Comparison of predictive validity of the Lupus Patient-Reported Outcome and Short-Form-12 for damage accrual in systemic lupus erythematosus

OBJECTIVES: A core set of patient-reported outcomes (PROs) for systemic lupus erythematosus (SLE) has not been established, and no studies have compared predictive validity of disease-specific and generic quality of life (QOL) instruments. We aimed to compare the predictive validity of the Lupus PRO and Medical Outcomes Study Short-Form-12 (SF-12) for damage accrual in patients with SLE. METHODS: The Lupus PRO questionnaire contains both health-related (HR) and non-HR-QOL measures, whereas the SF-12 indices are the physical component summary (PCS), mental component summary (MCS), and role-social component summary (RCS). Damage accrual was evaluated using an increase of one unit in the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). We examined the association and predictive accuracy of the Lupus PRO and SF-12 scores at baseline for damage accrual using survival models for recurrent events. RESULTS: Among 1326 patients, those with a higher HR-QOL on Lupus PRO at baseline showed significantly lower damage accrual (hazard ratio: 0.94, 95% confidence interval [CI]: 0.89-0.99), whereas higher PCS and RCS of SF-12 were associated with lower damage accrual (0.92, 95% CI: 0.86-0.98; 0.92, 95% CI: 0.86-0.99). The Akaike Information Criterion, Bayesian Information Criterion, C-index, and area under the curve were comparable between the Lupus PRO and SF-12. Only higher PCS of the SF-12 was associated with glucocorticoid-independent SDI. CONCLUSION: Predictive metrics and discriminatory performance were comparable between the Lupus PRO and SF-12. Our findings highlight both disease-specific and generic QOL measurements can be valuable options for core set outcomes.