Impact of methodological choices in comparative effectiveness studies: application in natalizumab versus fingolimod comparison among patients with multiple sclerosis

Background

Natalizumab and fingolimod are used as high-efficacy treatments in relapsing–remitting multiple sclerosis. Several observational studies comparing these two drugs have shown variable results, using different methods to control treatment indication bias and manage censoring. The objective of this empirical study was to elucidate the impact of methods of causal inference on the results of comparative effectiveness studies.

Methods

Data from three observational multiple sclerosis registries (MSBase, the Danish MS Registry and French OFSEP registry) were combined. Four clinical outcomes were studied. Propensity scores were used to match or weigh the compared groups, allowing for estimating average treatment effect for treated or average treatment effect for the entire population. Analyses were conducted both in intention-to-treat and per-protocol frameworks. The impact of the positivity assumption was also assessed.

Results

Overall, 5,148 relapsing–remitting multiple sclerosis patients were included. In this well-powered sample, the 95% confidence intervals of the estimates overlapped widely. Propensity scores weighting and propensity scores matching procedures led to consistent results. Some differences were observed between average treatment effect for the entire population and average treatment effect for treated estimates. Intention-to-treat analyses were more conservative than per-protocol analyses. The most pronounced irregularities in outcomes and propensity scores were introduced by violation of the positivity assumption.

Conclusions

This applied study elucidates the influence of methodological decisions on the results of comparative effectiveness studies of treatments for multiple sclerosis. According to our results, there are no material differences between conclusions obtained with propensity scores matching or propensity scores weighting given that a study is sufficiently powered, models are correctly specified and positivity assumption is fulfilled.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01623-8.

Do modern therapies change natural history of Neuromyelitis optica?

Neuromyelitis optica spectrum disorder (NMOSD) is an uncommon antibody-mediated disease of the central nervous system. Approximately 75% of patients have antibodies against aquaporin-4, a water channel expressed on astrocytes. Untreated, approximately 50% of NMOSD patients will be wheelchair users and blind, and a third will have died within 5 years of their first attack. Unlike multiple sclerosis, a progressive clinical course is very unusual and the accrual of disability is related to relapses. Aggressive treatment of attacks and highly efficient maintenance therapies to prevent attacks are therefore crucial to prevent residual disability. In this article, we review how high dose steroids and most importantly apheresis and modern therapies implicating B cell depletion, inhibition of complement and IL-6 reception are effective to change its natural history. We will emphasize the results of three recent double blind randomized controlled studies using monoclonal antibodies allowing strong hope to modify natural history of NMOSD.

Visual Phenotype of Multiple Sclerosis in the Afro-Caribbean Population and the Influence of Migration to Metropolitan France

PURPOSE

To describe the visual phenotype of multiple sclerosis (MS) in the Afro-Caribbean population living in Martinique (French West Indies) and to specify the influence of the migration to metropolitan France on ocular impairment.

DESIGN

Prospective consecutive observational case series.

METHODS

A complete ophthalmologic examination was performed.

PARTICIPANTS

A total of 112 patients of Afro-Caribbean origin with MS satisfying McDonald's diagnostic criteria, divided into 53 cases (47.3%), the non-migrant patients (group NM), who had never left the Caribbean basin, and 59 cases (52.7%), the migrant patients (group M), who had lived in metropolitan France for at least 1 year before age 15.

RESULTS

MS first manifested as an impairment of the optic nerve in 41 cases (36.6%): 25 cases (47.1%) in group NM and 16 cases (27.1%) in group M. Visual function was recovered in 13/25 cases (52%) in group NM compared to 13/16 cases (81%) in group M. Two-thirds of patients presented with a clinical ocular impairment, which was bilateral in 58.5% of cases in group NM. Fourteen cases (12.5%) met the criteria of neuromyelitis optica, nine cases (17%) in group NM and five cases (8.5%) in group M. In group NM, when the initial visual attack did not regress, the visual Expanded Disability Status Scale (EDSS) score was 5+/-1.5 ; 75% of patients had monocular blindness and 50% binocular.

CONCLUSIONS

In the non-migrants (group NM), MS manifested more frequently with an optical neuropathy, the ocular impairment was more severe, and corresponded to neuromyelitis optica in 17% of the cases; a visual presentation and the absence of complete recovery from the first attack represented a factor of poor prognosis. This series is the largest description of the visual phenotype of MS in patients of African origin. The results confirm the preferential impairment of the optic nerve in the black population in the course of the disease. The migration towards an area of high prevalence of MS influences the visual phenotype in terms of a lower incidence and less severe prognosis of ocular impairment.

