina D e a incapacidade em pacientes com esclerose múltipla entre as latitudes Sul 18° e 30°

ABSTRACT Objective: Vitamin D has taken center stage in research and treatment of multiple sclerosis (MS). The objective of the present study was to assess the serum vitamin D levels of a large population of patients with MS and controls living in a restricted tropical area. Methods: Data from 535 patients with MS and 350 control subjects were obtained from 14 cities around the Tropic of Capricorn. Results: The mean serum 25-OH vitamin D level was 26.07 ± 10.27 ng/mL for the control subjects, and 28.03 ± 12.19 ng/mL for patients with MS. No correlation was observed between vitamin D levels and the disability of patients over the disease duration. Conclusion: At least for the region around the Tropic of Capricorn, serum levels of vitamin D typically are within the range of 20 to 30 ng/mL for controls and patients with MS.

RESUMO Objetivo: Vitamina D assumiu um papel central na pesquisa e tratamento da esclerose múltipla (EM). O objetivo deste estudo foi avaliar os níveis séricos de vitamina D de pacientes com EM e controles que residem em uma área tropical. Métodos: Foram analisados dados de 535 pacientes com EM e 350 indivíduos controle em 14 cidades próximas ao Trópico de Capricórnio. Resultados: O valor médio da determinação de 25-OH vitamina D foi 26,07 ± 10,27 ng/mL para controles e 28,03 ± 12,19 ng/mL para pacientes com EM. Não houve correlação entre os níveis de vitamina D e o grau de incapacidade ao longo da duração da doença. Conclusão: Pelo menos na região que cerca o Trópico de Capricórnio, os níveis séricos de vitamina D estão entre valores de 20 a 30 ng/mL tanto para controles quanto para pacientes com EM.

Higher latitude is significantly associated with an earlier age of disease onset in multiple sclerosis.

BACKGROUND: Age at onset (AAO) in multiple sclerosis (MS) is an important marker of disease severity and may have prognostic significance. Understanding what factors can influence AAO may shed light on the aetiology of this complex disease, and have applications in the diagnostic process. METHODS: The study cohort of 22 162 eligible patients from 21 countries was extracted from the MSBase registry. Only patients with MS aged ≥16 years were included. To reduce heterogeneity, only centres of largely European descent were included for analysis. AAO was defined as the year of the first symptom suggestive of inflammatory central nervous system demyelination. Predictors of AAO were evaluated by linear regression. RESULTS: Compared with those living in lower latitudes (19.0-39.9°), onset of symptoms was 1.9 years earlier for those at higher latitudes (50.0-56.0°) (p=3.83×10-23). A reciprocal relationship was seen for ambient ultraviolet radiation (UVR), with a significantly increasing AAO for patients with MS per each quartile increment of ambient UVR (p=1.56×10-17). We found that the AAO of female patients was ∼5 months earlier than male patients (p=0.002). AAO of progressive-onset patients with MS were ∼9 years later than relapsing-onset patients (p=1.40×10-265). CONCLUSIONS: An earlier AAO in higher latitude regions was found in this worldwide European-descent cohort and correlated inversely with variation in latitudinal UVR. These results suggest that environmental factors which act at the population level may significantly influence disease severity characteristics in genetically susceptible populations.

The real-life experience with cardiovascular complications in the first dose of fingolimod for multiple sclerosis.

Fingolimod is a new and efficient treatment for multiple sclerosis (MS). The drug administration requires special attention to the first dose, since cardiovascular adverse events can be observed during the initial six hours of fingolimod ingestion. The present study consisted of a review of cardiovascular data on 180 patients with MS receiving the first dose of fingolimod. The rate of bradycardia in these patients was higher than that observed in clinical trials with very strict inclusion criteria for patients. There were less than 10% of cases requiring special attention, but no fatal cases. All but one patient continued the treatment after this initial dose. This is the first report on real-life administration of fingolimod to Brazilian patients with MS, and one of the few studies with these characteristics in the world.

The real-life experience with cardiovascular complications in the first dose of fingolimod for multiple sclerosis / A experiência da vida real com complicações cardiovasculares na primeira dose de fingolimode

Fingolimod is a new and efficient treatment for multiple sclerosis (MS). The drug administration requires special attention to the first dose, since cardiovascular adverse events can be observed during the initial six hours of fingolimod ingestion. The present study consisted of a review of cardiovascular data on 180 patients with MS receiving the first dose of fingolimod. The rate of bradycardia in these patients was higher than that observed in clinical trials with very strict inclusion criteria for patients. There were less than 10% of cases requiring special attention, but no fatal cases. All but one patient continued the treatment after this initial dose. This is the first report on real-life administration of fingolimod to Brazilian patients with MS, and one of the few studies with these characteristics in the world.

