Psoriatic arthritis and ankylosing spondylitis impact on health-related quality of life and working life: a comparative population-based study

Introduction: Psoriatic arthritis (PsA) and ankylosing spondylitis (AS) are chronic disorders that significantly impact patients’ quality of life (QoL), health care systems and society. There is very little data on the epidemiology and the impact of PsA and AS in Portugal, so in this study we aim to: 1) estimate the prevalence of PsA and AS in the adult Portuguese population; 2) compare health-related quality of life (QoL) of PsA and AS with the one of other rheumatic and musculoskeletal diseases (RMD) and with subjects with no rheumatic diseases; 3) compare early retirement and productivity loss among PsA and AS with other RMD. Methods: We used data from EpiReumaPt, a population-based survey, conducted from 2011 to 2013, in which 10661 subjects over 18 years old were screened for RMD. Spondyloarthritis (SpA) was defined by a positive expert opinion combined with the fulfillment of the assessment of spondyloarthritis international society (ASAS) criteria for axial and peripheral SpA. Estimates were computed as weighted proportions considering the study design. Logistic regressions were used to compare AS/PsA subjects with other RMD and the adult Portuguese population without rheumatic diseases. Results: Prevalence rate of SpA was 1.6% (95% CI 1.2% to 2.1%). Subjects with AS or PsA had worse QoL, reflected by EQ5D score when compared with the adult Portuguese population without rheumatic diseases (β=- 0.08; p=0.031). AS and PsA also had worst QoL when compared with participants with other RMD (β=-0.22; p>0.001). AS and in comparison to patients with other RMD, PsA subjects retired early due to their illness (OR=4.95; 95% CI 1.54% to 15.93%). A significant proportion of patients with SpA (13.6%) referred absenteeism in the previous 12 months to the interview. Conclusions: AS and PsA were found to be associated with poor QoL and a high rate of disease-related early retirement, emphasizing the burden of such rheumatic conditions in Portugal.