title: Data quality evaluation for observational multiple sclerosis registries.
abstract: OBJECTIVE
  Objective and reproducible evaluation of data quality is of paramount importance for studies of 'real-world' observational data. Here, we summarise a standardised data quality, density and generalisability process implemented by MSBase, a global multiple sclerosis (MS) cohort study.
  
  
  METHODS
  Error rate, data density score and generalisability score were developed using all 35,869 patients enrolled in MSBase as of November 2015. The data density score was calculated across six domains (follow-up, demography, visits, MS relapses, paraclinical data and therapy) and emphasised data completeness. The error rate evaluated syntactic accuracy and consistency of data. The generalisability score evaluated believability of the demographic and treatment information. Correlations among the three scores and the number of patients per centre were evaluated.
  
  
  RESULTS
  Errors were identified at the median rate of 3 per 100 patient-years. The generalisability score indicated the samples' representativeness of the known MS epidemiology. Moderate correlation between the density and generalisability scores (ρ = 0.58) and a weak correlation between the error rate and the other two scores (ρ = -0.32 to -0.33) were observed. The generalisability score was strongly correlated with centre size (ρ = 0.79).
  
  
  CONCLUSIONS
  The implemented scores enable objective evaluation of the quality of observational MS data, with an impact on the design of future analyses.
authors.affiliation: Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia/Department of Neurology, Royal Melbourne Hospital, Melbourne, VIC, Australia.
authors.forename: Tomas
authors.initials: T
authors.lastname: Kalincik
authors.affiliation: Neurology, Departments of Medicine, Biomedicine and Clinical Research, University Hospital Basel, Basel, Switzerland.
authors.forename: Jens
authors.initials: J
authors.lastname: Kuhle
authors.affiliation: Neurology Unit, ASUR Marche AV3, Macerata, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Pucci
authors.affiliation: Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Juan Ignacio
authors.initials: JI
authors.lastname: Rojas
authors.affiliation: 3rd Department of Neurology, G. Papanikolaou Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Magda
authors.initials: M
authors.lastname: Tsolaki
authors.affiliation: Central Military Emergency University Hospital, Bucharest, Romania.
authors.forename: Carmen-Adella
authors.initials: CA
authors.lastname: Sirbu
authors.affiliation: Flinders University and Medical Centre, Adelaide, SA, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Slee
authors.affiliation: Department of Medicine, University of Melbourne, Melbourne, VIC, Australia/Department of Neurology, Royal Melbourne Hospital, Melbourne, VIC, Australia/Department of Neurology, Box Hill Hospital, Monash University, Melbourne, VIC, Australia.
authors.forename: Helmut
authors.initials: H
authors.lastname: Butzkueven
mesh_terms: D000328:Adult; D015982:Bias; D015331:Cohort Studies; D000068598:Data Accuracy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016899:Interferon-beta / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000188:drug therapy* / Q000453:epidemiology; D012008:Recurrence; D012042:Registries / Q000706:statistics & numerical data*
chemical_list: D016899:Interferon-beta
keywords: Multiple sclerosis; cohort study; data reporting; generalisability; quality; representativeness