Fingolimode é um tratamento novo e eficaz para esclerose múltipla (EM). A administração desta droga requer atenção especial para a primeira dose, uma vez que eventos adversos cardiovasculares podem ser observados nas seis horas iniciais da ingestão de fingolimode. O presente estudo consistiu de uma revisão de dados cardiovasculares de 180 pacientes com EM ao receberem a primeira dose de fingolimode. A taxa de bradicardia nestes pacientes foi maior do que aquele observada em estudos clínicos que tem critérios de inclusão muito rigorosos para seleção de pacientes. Menos de 10% dos casos necessitou de atenção especial, mas não houve casos fatais. Todos os pacientes exceto por um continuaram o tratamento após esta dose inicial. Este é o primeiro relato de dados de administração de fingolimode na vida real de pacientes brasileiros com EM, e um dos poucos trabalhos com estas características no mundo.

Nearly one-half of Brazilian patients with multiple sclerosis using natalizumab are DNA-JC virus positive.

OBJECTIVE: Natalizumab is a new and efficient treatment for multiple sclerosis (MS). The risk of developing progressive multifocal leukoencephalopathy (PML) during the use of this drug has created the need for better comprehension of JC virus (JCV) infection. The objective of the present study was to assess the prevalence of JCV-DNA in Brazilian patients using natalizumab. METHOD: Qualitative detection of the JCV in the serum was performed with real-time polymerase chain reaction (PCR). RESULTS: In a group of 168 patients with MS who were undergoing treatment with natalizumab, JCV-DNA was detectable in 86 (51.2%) patients. DISCUSSION: Data on JCV-DNA in Brazil add to the worldwide assessment of the prevalence of the JCV in MS patients requiring treatment with natalizumab.

Multiple sclerosis starting before the age of 18 years: the Brazilian experience.

Multiple sclerosis (MS) starting in childhood and adolescence poses a challenge for diagnosis and management of the disease. The aim of the present study was to assess the characteristics of early onset MS in Brazilian patients. Methods Retrospective data collection from specialized MS units. Results From 20 MS units in 11 Brazilian states, 117 cases of MS starting before the age of 18 years were collected. These patients had an average of 10 years of disease duration, still typically with low disability and one relapse every 2.5 years. The mean age for disease onset was 13.7 years. Conclusion The present study introduces a large series of Brazilian cases of pediatric MS. Although some patients presented a very severe form of MS, on the whole the group of patients with MS starting in childhood or adolescence presented a relatively mild form of this disease in Brazil.

Multiple sclerosis in South America: month of birth in different latitudes does not seem to interfere with the prevalence or progression of the disease.

OBJECTIVE: To assess whether the month of birth in different latitudes of South America might influence the presence or severity of multiple sclerosis (MS) later in life. METHODS: Neurologists in four South American countries working at MS units collected data on their patients' month of birth, gender, age, and disease progression. RESULTS: Analysis of data from 1207 MS patients and 1207 control subjects did not show any significant variation in the month of birth regarding the prevalence of MS in four latitude bands (0-10; 11-20; 21-30; and 31-40 degrees). There was no relationship between the month of birth and the severity of disease in each latitude band. CONCLUSION: The results from this study show that MS patients born to mothers who were pregnant at different Southern latitudes do not follow the seasonal pattern observed at high Northern latitudes.

Multiple sclerosis starting before the age of 18 years: the Brazilian experience / Esclerose multipla com inicio antes dos 18 anos de idade: a experiencia brasileira

Multiple sclerosis (MS) starting in childhood and adolescence poses a challenge for diagnosis and management of the disease. The aim of the present study was to assess the characteristics of early onset MS in Brazilian patients. Methods Retrospective data collection from specialized MS units. Results From 20 MS units in 11 Brazilian states, 117 cases of MS starting before the age of 18 years were collected. These patients had an average of 10 years of disease duration, still typically with low disability and one relapse every 2.5 years. The mean age for disease onset was 13.7 years. Conclusion The present study introduces a large series of Brazilian cases of pediatric MS. Although some patients presented a very severe form of MS, on the whole the group of patients with MS starting in childhood or adolescence presented a relatively mild form of this disease in Brazil. .

