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Abstract
Purpose Optimising health-related quality of life (HRQoL) is an overarching principle in the EULAR recommendationsfor managing SLE. Objective measures of HRQoL are favoured by healthcare payers to permit comparisonsacross populations. How these measures refl ect HRQoL in SLE is not well established. We sought to assesshow fatigue, pain, and functional ability relate to objective HRQoL or subjective overall disease status, andwhich overall measure better refl ects symptoms in SLE.
Methods Data were obtained from a longitudinal cohort of adult Swedish SLE patients: the Clinical Lupus Register inNortheastern Gothia (KLURING). Patient-reported outcomes (PROs) included were: the EQ-5D (an objectivemeasure of HRQoL), the Health Assessment Questionnaire (HAQ) (assessing functional ability), and visualanalogue scales (VAS) to assess pain, fatigue, and subjective overall disease status.
Associations between PROs were examined using Spearman’s correlations. Mixed-effects regression modelswere used to assess associations between symptom-specifi c measures (pain, fatigue, and HAQ) and overallhealth (VAS disease status and EQ-5D).
Results Fatigue, pain, and functional ability were signifi cantly associated with EQ-5D scores (table 1). Correlationplots suggest that limited impairment on symptom measures are associated with better EQ-5D, but greaterimpairment was not clearly associated with worse EQ-5D (figure 1). Symptom measures were signifi cantlyassociated with VAS disease status, and correlations were stronger with disease status than with the EQ-5D.In addition, symptom measures explained more of the variance in subjective disease status than with EQ-5D(R2 0.77 vs. 0.54). VAS disease status was correlated with the EQ-5D, however the plot showed littleassociation in poorer health states.
Mixed-effects regressions for EQ-5D and VAS overall disease status and association with other PROs
Correlation matrix for PROs at the first recorded visit after enrolment in the KLURING registry
Conclusions Fatigue, pain, and functional ability were signifi cant predictors of disease status, indicating that these maybe factors infl uencing HRQoL in SLE. However, objective HRQoL scales may be inadequate indicators of SLEburden, as symptom-specifi c measures were not as strong predictors of EQ-5D. Subjective disease statuswas not clearly associated with objective health status across the spectrum of health states, and thereforethe overall association may not be clinically meaningful. PROs that capture facets of HRQoL impacting SLEpatients may be better indicators of disease status to consider when attempting to optimise HRQoL undertreatment.
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