J.I. Rojas

The epidemiology of multiple sclerosis in Latin America and the Caribbean: a systematic review

The incidence and prevalence of multiple sclerosis (MS) varies geographically as shown through extensive epidemiological studies performed mainly in developed countries. Nonetheless, scant data is available in Latin America and the Caribbean (LAC). The objective of this review is to assess epidemiological data of MS in LAC. We conducted a systematic review of published articles and gray literature from January 1995 to May 2011. Twenty-two studies met the inclusion criteria after full-text review. Incidence data were found in only three studies and ranged from 0.3 to 1.9 annual cases per 100,000 person-years. Prevalence was reported in 10 studies and ranged from 0.83 to 21.5 cases per 100,000 inhabitants. The most prevalent subtype of MS was the relapsing–remitting form (48% to 91% of the series). No data about mortality were found. This study showed low frequency for MS in LAC compared with North American and European countries. The role of environmental and genetic factors should be well studied, providing new insights about its etiology.

Application of the McDonald 2010 criteria for the diagnosis of multiple sclerosis in an Argentinean cohort of patients with clinically isolated syndromes.

Background: The International Panel on Diagnosis of Multiple Sclerosis has proposed new magnetic resonance imaging (MRI) criteria for the diagnosis of multiple sclerosis (MS) in patients with clinically isolated syndrome (CIS). We aimed to evaluate these new criteria in a cohort of patients from Buenos Aires, Argentina. Methods: Patients with CIS, in whom MRI was performed within three months of onset of symptoms, were included between January 2005–June 2010. Poser or McDonald 2005 criteria were used as gold standard diagnostic criteria for MS. MRI was assessed by a blind evaluator identifying recently diagnostic MS criteria. New criteria sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were determined. Results: Altogether 101 patients were included. Of these, 86 patients converted to MS (McDonald 2005/Poser) during the follow-up. The mean follow-up time was 7.3±3.2 years (range 1.8–11 years). Sensitivity was 84%, specificity 80%, PPV 96%, NPV 46% and accuracy 82%. The sub-analysis applied only to non-European descendants (mestizos, natives and zambos) showed a high level of accuracy for these new diagnostic criteria in this local ethnic/genetic population (sensitivity 77%, specificity 72%, PPV 94%, NPV 38%). Conclusions: This study assessing McDonald 2010 criteria in a Latin-American population may contribute to its international validation.

Oligoclonal bands in multiple sclerosis patients: worse prognosis?

Abstract Introduction: Cerebrospinal fluid (CSF) oligoclonal bands (OB) imply intrathecal immunoglobulin synthesis and B-cell immune process. There is scarce evidence of OB having a role in disease prognosis. The objective of the present study was to determine OB’s prognostic value regarding disease progression. Methods: Between January 1994 and January 2007, relapsing–remitting MS (RRMS) patients in which OB were determined were included. Demographic, clinical aspects and presence of OB were analyzed. We compared OB+ versus OB− patients regarding progression to expanded disability status scale (EDSS) of 6·0 and to secondary progressive MS (SPMS). Cox proportional hazard models were used to compare the outcome between groups. P values <0·05 were considered significant. Results: One hundred and ninety-six patients were included. In 176 patients (90%), the CSF showed type II OB, 20 (10%) patients were OB negative. There were no differences between age, clinical presentation and EDSS at onset or in the immunomodulatory treatment received between OB+ and OB− patients. Sixty-two (31·6%) patients converted to SPMS during the follow-up, 59 (33·5%) were OB+ and 3 (15%) were OB−. EDSS of 6 was recorded in 56 (28·5%) patients during the follow-up; 54 (31%) were OB+ while only 2 (10%) OB- patients reached this outcome (reach SP phase, P = 0·032; HR: 2·2; 95% CI: 1·3–7·5 and EDSS of 6, P = 0·037; HR: 1·9; 95% CI: 1·3–8·5). Conclusion: We observed during the follow-up that OB− patients had a better prognosis and milder disability compared to OB+ patients.