Esclerose múltipla (EM) com início na infância e adolescência constitui um desafio para o diagnóstico e manejo da doença. A proposta do presente estudo foi avaliar as características da EM de início precoce em pacientes brasileiros. Métodos Coleta de dados retrospectiva de arquivos de unidades especializadas em atendimento da EM. Resultados A partir de 20 unidades de EM de nove estados brasileiros, foram coletados 117 casos de EM com início antes dos 18 anos de idade. Estes pacientes tinham uma média de 10 anos de duração da doença, de maneira geral apresentavam pouca incapacidade , com um surto a cada dois anos e meio. A média de idade no início da doença era 13,7 anos. Conclusão O presente estudo apresenta uma grande série de casos brasileiros de EM pediátrica. Embora alguns pacientes tenham apresentado forma grave de EM, de maneira geral o grupo de pacientes cuja EM iniciou-se na infância ou adolescência apresentou uma forma relativamente leve da doença no Brasil. .

Nearly one-half of Brazilian patients with multiple sclerosis using natalizumab are DNA-JC virus positive / Cerca de metade dos pacientes brasileiros recebendo natalizumabe para tratamento de esclerose multipla tem DNA-JC virus positivo

Objective Natalizumab is a new and efficient treatment for multiple sclerosis (MS). The risk of developing progressive multifocal leukoencephalopathy (PML) during the use of this drug has created the need for better comprehension of JC virus (JCV) infection. The objective of the present study was to assess the prevalence of JCV-DNA in Brazilian patients using natalizumab. Method Qualitative detection of the JCV in the serum was performed with real-time polymerase chain reaction (PCR). Results In a group of 168 patients with MS who were undergoing treatment with natalizumab, JCV-DNA was detectable in 86 (51.2%) patients. Discussion Data on JCV-DNA in Brazil add to the worldwide assessment of the prevalence of the JCV in MS patients requiring treatment with natalizumab. .

Objetivo Natalizumabe é um tratamento novo e eficaz para esclerose múltipla (EM). O risco constatado de desenvolver leucoencefalopatia multifocal progressiva (LEMP) durante o uso desta droga criou a necessidade de melhor estudar a infecção pelo vírus JC (JCV). O objetivo do presente estudo foi avaliar a prevalência de DNA-JCV em paciente brasileiros usando natalizumabe. Método Detecção qualitativa de JCV no soro foi realizada através de reação em cadeia por polimerase (PCR) em tempo real. Resultados DNA-JCV foi detectado em 86 pacientes (51,2%) de um grupo de 168 pessoas com EM recebendo tratamento com natalizumabe,). Discussão Dados do DNA-JCV no Brasil complementam as avaliações mundiais sobre a prevalência de JCV em pacientes com EM que necessitam tratamento natalizumabe. .

Multiple sclerosis in South America: month of birth in different latitudes does not seem to interfere with the prevalence or progression of the disease / Esclerose multipla na America do Sul: mes de nascimento em diferentes latitudes nao parece interferir com a prevalencia ou progressao da doenca

Objective To assess whether the month of birth in different latitudes of South America might influence the presence or severity of multiple sclerosis (MS) later in life. Methods Neurologists in four South American countries working at MS units collected data on their patients' month of birth, gender, age, and disease progression. Results Analysis of data from 1207 MS patients and 1207 control subjects did not show any significant variation in the month of birth regarding the prevalence of MS in four latitude bands (0–10; 11–20; 21–30; and 31–40 degrees). There was no relationship between the month of birth and the severity of disease in each latitude band. Conclusion The results from this study show that MS patients born to mothers who were pregnant at different Southern latitudes do not follow the seasonal pattern observed at high Northern latitudes. .

Objetivo Avaliar se o mês de nascimento em diferentes latitudes da América do Sul pode influenciar a presença ou gravidade da esclerose múltipla (EM) na vida. Método Neurologistas de quatro países da América do Sul trabalhando em unidades de EM coletaram os dados de seus pacientes com referência ao mês de nascimento, gênero, idade e progressão da doença. Resultados A análise dos dados mostrou que, para 1207 pacientes com EM e 1207 controles, não havia diferença significativa no mês de nascimento com relação à prevalência de EM em quatro zonas de latitude (0–10; 11–20; 21–30; e 31–40 graus). Não houve relação entre o mês de nascimento e a gravidade da doença em nenhuma destas zonas. Conclusão Os resultados deste estudo mostram que pacientes com EM nascidos de mães grávidas em diferentes latitudes sul não seguem o padrão dos resultados sazonais encontrados nas latitudes norte. .

Clinical relevance of "bulging eyes" for the differential diagnosis of spinocerebellar ataxias.

OBJECTIVE: To investigate the relevance of the clinical finding of bulging eyes (BE) in a large Brazilian cohort of spinocerebellar ataxias (SCA), to assess its importance in clinical differential diagnosis among SCA. METHODS: Three hundred sixty-nine patients from 168 Brazilian families with SCA were assessed with neurological examination and molecular genetic testing. BE was characterized by the presence of eyelid retraction. Genetically ascertained SCA3 was detected in 167 patients, SCA10 in 68 patients, SCA2 in 20, SCA1 in 9, SCA7 in 6, and SCA6 in 3 patients. RESULTS: BE was detected in 123 patients with SCA (33.3%), namely 109 of the 167 SCA3 patients (65.3%) and in 5 of the others SCA patients (1 SCA10 patient, 2 SCA1 patients and 2 SCA2 patients). CONCLUSION: BE was detected in the majority of patients with SCA3 (65.3%) and could be used with a clinical tool for the differential diagnosis of SCA.

