Background/Purpose: Fatigue in patients with rheumatoid arthritis (RA) may be measured with the 13-item Functional Assessment of Chronic Illness Therapy-Fatigue instrument (FACIT-F). The Patient-Reported Outcomes Measurement Information System (PROMIS) was developed using a population-calibrated T-score metric (mean 50, SD 10). PROMIS Fatigue includes the FACIT-F items, making their scores interchangeable. Crosswalk tables and a pattern scoring system have been developed to link legacy to PROMIS instruments, including fatigue.¹ A subset of 10 FACIT-F items has also been identified as relevant to patients with RA. We assessed treatment response in two phase 3 baricitinib RA trials based on linked FACIT and PROMIS Fatigue scores using both crosswalk tables and the scoring algorithm.

Methods: In RA-BEAM, patients with inadequate response to MTX were randomized 3:3:2 to placebo (PBO) once daily (QD), baricitinib (bari) 4 mg QD, or adalimumab (ADA) 40 mg biweekly.² In RA-BEACON, patients with inadequate response to biological DMARDs were randomized 1:1:1 to receive PBO or bari 2 mg or 4 mg QD.³ Patient-level FACIT-F scores were linked to PROMIS Fatigue scores using validated crosswalk tables¹ (www.prosettastone.org) and the scoring algorithm at http://www.healthmeasures.net/explore-measurement-systems/promis. Analysis of covariance was conducted on PROMIS score conversions to compare bari to all treatment arms.

Results: At baseline, average PROMIS Fatigue scores across treatment groups and scoring methods ranged from 56.8 to 59.7 in RA-BEAM (FACIT-F range 27.6 to 28.6) and 60.1 to 63.7 in RA-BEACON (FACIT-F range 22.2 to 23.4); they thus reflected severe fatigue compared with the population means (e.g., approaching or exceeding 1 SD above). PROMIS Fatigue scores in RA-BEAM reached normal levels (mean <55) by week 4 for bari and ADA (data not shown). For both studies, at 24 weeks, bari was associated with clinically meaningful improvements from baseline (exceeding 0.5 SD/5 points on the T-score metric) for PROMIS Fatigue scores, and with significant improvements in PROMIS Fatigue for bari 4-mg versus placebo (Table).

Conclusion: These results support the FACIT-F to PROMIS Fatigue crosswalk and scoring algorithm approaches, with similar results shown for the subset of 10 FACIT-F items deemed most relevant to RA. This approach enables comparisons across studies using FACIT-F or PROMIS Fatigue item subsets, and their interpretation relative to US general population norms. 

¹Lai J-S, et al. J Pain Symptom Manage 2014;48: 639–48; ²Taylor PC, et al. N Engl J Med 2017;376:652–62; ³Genovese MC, et al. N Engl J Med 2016;374:1243–52.

Table. FACIT-F and PROMIS^a Fatigue Patient-Reported Outcomes