Incidence of Multiple Sclerosis in Germany: A Cohort Study Applying Different Case Definitions Based on Claims Data.
BACKGROUND
Data on the incidence of multiple sclerosis (MS) on the national level is scarce. We aimed to estimate the incidence of MS in Germany and to compare different MS case definitions based on claims data.


METHODS
We conducted a cohort study with the German Pharmacoepidemiological Research Database in 2012 and calculated age- and gender-standardized incidence rates (sIRs) for 3 case definitions. In addition, the effect of stepwise reduction of the look-back period without MS diagnosis on the incidence rate was evaluated.


RESULTS
Our cohort comprised 4,175,877 individuals. The first case definition based on ICD-10 diagnoses yielded an sIR of 21.8 (95% CI 20.2-23.5) per 100,000 person years, whereas the second and third case definitions with additional requirements for drug treatment and diagnostic tests resulted in lower sIRs of 10.1 (9.1-11.3) and 6.6 (5.8-7.6) respectively. We observed a higher incidence for shorter look-back periods.


CONCLUSION
The incidence of MS in Germany might be substantially higher than suggested in earlier studies. In addition, our study highlights the importance of a look-back period of at least 36 months to identify incident MS cases based on claims data.
['Schmedt|Niklas|N|', 'Khil|Laura|L|', 'Berger|Klaus|K|', 'Riedel|Oliver|O|']
D000328:Adult D017677:Age Distribution D015331:Cohort Studies D016208:Databases, Factual D005260:Female D005858:Germany D006801:Humans D015994:Incidence D038801:International Classification of Diseases D008297:Male D008875:Middle Aged D009103:Multiple Sclerosis D012189:Retrospective Studies D017678:Sex Distribution
Incidence Multiple sclerosis Germany Cohort study Case definitions Databases Epidemiology Immunosuppressive agents