OBJECTIVES:  To evaluate whether scores from paper (P) and electronic tablet (E) versions of seven PRO measures [SF-36v2 Health Survey (Standard), Bath Ankylosing Spondylitis Disease Activity Index, Health Assessment Questionnaire, Dermatology Quality of Life Instrument, Patient Global Assessment of Disease Activity, Subject Assessment of Pain, and, Fatigue Visual Analogue Scale are equivalent. 

METHODS:  After establishing that patients interpreted P and E instruments in similar ways using cognitive interviews, a crossover study was conducted in 53 patients (34 women) aged 18-83 years. A three-period design was used, with the first two periods being E and P in randomised order, the third period being P for all patients. This allowed both P-E and P-P reliabilities to be compared. Patients’ opinions on ease of use and acceptability of the electronic version were collected. RESULTS:   Intraclass Correlation Coefficients ranged from 0.75 to 0.97, all above the generally accepted threshold of .70. Correlations were in general similar for P-E (mode equivalence) and P-P (test-retest reliability for paper|) T-tests revealed no significant mean difference between P and E scores.  Mean score differences between P and E measures were small and within an acceptable limit of equivalence. The majority of patients reported that the electronic tablet was acceptable (99%), and ‘very easy’ (81.8%) or ‘quite easy’ (14.3%) to use.  Few subjects (5%) reported problems using the tablet.  The majority of patients (37; 74%) preferred the tablet version to paper, while 12 (24%) had no preference, and 1 (2%) preferred paper. CONCLUSIONS: Results indicate that the PRO scores are equivalent when administered to patients with PsA via electronic and paper modes.  The tablet versions were easy and acceptable to use, and preferred over paper versions.  These results support the use of the electronic tablet versions of the PRO measures in PsA clinical trials.