Development and preliminary evaluation of a short self-report measure of generalized pain hypersensitivity

Limited content overlap between commonly used self-report instruments for central (pain) sensitization in rheumatology

Objectives

Central pain mechanisms may be prominent in a considerable subset of rheumatology patients with persistent pain. Several self-report instruments have been used in previous research to infer the presence and severity of central sensitization (CS) that stem from different definitions or approaches of CS. The current study aimed to evaluate and quantify the overlap of actual symptoms measured among self-report measures of CS in rheumatology.

Methods

We used Fried's (2017) comprehensive systematic approach to analyse the content of five commonly used or typical self-report measures (Generalized Pain Questionnaire, Pain Sensitivity Questionnaire, Central Sensitization Inventory, Central Aspects of Pain in the Knee scale and the painDETECT) used in rheumatology research and to visualize and quantify the overlap in symptoms measured.

Results

The five instruments together measured 39 different symptoms, most of which could be grouped into nociplastic pain manifestations (7 symptoms), neuropathic pain qualities (5 symptoms), and psychosomatic symptoms and emotional distress (25 symptoms). Most symptoms (74.4%) were unique to a single instrument. Thermal allodynia was the most frequently measured symptom across the different instruments, assessed in four of the measures. Average content overlap was very low and ranged from no overlap at all to moderate overlap (Jaccard index = 0.43) between pairs of instruments.

Conclusion

There is high heterogeneity and limited overlap in the content of self-report measures used to infer central pain sensitization. This may lead to results that are specific to the particular instrument and may limit the generalizability and comparability of study findings in rheumatology research.

Later-Life Functionality in Married Women: The Mediating Role of Self-Perpetuating BMI and Pain Trajectories

The current study investigated how pain and BMI trajectories mediate the influence of family stress (1991-1994) on later-life impaired functionality (2017) in women. The study used prospective data from 244 mid-older rural Midwest Caucasian women who were in long-term marriages over a span of 27 years. Within the structural equation framework, the analytical model used latent constructs of family stress and trajectories of pain and BMI to predict later-life functionality. BMI and pain trajectories mutually influenced each other in forming a self-perpetuating cycle over time in mid-older women. Further, midlife family stress shaped BMI and pain trajectories, and these trajectories had consequences for later-life functionality, as defined by three kinds of impairments: physical, cognitive (subjective memory), and social (loneliness). The findings emphasize the need for policies and interventions that focus on reducing women's stressful family circumstances in middle years to weaken and redirect their association with BMI and pain trajectories.

Test-Retest Reliability of the Generalized Pain Questionnaire in Patients with Rheumatoid Arthritis and Preliminary Reference Values for Non-Clinical and Several Clinical Samples

Introduction

Generalized pain hypersensitivity is a characteristic feature in many different types of chronic pain. Recently, a 7-item self-reported Generalized Pain Questionnaire (GPQ) was developed to evaluate the presence and severity of generalized pain hypersensitivity in chronic pain patients. Here, we evaluate the test-retest reliability of the GPQ and report on preliminary reference values for various patient groups and healthy subjects.

Methods

Eighty-five patients diagnosed with Rheumatoid Arthritis (RA) completed the GPQ twice over a 2-week interval. Relative and absolute indicators of reliability were determined using data of 69 patients (81.2% retest response rate). Using readily available datasets, preliminary reference data were established in two nonclinical populations (NCP1; N = 30 and NCP2; N = 111), and for patients diagnosed with RA (N = 114), gout (N = 97), fibromyalgia (N=98), or neuropathy (N = 25), or participants in a pain rehabilitation program (N = 33).

Results

Total GPQ scores had an ICC of 0.78 (95% CI: 0.67 to 0.86). While no systematic or proportional differences were found for the GPQ total score; two (near-)significant systematic differences were observed for the individual questions. The standard error of measurement and minimal detectable change were 2.22 and 6.2, respectively. Mean ± SD scores were found to be 0.8 ± 1.2 (NCP1), 4.0 ± 4.6 (NCP2), 6.4 ± 5.5 (Gout), 6.5 ± 5.1 (RA), 8.1 ± 4.5 (Neuropathy), 13.6 ± 4.0 (Rehabilitation) and 16.0 ± 5.0 (Fibromyalgia).

Discussion

This study shows that the GPQ has acceptable reliability to be used as a tool to evaluate the presence and intensity of generalized pain hypersensitivity. The absolute measures of reliability and the preliminary reference values reported here aid in the interpretation of future studies with the GPQ.

Further evaluation of inflammatory and non-inflammatory aspects of pain in rheumatoid arthritis patients

Objective

A high discrepancy between the number of tender and swollen joints (e.g. ΔTSJ ≥ 7) has previously been used as an indication for the presence of changes in central mechanisms in patients with moderate-to-high disease activity. In this study, we explored whether the ΔTSJ can also be used to obtain insights into the underlying pain mechanisms in patients with on average well-controlled disease activity.

Methods

A 2 year retrospective analysis of routinely obtained 28-joint DAS (DAS28) components was performed on 45 patients with low inflammatory activity at the group level. All patients underwent pressure pain threshold (PPT) and electrical pain threshold (EPT) measurements and completed four self-report questionnaires [short-form 36 (SF-36v2); central sensitization inventory (CSI); generalized pain questionnaire (GPQ); and the pain catastrophizing scale (PCS)].

Results

Patients with a ΔTSJ ≥ 3 at least once in the past 2 years showed significantly lower EPT and PPT values and higher levels of pain and disability on the SF-36v2 compared with the ΔTSJ < 3 group. Furthermore, GPQ scores were significantly higher in those with ΔTSJ ≥ 3, while CSI and PCS scores were similar.

