Joint protection (JP) is an important part of the treatment concept for patients with rheumatoid arthritis (RA). The Joint Protection Behavior Assessment short form (JPBA-S) assesses the use of hand JP methods by patients with RA while preparing a hot drink. The purpose of this study was to develop a German version of the JPBA-S (D-JPBA-S) and to test its validity and reliability.
A manual was developed through consensus with 8 occupational therapist (OT) experts as the reference for assessing patients' JP behavior. Twenty-four patients with RA and 10 healthy individuals were videotaped while performing 10 tasks reflecting the activity of preparing instant coffee. Recordings were repeated after 3 months for test-retest analysis. One rater assessed all available patient recordings (n = 23, recorded twice) for test-retest reliability. The video recordings of 10 randomly selected patients and all healthy individuals were independently assessed for interrater reliability by 6 OTs who were explicitly asked to follow the manual. Rasch analysis was performed to test construct validity and transform ordinal raw data into interval data for reliability calculations.
Nine of the 10 tasks fit the Rasch model. The D-JPBA-S, consisting of 9 valid tasks, had an intraclass correlation coefficient of 0.77 for interrater reliability and 0.71 for test-retest reliability.
The D-JPBA-S provides a valid and reliable instrument for assessing JP behavior of patients with RA and can be used in German-speaking countries.