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Table 1 Physical function instruments, baseline, 12-month, and change scores

From: Improved responsiveness and reduced sample size requirements of PROMIS physical function scales with item response theory

      Change Scores (12 months - Baseline)
  Items (n) Response options (n) Baseline mean ± SD1 12-Months Mean ± SD Mean SD
(95% CL2 for SD)
P-value 3
Legacy PF-10 10 3 47.2 ± 29 49.0 ± 29 1.8 18.4 (16.5, 20.2) 0.04
Legacy HAQ 20 4 29.2 ± 23 30.7 ± 24 1.5 10.6 (9.4, 11.8) 0.002
Item-Improved PF-10 10 5 41.5 ± 26 43.0 ± 27 1.5 16.3 (13.9, 18.6) 0.05
Item-Improved HAQ 20 5 21.0 ± 21 22.1 ± 21 1.1 8.6 (7.7, 9.6) 0.01
PROMIS PF 10 10 5 33.9 ± 22 35.2 ± 23 1.3 11.1 (10.0, 12.2) 0.01
PROMIS PF 20 20 5 30.6 ± 21 31.8 ± 22 1.2 9.4 (8.4, 10.1) 0.01
  1. 1 Standard Deviation, 2 Confidence Limits, 3 Pair-wise t-test.
  2. HAQ, health assessment questionnaire; Item-Improved, Changes to items intended to improve their performance by altering parameters such as time frame and response options while retaining the same item stem; PF, physical function; PROMIS, Patient-Reported Outcomes Measurement Information System.