Epidemiology of NMOSD in Catalonia: Influence of the new 2015 criteria in incidence and prevalence estimates

BACKGROUND

Population-based studies on neuromyelitis optica spectrum disorders (NMOSD) are limited, and it is unclear whether the rates have changed with the implementation of the new 2015 criteria.

OBJECTIVES

To estimate the incidence and prevalence of NMOSD in Catalonia (Spain), using both the 2006 and the 2015 criteria.

METHODS

In this clinic-based retrospective study, patients diagnosed with NMOSD between 2006 and 2015 were identified using multiple sources, including direct contact to all Catalan hospitals, identification of cases through the Catalan Health Surveillance System, and registry of antibodies to aquaporin-4 (AQP4-IgG) and myelin oligodendrocyte glycoprotein (MOG-IgG) in a reference laboratory. The incidence rate was calculated for the period 1 January 2006-1 January 2016 and prevalence for the date 1 January 2016.

RESULTS

We identified 74 patients (by the 2015 criteria). Most patients were Caucasian (81%), and female (76%) with a median age at disease onset of 42 years (range, 10-76 years). In total, 54 (73%) patients were positive for AQP4-IgG, 11 (15%) double-seronegative, and 9 (12%) MOG-IgG-positive. Rates of incidence and prevalence (0.63/1,000,000 person-years and 0.89/100,000, respectively) were 1.5-fold higher than those reported by the 2006 criteria. Lowest rates were seen in children and elder people and highest in women and middle-aged people (40-59 years). The female predominance was lost in incident AQP4-IgG-seronegative children and AQP4-IgG-positive elder people. MOG-IgG and double-seronegativity contributed similarly but did not influence the long-term outcome.

CONCLUSION

The new criteria increase the estimates, but NMOSD remains as a rare disease. The differences in age- and sex-specific estimates highlight the importance of the serologic classification.

HLA-DRB1: genetic susceptibility and disability progression in a Spanish multiple sclerosis population

BACKGROUND AND OBJECTIVE

The association of HLA-DRB1*15 with susceptibility to multiple sclerosis (MS) has been consistently reported although its effect on the clinical phenotype is still controversial. The objectives of this study are to investigate the influence of the HLA-DRB1 alleles on the genetic susceptibility to MS and to study their impact on disability progression in a Spanish population.

METHODS

HLA-DRB1 typing was performed by PCR-SSP in 380 patients with sporadic MS and 1088 unrelated healthy controls. Allelic frequencies were compared between groups. We studied the correlation between the different alleles and the progression of MS.

RESULTS

The HLA-DRB1*15 allele in patients with MS had a statistically significant higher frequency when compared with controls (18.9% in patients vs. 10.1% in controls, Odds ratio (OR)=2.07, 95% CI=1.64-2.60, P<0.001). In the univariate analysis, the DRB1*01 and DRB1*04 alleles were associated with a worse prognosis when considering the time to reach an EDSS of 6, whereas the DRB1*03 was correlated with a better outcome. In the multivariate analysis, the alleles*01 and *04 were demonstrated to be independent factors to have a worse prognosis.

CONCLUSIONS

HLA-DRB1*15 is associated with MS when comparing patients with unrelated healthy controls in a Spanish population. The HLA-DRB1*01 and HLA-DRB1*04 alleles are related to a worse prognosis when considering the time taken to reach severe disability.

Association of HLA-DRB1*15 allele and CSF oligoclonal bands in a Spanish multiple sclerosis cohort

BACKGROUND AND OBJECTIVE

The HLA-DRB1*15 allele is consistently associated with multiple sclerosis (MS) susceptibility in most studied populations. This study investigated the association between HLA-DRB1 alleles and the presence of oligoclonal immunoglobulin G bands (OCB) in the cerebrospinal fluid (CSF) in a Spanish population with MS.

METHODS

The HLA-DRB1 typing was performed in 268 patients with sporadic MS and the detection of OCB in CSF. HLA-DRB1 allelic frequencies were compared between OCB-positive and OCB-negative patients, and both groups were also compared with 1088 unrelated healthy controls. Moreover, we correlated the various HLA-DRB1 genotypes, considering all the combinations of both parental alleles found with the presence or absence of OCB.

RESULTS

We found 206 OCB-positive and 62 OCB-negative patients. The HLA-DRB1*15 allele in OCB-positive patients had a higher frequency when compared with OCB-negative patients (39.3% in OCB-positive vs. 16.1% in OCB-negative, OR = 1.38 95% CI = 1.18-1.61, P < 0.001). The other alleles did not show differences. When we compared with controls, the HLA-DRB1*15 allele was associated with the disease only in the OCB-positive patients group. None of the 55 genotypes found showed any association with the presence or absence of OCB.

