Get a grip on factors related to grip strength in persons with hand osteoarthritis: Results from the Nor-Hand study

Objective To compare levels of grip strength in persons with hand osteoarthritis (OA) with normative values, and examine how hand OA severity and other biopsychosocial factors are associated with grip strength. Methods Levels of grip strength across age groups were compared with normative values from the general population in sex‐stratified analyses using two‐sample T‐tests. Associations between radiographic hand OA severity (Kellgren‐Lawrence sum score) in different joint groups and grip strength of the same hand were examined in 300 persons from the Nor‐Hand study using linear regression. Analyses were repeated using markers of pain, demographic factors, comorbidities, psychological and social factors as independent variables. We adjusted for age, sex and body mass index. Results Persons with hand OA had lower grip strength than the general population, especially in persons below 60 years. In thumb base joints, increasing radiographic severity (range 0‐8) and presence of pain were associated with lower grip strength (beta=‐0.83, 95% CI ‐1.12, ‐0.53 and beta=‐2.15, 95% CI ‐3.15, ‐1.16, respectively). Negative associations with grip strength were also found for women, low education, higher comorbidity index and higher resting heart rate. Conclusion Persons with hand OA have lower grip strength than the general population. Our results support that studies on thumb base OA should include grip strength as an outcome measure. However, other biopsychosocial factors should also be considered when the grip strength is being interpreted, as other factors such as sex, socioeconomic factors, physical fitness, and comorbidities are negatively associated with grip strength

Associations Between Radiographic and Ultrasound‐Detected Features in Hand Osteoarthritis and Local Pressure Pain Thresholds

Objective Pain sensitization contributes to the complex osteoarthritis (OA) pain experience. The relationship between imaging features of hand OA and clinically assessed pain sensitization is largely unexplored. This study was undertaken to examine the association of structural and inflammatory features of hand OA with local pressure pain thresholds (PPTs) in the Nor‐Hand study. Methods The cross‐sectional relationship of severity of structural radiographic features of hand OA (measured according to the Kellgren/Lawrence scale [grade 0–4] and the absence or presence of erosive joint disease) as well as ultrasound‐detected hand joint inflammation (assessed by gray‐scale synovitis [grade 0–3] and the absence or presence of power Doppler activity) to the PPTs of 2 finger joints was examined by multilevel regression analyses adjusted for age, sex, and body mass index, using beta values with 95% confidence intervals (95% CIs). Results A total of 570 joints in 285 participants included in the Nor‐Hand study were assessed. Greater structural and inflammatory severity was associated with lower PPTs, with adjusted beta values of −0.5 (95% CI −0.6, −0.4) per Kellgren/Lawrence grade increase, −1.4 (95% CI −1.8, −0.9) for erosive versus non‐erosive joints, −0.7 (95% CI −0.9, −0.6) per gray‐scale synovitis grade increase, and −1.5 (95% CI −1.8, −1.1) for joints with power Doppler activity on ultrasound versus those without. Conclusion Greater severity of structural pathologic features and hand joint inflammation was associated with lower PPTs in the finger joints of patients with hand OA, indicating pain sensitization. Our results indicate that pain sensitization might be driven by structural and inflammatory pathology in hand OA

Associations between joint pathologies and central sensitization in persons with hand osteoarthritis: results from the Nor-Hand study

Objective: Pain sensitization is associated with pain severity in persons with hand osteoarthritis (OA). What contributes to pain sensitization is unclear. This study explores whether hand OA pathologies and symptom duration are related to central sensitization. Method: Participants with hand OA in the Nor-Hand study underwent bilateral hand radiography and ultrasound examination. Central sensitization was assessed with pressure pain thresholds (PPT) at remote sites (wrist, trapezius and tibialis anterior muscles) and temporal summation (TS). We examined whether hand OA pathologies, independent of each other, including structural severity (Kellgren-Lawrence sum score, presence of erosive hand OA), inflammatory severity (greyscale synovitis and power Doppler activity sum scores) and symptom duration, were related to central sensitization, adjusting for age, sex, body mass index, comorbidities and OA-severity of knee/hip. Results: In 291 participants (88% women, median age 61, IQR 57-66 years) Kellgren-Lawrence, greyscale synovitis and power Doppler activity sum scores were not associated with lower PPTs at remote sites. Persons with erosive hand OA had lower PPTs at the wrist (adjusted beta -0.75, 95%CI -1.32, -0.19) and tibialis anterior (adjusted beta -0.82, 95%CI -1.54, -0.09) and had greater TS (adjusted beta 0.56, 95%CI 0.12, 1.01) compared with persons with non-erosive disease. No associations were found for symptom duration. Conclusions: A person's overall amount of structural or inflammatory hand OA pathologies does not appear to drive central sensitization. Although persons with erosive hand OA showed greater signs of central sensitization, the small differences suggest that central sensitization is mainly explained by other factors than joint pathologies

