Pain hypervigilance is associated with greater clinical pain severity and enhanced experimental pain sensitivity among adults with symptomatic knee osteoarthritis.

BACKGROUND: Pain hypervigilance is an important aspect of the fear-avoidance model of pain that may help explain individual differences in pain sensitivity among persons with knee osteoarthritis (OA). PURPOSE: The purpose of this study was to examine the contribution of pain hypervigilance to clinical pain severity and experimental pain sensitivity in persons with symptomatic knee OA. METHODS: We analyzed cross-sectional data from 168 adults with symptomatic knee OA. Quantitative sensory testing was used to measure sensitivity to heat pain, pressure pain, and cold pain, as well as temporal summation of heat pain, a marker of central sensitization. RESULTS: Pain hypervigilance was associated with greater clinical pain severity, as well as greater pressure pain. Pain hypervigilance was also a significant predictor of temporal summation of heat pain. CONCLUSIONS: Pain hypervigilance may be an important contributor to pain reports and experimental pain sensitivity among persons with knee OA.

Racial and ethnic differences in older adults with knee osteoarthritis.

OBJECTIVE: Knee osteoarthritis (OA) contributes significantly to disability in older individuals, and racial/ethnic minorities are disproportionately affected. The present study aimed to characterize differences in clinical and experimental pain, including pain inhibition, among older African American (AA) and non-Hispanic white (NHW) subjects with knee OA. METHODS: AA and NHW subjects with knee OA (n = 267) completed clinical and functional pain assessments, including quantitative sensory testing (QST). We hypothesized that, when compared to NHW subjects, AA subjects would display 1) lower pain tolerance and higher ratings of heat-, mechanical-, and cold-induced pain, 2) greater temporal summation of pain, 3) reduced pain inhibition, and 4) greater clinical pain and poorer function. In addition, we hypothesized that the findings from QST would significantly predict the severity of clinical pain within each race/ethnicity. RESULTS: AA subjects with knee OA displayed increased pain sensitivity, greater temporal summation, and reduced pain inhibition when compared to NHW subjects with knee OA. Moreover, AA subjects reported greater clinical pain and poorer function. Racial/ethnic differences in clinical pain became nonsignificant when the analyses were controlled for education and annual income, whereas differences in QST findings remained highly significant. Although the extent of pain inhibition predicted the severity of clinical pain in both groups, different QST measures were additionally predictive of clinical pain within each group. CONCLUSION: The results of this study establish that there are racial/ethnic differences in experimental and clinical pain and function in older individuals with knee OA. Our findings indicating that different QST measures were associated with clinical pain within the 2 racial/ethnic groups, whereas reduced pain inhibition was important in all participants, warrant further study in order to elucidate the common and group-specific pathophysiologic mechanisms contributing to clinical pain in OA.