Correlates of Neuropathic Pain in Knee Osteoarthritis: The Modified Paindetect Questionnaire and the Osteoarthritis Initiative

Joshua Bernick¹, Wilma M. Hopman^2,3, Marc C. Hochberg⁴ and Jacqueline Hochman⁵, ¹Queen's University, Kingston, ON, Canada, ²Research Methodologist, Kingston General Health Research Institute, Queen's University, Kingston, ON, Canada, ³Adjunct Faculty, Department of Public Health Sciences, Faculty of Medicine, Queen's University, Kingston, ON, Canada, ⁴Head, Division of Rheumatology & Clinical Immunology; Vice Chair, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, ⁵Women's College Hospital, University of Toronto, Toronto, ON, Canada

Meeting: ACR/ARHP Annual Meeting 2018

Keywords: osteoarthritis and pain management

Session Information

Date: Monday, October 22, 2018

Title: Osteoarthritis – Clinical Poster II

Session Type: ACR Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose: Cumulative evidence suggests central sensitization contributes to a neuropathic-like phenotype in a subset of patients with knee osteoarthritis (OA). Using a variety of validated neuropathic pain (NP) questionnaires in musculoskeletal patient cohorts, factors including gender, body mass index, depression, insomnia and pain catastrophizing have been associated with neuropathic symptoms. In the current study, the modified painDetect Questionnaire (mPDQ) was administered to subjects enrolled in the Osteoarthritis Initiative (OAI), a well-established, longitudinal knee OA cohort, with the aim of further exploring the prevalence and correlates of NP specific to knee OA. A better understanding of the factors associated with NP in knee OA can help identify affected patients who may benefit from alternative treatment approaches that target NP pathways.

Methods: The mPDQ was administered to 699 subjects enrolled in the Baltimore OAI cohort during their scheduled 72-month follow up visit. Standard demographic, clinical, and radiographic data were collected as per the OAI study protocol. The presence of NP was determined using a previously defined mPDQ cut-point. Correlates of NP were evaluated through univariate analysis and logistic regression, and included factors relating to demographics, knee OA symptom severity, markers of chronic pain and pain intensity, psychological factors, functional disability, medical comorbidities and concurrent medication usage.

Results: Of the 699 subjects in the cohort, 476 were eligible for the analysis; 99 (21%) subjects were found to have NP symptoms (mPDQ score ≥ 13). Knee Injury and Osteoarthritis (KOOS) pain score, The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score, WOMAC physical function score, Von Korff pain score (VKP) and the Late Life Disability Instrument (LLDI) – limitation dimension were shown to be different between patients with and without NP (p< 0.01). Independent correlates (p<0.01) of NP were: WOMAC total score (OR=1.93), coping strategies – pain catastrophizing subscale (OR=1.23), VKP (OR=1.06), WOMAC physical function score (OR=1.02) and LLDI – limitation dimension (OR=0.98). Multivariate modelling found WOMAC total score (OR=2.07, p=0.018), coping strategies – pain catastrophizing subscale (OR=1.22, p=0.035) and VKP (OR=1.07, p<0.001) to be significant predictors of NP.

Conclusion: Similar to other studies, a subset of the Baltimore OAI knee OA cohort had a NP phenotype, which was associated with more pain catastrophizing and greater symptom burden. This study additionally found that a NP phenotype was associated with greater disability. Further studies are needed to determine if treatment targeted to the NP phenotype reduces knee OA symptom severity and functional impairment in affected individuals.

Domain	Variable	NP⁺ Median (Range)	NP^– Median (Range)	NP⁺ Odds Ratio (95% CI)	NP⁺ (p-value)
Demographics	Age	63 (52-83)	65 (51-85)	0.98 (0.96-1.01)	0.159
Knee OA Symptom Severity	KOOS: Pain Score	83.3 (18.8-100)	91.7 (0-100)	0.99 (0.98-1.00)	0.014
	WOMAC: Total Score	15.35 (0-75.4)	7 (0-76)	1.01 (1.00-1.03)	0.013
	WOMAC: Pain Score	3 (0-15)	1 (0-20)	1.05 (0.99-1.10)	0.085
Pain Intensity	Von Korff Pain Score	63.33 (10-100)	26.67 (0-100)	1.06 (1.05-1.08)	< 0.001**
Psychological Factors	Coping Strategies – Pain Catastrophizing Subscale	1 (0-6)	0 (0-6)	1.23 (1.08-1.40)	0.002*
	Center for Epidemiologic Studies Depression Scale Score	8 (0-36)	5.50 (0-40)	1.03 (1.00-1.05)	0.023
	KOOS: Quality of Life Score	68.8 (6.3-100)	68.8 (0-100)	0.99 (0.98-1.00)	0.017
Functional Disability	Late Life Disability Instrument: Frequency Dimension	52.23 (35.23-70.61)	53.71 (37.39-76.31)	0.96 (0.93-1.00)	0.046
	Late Life Disability Instrument: Limitation Dimension	68.19 (39.63-100)	77.57 (41.54-100)	0.98 (0.97-0.99)	0.003*
	WOMAC: Physical Function Score	10.1 (0-54.4)	4.3 (0-53.1)	1.02 (1.01-1.04)	0.005*

Domain	Variable	NP⁺ Frequency (%)	NP^– Frequency (%)	NP⁺ Odds Ratio (95% CI)	NP⁺ (p-value)
Demographics	Gender (female)	68 (68.7)	218 (57.8)	1.6 (1.00-2.56)	0.051
Knee OA Symptom Severity	WOMAC: Total Score, (≥ 17)	48 (48.5)	172 (36.1)	1.93 (1.23-3.03)	0.004*
Psychological Factors	Center for Epidemiologic Studies Depression Scale Score (≥ 16)	26 (26.3)	84 (17.7)	1.96 (1.15-3.32)	0.013

Table 1: Variables associated with neuropathic pain. *p<0.01; **p<0.001

Disclosure: J. Bernick, None; W. M. Hopman, None; M. C. Hochberg, None; J. Hochman, None.

To cite this abstract in AMA style:

Bernick J, Hopman WM, Hochberg MC, Hochman J. Correlates of Neuropathic Pain in Knee Osteoarthritis: The Modified Paindetect Questionnaire and the Osteoarthritis Initiative [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 9). https://acrabstracts.org/abstract/correlates-of-neuropathic-pain-in-knee-osteoarthritis-the-modified-paindetect-questionnaire-and-the-osteoarthritis-initiative/. Accessed .

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