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

Abstract

ObjectiveAs 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.MethodsPatients 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.ResultsA 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.ConclusionAll 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.

Comparison of the Sensitivity to Change of the 36‐Item Short Form Health Survey and the Lupus Quality of Life Measure Using Various Definitions of Minimum Clinically Important Differences in Patients With Active Systemic Lupus Erythematosus

“…The results of the association between disease activity and HRQoL may be altered by the choice of different disease activity measures, as has been shown in several observational studies and clinical trials. For instance, McElhone et al (10) found that little to no change was identified by HRQoL questionnaires when disease activity (measured by the British Isles Lupus Assessment Group index) worsened, while slightly higher consistency was reflected by these questionnaires when disease activity improved. In a post hoc analysis of the phase III belimumab trials, Furie et al showed that improvement in disease activity, as determined by the SLE Responder Index (SRI) response in patients with active disease, was associated with improvements in clinical, laboratory, and HRQoL measures.…”

“…SF-36 MCID definitions by Strand and Crawford (12) were based on patient-reported changes in the Guyatt "feeling thermometer" (27) in an RCT and are currently being used to identify patients with clinically important changes in RCTs. Devilliers et al and McElhone et al have derived MCID definitions for the SF-36 and, more importantly, for the LupusQoL (10,11), based on longitudinal observational studies. This study is the first to compare the performance of different MCID definitions in the SF-36 and LupusQoL.…”

“…Devilliers et al reported that both the SF-36 and LupusQoL were responsive over a 3-month interval (11). The minimum clinically important differences (MCIDs) for SF-36 and LupusQoL have been established in longitudinal observational studies and in 1 RCT (10,12). To the best of our knowledge, there is yet to be a study comparing the performance of differently defined MCIDs for the SF-36 with the LupusQoL in a cohort of patients with active SLE.…”

“…To the best of our knowledge, there is yet to be a study comparing the performance of differently defined MCIDs for the SF-36 with the LupusQoL in a cohort of patients with active SLE. The objectives of this study were, first, to determine the hypothesis-testing construct validity of the SF-36 and LupusQoL against disease activity in SLE patients with active disease and, second, to compare the sensitivity to change by the SF-36 and LupusQoL according to differently defined MCIDs, based on improvement and worsening (10)(11)(12) in the current cohort.…”

“…SF-36 MCID cutoffs, set by Strand and Crawford, were defined as follows: ≥+2.5 = improved, À0.8 to +2.5 = unchanged, and ≤ À0.8 = worse for summary scores (i.e., SF-36 PCS and MCS scores), and ≥+5.0 = improved, À2.5 to +5.0 = unchanged, and ≤À2.5 = worse for domain scores (12). Devilliers et al and McElhone et al have specified MCID cutoffs for each domain score (10,11).…”