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Table 3 PUQ-R measurement scales item-level data

From: Patient Uncertainty Questionnaire-Rheumatology (PUQ-R): development and validation of a new patient-reported outcome instrument for systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) in a mixed methods study

Item String Loc. SE Fit Res. Chi Sq. Prob. res. r DIF ANOVA (df = 1)
MS F Prob.
PUQ-R Symptoms & Flares Scale (PSI = 0.91)
1 straight away −1.82 0.11 −2.00 14.09 0.00 0.33 5.93 8.68 0.00
2 specific symptoms −1.64 0.10 −0.98 3.39 0.34 <0.30 1.31 1.57 0.21
3 everyday symptoms −1.22 0.10 −0.40 5.48 0.14 0.33 2.51 2.90 0.09
4 serious symptoms −1.12 0.09 0.40 0.87 0.83 <0.30 0.90 0.93 0.34
5 getting older −1.04 0.09 0.80 2.75 0.43 <0.30 1.91 1.91 0.17
6 side-effects −0.87 0.09 2.35 4.48 0.21 <0.30 0.36 0.31 0.58
7 all different −0.80 0.09 −0.89 10.36 0.02 <0.30 0.08 0.10 0.76
8SLE symptom triggers −0.39 0.10 2.09 11.03 0.01 0.37 0.00 0.00 1.00
9 flare type 0.36 0.08 −0.24 2.99 0.39 <0.30 2.09 2.33 0.13
10 symptom timing 0.46 0.09 0.84 1.79 0.62 0.37 2.27 2.24 0.14
8RA symptom triggers 0.80 0.14 2.05 7.49 0.06 <0.30 0.00 0.00 1.00
11 future effect 1.21 0.09 1.44 3.75 0.29 0.42 0.29 0.26 0.61
12 flare timing 1.39 0.10 0.11 7.08 0.07 0.32 8.93 10.13 0.00
13 flare severity 2.11 0.11 −0.38 1.67 0.64 0.51 2.40 2.77 0.10
14 flare frequency 2.57 0.12 −1.12 5.15 0.16 0.51 0.67 0.88 0.35
PUQ-R Medication Scale (PSI = 0.91)
15RA need medication −1.54 0.17 −0.96 1.81 0.61 0.32 0.00 0.00 1.00
16 help symptoms −0.91 0.10 −0.75 1.38 0.71 0.44 27.30 39.46 0.00
17 controls condition −0.56 0.09 −1.23 5.21 0.16 0.49 1.02 1.34 0.25
15SLE need medication −0.52 0.11 2.56 31.68 0.00 0.49 0.00 0.00 1.00
18 stronger dose −0.24 0.09 −0.68 3.32 0.34 0.48 2.01 2.44 0.12
19 will help symptoms −0.20 0.10 0.63 1.80 0.61 0.51 0.22 0.23 0.63
20 need additional −0.08 0.09 −1.61 5.27 0.15 0.52 0.25 0.33 0.57
21 need alternative 0.05 0.09 0.16 0.21 0.98 0.52 0.66 0.71 0.40
22 will control 0.07 0.10 0.43 2.44 0.49 0.51 0.04 0.04 0.84
23 will need stronger 1.22 0.09 −0.30 2.18 0.54 0.75 4.38 5.13 0.02
24 will need additional 1.32 0.10 0.66 4.21 0.24 0.75 2.98 3.24 0.07
25 will not alternative 1.37 0.09 1.05 2.26 0.52 0.62 0.29 0.28 0.60
Item Loc. SE Fit Res. Chi Sq. Prob. res. r DIF ANOVA (df = 1)
MS F Prob.
PUQ-R Trust in Doctor Scale (PSI = 0.73)
26 best dose −1.16 0.11 −2.75 16.24 0.00 0.71 0.76 1.29 0.26
27 which medication −1.10 0.11 −2.66 22.06 0.00 0.71 1.43 2.49 0.12
28 help physical −0.88 0.10 −1.15 10.30 0.02 <0.30 3.69 5.09 0.02
29 what’s wrong −0.67 0.10 0.37 4.05 0.26 <0.30 1.95 2.16 0.14
30 physically active −0.19 0.10 −1.59 8.02 0.05 <0.30 0.13 0.18 0.67
31 help non-physical 0.67 0.09 1.28 1.41 0.70 <0.30 0.21 0.21 0.65
32 future progress 1.61 0.09 1.63 1.52 0.68 <0.30 4.56 4.45 0.04
33 cause 1.72 0.08 4.23a 36.72 0.00b <0.30 0.24 0.17 0.68
PUQ-R Self-management Scale (PSI = 0.86)
34 questions −0.52 0.10 0.93 10.46 0.02 <0.30 0.55 0.59 0.44
35 symptom report −0.49 0.11 −0.56 3.69 0.30 <0.30 4.20 5.60 0.02
36 test results 0.11 0.09 0.91 3.65 0.30 <0.30 6.49 7.34 0.01
37 activities to avoid 0.15 0.09 0.10 1.84 0.61 <0.30 0.06 0.07 0.79
38 how to manage 0.32 0.10 −1.11 9.91 0.02 <0.30 3.19 4.61 0.03
39 help control 0.43 0.09 0.93 7.34 0.06 <0.30 2.50 2.81 0.10
PUQ-R Impact Scale (PSI = 0.87)
40 education −1.24 0.16 0.56 1.20 0.75 <0.30 0.48 0.47 0.49
41 relationship −0.91 0.10 2.11 15.09 0.00b 0.32 9.20 8.89 0.00
42 children −0.53 0.13 1.66 5.36 0.15 0.32 4.41 4.21 0.04
43 plan life 0.01 0.10 −1.92 13.60 0.00 <0.30 1.57 2.39 0.12
44 finances 0.02 0.09 1.10 1.73 0.63 <0.30 0.00 0.00 0.97
45 functionality 0.12 0.10 −3.60a 14.73 0.00b <0.30 8.29 16.21 0.00c
46 exercise 0.46 0.10 0.48 1.46 0.69 <0.30 0.55 0.61 0.44
47 mobility 0.54 0.09 −1.36 7.06 0.07 <0.30 5.21 7.45 0.01
48 job prospects 0.54 0.11 −0.58 5.71 0.13 <0.30 0.71 0.94 0.33
49 pregnancy 0.99 0.16 3.31a 27.10 0.00b <0.30 0.63 0.32 0.58
  1. Loc item Location; SE standard error; res. r residual correlation; DIF differential item functioning
  2. afit residuals outside the recommended range is −2.5 to +2.5
  3. bChi-square probability significant after Bonferroni adjustment at p < 0.01
  4. cDIF by patient group (SLE Vs RA) significant after Bonferroni adjustment at <0.01