Conclusion

These findings suggest that in patients in the ΔTSJ ≥ 3 group, mechanisms other than inflammation (only) underlie the pain. Moreover, our findings suggest that among the multiple potential underlying psychological mechanisms, pain catastrophizing (as measured by the PCS) and psychological hypervigilance (as measured by the CSI) do not play an important role. These findings could be useful in the clinical management of the patient. Depending on the dominant mechanism underlying the (persistent) pain, patients might respond differently to treatment.

Assessing Multisensory Sensitivity Across Scales: Using the Resulting Core Factors to Create the Multisensory Amplification Scale

Multisensory sensitivity (MSS), observed in some chronic pain patients, may reflect a generalized central nervous system sensitivity. While several surveys measure aspects of MSS, there remains no gold standard. We explored the underlying constructs of 4 MSS-related surveys (80 items in total) using factor analyses using REDCap surveys (N = 614, 58.7% with pain). Four core- and 6 associated-MSS factors were identified from the items assessed. None of these surveys addressed all major sensory systems and most included additional related constructs. A revised version of the Somatosensory Amplification Scale was developed, encompassing 5 core MSS systems: vision, hearing, smell, tactile, and internal bodily sensations: the 12-item Multisensory Amplification Scale (MSAS). The MSAS demonstrated good internal consistency (alpha = 0.82), test-retest reliability (ICC3,1 = 0.90), and construct validity in the original and in a new, separate cohort (R = 0.54-0.79, P < .0001). Further, the odds of having pain were 2-3.5 times higher in the highest sex-specific MSAS quartile relative to the lowest MSAS quartile, after adjusting for age, sex, BMI, and pain schema (P < .03). The MSAS provides a psychometrically comprehensive, brief, and promising tool for measuring the core-dimensions of MSS. PERSPECTIVE: Multiple multisensory sensitivity (MSS) tools are used, but without exploration of their underlying domains. We found several measures lacking core MSS domains, thus we modified an existing scale to encompass 5 core MSS domains: light, smell, sound, tactile, and internal bodily sensations using only 12 items, with good psychometric properties.

Generalized pain hypersensitivity and associated factors in gout

OBJECTIVES

Previous studies have indicated that a sizeable proportion of patients with inflammatory arthritis present with features characteristic of central pain sensitization. However, this has not yet been examined in patients with gout. The objective of this study was to explore the presence of generalized pain hypersensitivity and associated factors in patients with diagnosed gout.

METHODS

A cross-sectional survey was performed in outpatients with crystal proven gout using the generalized pain questionnaire (GPQ) to screen for the presence of generalized pain hypersensitivity. Additional self-reported socio-demographic and medical information was collected and several patient-reported outcome measures were completed. Univariable logistic regressions and multivariable LASSO regression analysis with 10-fold cross-validation was used to explore relationships with patient characteristics, clinical features and PROMs.

RESULTS

Of the 97 included patients (84.5% male; mean ± standard deviation age: 68.9 ± 11.9 years), 20 patients (20.6%, 95% CI: 13.0-30.0) reported possible generalized pain hypersensitivity defined as a GPQ score ≥11 (range: 0-28; mean ± standard deviation GPQ: 6.3 ± 5.3). Lower age, concomitant fibromyalgia, and more experienced difficulties in performing their social role were independently associated with generalized pain hypersensitivity. Notably, use of urate lowering therapy was significantly lower in those with generalized pain hypersensitivity.

CONCLUSIONS

Generalized pain hypersensitivity appears to be quite common in gout, despite its more intermittent nature compared with other inflammatory arthritides. As this kind of pain does not respond well to regular treatment, screening for non-inflammatory pain may be important for improving pain management in gout.

The Central Aspects of Pain in the Knee (CAP-Knee) questionnaire; a mixed-methods study of a self-report instrument for assessing central mechanisms in people with knee pain

OBJECTIVES

Pain is the prevailing symptom of knee osteoarthritis. Central sensitisation creates discordance between pain and joint pathology. We previously reported a Central Pain Mechanisms trait derived from eight discrete characteristics: Neuropathic-like pain, Fatigue, Cognitive-impact, Catastrophising, Anxiety, Sleep disturbance, Depression, and Pain distribution. We here validate and show that an 8-item questionnaire, Central Aspects of Pain in the Knee (CAP-Knee) is associated both with sensory- and affective- components of knee pain severity.

METHODS

Participants with knee pain were recruited from the Investigating Musculoskeletal Health and Wellbeing study in the East Midlands, UK. CAP-Knee items were refined following cognitive interviews. Psychometric properties were assessed in 250 participants using Rasch-, and factor-analysis, and Cronbach's alpha. Intra-class correlation coefficients tested repeatability. Associations between CAP-Knee and McGill Pain questionnaire pain severity scores were assessed using linear regression.

RESULTS

CAP-Knee targeted the knee pain sample well. Cognitive interviews indicated that participants interpreted CAP-Knee items in diverse ways, which aligned to their intended meanings. Fit to the Rasch model was optimised by rescoring each item, producing a summated score from 0 to 16. Internal consistency was acceptable (Cronbach's alpha = 0.74) and test-retest reliability was excellent (ICC2,1 = 0.91). Each CAP-Knee item contributed uniquely to one discrete 'Central Mechanisms trait' factor. High CAP-Knee scores associated with worse overall knee pain intensity, and with each of sensory- and affective- McGill Pain Questionnaire scores.

CONCLUSION

CAP-Knee is a simple and valid self-report questionnaire, which measures a single 'Central Mechanisms' trait, and may help identify and target centrally-acting treatments aiming to reduce the burden of knee pain.