Brainstem manifestations in neuromyelitis optica: a multicenter study of 258 patients

BACKGROUND

Neuromyelitis optica (NMO) is a severe autoimmune disease of the central nervous system characterized by spinal cord and optic nerve involvement. Brainstem manifestations have recently been described.

OBJECTIVE

To evaluate the time of occurrence, the frequency and the characteristics of brainstem symptoms in a cohort of patients with NMO according to the ethnic background and the serologic status for anti-aquaporin-4 antibodies (AQP4-abs).

METHODS

We performed a multicenter study of 258 patients with NMO according to the 2006 Wingerchuk criteria and we evaluated prospectively the frequency, the date of onset and the duration of various brainstem signs in this population.

RESULTS

Brainstem signs were observed in 81 patients (31.4%). The most frequently observed signs were vomiting (33.1%), hiccups (22.3%), oculomotor dysfunction (19.8%), pruritus (12.4%), followed by hearing loss (2.5%), facial palsy (2.5%), vertigo or vestibular ataxia (1.7%), trigeminal neuralgia (2.5%) and other cranial nerve signs (3.3%). They were inaugural in 44 patients (54.3%). The prevalence was higher in the non-Caucasian population (36.6%) than in the Caucasian population (26%) (p<0.05) and was higher in AQP4-ab-seropositive patients (32.7%) than in seronegative patients (26%) (not significant).

CONCLUSIONS

This study confirms the high frequency of brainstem symptoms in NMO with a majority of vomiting and hiccups. The prevalence of these manifestations was higher in the non Caucasian population.

Different HLA class II (DRB1 and DQB1) alleles determine either susceptibility or resistance to NMO and multiple sclerosis among the French Afro-Caribbean population

BACKGROUND

Despite similarities, neuromyelitis optica (NMO) can be distinguished from multiple sclerosis (MS) by clinical, radiological and serological findings.

OBJECTIVE

This case-control study aimed to determine whether patients with NMO or with MS in an Afro-Caribbean population originating from French West Indies shared the same or different HLA class I and II pattern distribution.

METHODS

The association with HLA class II (DRB1 and DQB1) alleles was tested in 42 NMO patients, 163 MS patients and 150 healthy controls. HLA-DRB1 and DQB1 typing was undertaken on genomic DNA extracted from peripheral blood leucocytes.

RESULTS

By comparison with healthy controls, significantly increased frequency of HLA-DRB1 03 (26.2% vs. 13%, odds ratio 2.4, 95% confidence interval 1.31-4.28, p after correction, cp 0.045) was observed in patients with NMO. By contrast, in MS patients, HLA-DRB1 15 (24.8% vs. 13%, odds ratio 2.21, 95% CI 1.45-3.36, cp < 0.0015), but not DRB1 03 allele, was positively associated with the disease. Moreover, a modest protective effect of HLA-DRB1 11 in the MS group, independently of DRB1 15 association, was found (13.7% vs. 7% in controls, odds ratio 0.48, p 0.006), but did not survive Bonferroni correction.

CONCLUSION

In conclusion, comparison of the HLA-DRB1 and DQB1 distribution in NMO and MS in this Afro-Caribbean population shows important differences in the HLA associations among NMO and MS.

Multiple sclerosis and solar exposure before the age of 15 years: case-control study in Cuba, Martinique and Sicily

Few studies report a protective role of childhood solar exposure to multiple sclerosis. Our objective was to confirm the protective role of childhood solar exposure in multiple sclerosis in Cuba, Martinique and Sicily. This was a matched case- control study, and cases met Poser criteria for clinically, laboratory (definite, probable) multiple sclerosis. Controls were resident population, without neurological disorder, living close to cases (within 100 km), matched for sex, age (+/-5 years), residence before age 15. We recruited 551 subjects during a 1-year period (193 cases, Cuba n = 95, Sicily n = 50, Martinique n = 48; 358 controls). Some (89%) met definite clinical multiple sclerosis criteria (relapsing remitting form (with and without sequel) (74%), secondary progressive (21%), primary progressive (5%)). Odds ratios in a uni-variate analysis were: family history of multiple sclerosis (5.1) and autoimmune disorder (4.0); wearing shirt (3.5), hat (2.7), pants (2.4); sun exposure causing sunburn (1.8); sun exposure duration (1 h more/day; weekends 0.91, weekdays 0.86); bare-chested (0.6); water sports (0.2). Independent factors in the multivariate analysis were family history of multiple sclerosis (4.8 (1.50-15.10)), wearing pants under sunlight (1.9 (1.10-3.20)), sun exposure duration (1 h more/ day, weekdays 0.90 (0.85-0.98), weekends 0.93 (0.87-0.99)), water sports (0.23 (0.13-0.40)). We conclude that outdoor leisure activities in addition to sun exposure reports are associated with a reduced multiple sclerosis risk, with evidence of dose response.

