Background In addition to reduce joint destruction progress and pain, one goal in psoriatic arthritis (PsA) treatment is to improve functional status (FS) and health-related quality of life (HRQoL). Demand for data on patient-reported outcomes is partly driven by the needs of cost-effectiveness analyses for reimbursement decisions. Several outcome measures are used for assessing the complex impact of PsA, but there is need for more information from studies with parallel assessment of FS and HRQoL measures.
Objectives To assess patient-reported functional status by HAQ (health assessment questionnaire) and by BASFI (Bath Ankylosing Spondylitis Functional Index), health-related quality of life by EQ-5D (EuroQol-five dimensions), by DLQI (Dermatology Life Quality Index) and by GH (general health) across sex, age, presence of psoriasis and drug treatment to explore trends of similarities.
Methods A sub cohort of PsA patients from the Swedish SpAScania cohort (age≥15 years, spondyloarthritis between 2003 and 2007 in the Skåne region) was used. 1181/2003 eligible PsA patients (diagnosed with PsA once by rheumatologist/internist or at least twice by other physician) responded to a questionnaire in 2009. Sex, age, disease duration, presence of psoriasis, HAQ, BASFI, EQ-5D, DLQI, and GH regarding joint (GH-rs) and skin symptoms (GH-ss) were assessed. Information about biologic disease modifying antirheumatic drugs (bDMARDs) treatment during 2008–2011 was collected from the Swedish Prescribed Drug Register and from the Southern Swedish Arthritis Treatment Group Register. Differences between groups were tested by chi-squared test for categorical data and Students t-test for continuous data.
Results Out of 1181 patients 43% were men. The mean age (standard deviation) was 58 (13) and 57 (17) years for men and women respectively. Mean disease duration was 13 (11) years. 77% of the patients reported psoriasis. bDMARD treatment during all 4 years was reported by 17% of the patients; 74% reported no use at all during the same period. Women reported significantly worse health across all six health status measures compared to men (Figure 1). Patients with irregular use of bDMARDs during the 4-year period reported significantly worse health compared to patients with use during the whole period or no use at all. There was a significant association between worse health and older age for HAQ, BASFI and GH-rs. Patients with psoriasis reported significantly worse health measured by DLQI and GH-ss.
Conclusions While all outcome measures seemed to capture differences in patient perceptions by treatment not all were sensitive to expected differences as to reporting psoriasis or age. This highlight the value of letting the choice of instrument match the decision problem. For reimbursement decisions, measures picking up differences by treatment group and direct disease related aspects such as skin problems seem important. This is also important knowledge in cost-effectiveness analyses where choice of effectiveness measure may have large impact on the ratio between costs and effects. The finding that patients with irregular bDMARD treatment seem to have worse health than those with long-term regular or no bDMARD treatment at all will be further investigated.
Disclosure of Interest None declared