TY - JOUR T1 - Observation Period Effects on Estimation of Systemic Lupus Erythematosus Incidence and Prevalence in Quebec JF - The Journal of Rheumatology JO - J Rheumatol SP - 1334 LP - 1336 DO - 10.3899/jrheum.121215 VL - 40 IS - 8 AU - Ryan Ng AU - Sasha Bernatsky AU - Elham Rahme Y1 - 2013/08/01 UR - http://www.jrheum.org/content/40/8/1334.abstract N2 - Objective. To determine how duration of observation affects estimation of incidence and prevalence of systemic lupus erythematosus (SLE). Methods. SLE incidence and prevalence estimates from data periods as brief as 3 years (2001–2003) were compared to estimates from a 15-year period (1989–2003). Results. The 15-year period incidence was 5.6/100,000 (95% CI 5.0–6.1) and the prevalence was 59.1/100,000 (95% CI 57.4–60.8). When a 3-year period was used, incidence was overestimated by 238.1% and prevalence underestimated by 66.0%. Conclusion. SLE incidence and prevalence estimates vary considerably according to the observation period; more than 5 years of data is likely required. ER -