Dr. Triantafyllias, et al reply.

We have read with great interest the letter of Verhoeven, et al,1 referring to our recent publication on the diagnostic value of optical spectral transmission (OST) in rheumatoid arthritis (RA).2 In our work we had described for the first time, to our knowledge, that OST values could be influenced not only by disease-associated factors (i.e., inflammatory activity) but also by patient-associated characteristics, such as sex, BMI, and age.2.