The original painDETECT questionnaire (PDQ) DANBIO study was a survey among all DANBIO users having an arthritis diagnosis 'Pain and pain mechanisms in patients with inflammatory arthritis: A Danish nationwide cross-sectional DANBIO registry survey'. The PDQ was implemented onto the DANBIO touch screens for a period of 6 months in 2013-14 and data from more than 7000 individual patients were collected. The overall background for the study was that central pain mechanisms may be prominent in subsets of patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and other spondyloarthritis (SpA). The study showed that approximately 50 % of patients experienced significant pain levels and that a high PDQ score was associated with higher levels of pain and DAS28 but not with markers of inflammatory activity such as CRP and swollen joint count. Furthermore, indications of more frequent bio-switch in the PDQ groups showing neuropathic pain features were found.
The aim of this study is to examine the association between drug retention of biological DMARDs (bDMARDs) and the PDQ pain classification categories (i.e. non-neuropathic vs. neuropathic features) and to investigate whether this categorization is predictive of drug retention and changes in clinical outcomes over a 5-year period.
