Validation and evaluation of the German Brief Index of Lupus Damage (BILD)--a self-reported instrument to record damage in systemic lupus erythematosus.

INTRODUCTION: Damage is a very important predictor for outcome in systemic lupus erythematosus (SLE) and should be routinely documented. Patient-reported assessments for damage are rare and neither the Lupus Damage Index Questionnaire (LDIQ) nor the Brief Index of Lupus Damage (BILD) is validated in German language. Our aim was to validate the BILD in German language and evaluate its use as a patient-administered instrument.
METHOD: We translated and adapted the BILD questionnaire to use it as a self-administered questionnaire for German-speaking SLE patients. It was applied to SLE outpatients at an academic centre and compared to the SLICC/SDI and other lupus outcome parameters.
RESULTS: The German BILD showed as strong a correlation with the SLICC/SDI as the original version of the BILD and a superior correlation compared to the LDIQ. It scored significantly higher with an increase of age, disease duration or disease activity, with a lower functional status or overall health and a higher probability of receiving an incapacity pension.
CONCLUSION: The German version of the BILD shows a comparable validity to the original BILD with even higher correlation to physician-reported damage even when used as a self-administered questionnaire. Hence it represents a promising instrument to survey damage in clinical routine as well as in clinical and epidemiological studies.