AB1201 PAIN DESCRIPTORS AND DETERMINANTS OF PAIN SENSITIVITY IN KNEE OSTEOARTHRITIS: A COMMUNITY-BASED CROSS-SECTIONAL STUDY

Abstract

BackgroundThe phenomenon of heightened pain sensitivity is implicated in the pain experiences of people with OA[1]. Limited research show that pain sensitivity is associated with poor health and treatment outcomes. However, epidemiological research investigating the extent and determinants of pain sensitivity in OA is scarce. In addition, the quality of pain is poorly described. Both the assessment of quality of pain and pain sensitivity can be important to inform clinical decision-making and treatment.ObjectivesTo explore pain characteristics in individuals with knee osteoarthritis (KOA), to compare pain sensitivity across individuals with KOA, chronic back pain (CBP) and pain-free individuals (NP), and to examine the relationship between clinical and pain characteristics with pain sensitivity in KOA.MethodsCross-sectional, community-based online survey. Two datasets were combined comprising Dutch individuals of ≥ 40 years of age, experiencing chronic knee pain (KOA, N=445; dataset 1), chronic back pain (CLP, N=504; dataset 2), or no pain (NP, N=256; dataset 2). Demographic and clinical characteristics, global health, physical activity/exercise, and pain characteristics including intensity, spreading, duration, quality (SF-MPQ), and sensitivity (PSQ) were assessed. Differences between (sub)groups were examined using analyses of variance or Chi-square tests. Regression analyses were performed to examine determinants of pain sensitivity in the KOA group.ResultsQuality of pain was most commonly described as aching, tender, and tiring-exhausting in the KOA group (Figure 1). Overall, the KOA group had higher levels of pain sensitivity compared to NP group, but lower levels than the CBP group (Table 1). Univariately, pain intensity, its temporality and spreading, global health, doing exercise, and having comorbidities were weakly related to pain sensitivity (standardized beta’s: 0.12-0.27). Symptom duration was not related to pain sensitivity. Older age, higher levels of continuous pain, lower levels of global health, and doing exercise uniquely contributed, albeit modest, to pain sensitivity (P<0.05).Table 1.Mean (SD) pain sensitivity scores across three groupsKOACBPNPKOA vs CBP¥KOA vs NP¥N=445N=504N=256Difference#95% CIDifference#95% CIPSQ-total, mean (SD)4.4 (1.5)4.7 (1.8)3.6 (1.4)-0.23-0.49, 0.030.680.36, 1.01PSQ-minor, mean (SD)3.2 (1.6)3.7 (2.0)2.4 (1.3)-0.32-0.60, -0.050.700.36, 1.05Abbreviations: PSQ=Pain Sensitivity Questionnaire, KOA=Knee OA pain group, CBP=Chronic Back Pain group, NP=Non-pain group. ¥CBP: N = 487, NP: N=242. #Mean differences adjusted for sex and age.Figure 1.Percentage of individuals with self-reported knee OA who rated pain descriptors as moderate to severeNote: Subgroups based on median split total score Pain Sensitivity Questionnaire. *P<0.05ConclusionContinuous pain such as aching and tenderness in combination with decreased physical activity may be indicative for individuals at risk for widespread pain and, ultimately, poor treatment outcomes.