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. 2016 May 21;18:114. doi: 10.1186/s13075-016-1004-3

Table 4.

Work productivity activity impairment questionnaire for rheumatoid arthritis (WPAI:RA) results at baseline, week 36, and change from baseline to week 36, according to week-36 concordance category

All patients Positive discordance (n = 187) Concordance (n = 549) Negative discordance (n = 18)
Mean (SD) Median (Q1, Q3) Mean (SD) Median (Q1, Q3) Mean (SD) Median (Q1, Q3) P valuea
Activity impairment (n = 754) Baseline, % 51.1 (20.7) 50.0 (40.0, 70.0) 41.3 (19.2) 40.0 (30.0, 50.0) 42.8 (19.9) 45.0 (30.0, 60.0) <0.0001
Week 36, % 35.4 (20.8) 30.0 (20.0, 50.0) 15.1 (16.6) 10.0 (0, 20.0) 25.6 (21.2) 20.0 (10.0, 50.0) <0.0001
Δ Baseline to week 36 −15.7 (24.5) −10.0 (–30.0, 0) −26.2 (21.7) −30.0 (–0.0, –10.0) −17.2 (25.9) −10.0 (–30.0, 0) <0.0001
Employed patients Positive discordance (n = 76) Concordance (n = 206) Negative discordance (n = 5)
Mean (SD) Median (Q1, Q3) Mean (SD) Median (Q1, Q3) Mean (SD) Median (Q1, Q3) P valuea
Impairment while working (n = 287) Baseline, % 50.0 (27.4) 40.0 (30.0, 70.0) 37.8 (25.5) 30.0 (20.0, 50.0) 42.0 (27.7) 50.0 (20.0, 50.0) 0.0026
Week 36, % 26.3 (18.7) 20.0 (20.0, 40.0) 10.7 (13.8) 10.0 (0, 20.0) 12.0 (13.0) 10.0 (0, 20.0) <0.0001
Δ Baseline to week 36 −23.7 (29.9) −20.0 (–0.0, 0) −27.1 (26.4) −20.0 (–40.0, –10.0) −30.0 (23.5) −20.0 (–50.0, –10.0) <0.0001
Overall work impairment (n = 287) Baseline, % 54.6 (27.1) 50.0 (33.2, 76.1) 41.5 (27.2) 40.0 (20.0, 60.0) 43.7 (28.6) 50.0 (20.0, 58.3) 0.0019
Week 36, % 28.7 (20.6) 20.0 (20.0, 40.0) 12.2 (15.9) 10.0 (0, 20.0) 12.0 (13.0) 10.0 (0, 20.0) <0.0001
Δ Baseline to week 36 −25.8 (30.9) −20.1 (–45.0, –8.6) −29.3 (27.4) −22.0 (–46.7, –10.0) −31.7 (25.4) −20.0 (–58.3, –10.0) <0.0001
Employed patients Positive discordance (n = 74) Concordance (n = 200) Negative discordance (n = 5)
Mean (SD) Median (Q1, Q3) Mean (SD) Median (Q1, Q3) Mean (SD) Median (Q1, Q3) p valuea
Work time missed (n = 279) Baseline, % 16.9 (30.2) 0 (0, 17.2) 10.7 (24.3) 0 (0, 6.3) 3.3 (7.5) 0 (0, 0) 0.1565
Week 36, % 5.9 (15.9) 0 (0, 1.8) 2.4 (11.0) 0 (0, 0) 0 (0) 0 (0, 0) 0.2608
Δ Baseline to week 36 −11.0 (30.9) 0 (–10.5, 0) −8.2 (22.9) 0 (–2.5, 0) −3.3 (7.5) 0 (0, 0) 0.2608

Activity impairment includes all patients who had both baseline and week 36 data for this parameter. The remaining WPAI parameters include only patients who were employed and had WPAI data at both baseline and week 36. A total of 305 patients were employed at both baseline and week 36; individual WPAI parameters differ due to missing baseline or week 36 values. Positive discordance: patient global assessment – physician global assessment ≥2. Negative discordance: patient global assessment – physician global assessment ≤ –2. Concordance: patient global assessment – physician global assessment = 0 or 1. Δ change; Q1 quartile 1, Q3 quartile 3. a P value for baseline is for one-way analysis of variance, and for week 36 it is for an analysis of covariance model adjusted for baseline of the parameter