Background/Purpose: Psoriatic arthritis (PsA) is a unique inflammatory musculoskeletal disorder associated with psoriasis. Related to its detrimental impact on health and quality of life, PsA patients have also been affected with reduced work productivity. Work productivity is an essential determinant of health because it affects a patient’s physical and psychological wellbeing. The purpose of this study was to identify the factors that predict reduced work productivity, as measured by the Work Limitations Questionnaire (WLQ), among patients with PsA. These predictors can be divided into demographic factors, clinical factors, and work related factors. 

Methods: Patients attending a single centre Psoriatic Arthritis Clinic were recruited for participation. Employed participants (including home makers) first completed a Questionnaire for the Assessment of Work Related Factors (QAWRF), to shed light upon the nature of their work. Eligible participants then completed the WLQ. The WLQ scores were used as the dependent variable in a linear regression analysis. The independent variables assessed in this study included work characteristics, demographic factors, and clinical measures, such as PASI, active joint count, damage joint count, and ESR.

Results: 152 patients participated (53% males) with a mean age of 50.7 years, disease duration of 14.6 years, and 85.6% with a post-secondary school education. The mean actively inflamed joint count was 5.3. The damage joint count was 10.4. The mean PASI was 3.2. All patients completed the WLQ, of whom 137 completed both the WLQ and the QAWRF. 18.8% of patients lost 1 or more full days at work and 28.3% lost 1 or more partial work days, due to their health. On both univariate and multivariate linear regression education status, PASI, active joint count, and ESR were associated with reduced work productivity among working PsA patients. Support in the workplace was negatively correlated with reduced work limitations.

Conclusion: Work productivity is associated with demographic, clinical, and work related factors.  This endorses the use of an effective drug to control disease activity and advocates for a more supportive work environment for these patients.

Table 1. Univariate and multivariate linear regression to determine associates of WLQ (N=137)

 

Univariate Model			Multivariate Models
			Full Model		Reduced Model
Covariate	Estimate	P-value	Estimate	P-value	Estimate	P-value
Age at visit	0.06	0.1543	0.03	0.56	—	—
Sex	-3.89	<0.0001	-1.28	0.18	—	—
Duration of PsA	-0.04	0.41	-0.08	0.11	—	—
Education status	-2.96	0.026	-2.57	0.03	-3.13	0.0003
PASI	0.25	0.061	0.26	0.03	0.27	0.017
Active joint count	0.36	<0.0001	0.33	<0.001	0.33	<0.0001
Damage joint count	-0.007	0.87	0.06	0.13	—	—
ESR	0.19	<0.0001	0.07	0.09	0.096	0.012
Physical labour work	0.50	0.1521	-0.19	0.61	—	—
Control work schedule	-0.38	0.2440	-0.06	0.87	—	—
Support at work	-1.32	0.0002	-0.35	0.38	—	—

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-predictors-of-reduced-work-productivity-in-patients-with-psoriatic-arthritis/