Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Adult Prevalence of Systemic Autoimmune Rheumatic Diseases (SARDs) in British Columbia, Canada.

Avina-Zubieta1,  J. Antonio, Sayre1,  Eric C., Bernatsky2,  Sasha, Lehman1,  Allen J., Shojania1,  Kamran, Esdaile3,  John, Lacaille1,  Diane

Arthritis Research Centre of Canada/University of British Columbia, Vancouver, BC
McGill UHC/RVH, Montreal, QC
University of Calgary, Calgary, AB

Background/Purpose:

There is a growing interest in the use of administrative health data to estimate the incidence and prevalence of systemic autoimmune rheumatic disorders (SARDs) such as systemic lupus erythematosus (SLE), systemic sclerosis (SSc), Sjögren's disease (SjD), and poly/dermatomyositis (PM/DM) [collectively called as connective tissue diseases CTD]; and, systemic vasculitides (polyarteritis nodosa, Wegener's disease, giant cell arteritis and Takayasu's disease). We estimated the prevalence and incidence rates of SARDs as a group and as individual diseases by sex in age 20+ years in the province of British Columbia (BC), Canada (population 3.3 million) using physician billing and hospitalization databases.

Methods:

Our data included all visits to health professionals and hospital admissions covered by the comprehensive provincial medical services plan from January 1, 1990 until December 31, 2007 for all individuals > 18 years of age. SARDs was defined as: (a)>= 2 ICD-9/10 codes for SARDs >= 2 months apart but within a two-year period by any physician other than rheumatologists or (b) one ICD-9/10 code for SARDs by a rheumatologist (at any time), or (c) >1 hospitalization diagnostic code of SARDs. To improve specificity of our algorithm, we excluded individuals with at least two visits >= 2 months apart subsequent to the first SARD visit (second for a non-rheumatologist) with diagnoses of other non-SARDs inflammatory arthritides (e.g. rheumatoid arthritis, psoriatic arthritis, spondyloarthropathy) and those where a diagnosis of SARDs by a non-rheumatologist was non confirmed when seen by a rheumatologist. The prevalence estimates were calculated for the year 2007, based on the number of cases that had been identified during the study period (1996–2007) who remained alive as of December 31, 2007, with the denominator being the total number of BC residents at that time. SARDs cases were identified as incident cases for 1996–2007 if they had no prior visit for SARDs since 1990.

Results:

The overall prevalence of CTD and systemic vasculitides in 2007 were 0.39% and 0.03%, respectively. The BC prevalence rates of CTD by sex and age are similar to those reported previously using Bayesian models (males: 176.3 versus 221.3 and females: 591.9 versus 605.9, for BC and Canada, respectively). The prevalence and incidence rates per 100,000 by disease, and sex in age 20+ are shown in the table below.

SARD DISEASEPrevalence per 100K Males 20+Prevalence per 100K Females 20+Prevalence per 100K Total 20+Incidence per 100K PY Males 20+Incidence per 100K PY Females 20+Incidence per 100K PY Total 20+
CONNECTIVE TISSUE DISEASES176.3591.9388.620.167.544.3
  SLE30.4193.9113.93.624.214.1
  SSc6.435.621.31.55.63.6
  SjD5.536.421.31.76.84.3
  DM3.27.55.40.41.61.0
  PM8.010.39.21.11.81.4
SYSTEMIC VASCULITIDES21.142.231.93.76.95.3
  Polyarteritis nodosa3.05.04.00.40.80.6
  Wegener's disease10.010.710.32.02.52.2
  Giant cell arteritis8.525.617.31.63.82.7
  Takayasu's disease0.62.81.70.20.50.4

Conclusion:

CTD and systemic vasculitis rates in this study are comparable with epidemiologic studies on SARDs. Administrative data are a valuable source to study the epidemiology and surveillance of SARDs.

To cite this abstract, please use the following information:
Avina-Zubieta, J. Antonio, Sayre, Eric C., Bernatsky, Sasha, Lehman, Allen J., Shojania, Kamran, Esdaile, John, et al; Adult Prevalence of Systemic Autoimmune Rheumatic Diseases (SARDs) in British Columbia, Canada. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1846
DOI:

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