Background/Purpose:

In the published literature, the prevalence rates of SLE have widely varied by as much as 12-fold over the years. This is likely due to the variability in study populations (region and race/ethnicity), case definitions (self-report, ICD codes, physician diagnosis, ACR criteria, and SLICC criteria), and case ascertainment sources (case registry, hospital, specialists, laboratory report, US renal database, death certificate, and insurance claims data). Most studies, thus far, covered relatively small population size such as a city, county or state or Medicaid database. To the best of our knowledge, there are no studies on SLE prevalence that cover the total population of the United States (US). Although, elegant reports from 5 CDC registries covering several counties in 5 states provide valuable information on SLE prevalence, there is an important unmet need to estimate the national prevalence of SLE in the US.

Methods:

We used ambulatory physician visits in the US derived from the 2001-2011 National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS) database to determine encounters that represent SLE, using ICD-9 code 710.0. Using the number of prior visits per patient, we estimated the number of patients with SLE from the visit encounters. STATA was then used to determine the mean proportion and 95% confidence interval.

Results:

The overall prevalence rate of SLE is 122/100,000 persons in the US. The annual prevalence of SLE increased from 104.2/100,000 in 2001 to 164.3/100,000 in 2011. The period prevalence of SLE from 2001-2011 is 14-fold higher in females (224/100,000) than males (16/100,000). Non-Hispanic black persons had the highest prevalence of SLE (206/100,000), followed by Hispanics (118/100,000), and non-Hispanic white persons (87/100,000). There were substantial variations in SLE prevalence by geographic regions: persons living in the West had the highest prevalence (143/100,000), followed by South (129/100,000), Northeast (120/100,000), and Midwest (90/100,000).

Conclusion:

Analysis of national survey data across the US reveals an increasing trend in the prevalence of SLE over the last decade, which may reflect an increased recognition of SLE, changes in physician’s coding practices, or an actual increase in the prevalence. Lack of verification of SLE diagnosis by rheumatologists is a major limitation of this study, especially since there is discordance even among rheumatologists as to what constitutes a diagnosis of lupus. Nevertheless, our data shows regional and demographic differences in SLE prevalence in communities across the US. The female: male ratio of 14:1 in SLE prevalence is higher than in previous studies, which might be due to a lack of recognition of SLE in males by primary care physicians or lack of men visiting clinics that were surveyed by NAMCS or NHAMCS. Like in previous studies, SLE prevalence was higher in black persons than in white persons. Racial/ethnic differences in SLE prevalence may also be due to racial/ethnic differences in individuals who visit clinics that were surveyed or due to lack of entry in the race/ethnicity column by persons of certain race/ethnicity.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/nationwide-estimated-prevalence-of-sle-united-states-population-based-study-2001-2011/