CONCLUSIONS

HLA-DRB1*15 allele is associated with OCB-positive patients with MS when studying a Spanish MS population.

Epistasis between HLA-DRB1 parental alleles in a Spanish cohort with multiple sclerosis

BACKGROUND AND OBJECTIVE

Multiple sclerosis (MS) has been consistently associated with the HLA-DR2 haplotype and particularly with the HLA-DRB1*15 allele. Epistatic interactions between both parental alleles in the DRB1 loci have been shown to modify the MS susceptibility risk. This study investigated the frequencies of various HLA-DRB1 genotypes, their impact on MS susceptibility and their correlation with the clinical severity in a Spanish population.

METHODS

A genotype was considered as the combination of the two parental DRB1 alleles. We compared the frequencies of the genotypes in a sporadic MS population (n=380) with those of an unrelated healthy control cohort (n=1088). We correlated the different genotypes with the age at onset, gender distribution, symptoms at onset, course of the disease and progression severity by means of the time to reach the progressive phase and EDSS scores of 3 and 6.

RESULTS

We found 81 different genotypes. There were four different MS-predisposing genotypes. Three of them contained the DRB1*15 allele (DRB1*03/15, DRB1*04/15, and DRB1*08/15) and the fourth was homozygote for the DRB1*03 allele. The highest odds ratio was found with the genotype DRB1*08/15 (OR=3.88, 95% CI=1.83-8.26, p<0.01), followed by DRB1*03/03 (OR=3.15, 95% CI=1.93-5.14, p<0.01), DRB1*03/15 (OR=2.72, 95% CI=1.88-3.94, p<0.01) and DRB1*04/15 (OR=2.54, 95% CI=1.64-3.98, p<0.01). The DRB1*01/04 and the DRB1*15/15 genotypes were associated with a shorter time to reach an EDSS score of 6.

CONCLUSIONS

Our results show the importance of epistatic interactions among the HLA-DRB1 alleles, modifying the risk for MS as well as its clinical severity.

Anticipation of age at onset in multiple sclerosis: methodologic pitfalls

BACKGROUND/AIM

There are several reports that claim anticipation in complex or polygenic diseases such as multiple sclerosis (MS), Crohn disease or schizophrenia. The aim of the present study was to assess age at onset of MS during the last 60 years in the region of Costa de Ponent (Barcelona, Spain) showing how apparent changes in age at onset between generations can be an artefact of analysis based on cohorts that have not been followed enough time.

METHODS

The study comprised 1100 patients diagnosed of MS. The method used to correct for follow-up time bias involves constructing comparison cohorts that had been observed for the same amount of time. To ensure equal follow-up times, we restricted our analysis to patients whose onset was by 37 years of age (percentile 75) and were at least 37 years old. We analysed differences in age at onset using log-rank test to compare survival curves estimated by Kaplan-Meier method.

RESULTS

Age at onset decreases progressively from older to younger generations. However, when adjustment to equal follow-up time was done, anticipation in age at onset was not found.

CONCLUSION

Anticipation of age at onset is undetectable when adjusted for follow-up time.

Anticipation of age at onset in familial multiple sclerosis

BACKGROUND AND OBJECTIVE

Anticipation of age at onset in the younger generations is a widely known characteristic of many diseases with genetic inheritance. This study was performed to assess whether there is anticipation of age at onset in younger generations of familial multiple sclerosis (MS) in a Spanish population and to compare clinical characteristics of familial and sporadic MS.

METHODS

We studied a cohort of 1110 patients diagnosed with MS and followed-up in our MS Unit. Patients were considered as familial MS if they had in their family at least one relative of first or second degree diagnosed with MS. Otherwise, patients were considered to have sporadic MS. We compared the age at onset between relatives from different generations, and we also compared the age at onset of familial and sporadic MS.

RESULTS

A lower age at onset in the younger generations was found (median 22 years vs. 30 years, P < 0.001) and a significant lower age at onset of the disease in familial MS comparing to sporadic MS (median 25 years vs. 29 years, P = 0.042).

CONCLUSIONS

There is an anticipation of the age at onset of MS in the younger generations of patients with familial MS. There is also a lower age at onset in familial versus sporadic MS.

Adult herpes simplex encephalitis: fifteen years' experience

INTRODUCTION

Herpes simplex encephalitis (HSE) is the most frequent cause of sporadic necrotizing encephalitis in adults. The aim of this study is to describe the characteristics of HSE and the factors influencing its outcome.

MATERIAL AND METHODS

Retrospective study of patients diagnosed with HSE in a tertiary care teaching hospital over a 15-year period. Diagnosis was based on a consistent clinical profile for HSE, plus either a PCR-positive CSF HSV study or consistent brain neuroimaging findings. Patients were divided into 2 groups according to the modified Rankin Scale: good outcome (Grades <=2) and poor outcome (Grades >=3).

