Background/Purpose:

Psoriatic arthritis (PsA) is a chronic inflammatory arthritis that is associated with joint damage, impaired quality of life and high levels of work disability (WD). However, data on the associations of WD in PsA is limited. Long Term Outcomes in Psoriatic Arthritis II is a prospective UK multicentre observational study of the impact of PsA on WD and the effect of treatment intervention. In this first analysis we set out to determine to what extent structural damage, clinical disease activity, demographic and social factors are associated with WD.

Methods:

Four hundred patients fulfilling CASPAR criteria for PsA were recruited from 23 hospitals across the UK at initiation of DMARD or anti-TNF therapy. Physician assessments (DAPSA score), radiographs (PsA Ratingen score) and patient reported outcomes (HAQ, EQ5D, FACIT, DLQI, global, joint and skin specific activity VAS scores, comorbidities, demographic details, education, location, employer awareness/helpfulness) and work type were collected. WD was assessed with the WPAI which reports work disability as percentage of absenteeism (work time missed), presenteeism (impairment at work/reduced effectiveness) and work productivity loss (overall work impairment/absenteeism plus presenteeism). All variables were considered for inclusion. Logistic and linear regressions were conducted to investigate independent associations with WD. Age demonstrated a non-linear relationship with WD and was therefore included as a quadratic term.

Results:

Of the 400 participants three hundred and fifty three were of UK working age (18-65 years), mean age 46.8 years (sd 11.02), mean disease duration 5.8 years (sd 8.00), 49.9% female. Two hundred and twenty six (64%) were in work with a further 10 over retirement age, but still working. Unemployed participants were older than those in employment, 55 years (sd 14.7) versus 47 years (sd 10.9), had longer disease duration, 8 years (sd 9.8) versus 6 years (sd 7.8), had worse physical function, HAQ 1.3 (sd 0.78) versus 1.0 (sd 0.68), had worse quality of life, EQ5D 0.4 (sd 0.36) versus 0.5 (sd 0.54) and had more radiographic damage, Ratingen score 19 (sd 31.9) versus 8 (sd 16.5). Of the 236 participants in work the mean absenteeism, presenteeism and productivity loss was 14% (sd 29.0), 39% (sd 27.2) and 46% (sd 30.4) respectively. Independent associations with WD are reported in table 1.

Conclusion:

Greater global, joint specific disease activity and worse physical function exerted a negative influence on presenteeism and productivity loss suggesting disease activity is important amongst those who are in work. Greater age, recent disease onset and worse physical function exert a negative influence on remaining in employment. Patient reported employer awareness and helpfulness exerts a strongly positive influence on remaining in employment, even if patients perceive no help is required.

Table 1: Regression models for work disability associations