• disease activity
• systemic sclerosis
• treatment

We thank Drs Jain and Sharma1 for their interest in our work.2 We agree that what may be deemed irreversible loss of organ structure and/or function in the current therapeutic landscape of systemic sclerosis (SSc), may one day be reversible and indeed even preventable as highly effective novel therapies become available.

We caution against the erroneous interpretation that the presence of damage is necessarily an indication for withdrawal or de-escalation of treatment. Unlike some other rheumatic diseases wherein relapsing remitting disease activity leads to damage, in SSc, activity and damage can occur concurrently. Therefore, therapeutic decisions must not rest solely on assessment of damage but also of concomitant activity in a particular organ. Indeed, the same working group of the Scleroderma Clinical Trials Consortium (SCTC) is currently working on the development of an Activity Index in SSc, using similar methodology to that deployed for the development of the Damage Index (DI).

We emphasise that the attribution of damage to SSc is fundamentally important to the application of the SCTC-DI.1 In the examples given by Drs Jain and Sharma, reduced forced vital capacity must be attributable to SSc interstitial lung disease, and low body mass index below 18.5 kg/m2 must be attributable to SSc for these items to be scored.

Finally, while digital pitting scars represent damage to the digital pulps and this item was included in the initial survey of experts, it was not ultimately included in the SCTC-DI as it did not correlate with morbidity and mortality endpoints independently of the digital ulceration and amputation items.