Relapsing neuromyelitis optica: long term history and clinical predictors of death

BACKGROUND

Relapsing neuromyelitis optica (RNMO) is an uncommon but devastating inflammatory disorder of the central nervous system. Long term history in a wide series of RNMO is required for better knowledge of the course of the disease and identification of patients at high risk of death.

METHODS

Clinical features of patients with RNMO (88 women/eight men) obtained from the geographic Caribbean database (Cuba and French West Indies) were used to determine the progression of disability and to identify clinical predictors of death.

RESULTS

Median age at onset of RNMO was 29.5 years (range 11-74). Median duration of disease was 9.5 years (1-40). Median relapse rate was 0.7 attack/patient/year (0.1-3). 66 patients experienced severe visual loss in at least one eye and 46 in both eyes. Median time from onset to unilateral and bilateral severe visual loss was 3 and 15 years, respectively. Median times to reach Kurtzke Disability Status Scale 3, 6 and 8 from onset of RNMO were 1, 8 and 22 years. There were 24 deaths (25%); within 5 years in 63% of cases. A higher attack frequency during the first year of disease (p = 0.009), blindness (p = 0.04) and sphincter signs at onset (p = 0.02) and lack of recovery of first attack (p = 0.003) were independently associated with a shorter time to death.

CONCLUSION

RNMO is a very rapidly disabling disease affecting primarily young women. This study has identified clinical features that predict a poor outcome. These findings suggest that early and aggressive immunotherapy might be warranted in RNMO.

Neuromyelitis optica positive antibodies confer a worse course in relapsing-neuromyelitis optica in Cuba and French West Indies

Background

In Caucasian populations Neuromyelitis Optica (NMO-IgG) antibody has been detected in 27.1% / 78.2% of patients with relapsing-NMO (R-NMO). The prevalence reported for the disease in the Caribbean is 3.1/100,000 in the French West Indies (FWI) and 0.52 /100,000 in Cuba, but the NMO antibody status is unknown.

Objective

To assess the NMO-IgG antibody status of Cuban/FWI RNMO patients, comparing with European cases tested at the same laboratories.

Methods

Serum NMO-IgG antibodies were assayed in 48 R-NMO patients (Wingerchuck´s 1999 criteria): Cuba (24)/FWI (24), employing Lennon et al´s method. We compared the demographic, clinical, disability and laboratory data between NMO-IgG +/- patients. All the data were reviewed and collected blinded to the NMO-IgG status.

Results

Seropositivity of the NMO-IgG antibody demonstrated a lower rate in the Caribbean (33.3%), as compared with Caucasian patients from Spain/Italy (62.5%) and France (53.8%). Caribbean patients with NMO-IgG (+) displayed more attacks, more spinal attacks and a higher EDSS than NMO-IgG (-) cases, while brain and spinal cord MRI lesions were more frequent during remission, with more vertebral segments, more gray, white matter and holocord involvement.

Conclusions

NMO IgG positive antibodies in NMO patients had a lower rate in the Caribbean area – where the population has a predominant African ancestry – than in Caucasian Europeans, suggesting the influence of a possible ethnic factor in the pathogenesis of the disease, but they confer a worse course with more attacks, more disability and MRI lesions.

Plasma exchange in severe spinal attacks associated with neuromyelitis optica spectrum disorder

Background

Plasma exchange (PE) is increasingly undertaken in diseases involving humoral factors and is proven to be beneficial in acute demyelinating diseases. Spinal attacks in relapsing neuromyelitis optica (NMO) and in extensive transverse myelitis (ETM) – a truncated form of NMO with spinal involvement – are usually devastating.

Objective

We retrospectively studied the outcome of PE-treated versus steroid-only treated spinal attacks in relapsing NMO and ETM.

Methods

We included 96 severe spinal attacks in 43 Afro-Caribbean patients. PE was given as an add-on therapy in 29 attacks. Expanded disability status score (EDSS) was obtained before attack, during the acute and residual stage. We defined the ΔEDSS as the rise from basal to residual EDSS.

Results

The ΔEDSS was found to be lower in the PE-treated group (1.2 ± 1.6 vs 2.6 ± 2.3; P < 0.01). A low basal impairment is associated with a better outcome. Improvement was obtained in both NMO-IgG negative and positive NMO attacks. Minor adverse events manifested in seven PE sessions (24%).

