Sensitivity to Change (Responsiveness) and Minimal Important Differences of the LupusQoL in patients with Systemic Lupus Erythematosus

Abstract

Objective: The LupusQoL is a reliable and valid health-related quality of life (HRQoL) measure for adults with systemic lupus erythematosus (SLE). This study evaluates the responsiveness and minimal important differences (MID) for the eight LupusQoL domains.
Methods: Patients experiencing a flare were recruited from nine UK centres. At each of the ten monthly visits, HRQoL (LupusQoL, SF-36), global rating of change (GRC) and disease activity (DA) using the BILAG-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, secondly, with changes in physician-reported DA. MIDs were estimated as mean changes when minimal change was reported on the GRC scale.
Results: 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 DA but when DA
worsened, there was no significant change. LupusQoL MID estimates for deterioration ranged from -2.4 to -8.7 and for improvement, 3.5 to 7.3; for the SF-36, -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 DA, 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 them, not captured by the SF-36.