TY - JOUR T1 - True Difference or Detection Bias: Racial Differences in Clinical Features and Comorbidities in Ankylosing Spondylitis in the United States JF - The Journal of Rheumatology JO - J Rheumatol SP - 1150 LP - 1150 DO - 10.3899/jrheum.191399 VL - 47 IS - 7 AU - PARAS KARMACHARYA AU - JOYCE E. BALLS-BERRY AU - JOHN M. DAVIS III Y1 - 2020/07/01 UR - http://www.jrheum.org/content/47/7/1150.1.abstract N2 - To the Editor:We read with interest about the study by Singh and Magrey (“Racial differences in clinical features and comorbidities in ankylosing spondylitis in the United States”)1. The authors selected patients with ankylosing spondylitis (AS) from a large clinical informatics tool, the Explorys platform, with multiple participating healthcare organizations, which increases the generalizability of the findings. To increase the validity of the cases, Singh and Magrey included AS patients with at least 2 visits with a rheumatologist. While this approach may increase case validity, it might miss patients who have not seen a rheumatologist or were lost to followup after the initial visit. Only 8% of the patients included in the study were African American. It is unclear whether such a low prevalence is from low detection in these patients or due … Address correspondence to P. Karmacharya, Division of Rheumatology, Mayo Clinic College of Medicine, 200 First St. S.W., Rochester, Minnesota 55905, USA. E-mail: paraskarmacharya{at}gmail.com ER -