Conclusion

PE appears to be a safe add-on therapy that may be employed early in severe spinal attacks in the NMO spectrum disorders in order to maximize improvement rate. PE efficiency is independent of NMO-IgG positivity.

MRI of the spinal cord in neuromyelitis optica and recurrent longitudinal extensive myelitis

BACKGROUND AND PURPOSE

Neuromyelitis optica (NMO) is a severe inflammatory and necrotizing disease that clinically affects the optic nerves and spinal cord in a relapsing course. We assessed the baseline and follow-up MRI characteristics of cord attacks in NMO and recurrent longitudinal extensive myelitis (RLEM).

METHODS

We retrospectively reviewed MRI data of 20 Afro-Caribbean patients diagnosed with either NMO or RLEM. MRI data from 51 cord or mixed attacks were evaluated, and 65 follow-up MRI studies were available for 30 baseline acute examinations.

RESULTS

The cervical cord was involved in 63% of cases. Four attacks were limited to the brainstem. MRI of the spinal cord revealed longitudinal extensive signal abnormalities extending over three vertebral segments, associated with cord swelling in 67% of the 51 relapses. Gadolinium enhancement was observed, preferentially surrounding edema, in 69% of attacks. In the axial plane, signal abnormalities typically involved central areas of the cord. Cavitation was observed in 16% of attacks. Cord attacks recurred in the same or contiguous areas in 67% of cases. Follow-up MRI revealed a gradual decrease in cord swelling and T2 signal hyperintensity, with fragmentation of signal abnormalities in some cases. Cord atrophy was evident in 57% of the follow-up MRI.

CONCLUSION

Given the poor prognosis of NMO and RLEM, radiologists need to be aware of the MRI pattern to prevent further attacks with the use of aggressive treatment.

[Star fruit (Averrhoa carambola) toxic encephalopathy]

Ingestion of star fruit (Averrhoa carambola) can induce severe intoxication in subjects with chronic renal failure. Oxalate plays a key role in the neurotoxicity of star fruit. We report the cases of two patients with unknown chronic renal insufficiency who developed severe encephalopathy after ingestion of star fruit. The two patients developed intractable hiccups, vomiting, impaired consciousness and status epilepticus. Diffusion-weighted MR imaging showed cortical and thalamic hyperintense lesions related to epileptic status. They improved after being submitted to continuous hemofiltration which constitutes the most effective treatment during the acute phase.

[Steroid treatment in four cases of anti-GAD cerebellar ataxia]

INTRODUCTION

Few neurological diseases are linked with anti-glutamic acid decarboxylase antibodies (GAD-ab); stiff man syndrome is an example. Cerebellar ataxia is a new feature of this expanding spectrum. No therapeutic trial is yet available in these diseases. We here report on four patients suffering from cerebellar ataxia linked with GAD-ab and review the data in the literature on this recently described syndrome.

METHOD

We conducted an open trial with monthly pulsed steroids. Steroid pulses were given six months followed with placebo for another six months. Main clinical and biological parameters were monitored monthly (International Cooperative Cerebellar Ataxia Rating Scale [ICARS] and GAD-ab).

RESULT

The clinical response was found limited and inconstant. Transient decline in GAD-ab level was noted in two patients. Moreover, GAD-ab level was found highly variable and did not correlate with clinical parameters.

DISCUSSION

Cerebellar ataxia with GAD-ab is an increasingly described syndrome. Outcome can be severe, leading to definitive cerebellar atrophy. Diagnosis is supported by high level of serum GAD-ab with intrathecal secretion. Experimental data have suggested a direct excitotoxic effect of GAD-ab on Purkinje cells. Response to various treatments is often disappointing. Improvement has been obtained with veinoglobulins in individual patients. A weak clinical and biological response was associated with monthly steroid pulses.

La leptospirose: une cause inhabituelle d'uvéite antérieure

INTRODUCTION

Leptospirosis is an anthropozoonosis, which affect 100000 people by year worldwide.

CASE REPORT

Leptospirosis and IgA deficiency were revealed in a young man by acute anterior uveitis, after canyoning practice in the French West Indies.

DISCUSSION

Uveitis should be added to the ocular phenotype of leptospirosis.

Un nouveau cas d'ataxie cérébelleuse à anticorps anti-GAD traité par corticoïdes et initialement séronégatif

INTRODUCTION

Cerebellar ataxia with antiglutamic acid decarboxylase antibodies (GAD-ab) is an exceptional newly recognized autoimmune disorder. The cerebellar ataxia may occur in isolation or be associated with stiff man syndrome another rare GAD-Ab induced disorder of central nervous system.

