Sensitivity to Change and Minimal Important Differences of the LupusQoL in Patients With Systemic Lupus Erythematosus

OBJECTIVE As a health-related quality of life (HRQOL) measure, the LupusQoL is a reliable and valid measure for adults with systemic lupus erythematosus (SLE). This study evaluates the responsiveness and minimal important differences (MIDs) for the 8 LupusQoL domains. METHODS Patients experiencing a flare were recruited from 9 UK centers. At each of the 10 monthly visits, HRQOL (LupusQoL, Short Form 36 health survey [SF-36]), global rating of change (GRC), and disease activity using the British Isles Lupus Assessment Group 2004 index were assessed. The responsiveness of the LupusQoL and the SF-36 was evaluated primarily when patients reported an improvement or deterioration on the GRC scale and additionally with changes in physician-reported disease activity. MIDs were estimated as mean changes when minimal change was reported on the GRC scale. RESULTS A total of 101 patients were recruited. For all LupusQoL domains, mean HRQOL worsened when patients reported deterioration and improved when patients reported an improvement in GRC; SF-36 domains showed comparable responsiveness. Improvement in some domains of the LupusQoL/SF-36 was observed with a decrease in disease activity, but when disease activity worsened, there was no significant change. LupusQoL MID estimates for deterioration ranged from -2.4 to -8.7, and for improvement from 3.5 to 7.3; for the SF-36, the same MID estimates were -2.0 to -11.1 and 2.8 to 10.9, respectively. CONCLUSION All LupusQoL domains are sensitive to change with patient-reported deterioration or improvement in health status. For disease activity, some LupusQoL domains showed responsiveness when there was improvement but none for deterioration. LupusQoL items were derived from SLE patients and provide the advantage of disease-specific domains, important to the patients, not captured by the SF-36.