Associations between joint pathologies and central sensitization in persons with hand osteoarthritis: results from the Nor-Hand study

Objective: Pain sensitization is associated with pain severity in persons with hand osteoarthritis (OA). What contributes to pain sensitization is unclear. This study explores whether hand OA pathologies and symptom duration are related to central sensitization. Method: Participants with hand OA in the Nor-Hand study underwent bilateral hand radiography and ultrasound examination. Central sensitization was assessed with pressure pain thresholds (PPT) at remote sites (wrist, trapezius and tibialis anterior muscles) and temporal summation (TS). We examined whether hand OA pathologies, independent of each other, including structural severity (Kellgren-Lawrence sum score, presence of erosive hand OA), inflammatory severity (greyscale synovitis and power Doppler activity sum scores) and symptom duration, were related to central sensitization, adjusting for age, sex, body mass index, comorbidities and OA-severity of knee/hip. Results: In 291 participants (88% women, median age 61, IQR 57-66 years) Kellgren-Lawrence, greyscale synovitis and power Doppler activity sum scores were not associated with lower PPTs at remote sites. Persons with erosive hand OA had lower PPTs at the wrist (adjusted beta -0.75, 95%CI -1.32, -0.19) and tibialis anterior (adjusted beta -0.82, 95%CI -1.54, -0.09) and had greater TS (adjusted beta 0.56, 95%CI 0.12, 1.01) compared with persons with non-erosive disease. No associations were found for symptom duration. Conclusions: A person's overall amount of structural or inflammatory hand OA pathologies does not appear to drive central sensitization. Although persons with erosive hand OA showed greater signs of central sensitization, the small differences suggest that central sensitization is mainly explained by other factors than joint pathologies

Associations of pain sensitisation with tender and painful joint counts in people with hand osteoarthritis: results from the Nor-Hand study

Objective: To examine associations of pain sensitisation with tender and painful joint counts and presence of widespread pain in people with hand osteoarthritis (OA). Methods: Pressure pain thresholds (PPT) at a painful finger joint and the tibialis anterior muscle, and temporal summation (TS) were measured in 291 persons with hand OA. We examined whether sex-standardised PPT and TS values were associated with assessor-reported tender hand joint count, self-reported painful hand and total body joint counts and presence of widespread pain using linear and logistic regression analyses adjusted for age, sex, body mass index, education and OA severity. Results: People with lower PPTs at the painful finger joint (measure of peripheral and/or central sensitisation) had more tender and painful hand joints than people with higher PPTs. PPT at tibialis anterior (measure of central sensitisation) was associated with painful total body joint count (beta=−0.82, 95% CI −1.28 to –0.35) and presence of widespread pain (OR=0.57, 95% CI 0.43 to 0.77). The associations between TS (measure of central sensitisation) and joint counts in the hands and the total body were statistically non-significant. Conclusion This cross-sectional study suggested that pain sensitisation (ie, lower PPTs) was associated with joint counts and widespread pain in hand OA. This knowledge may be used for improved pain phenotyping of people with hand OA, which may contribute to better pain management through more personalised medicine. Further studies are needed to assess whether a reduction of pain sensitisation leads to a decrease in tender and painful joint counts

Associations of pain sensitisation with tender and painful joint counts in people with hand osteoarthritis: results from the Nor-Hand study

