title: Prevalence and incidence of ischemic heart disease in multiple sclerosis: A population-based validation study.
abstract: BACKGROUND
  Studies suggest an altered risk of ischemic heart disease (IHD) in multiple sclerosis (MS), but data are limited. We aimed to validate and apply administrative case definitions to estimate the incidence and prevalence of IHD in MS.
  
  
  METHODS
  Using administrative data we identified persons with incident MS (MSPOP) and a matched general population (GPOP) cohort. We developed case definitions for IHD using ICD-9/10 codes and prescription claims, compared them to medical records, then applied them to evaluate the incidence and prevalence of IHD.
  
  
  RESULTS
  Agreement between medical records and the administrative definition using ≥1 hospital or ≥2 physician claims over 5 years was moderate (kappa=0.66; 95% CI: 0.42-0.90). In 2005, the age-standardized prevalence of IHD was 6.77% (95% CI: 5.48-8.07%) in the MSPOP and 6.11% (95% CI: 5.56-6.66%) in the GPOP. The prevalence of IHD was higher in the MSPOP than the GPOP among persons aged 20-44 years (prevalence ratio 1.87; 95% CI: 1.65-2.12) and aged 45-59 years (prevalence ratio 1.21; 95% CI: 1.08-1.35). The incidence of IHD was also higher in the MSPOP (incidence rate ratio 1.24; 95% CI: 0.97-1.59).
  
  
  CONCLUSIONS
  More than 5% of the MSPOP has IHD. The incidence of IHD was higher than expected in persons aged <60 years. Further evaluation of this issue is warranted.
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9. Electronic address: rmarrie@hsc.mb.ca.
authors: Ruth Ann
authors: RA
authors: Marrie
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: Bo N
authors: BN
authors: Yu
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: Stella
authors: S
authors: Leung
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: Lawrence
authors: L
authors: Elliott
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: Patricia
authors: P
authors: Caetano
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: Sharon
authors: S
authors: Warren
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: Christina
authors: C
authors: Wolfson
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: Scott B
authors: SB
authors: Patten
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: Lawrence W
authors: LW
authors: Svenson
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: Helen
authors: H
authors: Tremlett
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: John
authors: J
authors: Fisk
authors: University of Manitoba, Health Sciences Centre, GF 533, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9.
authors: James F
authors: JF
authors: Blanchard
keywords: Administrative data; Cardiac disease; Incidence; Multiple sclerosis; Prevalence; Validation