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Table 5 WPS baseline scores assessed by defined known-groups: patient workplace productivity (randomized set, observed cases)

From: Discriminant validity, responsiveness and reliability of the arthritis-specific Work Productivity Survey assessing workplace and household productivity in patients with psoriatic arthritis

Instrumenta Number of days of work missed over the previous month Number of days with productivity ≤50% at work over the previous month Rate of arthritis interference with work productivity over previous monthb
Worse Better Worse Better Worse Better
HAQ-DI 3.51* 0.99 6.77* 3.17 5.71** 3.00
(cutoff 0.75 and 1.50) n = 71 n = 78 n = 71 n = 78 n = 71 n = 78
DAS28(CRP) 3.54** 0.57 5.30 3.10 4.49# 3.18
(cutoff 4.13 and 5.64) n = 61 n = 61 n = 61 n = 61 n = 61 n = 61
SF-36 PCS 3.18* 0.87 6.85* 2.51 5.61** 2.69
(cutoff 29.56 and 40.43) n = 61 n = 61 n = 61 n = 61 n = 61 n = 61
SF-36 MCS 2.89** 0.33 7.20** 3.03 5.32** 3.15
(cutoff 35.77 and 52.45) n = 61 n = 61 n = 61 n = 61 n = 61 n = 61
PsAQoL 3.67** 0.47 8.11** 1.85 5.47** 2.71
(cutoff 6.00 and 15.00) n = 61 n = 78 n = 61 n = 78 n = 61 n = 78
PASI 2.79 1.33 4.49 3.25 3.67 3.78
(cutoff 3.60 and 14.40) n = 39 n = 40 n = 39 n = 40 n = 39 n = 40
  1. Data presented as mean. DAS28(CRP), Disease Activity Score – 28-joint count based on C-reactive protein; HAQ-DI, Health Assessment Questionnaire – Disability Index; MCS, mental component summary; PASI, Psoriasis Area and Severity Index; PCS, physical component summary; PsAQoL, Psoriatic Arthritis Quality of Life; SF-36, Short Form-36 items; WPS, Work Productivity Survey. aCutoff points represent the first and third quartiles of baseline scores. Worse state defined for each individual measure as: DAS28(CRP) score ≥ third quartile, HAQ-DI ≥ third quartile, PsAQoL ≥ third quartile, SF-36 MCS ≤ first quartile, SF-36 PCS ≤ first quartile, PASI ≥ third quartile. Better state defined for each individual measure as: DAS28(CRP) score ≤ first quartile, HAQ-DI ≤ first quartile, PsAQoL ≤ first quartile, SF-36 MCS ≥ third quartile, SF-36 PCS ≥ third quartile, PASI ≤ first quartile. bWPS Question 4 is a 0 to 10 scale, where 0 = no interference and 10 = complete interference. **P ≤ 0.001. *P ≤ 0.01. #P ≤ 0.05. Nonparametric bootstrap t method with a variance stabilizing transformation, 10,000 replications.