Objective: To examine associations of pain sensitisation with tender and painful joint counts and presence of widespread pain in people with hand osteoarthritis (OA). Methods: Pressure pain thresholds (PPT) at a painful finger joint and the tibialis anterior muscle, and temporal summation (TS) were measured in 291 persons with hand OA. We examined whether sex-standardised PPT and TS values were associated with assessor-reported tender hand joint count, self-reported painful hand and total body joint counts and presence of widespread pain using linear and logistic regression analyses adjusted for age, sex, body mass index, education and OA severity. Results: People with lower PPTs at the painful finger joint (measure of peripheral and/or central sensitisation) had more tender and painful hand joints than people with higher PPTs. PPT at tibialis anterior (measure of central sensitisation) was associated with painful total body joint count (beta=−0.82, 95% CI −1.28 to –0.35) and presence of widespread pain (OR=0.57, 95% CI 0.43 to 0.77). The associations between TS (measure of central sensitisation) and joint counts in the hands and the total body were statistically non-significant. Conclusion This cross-sectional study suggested that pain sensitisation (ie, lower PPTs) was associated with joint counts and widespread pain in hand OA. This knowledge may be used for improved pain phenotyping of people with hand OA, which may contribute to better pain management through more personalised medicine. Further studies are needed to assess whether a reduction of pain sensitisation leads to a decrease in tender and painful joint counts

Associations of pain sensitisation with tender and painful joint counts in people with hand osteoarthritis: results from the Nor-Hand study

Objective: To examine associations of pain sensitisation with tender and painful joint counts and presence of widespread pain in people with hand osteoarthritis (OA). Methods: Pressure pain thresholds (PPT) at a painful finger joint and the tibialis anterior muscle, and temporal summation (TS) were measured in 291 persons with hand OA. We examined whether sex-standardised PPT and TS values were associated with assessor-reported tender hand joint count, self-reported painful hand and total body joint counts and presence of widespread pain using linear and logistic regression analyses adjusted for age, sex, body mass index, education and OA severity. Results: People with lower PPTs at the painful finger joint (measure of peripheral and/or central sensitisation) had more tender and painful hand joints than people with higher PPTs. PPT at tibialis anterior (measure of central sensitisation) was associated with painful total body joint count (beta=−0.82, 95% CI −1.28 to –0.35) and presence of widespread pain (OR=0.57, 95% CI 0.43 to 0.77). The associations between TS (measure of central sensitisation) and joint counts in the hands and the total body were statistically non-significant. Conclusion This cross-sectional study suggested that pain sensitisation (ie, lower PPTs) was associated with joint counts and widespread pain in hand OA. This knowledge may be used for improved pain phenotyping of people with hand OA, which may contribute to better pain management through more personalised medicine. Further studies are needed to assess whether a reduction of pain sensitisation leads to a decrease in tender and painful joint counts

Associations of Body Mass Index With Pain and the Mediating Role of Inflammatory Biomarkers in People With Hand Osteoarthritis

Objective To examine the association of body mass index (BMI) with pain in people with hand osteoarthritis (OA), and explore whether this association, if causal, is mediated by systemic inflammatory biomarkers. Methods In 281 Nor-Hand study participants, we estimated associations between BMI and hand pain, as measured by the Australian/Canadian Osteoarthritis Hand Index (AUSCAN; range 0–20) and Numerical Rating Scale (NRS; range 0–10); foot pain, as measured by NRS (range 0–10); knee/hip pain, as measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC; range 0–20); painful total body joint count; and pain sensitization. We fit natural-effects models to estimate natural direct and natural indirect effects of BMI on pain through inflammatory biomarkers. Results Each 5-unit increase in BMI was associated with more severe hand pain (on average increased AUSCAN by 0.64 [95% confidence interval (95% CI) 0.23, 1.08]), foot pain (on average increased NRS by 0.65 [95% CI 0.36, 0.92]), knee/hip pain (on average increased WOMAC by 1.31 [95% CI 0.87, 1.73]), generalized pain, and pain sensitization. Mediation analyses suggested that the effects of BMI on hand pain and painful total body joint count were partially mediated by leptin and high-sensitivity C-reactive protein (hsCRP), respectively. Effect sizes for mediation by leptin were larger for the hands than for the lower extremities, and were statistically significant for the hands only. Conclusion In people with hand OA, higher BMI is associated with greater pain severity in the hands, feet, and knees/hips. Systemic effects of obesity, measured by leptin, may play a larger mediating role for pain in the hands than in the lower extremities. Low-grade inflammation, measured by hsCRP, may contribute to generalized pain in overweight/obese individuals