Contributions
Abstract: P343
Type: Poster
Abstract Category: Clinical aspects of MS - 5 Epidemiology
Background: The incidence of multiple sclerosis (MS) has been estimated for some local areas in Sweden; 4.3/105, 5.2/105 and 6.4 /105 person years, all analysed by year of onset and by checking medical records. A recent study of the national incidence showed an unexpectedly high figure: 10.2/105 person years (2001-08) assessing incidence of MS diagnoses from the Swedish MS register (SMSreg) and the National Patient Register (NPR) in combination. However, since information about reported year of onset/year of clinical diagnosis are lacking in NPR, to calculate MS incidence by data from NPR obviously has some limitations.
Objectives: The aim of this study was to carefully examine MS-incidence by year of onset in the county of Värmland, a defined geographic area and to investigate sensitivities and specificities of an MS diagnosis in SMSreg and NPR.
Methods: Patients with an ICD-code for MS, living in Värmland were identified from the SMSreg (485) and NPR (435) registries. Patients medical records, identified from NPR, were scrutinized regarding ICD-code and year of onset.
Results: The linked registers showed that out of the 900 patients, 435 patients were registered in NPR only. After detailed review of medical records, the diagnosis in 15 % of MS patients in the NPR turned out to be false, a recorded diagnosis most often due to a initial suspicion of MS that eventually failed to be confirmed, or due to technical errors regarding coding. In addition, patients with a true MS diagnosis were missing in the SMSreg.
After scrutinizing individual records, 290 individuals (209 SMSreg, 81 NPR) remained with the ICD-code MS and with an onset 2001-13, and the adjusted average annual incidence in the county was 8.7/105 person years (CI 95% 7.7 - 9.7), 12.7 for women (CI 95% 10.9-14.4) and 5.0 for men (CI 95% 3.9-6.1).
Conclusion: Calculating occurrence of MS by data from administratively collected data can be associated with some problems. The accurate calculation of MS incidence in the county of Värmland, analysed by year of onset and scrutinized medical records, indicates that previous local surveys may have missed a complete coverage, or the earlier reported national incidence figures may be exaggerated due to methodological issues.
Disclosure: Dr Hillert has received honoraria for serving on advisory boards for Biogen, Sanofi-Genzyme and Novartis and speaker's fees from Biogen, Novartis, Merck-Serono, Bayer-Schering, Teva and Sanofi-Genzyme. He has served as P.I. for projects, or received unrestricted research support from, BiogenIdec, Merck-Serono, TEVA, Sanofi-Genzyme and Bayer-Schering.
His MS research is funded by the Swedish Research Council and the Swedish Brain foundation.
Dr Landtblom: Lectures sponsored by Teva, Biogen, Sanofi Genzyme, Merck Serono.
Dr Manouchehrinia and Dr Boström: no conflicts of interest
Abstract: P343
Type: Poster
Abstract Category: Clinical aspects of MS - 5 Epidemiology
Background: The incidence of multiple sclerosis (MS) has been estimated for some local areas in Sweden; 4.3/105, 5.2/105 and 6.4 /105 person years, all analysed by year of onset and by checking medical records. A recent study of the national incidence showed an unexpectedly high figure: 10.2/105 person years (2001-08) assessing incidence of MS diagnoses from the Swedish MS register (SMSreg) and the National Patient Register (NPR) in combination. However, since information about reported year of onset/year of clinical diagnosis are lacking in NPR, to calculate MS incidence by data from NPR obviously has some limitations.
Objectives: The aim of this study was to carefully examine MS-incidence by year of onset in the county of Värmland, a defined geographic area and to investigate sensitivities and specificities of an MS diagnosis in SMSreg and NPR.
Methods: Patients with an ICD-code for MS, living in Värmland were identified from the SMSreg (485) and NPR (435) registries. Patients medical records, identified from NPR, were scrutinized regarding ICD-code and year of onset.
Results: The linked registers showed that out of the 900 patients, 435 patients were registered in NPR only. After detailed review of medical records, the diagnosis in 15 % of MS patients in the NPR turned out to be false, a recorded diagnosis most often due to a initial suspicion of MS that eventually failed to be confirmed, or due to technical errors regarding coding. In addition, patients with a true MS diagnosis were missing in the SMSreg.
After scrutinizing individual records, 290 individuals (209 SMSreg, 81 NPR) remained with the ICD-code MS and with an onset 2001-13, and the adjusted average annual incidence in the county was 8.7/105 person years (CI 95% 7.7 - 9.7), 12.7 for women (CI 95% 10.9-14.4) and 5.0 for men (CI 95% 3.9-6.1).
Conclusion: Calculating occurrence of MS by data from administratively collected data can be associated with some problems. The accurate calculation of MS incidence in the county of Värmland, analysed by year of onset and scrutinized medical records, indicates that previous local surveys may have missed a complete coverage, or the earlier reported national incidence figures may be exaggerated due to methodological issues.
Disclosure: Dr Hillert has received honoraria for serving on advisory boards for Biogen, Sanofi-Genzyme and Novartis and speaker's fees from Biogen, Novartis, Merck-Serono, Bayer-Schering, Teva and Sanofi-Genzyme. He has served as P.I. for projects, or received unrestricted research support from, BiogenIdec, Merck-Serono, TEVA, Sanofi-Genzyme and Bayer-Schering.
His MS research is funded by the Swedish Research Council and the Swedish Brain foundation.
Dr Landtblom: Lectures sponsored by Teva, Biogen, Sanofi Genzyme, Merck Serono.
Dr Manouchehrinia and Dr Boström: no conflicts of interest