Change in psoriatic arthritis outcome measures impacts SF-36 physical and mental component scores differently: an observational cohort study

Abstract

Objective: The objective was to investigate interplay and physical and mental component scores between change (Δ) in health-related quality of life (HRQoL) quantified by the physical component score (PCS) and mental component score (MCS) retrieved from short-form health survey (SF-36), change in disease activity (ΔDAS28CRP) and manifestations of PsA.

Methods: PsA patients initiating new medical therapy were enrolled. Independent disease measures evaluating disease activity, enthesitis, psoriasis, pain and fatigue were collected at treatment initiation and after 4 months. Interplay between independent disease measures and dependent outcome measures, ΔPCS and ΔMCS, was described with univariate regression analyses. Multivariate regression analyses were applied to assess the impact of independent variables, such as individual disease outcome measures vs ΔDAS28CRP on ΔPCS and ΔMCS.

Results: One hundred and eight PsA patients were included. In the univariate regression analyses, improvement in fatigue, pain and disability were associated with improvement in ΔPCS (β; -2.08, -0.18 and -13.00, respectively; all P < 0.001) and ΔMCS (β; -1.59, -0.12 and -6.07, respectively; P < 0.001, P < 0.001 and P = 0.003, respectively). When patient-reported outcomes were included in the final multivariate models, improvements in ΔPCS and ΔMCS were associated with improvements in pain, fatigue and disability (P < 0.001). Improvement in enthesitis impacted ΔPCS positively (β -0.31, P < 0.001). No association was found between change in skin psoriasis, ΔPCS and ΔMCS (β 0.15, P = 0.056 and β 0.05, P = 0.561, respectively).

Conclusion: In this PsA patient cohort, diminishing pain, disability and fatigue improved PCS and MCS significantly. Changes in enthesitis and psoriasis did not grossly impact HRQoL compared with DAS28CRP. Individual PsA manifestations influence HRQoL differently, which is important clinically when targeting treatment.

Trial registration: ClinicalTrials.gov, http://clinicaltrials.gov, NCT02572700.

Keywords: DAS28CRP; PsA; enthesitis; fatigue; health-related quality of life; pain; psoriasis.

Fig. 1

Patient inclusion flow chart Data were included from the PIPA cohort study [19]. ^aPatients were screened for eligibility by initial interviews at departments of rheumatology or by telephone and later clinical assessment. ^bInclusion criteria included age ≥18 years, diagnosed with PsA fulfilling the CASPAR criteria, presenting with peripheral joint involvement and about to initiate a new conventional synthetic DMARD or biological DMARD treatment course. Data were retrieved on 18 November 2020 from the consecutive cohort.

Fig. 2

SF-36 spydergram for PsA patients before and 4 months after treatment compared with Danish SF-36 normative data Mean SF-36 scores at baseline (yellow) and 4 months follow-up (blue) and Danish normative data (green). BP: bodily pain; GH: general health; MH: mental health; PF: physical functioning; RE: role emotional; RP: role physical; SF: social functioning; VT: vitality.

Fig. 3

3D associations between change in specific individual disease outcome measures, ΔDAS28CRP and change in physical and mental component scores Three-dimensional associations between outcome measures from baseline to follow-up (ΔDAS28CRP and ΔPCS/ΔMCS) and ΔPsAID fatigue (A), ΔVAS pain (B), ΔSPARCC (C) and ΔPASI (D), respectively, presented in xyz plots, with blue arrows indicating positive change and red arrows negative change from baseline to follow-up. The green and blue regression planes represent ΔPCS- and ΔMCS-related data, respectively. DAS28CRP: DAS for 28 joints and CRP; MCS: mental component score; PASI: Psoriasis Area Severity Index; PCS: physical component score; PsAID: PsA impact of disease; SPARCC: Spondyloarthritis Research Consortium of Canada enthesitis index; VAS: visual analog scale.