RESULTS

Thirty-five patients were included. Mean age was 53.9 years. More than half presented febricula or fever, headache, disorientation, behavioral changes, decreased level of consciousness, or neurological deficit. CSF glucose concentration was normal in all patients and WBC count was normal in 8 (23%). PCR for HSV was positive in 92% and cranial MRI was suggestive of HSE in 100% of patients. Mortality was 8.6%. In relation to outcome, age (OR=1.079; 95% CI, 1.023-1.138) and serum albumin level at admission (OR=0.87; 95% CI, 0.794-0.954) were independent prognostic factors at discharge. At 6 months, days of fever after initiation of acyclovir therapy (OR=1.219; 95% CI, 1.046-1.422) and serum albumin level at admission (OR=0.917; 95% CI, 0.87-0.967) were independent prognostic factors.

CONCLUSIONS

Normal brain MRI or detection of low CSF glucose concentration requires consideration of diagnoses other than HSE. Age, serum albumin level at admission, and days of fever after initiation of acyclovir therapy were independent prognostic factors of the disease.

An approach to estimating the intangible costs of multiple sclerosis according to disability in Catalonia, Spain

Multiple sclerosis (MS) is a chronic demyelinating disease, which represents a great economic burden to society. Cost-of-illness studies of MS tend to underestimate the intangible costs related to pain, anxiety and helplessness. The purpose of this study was to estimate the intangible costs of MS, and determine whether these costs increase as disability progresses. We studied 211 consecutive patients with MS who attended our MS unit. Patients mean age was 41.6 (SD: 10.7) years, 69% were female, and their mean Expanded Disability Status Scale (EDSS) score was 2.47 (SD: 2.05). Quality-of-life was measured with the EuroQoL visual analogue scale. Quality-adjusted life year (QALY) was calculated for each patient. Patients were grouped into five disability stages according to their EDSS, and QALY was compared between patients and a group of healthy controls matched by age and sex. A benchmark value was ascribed to each QALY lost, and the intangible costs per patient-year were calculated as Euros 0 (EDSS =0), Euros 1100 (EDSS =1-3), Euros 8250 (EDSS =3.5-5.5), Euros 9900 (EDSS =6-7) and Euros 11,000 (EDSS >7.5). Sensitivity analysis showed a similar progression of costs. We conclude that intangible costs are relevant in MS, especially when disability increases. Although the method to calculate the costs remains controversial, we consider that they should be included in cost analysis of MS.

Direct and indirect costs of Multiple Sclerosis in Baix Llobregat (Catalonia, Spain), according to disability

BACKGROUND

Multiple sclerosis (MS) is an incurable chronic disease that predominantly affects young adults. It has a high socio-economic impact which increases as disability progresses. An assessment of the real costs of MS may contribute to our knowledge of the disease and to treat it more efficiently. Our objective is to assess the direct and indirect costs of MS from a societal perspective, in patients monitored in our MS Unit (Baix Llobregat, Catalonia) and grouped according to their disability (EDSS).

METHODS

We analysed data from 200 MS patients, who answered a questionnaire on resource consumption, employment and economical status. Mean age was 41.6 years, mean EDSS 2.7, 65.5% of patients were female, 79.5% had a relapsing-remitting course, and 67.5% of them were receiving immunomodulatory treatment (IT). Patients were grouped into five EDSS stages. Data from the questionnaires, hospital charts, Catalan Health Service tariffs, and figures from Catalan Institute of Statistics were used to calculate the direct and indirect costs. The cost-of-illness method, and the human capital approach for indirect costs, were applied. Sensitivity analyses were performed to strengthen results.

RESULTS

The mean total annual cost of MS per patient results 24,272 euros. This cost varied according to EDSS: 14,327 euros (EDSS = 0), 18,837 euros (EDSS = 1-3), 27,870 euros (EDSS = 3.5-5.5), 41,198 euros (EDSS = 6-7) and 52,841 euros (EDSS>7.5). When the mean total annual costs was adjusted by the mean % of patients on IT in our Unit (31%) the result was 19589 euros. The key-drivers for direct costs were IT in low EDSS stages, and caregiver costs in high stages. Indirect costs were assessed in terms of the loss of productivity when patients stop working. Direct costs accounted for around 60% of total costs in all EDSS groups. IT accounts from 78% to 11% of direct costs, and decreased as disability progressed.

CONCLUSION

The total mean social costs of MS in a cohort from Baix Llobregat (Catalonia) were estimated at 24,272 euros per patient/year, and ranged between 14,327 euros (EDSS = 0) and 52,841 euros (EDSS = 7.5-9.5). Total costs, and particularly informal and direct costs, increased as the disability progressed. IT should be able to delay the progression of disability to be efficient and not only effective.