Validity and reliability of the Lupus QoL index in Turkish systemic lupus erythematosus patients

Background: Systemic lupus erythematosus (SLE) patients have seriously impaired quality of life (QoL). In addition to activity and damage indices used in the past, tools to evaluate QoL in SLE have been developed in recent years. In this study, we test the validity of the Turkish version of the Lupus-QoL (LupusQoL-TR) score, and investigate its association with clinical findings and activity indices.

Methods: A total of 132 patients diagnosed with SLE according to ACR 1997 criteria were included. The clinical and demographic features, and biochemical data were retrieved from hospital records. SLE Disease Activity Index (SLEDAI) and damage score (SLICC-ACR) were determined at the time of administration of Lupus-QoL questionnaire. The Lupus-QoL includes 34 questions divided into eight domains. We reevaluated the LupusQoL-TR and pretested its understandability. SLE patients were concomitantly administered the LupusQoL-TR and generic SF-36. Internal consistency, test-retest reliability, convergent and discriminant validity were calculated.

Results: The mean age of our SLE patients was 37.9 ± 12.8 years. Internal consistency reliability ranged from 0.88 to 0.93, and test-retest reliability from 0.84 to 0.94. LupusQoL-related domains in SF-36 were correlated (from 0.66 to 0.74). Most LupusQoL-TR domains, except planning, were able to discriminate between active and inactive SLE groups. Scores in all domains of the LupusQoL-TR were found to be discriminative for patients with and without damage according to SLICC-ACR score.

Conclusion: The LupusQoL-TR was found to be a valid patient-reported outcome measure method when evaluating QoL in Turkish SLE patients.