Table 1 Search strategy in PubMed

1. Construct

Stiffness

Key words

stiffn*

2. Population

Adults with rheumatoid arthritis

Mesh

((“Arthritis, Rheumatoid”[Mesh:NoExp] OR “Caplan’s Syndrome”[Mesh]) OR “Felty’s Syndrome”[Mesh]) OR “Rheumatoid Nodule”[Mesh])

OR

Key words

(Arthriti*[tiab] OR rheuma*[tiab] OR caplan[tiab] OR felty[tiab])

3. Instrument

Patient reported outcome measures or instruments i.e. questionnaires, scales, subscales, indexes

Key words

(Questionnaire* OR scale OR instrument OR tool OR diary OR assessment OR self-report OR measure* OR PRO OR PROM)

4. Sensitive filter[18]

1 + 2 + 3 AND sensitive filter

5. exclusion filter[18]

4 NOT exclusion filter