POS0123 NEUROPATHIC PAIN SYMPTOMS IN INFLAMMATORY HAND OSTEOARTHRITIS(OA) LOWERS HEALTH RELATED PHYSICAL QUALITY OF LIFE AND MAY REQUIRE ANOTHER APPROACH THAN ANTI-INFLAMMATORY TREATMENT

Abstract

Background: Pain is a common, difficult to manage symptom in hand osteoarthritis (OA). Multiple pain mechanisms may play a role in hand OA. Objectives: To investigate presence of neuropathic pain symptoms in patients with inflammatory hand OA, characteristics of those patients, their impact on health related quality of life (HR‐QoL), and the influence of anti‐inflammatory treatment on neuropathic pain symptoms. Methods: Data from a randomised, double‐blind, placebo‐controlled trial of prednisolone including 92 patients with hand OA fulfilling ACR criteria were used. At baseline patients had signs of synovial inflammation, a VAS finger pain of ≥30 mm and who flared ≥20 mm upon NSAID washout. The primary endpoint was VAS finger pain (0‐100) at week 6. Neuropathic pain symptoms were measured at baseline and week 6 using the validated painDETECT questionnaire, consisting of questions on pain quality, pain intensity over time and radiating pain. Scores range ‐1 to 38 and patients are classified as having unlikely (<13), indeterminate (13‐18) and likely (>18) neuropathic pain. HR‐QoL was measured with physical component scale (PCS) of Short‐Form 36 (SF36; 0‐100), comorbidities with the Self‐administered Comorbidities Questionnaire (SCQ; 0‐45), radiographic severity with Kellgren‐Lawrence (KL) sum score (0‐120), and treatment response with OMERACT‐OARSI responder criteria. Association of patient characteristics with neuropathic pain symptoms was analysed with univariate and multivariate ordinal logistic regression, with painDETECT as dependent variable. Association of neuropathic pain symptoms with HR‐QoL was analysed with multivariate linear regression, adjusted for age, sex, BMI, VAS finger pain, SCQ score and KL sum score, with PCS as dependent variable. Response of neuropathic pain symptoms and VAS pain to prednisolone was analysed with generalised estimating equations. Association of neuropathic pain symptoms at baseline with response to treatment was analysed using χ2‐tests and GEE. Results: 91 patients had complete painDETECT data at baseline (mean pain‐DETECT score 12.8 [SD 5.9]). Scores were <13 in 53%, 13‐18 in 31% and >18 in 16%. Higher painDETECT score categories were associated with less radiographic damage, more comorbidities, female sex and higher VAS finger pain in multivariate analysis. (table 1) Patients with painDETECT scores >18 had a lower HR‐QoL (PCS ‐6.5 [95%CI ‐10.4 to ‐2.6]) than those with painDETECT scores <13. PainDETECT scores remained unchanged throughout the trial in both prednisolone‐treated and placebo‐treated patients, and there was no between‐group difference at week 6. VAS pain improved more in the prednisolone group than in the placebo group (mean between‐group difference ‐16.5 [95%CI ‐26.1 to ‐6.9]) (figure 1). No association between the presence of neuropathic pain symptoms at baseline and OMERACT‐OARSI response to treatment was found. Conclusion: Patients with inflammatory hand OA and additional neuropathic pain symptoms are more often female and have more comorbidities, and report a lower QoL, than those without. Neuropathic pain symptoms seem unresponsive to anti‐inflammatory therapy. Clinicians should be aware of neuropathic pain symptoms in their patients as they might benefit from additional, specific treatment.