Predictive validity of Lupus Patient-Reported Outcome for damage accrual in patients with systemic lupus erythematosus: the LUNA Registry.

Abstract

The predictive validity of disease-specific quality of life (QOL) remains unknown in patients with systemic lupus erythematosus (SLE), although disease-specific measures are equally or more responsive to changes than generic QOL. We aimed to examine the predictive validity of the Lupus Patient-Reported Outcome (PRO) for damage accrual. Patients with SLE and ≥2 measurements over time were included in the Japanese nationwide multicentre registry (LUNA). The Lupus PRO questionnaire contains both health-related (HR) and non-HR QOL measures. Damage accrual was evaluated using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). We examined the association between the Lupus PRO score at baseline and longitudinal SDI scores using mixed-effects models adjusted for prognostic factors. Among 1295 patients, those with higher HR-QOL of Lupus PRO at baseline demonstrated a significantly lower increase in SDI (-0.005/year, 95% confidence interval [CI]: -0.007 to -0.004, P < 0.001). According to the categorization of HR-QOL based on tertile, a similar dose-dependent effect of HR-QOL on longitudinal SDI was identified (second vs first tertile category: -0.101/year, 95% CI: -0.172 to -0.030; third tertile category: -0.211/year, 95% CI: -0.281 to -0.142). Non-HR-QOL was not significantly associated with the SDI scores. Among the HR-QOL domains, cognition, procreation and physical health were significantly associated with the total SDI scores over time. HR-QOL was associated with corticosteroid-dependent and -independent SDI scores. A higher HR-QOL of Lupus PRO was associated with a lower increase in SDI scores. Our findings imply the importance of disease-specific HR-QOL measurements in assessing prognosis.