Brain atrophy in clinically isolated syndrome

INTRODUCTION Previous reports have shown that brain atrophy appears early in the course of multiple sclerosis (MS). The aim of the present study was to evaluate whether brain atrophy already exists in clinically isolated syndrome (CIS) by comparing with a control sample. METHODS Patients with CIS were included prospectively from June 2008 to June 2009. A control group of healthy persons, matched by age and gender with CIS, was also included during the same period of time. An automated analysis tool, SIENAX, was used to obtain total brain volume (TBV), gray matter volume (GMV) and white matter volume (WMV). Mann-Whitney U test was used to analyze the data. RESULTS Twenty CIS patients and 30 healthy controls were included (8 vs. 17 females, p=0.11). Mean age for CIS was 35 ± 6 years vs. 34.4±5 in controls (p=0.61). Mean EDSS in CIS was 1.1 ± 0.5. Eighteen patients with CIS (90%) had abnormal baseline MRI. The TBV in CIS was 1.6.l ± 0.22.l × 106 vs.1.65 ± 0.15 × 106 in controls (p=0.005), the GMV in CIS was 0.58 ± 0.05 × 106 vs. 0.67 ± 0.03 × 106 in controls (p ≤ 0.001) and the WMV in CIS was 1 ± 0.1 × 106 vs. 1.12 ± 0.02 × 106 in controls (p=0.03). CONCLUSIONS This is the first study dealing with brain atrophy in a CIS sample from Latin America in which brain atrophy, mainly grey matter atrophy, was shown in early stages of the disease compared with healthy individuals.

Brain structural changes in patients in the early stages of multiple sclerosis with depression

Abstract Some studies suggest an inflammatory mechanism associated with the presence of depression in multiple sclerosis (MS); however, there is little data concerning these findings. The purpose of this study was to investigate the presence of brain structural changes in patients with MS and depression and to compare them with patients suffering from MS without depression and healthy controls. Methods: A case-control study that included patients with relapsing-remitting MS (RRMS) defined by validated criteria, over 18 years of age, with less than three years from disease onset, EDSS ≤ 3, with no history of previous depression and under immunomodulatory treatment with interferon beta, if any. A control group paired by age and gender was also included. Patients were clinically assessed to determine the presence of depression. Demographic clinical and structural aspects of parameters from the scan, such as lesion volume, total brain volume (TBV), white matter volume (WMV), neocortical gray matter volume (NGMV), and fractional anisotropy (FA) were analyzed. Results: Sixty-five individuals were enrolled: 20 healthy controls, 22 patients with MS without depression, and 23 patients with MS with depression. Patients with MS and depression showed a lower TBV (P = 0.01), NGMV (0.01) together with an increase in lesion burden in T2 (P < 0.01) but not in T1 (P = 0.09) and no differences in global FA among groups (P = 0.23) and in WMV (P = 0.12). Conclusion: Patients with RRMS and depression had a reduced total brain volume and a significantly increased lesion burden at T2 MR than patients with RRMS without depression.

Diferencias en la tasa de atrofia global y regional y del volumen lesional entre género en esclerosis múltiple

INTRODUCTION Previous studies showed gender-associated clinical and MRI differences in multiple sclerosis (MS) evolution. However, only few studies were done with non conventional MRI techniques and no one was done in a South American MS population. The aim of this study was to investigate gender differences according to nonconventional MRI measures in patients with MS from Buenos Aires, Argentina. METHODS Relapsing-remitting MS patients (RRMS) with at least 6 years of follow up and an MRI at onset and at 6 years were included. Patients were assessed using nonconventional MRI measures: total brain volume (TBV), neocortical grey brain volume (GBV), white brain volume (WBV), lesion load (LL), % of brain volume change between onset and year 6 (% BVC) and regional brain volume change. Gender-related MRI differences were investigated using general linear model analysis. RESULTS The 45 patients were included (25 female). Mean follow up time was 7.3 ± 0.2 years. No differences in age, EDSS at onset, DMD treatment, TBV, GBV, WBV neither LL were found between gender at baseline. Six years later, males showed a decrease in TBV (P=.002) and GBV (P ≤ 0.001) and an increase in LL (P=.02) and % BVC (P<.001) vs. females. Female patients showed a decrease in the volume of frontal subcortical region. DISCUSSION This is the first study showing differences in brain volume changes between gender in MS patients from South America. Future studies will confirm our initial findings.