EXEGESIS

A 38-year-old woman with a past history of Graves disease presented with insidious cerebellar symptoms including ataxic gait, dysmetria, dysarthria, and oscillopsia. A thorough survey of markers of paraneoplastic cerebellar ataxia and collagen diseases was negative. Her serum contained high level of GAD-ab (647.2 U/ml) and MRI evidenced pure cerebellar atrophy leading to diagnosis of autoimmune cerebellar ataxia. Under corticosteroids, cerebellar symptoms partially improved, but serum GAD-ab titre dramatically decreased.

CONCLUSION

Testing for GAD-ab may be indicated in patients with idiopathic cerebellar ataxia, particularly mature women with organ-specific autoimmune diseases. Corticosteroids must be started to prevent irreversible cerebellar atrophy.

La neuromyélite optique rémittente: données neuroradiologiques

INTRODUCTION

Neuromyelitis optica (NMO) is a rare inflammatory and demyelinating disorder of the central nervous system, restricted to optical nerves and spinal cord. The main neuroradiological aspects, now summarized into a complete set of diagnosis criteria, are a normal cerebral MRI at onset and longitudinal involvement of the spinal cord concerning more than 3 vertebral segments. The clinical course and frequency of typical lesions remain unknown.

OBJECTIVE

We here report neuroradiological data from patients suffering from NMO.

METHODS

Brain and spinal cord MRI were systematically reviewed for 32 afro-Caribbean patients.

RESULTS

A typical longitudinal spinal lesion was seen in 44.7 percent with or without edema; a lesion involving less than 3 vertebral segments in 26.3 percent and no lesion in 21.1 percent. Longitudinal study of a few bouts suggested a progressive normalisation of spinal cord appearance. Atrophy was negatively correlated with immunosuppressive treatment. Cerebral lesions usually absent at onset were correlated to the follow-up. In a non-recursive condition, patients completed diagnostic criteria for encephalic and spinal lesions in 82.8 percent and 48.1 percent.

CONCLUSION

Radiology of spinal bouts showed multiple aspects besides the typical form. The notion of multiple bouts must be added to the spinal criteria to achieve good sensitivity. A typical extensive spinal lesion is usual in the follow-up, but seen after less then half of the bouts. Requiring such a lesion would delay the diagnosis.

Role of return migration in the emergence of multiple sclerosis in the French West Indies

The emergence of multiple sclerosis in island societies has been investigated only in a few Caucasian populations living in temperate regions. The effect of human migration on the risk of developing this disease is still an open question because of possible genetic selection. We conducted an epidemiological study of the multiple sclerosis population in the French West Indies (Martinique and Guadeloupe), a population which includes large numbers of West Indians who have returned after emigrating to metropolitan France. Standardized incidence ratios (SIRs) for multiple sclerosis among migrants were calculated and their genetic characteristics were compared to those of non-migrants. The crude prevalence of multiple sclerosis was 14.8/10(5) on December 31, 1999 (95% CI: 11.9-17.7); and its crude mean annual incidence for the period July 1, 1999 to June 30, 2002 was 1.4/10(5) (95% CI: 1.0-1.8), confirming its emergence in the French West Indies. Recurrent neuromyelitis optica, which is virtually the only form of multiple sclerosis in black African populations in tropical regions, represented not >17.8% of these cases. During the 1,440,000 person-years of follow-up, 33 incidence cases were identified in migrants. Since the number of expected cases was 19.3, the overall SIR was 1.71 (95% CI: 1.19-2.38; P < 0.01) among migrants. The increase in the SIR was more marked if the stay was made before the age of 15 years (4.05, 95% CI: 2.17-6.83; P < 0.0001). European ancestry in the two migrating and non-migrating populations was similar. Martinique, which has a higher rate of return migration, has a higher prevalence of multiple sclerosis (21.0/10(5) versus 8.5/10(5)) and a higher incidence (2.0/10(5) versus 0.7/10(5)) than Guadeloupe. The emergence of the disease in the French West Indies is of environmental rather than genetic origin. It may be explained either through the introduction by migrants of precipitating environmental factors that operate in a critical way before the age of 15 years, and/or by the recent disappearance from the French West Indies of protective environmental factors acting before this age.

