Background & Aims

Individuals with knee osteoarthritis (KOA) have large variability in pain intensity that is not strongly associated with radiographic severity. High impact chronic pain (HICP) has been defined as pain occurring on at least half of days in the prior 3-6 months with substantial restriction of daily activities. Data from the United States indicated that 22% of individuals with arthritis have HICP, which is concerning because of increased risk for negative health outcomes. Therefore, the aims of this abstract are to further describe HICP for individuals with KOA in two important areas: a) clinical characteristics and b) response to an exercise-based intervention and physical therapy. These analyses may allow for a better understanding of how HICP leads to negative health outcomes for individuals with KOA.

Methods

These analyses were completed in two different KOA cohorts. For part a), data from the Johnston County Health Study (JoCoHS), including sociodemographic factors, health care use, and psychosocial distress were compared in those with and without HICP. HICP status was defined as a score ?35 on the PROMIS Physical Function instrument. Analyses for JoCoHS included uni- and multi-variable, group comparisons of HICP status based on the aforementioned participant characteristics. For part b), data from the PhysicAl THerapy vs. INternet-Based Strength Training (PATH-IN) Trial, were used to compare treatment response based on HICP status. In this analysis, two intervention groups were combined because there were no differences in trial outcomes. In PATH-IN, HICP was defined as having severe/moderate pain with walking or on stairs. Analyses for PATH-IN involved reporting of changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC total score) at 4 and 12 months.

Results

In JoCoHS (n = 330), 22.1% had HICP. There were no sex or racial/ethnic differences for those with HICP. Those with HICP were likely to have higher BMI and comorbidities, report using pain medication, not have a college degree, and be currently smoking (p-values< 0.05). There were differences (p< 0.001) in all psychosocial measures with higher scores consistently associated with HICP. In multivariable analyses, stronger associations (p<0.01) with HICP were for kinesiophobia, pain medication, pain catastrophizing, and fatigue. In PATH-IN (n = 280 with KOA), 22.8% had HICP. As expected, those with HICP had higher baseline WOMAC total scores (52.2, (Standard Deviation (SD) 14.7) vs. 25.6 (13.3))). Mean changes in WOMAC scores were larger for those with HICP (4 month: -13.4 (13.6) vs. -5.1 (11.0) and 12 month: -10.8 (12.9) vs. -3.8 (13.0). Final 12-month outcomes indicated much higher WOMAC total scores for those with HICP (40.5 (19.6) vs. 21.5 (15.2)).

Conclusions

The rates of HICP were similar across these two KOA cohorts. In addition to differences in several sociodemographic factors, individuals with KOA and HICP in JoCoHS had worse clinical and psychological profiles. Factors with strong associations with HICP included kinesiophobia, pain catastrophizing, and fatigue. Interestingly and somewhat paradoxically, individuals with KOA and HICP had larger improvements in WOMAC scores when standardized exercise-based and physical therapy interventions were delivered for the PATH-IN trial. However, despite these larger improvements, post-treatment pain and function scores were still much higher than those without HICP, indicating that a more intensive intervention approach is likely needed for this group. Furthermore, and informed by our multivariable findings, exercise approaches that directly address kinesiophobia, pain catastrophizing, and/or fatigue might warrant future investigation in individuals with KOA and HICP.

References

George, S. Z., Rubenstein, D., Bolognesi, M. P., & Horn, M. E. (2023). Can Patient-Reported Outcome Measurement Information System Measures Estimate High Impact Chronic Pain After Total Joint Arthroplasty?. The Journal of Arthroplasty. 2023: 38(6S), S47-S51. doi:10.1016/j.arth.2023.03.028

Williams et al. Physical therapy vs. internet-based exercise training (PATH-IN) for patients with knee osteoarthritis: study protocol of a randomized controlled trial. BMC Musculoskelet Disord. 2015: Sep 28:16:264.

Novin S, Alvarez C, Renner JB, Golightly YM, Nelson AE. Features of Knee and Multijoint Osteoarthritis by Sex and Race and Ethnicity: A Preliminary Analysis in the Johnston County Health Study. J Rheumatol. 2023 Sep 15:in press.

Presenting Author

Steven George

Poster Authors

Steven George

PT, PhD

Duke University

Lead Author

Kelli Allen

PhD

University of North Carolina at Chapel Hill and Durham VA Health Care System

Lead Author

Carolina Alvarez MS

University of North Carolina

Lead Author

Liubov Arbeeva MS

University of North Carolina

Lead Author

Leigh Callahan PhD

University of North Carolina

Lead Author

Amanda Nelson MD

MSCR

University of North Carolina

Lead Author

Todd Schwartz DrPH

University of North Carolina

Lead Author

Yvonne Golightly PT

PhD

University of Nebraska and University of North Carolina

Lead Author

Topics

  • Evidence, Clinical Trials, Systematic Review, Guidelines, and Implementation Science