Clinical relevance of "bulging eyes" for the differential diagnosis of spinocerebellar ataxias / Relevância clínica do "bulging eyes" para o diagnóstico diferencial das ataxias espinocerebelares

Objective To investigate the relevance of the clinical finding of bulging eyes (BE) in a large Brazilian cohort of spinocerebellar ataxias (SCA), to assess its importance in clinical differential diagnosis among SCA. Methods Three hundred sixty-nine patients from 168 Brazilian families with SCA were assessed with neurological examination and molecular genetic testing. BE was characterized by the presence of eyelid retraction. Genetically ascertained SCA3 was detected in 167 patients, SCA10 in 68 patients, SCA2 in 20, SCA1 in 9, SCA7 in 6, and SCA6 in 3 patients. Results BE was detected in 123 patients with SCA (33.3%), namely 109 of the 167 SCA3 patients (65.3%) and in 5 of the others SCA patients (1 SCA10 patient, 2 SCA1 patients and 2 SCA2 patients). Conclusion BE was detected in the majority of patients with SCA3 (65.3%) and could be used with a clinical tool for the differential diagnosis of SCA. .

Objetivo Investigar a relevância do achado clínico de bulging eyes (BE) em uma grande amostra brasileira de pacientes com ataxias espinocerebelares (AEC), para avaliar sua importância no diagnóstico diferencial entre as AEC. Métodos Foram avaliados 369 pacientes de 168 famílias brasileiras com AEC através de exame neurológico e testes de genética molecular. BE foi caracterizado pela presença de retração palpebral. AEC3 foi determinada geneticamente em 167 pacientes, AEC10 em 68 pacientes, AEC2 em 20, AEC1 em 9, AEC7 em 6 e AEC6 foi encontrada em 3 pacientes. Resultados BE foi detectado em 123 pacientes com AEC (33,3%), correspondendo a 109 dos 167 pacientes com AEC3 (65,3%) e 5 pacientes com outras AEC (1 paciente com AEC10, 2 AEC1 e 2 pacientes com AEC2). Conclusão BE foi detectado na maioria dos pacientes com AEC3 (65,3%) e poderia ser usado com uma ferramenta clínica para o diagnóstico diferencial das AEC. .

Persistence on therapy and propensity matched outcome comparison of two subcutaneous interferon beta 1a dosages for multiple sclerosis.

OBJECTIVES: To compare treatment persistence between two dosages of interferon ß-1a in a large observational multiple sclerosis registry and assess disease outcomes of first line MS treatment at these dosages using propensity scoring to adjust for baseline imbalance in disease characteristics. METHODS: Treatment discontinuations were evaluated in all patients within the MSBase registry who commenced interferon ß-1a SC thrice weekly (n = 4678). Furthermore, we assessed 2-year clinical outcomes in 1220 patients treated with interferon ß-1a in either dosage (22 µg or 44 µg) as their first disease modifying agent, matched on propensity score calculated from pre-treatment demographic and clinical variables. A subgroup analysis was performed on 456 matched patients who also had baseline MRI variables recorded. RESULTS: Overall, 4054 treatment discontinuations were recorded in 3059 patients. The patients receiving the lower interferon dosage were more likely to discontinue treatment than those with the higher dosage (25% vs. 20% annual probability of discontinuation, respectively). This was seen in discontinuations with reasons recorded as "lack of efficacy" (3.3% vs. 1.7%), "scheduled stop" (2.2% vs. 1.3%) or without the reason recorded (16.7% vs. 13.3% annual discontinuation rate, 22 µg vs. 44 µg dosage, respectively). Propensity score was determined by treating centre and disability (score without MRI parameters) or centre, sex and number of contrast-enhancing lesions (score including MRI parameters). No differences in clinical outcomes at two years (relapse rate, time relapse-free and disability) were observed between the matched patients treated with either of the interferon dosages. CONCLUSIONS: Treatment discontinuations were more common in interferon ß-1a 22 µg SC thrice weekly. However, 2-year clinical outcomes did not differ between patients receiving the different dosages, thus replicating in a registry dataset derived from "real-world" database the results of the pivotal randomised trial. Propensity score matching effectively minimised baseline covariate imbalance between two directly compared sub-populations from a large observational registry.