Response to: ‘Assessment of responsiveness of the musculoskeletal component of SLE-DAS in an independent cohort’, by Hassan et al

It was with great interest that we read the letter ‘Assessment of responsiveness of the musculoskeletal component of SLE-DAS in an independent cohort’ by Hassan et al .1 We recently published the derivation and validation of the Systemic Lupus Erythematosus Disease Activity Score (SLE-DAS), a new continuous measure of SLE disease activity with high sensitivity and specificity to change.2 Hassan et al report in their letter that in an analysis of 20 SLE …