Accident vasculaire cérébral chez le jeune Afro-Caribéen en Martinique : étude prospective épidémiologique et étiologique

Few data are available regarding stroke among young black patients. We have conducted, in Martinique, a prospective study among young Afro-Caribbeans aged 15 to 45 Years, from June 1994 through May 1999. We identified 60 cerebral infarcts (CI) and 20 cases of intracerebral hemorrhage (ICH). Annual incidence and case fatality rate at 30 days were 7.6/100000/Year (95p.cent confidence interval, 3.13 to 11.35) and 8.3p.cent respectively for CI, and 2.42/100000/Year (95p.cent confidence interval, 0.06 to 4.7) and 25p.cent for ICH. Hypertension was the most prevalent stroke risk factor: 35p.cent in CI and 68p.cent in ICH. According to the TOAST criteria, a probable cause of ischemic stroke was identified in 61.3p.cent. Atherosclerosis, lacunar infarcts and cardioembolism were the main causes of CI (13.3p.cent for each etiology). Spontaneous cervical arterial dissection was found in only 6.7p.cent. Hypertensive ICH (60p.cent) was the most common subtype of ICH. In Martinique, high frequencies of ICH and lacunar infarcts are characteristic of stroke in young Afro-Carribeans. These suggest the role of the high prevalence of hypertension in the black population. We confirm the heterogeneity of stroke etiologies and the low prevalence of cervical arterial dissection in black people.

[Hypophysis metastasis of a hypernephroma tumor revealed by a chiasma syndrome]

In a 45-year-old man with a hypernephroma tumor of the right kidney, a metastasis in the pituitary gland of this neoplasm was diagnosed 9 years after removal of this kidney. He complained of bitemporal hemianopsia and slight impairment of vision. A hypernephroma metastasis in the pituitary gland is very rare and few have been reported to date. In general, these metastases occur in cases with multiple metastasis to many organs, which suggests that the appearance of pituitary metastasis represents extensive disease. Many of these patients present diabetes insipidus. Visual defects are frequently associated. The Goldmann perimeter is important to detect visual field anomalies. MRI is the key radiological exam to localize the tumor. Surgery is the preferred treatment and should be undertaken quickly if visual function is affected. The histological exam should be made to confirm the diagnosis.

Acute stroke in the very elderly: epidemiological features, stroke subtypes, management, and outcome in Martinique, French West Indies

BACKGROUND AND PURPOSE

Stroke incidence increases with increasing age and has an impact on daily living in many areas. With increasing life expectancy, old people will constitute the majority of stroke victims. We present the first stroke study focusing on very old patients in a black Caribbean population (Martinique, French West Indies).

METHODS

All Martinican patients suffering from their first-ever stroke during 1 calendar year between June 1, 1998, and May 31, 1999, were included. Epidemiological, clinical, neuroimaging, management, and outcome data during the first month were collected and compared between very old patients (>or=85 years) and patients aged <85 years.

RESULTS

One hundred patients aged >or=85 years and 480 patients aged <85 years were included (sex ratio, women/men, 2.84 and 0.85, respectively; mean+/-SD age, 88.8+/-3.6 and 65.8+/-13.3 years, respectively). The incidence of first-ever stroke was 1.64/1000 per year in the Martinique population and 18.2/1000 per year in patients aged >or=85 years. Elderly patients showed a significantly lower proportion of diabetes (19.1% versus 32.2%; P=0.012) and smoking (0% versus 8.4%; P=0.004) and a higher proportion of peripheral artery disease (23.4% versus 11.4%; P=0.002). Prevalence of hypertension was identical in the 2 groups (70%). There were no significant differences in stroke types or ischemic stroke subtypes between the 2 groups. Active medical care was poorer in older than in younger patients (hospitalization rate, 89% versus 94.4%; admission to neurological ward, 8% versus 23.8%; rate of performance of a CT scan, 82% versus 94%). The 30-day case fatality rate was approximately twice as high in elderly patients (31% versus 16.7%; P=0.0009), and disability (Rankin Scale score >or=3) in survivors was markedly higher (78% versus 48%; P<0.0001).

CONCLUSIONS

In Martinique, the incidence of first-ever stroke in very old black Caribbean patients seems similar to that in white patients. They have the same pathological type and subtype of stroke as do young patients. The poorer stroke outcome found in the elderly during the first month may be related in large part to less active management than in younger patients.

