The study, which was designed to analyse the sensitivity to change of the HAQ in patient groups with different durations of RA, pooled data from clinical trials published between 1980 and 2005 using HAQ as an evaluation measure comparing biologics (drugs derived from living organisms designed to either inhibit or supplement messenger chemicals which play a pivotal role in either fueling or suppressing inflammation), traditional DMARDs (disease-modifying antirheumatic drugs, with the potential to reduce or prevent joint damage and preserve joint integrity and function) and placebo.
As functional assessment by the HAQ is a key outcome measure in clinical trials and practice, the research aimed to further investigate the effects of disease duration on its sensitivity to change.
Using a generalized linear model based on the data from the identified trials, HAQ changes (measured as effect sizes) were modeled for patient groups with different durations of RA. The effects of biologics on the HAQ were striking in early RA, but decreased significantly with increasing duration of RA; effect sizes of biologics were significantly different from those of placebo, but this difference decreased with longer RA duration of the patient groups. At about 10 years of average RA duration, the model indicated insufficient discrimination of biologicals from placebo with respect to the HAQ.
"The results of this research suggest HAQ responsiveness is inversely associated with the mean duration of rheumatoid arthritis in clinical trials – perhaps as a result of an irreversible disability component in long-standing RA that makes it difficult to detect a response signal of functional improvement, and to discriminate this signal from responses seen with placebo treatment" concluded Dr. Daniel Aletaha, Department of Rheumatology, Vienna Medical University, Wien, Austria and the study's lead author. "This research indicates that assessment of functional outcomes needs to be interpreted in the context of the study and its population, and is not a priori interchangeable or comparable between studies of RA", he concluded.
For further information on this study, or to request an interview with the study lead, please do not hesitate to contact the EULAR congress press office on:
Jim Baxter - Onsite tel: 44-0-7900-605652
Jo Spadaccino - Onsite tel: 44-0-7773-271930
Mia Gannedahl - Office tel: 44-0-20-7331-2325 6/22/2006
Abstract number: OP0135
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