305 Pregabalin has efficacy for hand osteoarthritis pain: a proof-of-concept study using pain sensitisation measures

Abstract

Background: Osteoarthritis (OA) is the most prevalent arthritis worldwide and is characterised by chronic pain and impaired physical function. Recent reports suggest that OA pain has inflammatory and neuropathic pain components, with many patients experiencing ongoing pain even after receiving treatment according to NICE guidelines including paracetamol, non‐steroidal anti‐inflammatory drugs (NSAIDs) and joint injections. We have previously demonstrated that people with hand OA report features of pain sensitisation. We therefore hypothesised that heightened pain in hand OA could be reduced with duloxetine or pregabalin. In this prospective, doubleblind, randomised clinical study, we recruited 65 participants, aged 40‐75 years, with a Numerical Rating Scale (NRS) for pain of at least 5. Methods: Participants were randomised to one of the following three groups: duloxetine, pregabalin, and placebo. The primary endpoint was the NRS pain score, and the secondary endpoints included the Australian and Canadian Hand Osteoarthritis Index (AUSCAN) pain, stiffness, and function scores and quantitative sensory testing by pain pressure algometry. Participants were recruited from St George's University Hospitals NHS Trust and participation identification centres across the South London region. Each randomised subject was in the trial for a total of 13 weeks. All data was collected prospectively throughout the trial. Results: After 13 weeks, compared to placebo, ANOVA comparison between the three groups found significant differences between the three groups (P=0.0078). In the intention‐to‐treat analysis, the pregabalin group showed improvement for NRS pain (P=0.023), AUSCAN pain (P=0.008), and AUSCAN function (P=0.009), but no difference was detected between duloxetine and placebo groups (P>0.05). In the per protocol analysis, NRS pain was reduced for pregabalin (P<0.0001) and duloxetine (P=0.029) compared to placebo. After 13 weeks' treatment, no significant differences were detected on pain pressure algometry in the three groups between baseline and completion of the trial. Conclusion: We conclude that centrally acting analgesics improve pain outcomes in people with hand arthritis. We observed that pregabalin had a superior analgesic effect over duloxetine and placebo in hand OA. Centrally‐acting analgesics offer new treatment paradigms for OA pain. We suggest that larger studies carried out over a longer treatment duration are required to fully understand the mechanism of action of centrally acting analgesics in OA.