Genetic and functional studies in multiple sclerosis patients from Martinique attest for a specific and direct role of the HLA-DR locus in the syndrome

Among candidate genes involved in multiple sclerosis (MS) genetic susceptibility, MHC genes and particularly HLA-DRB1*1501-DQB1*0602 haplotype play a major role. Based on the strong linkage disequilibrium observed in Caucasians between DRB1*1501 and DQB1*0602 alleles, it is still impossible to draw a firm conclusion about the DRB1 or DQB1 locus involvement. In order to address this issue a strategy associating a genetic and a functional approach was conducted in a population of-non-Caucasian MS patients. We observed that in Martinicans (55 MS and 100 controls), the DRB1*15 and DRB1*07 alleles were positively associated with the disease. However in Martinicans the most common DRB1*15 subtype was *1503 and not *1501. Moreover, in Martinicans, the frequency of DQB1*0602, found in association with other DRB1 alleles than DRB1*15 (42% of DQB1*0602 haplotypes), was not increased in DRB1*15-negative MS patients, suggesting a neutral role of DQB1*0602 in MS genetics. In a second step, we demonstrated the capability of the DRB1*1503 allele associated with MS in Martinicans to present the immunodominant autoantigen MBP 85-99 peptide to a DRB1*1501 restricted MBP specific T cell line. Interestingly, structural features of DRB1*1501 or DRB1*1503 molecules are in good fit with the hypothesis that *1501 and *1503 molecules may act similarly in MS development by presenting the same immunodominant MBP peptide. On the whole, our results show a prominent role of the DRB1 locus (DRB1*1501 and/or DRB1*1503 alleles) in the immunodominant MBP 85-99 peptide presentation to genetically different MS patients and suggest a neutral role of the DQB1 encoded molecule in MS susceptibility.

ERMANCIA: Epidemiology of Stroke in Martinique, French West Indies: Part I: methodology, incidence, and 30-day case fatality rate

BACKGROUND AND PURPOSE

The ERMANCIA (Etude Réalisée en Martinique et Centrée sur l'Incidence de Accidents vasculaires cérébraux) study was designed to provide the first comparable epidemiological data on stroke in a black Caribbean population.

METHODS

ERMANCIA was a prospective community-based study performed in Martinique (French West Indies) from June 1, 1998, to May 31, 1999. The black at-risk population was approximately 360 000. Multiple sources were used to identify hospitalized and nonhospitalized patients with first-ever stroke.

RESULTS

Five hundred eighty patients (285 men and 295 women; mean+/-SD age, 71.2+/-14 years) suffered from a first-ever in a lifetime stroke, yielding a crude annual incidence of 164/100 000 per year (95% CI, 151 to 177). The rates adjusted by age and sex to the French population (1999 census) and to the European population were 202 (95% CI, 185 to 218) and 151 (95% CI, 139 to 164), respectively. Thirty-eight patients (6.5%) were not hospitalized during the acute phase of the stroke; 92.8% had CT scan. Pathological types of strokes were infarction (79.8%, including 23% of lacunar strokes), intracerebral hemorrhage (14.3%), subarachnoid hemorrhage (3.4%), and undetermined (2.4%). The main risk factors for stroke were hypertension (69.1%) and diabetes (29.5%). The 30-day case fatality rate was 19.3% (15.8% for cerebral infarction and 37.3% for intracerebral hemorrhage).

CONCLUSIONS

In Martinique, the ERMANCIA population-based study showed a high stroke incidence and a high prevalence of hypertension and diabetes in the stroke population compared with those observed in continental France. Epidemiological data on stroke in African Caribbeans from Martinique are comparable to those reported in blacks from the United States and United Kingdom.

[Optical involvement in multiple sclerosis. Results of a cross-sectional study with 57 patients from Martinique]

INTRODUCTION

The optical disease observed concurrent with multiple sclerosis is poorly known in blacks because of the rare occurrence of this pathology in the black population. The few studies currently available suggest more severe problems in black subjects than in Caucasians. Martinique has subjects who are genetically close or even identical but who acquired multiple sclerosis in two very different endemic areas: some in Martinique and others in France.

PATIENTS AND METHODS

We performed an ophthalmological transversal descriptive study in a population of 57 black multiple sclerosis patients living in Martinique, selected according to the Poser criteria. Patients were divided into two groups: an M group (26 cases) made up of patients who had never left Martinique or the West Indies and an FM group (31 patients) made up of patients who had lived at least one year in France between the ages of 5 and 15.

RESULTS

At least one episode of retrobulbar optic neuritis was observed in 16 cases (61.5%) in the M group and in 11 cases (31.5%) in the FM group. The number of eyes with either one episode or more of retrobulbar optic neuritis or papillitis was higher in the M group, 26 cases (50%) than in the FM group, 14 cases (22.6%). Multiple sclerosis began by a disease of the optic nerve in 12 cases (46%) in the M group and in 7 cases (22.6%) in the FM group. The mean visual acuity is 20/30 in the M group and 20/20 in the FM group. The mean value of the p 100 wave was 131 ms in the M group and 113 ms in the FM group.

