A Sex Difference in HandScan Scores in Rheumatoid Arthritis Patients and Controls? An Ongoing Analysis of the Sex Difference and Other Potential Confounders

To the Editor: A recent paper by Triantafyllias, et al described that optical spectral transmission (OST) scores, obtained by the HandScan, were significantly higher in male compared to female patients with rheumatoid arthritis (RA) and controls, and an association between OST score and age, BMI, and hand surface area was found.1 The difference in sex that Triantafyllias, et al showed is in line with results of studies performed at our department. We developed and validated a new disease activity index, Disease Activity Score (DAS)-OST, in which tender and swollen joint counts are replaced by the OST score. In the construction of the DAS-OST formula, sex had to be taken into account, because in this study, OST scores were higher in males than in females.2 In addition, by comparing single OST scores to the rheumatologist’s clinical classification into active or inactive RA as reference, different optimal cutoffs for males and females were calculated, again indicating a sex difference. Based on these findings, we investigated whether this difference in sex was also … Address correspondence to Dr. M.M. Verhoeven, Department of Rheumatology & Clinical Immunology G02.228, P.O. Box 85500, 3508GA Utrecht, the Netherlands. Email: m.m.a.verhoeven-15{at}umcutrecht.nl.