DISCUSSION

Multiple sclerosis observed in the black population living in Martinique (M group) is characterized by frequent and severe visual problems. The visual phenotype of the FM group is quite similar to the visual phenotype of Caucasians. More than ethnic and genetic factors, the tropical area of acquisition should have an influence on the visual phenotype. For unknown reasons, the optical problems appear severe when multiple sclerosis is acquired in a low endemic area.

A description of human T-lymphotropic virus type I-related chronic interstitial keratitis in 20 patients

OBJECTIVE

This study aimed to describe a syndrome that the authors call human T-lymphotropic virus type I-related chronic interstitial keratitis.

METHODS

A consecutive series of 194 human T-lymphotropic virus type I-infected patients (divided into 119 patients with human T-lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis and 75 asymptomatic human T-lymphotropic virus type I carriers) was systematically examined.

RESULTS

Twenty patients (10.3%) had bilateral anterior stromal lesions made up of approximately 10 elevated, rounded or cloudy whitish opacities that were more or less confluent. The opacities were characteristically situated at the periphery of the anterior stroma, and the visual axis remained unaffected. The interstitial keratitis was chronic and unresponsive to topical administration of corticosteroids. It was mainly observed in patients affected by human T-lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis among whom there were 18 cases (15.1%), as opposed to two cases (2.7%) in asymptomatic carriers.

CONCLUSION

A new cause of interstitial keratitis is reported. Human T-lymphotropic virus type I infection may have a much broader spectrum of ocular manifestations than previously described. As with the other manifestations of human T-lymphotropic virus type I infection, corneal lesions could be linked to a lymphoplasmocytic infiltration of the stroma leading to corneal opacities.

Six cases of cervical ligamentum flavum calcification in Blacks in the French West Indies

OBJECTIVE

Calcification of the ligamentum flavum at the cervical spine is an uncommon condition reported mainly in Japanese patients. We describe the clinical manifestations, imaging study findings, and outcomes in six cases seen in the French West Indies.

MATERIAL AND METHODS

We retrospectively reviewed the medical charts of six patients admitted to an orthopedics department for spinal cord compression shown upon computed tomography to be caused by calcification of the ligamentu flavum. There were five women and one man, mean age at admission was 71.7 years (range, 64-79 years) and all six patients were Black.

RESULTS

Five patients had cervical myelopathy and one was asymptomatic. All five symptomatic patients had cervical spinal stenosis, explaining the rapid symptom onset (within six and a half months) and severe motor loss. Computed tomography reconstruction in the sagittal plane ruled out ossification of the ligamentum flavum. Magnetic resonance imaging of the neck failed to demonstrate the calcifications but was useful in evaluating the severity of the spinal cord compression. One patient had articular chondrocalcinosis in both knees and another had calcifications in the basal ganglia. Surgical decompression by the posterior route was performed in two patients and was effective in both, whereas two of the three symptomatic patients who did not have surgery experienced worsening neurological loss. Analysis of the operative specimens from the two surgically treated patients showed a mixture of calcium pyrophosphate dihydrate crystals and apatite microcrystals.

CONCLUSION

Calcification of the ligamentum flavum is probably underrecognized in blacks. This condition causes severe neurological loss. Imaging studies provide the diagnosis. The pathogenesis remains unclear.

MS and neuromyelitis optica in Martinique (French West Indies)

BACKGROUND AND OBJECTIVE

A population-based study is reported of MS in French Afro-Caribbeans (FAC) in Martinique. FAC are descendants of interracial mating that occurred between French Caucasians and black Africans in the 17th and the 18th centuries.

METHODS

The authors surveyed the entire island of Martinique (area 1,128 km(2), population 357,000) between November 1997 and October 1999.

RESULTS

Sixty-two patients (46 females, 16 males, ratio 2.9:1) were identified with definite or probable disease by the Poser criteria. Prevalence for all patients on December 31, 1998, was 17.4/10(5) (95% CI 13.1 to 21.7) and 14.3/10(5) (95% CI 10.4 to 18.2) for clinically definite cases (n = 51). Age range of patients on prevalence day was 17 to 73 years (mean +/- SD 39 +/- 11.3 years). Mean age at onset was 31.2 +/- 11 years. Overall, 9.7% had primary progressive disease and 19.4% had benign MS. A low proportion of definite and probable MS cases had oligoclonal bands in CSF (50.9%). Seventeen patients, 13 of whom were alive on prevalence day, had a relapsing form of neuromyelitis optica.

CONCLUSION

The island of Martinique appears to have a low to medium prevalence of MS. MS was almost unknown in FAC in Martinique until the late 1970s. The apparent recent increase may be explained by improved recognition of patients, increased availability of MRI for diagnosis, increased disease awareness among physicians, increased survival of MS patients, or an actual increase in disease frequency.