Staircase-evoked Pain May be More Sensitive Than Traditional Pain Assessments in Discriminating Analgesic Effects: A Randomized, Placebo-controlled Trial of Naproxen in Patients With Osteoarthritis of the Knee

Minimal Clinically Important Change of Movement Pain in Musculoskeletal Pain Conditions

Movement pain, which is distinct from resting pain, is frequently reported by individuals with musculoskeletal pain. There is growing interest in measuring movement pain as a primary outcome in clinical trials, but no minimally clinically important change (MCIC) has been established, limiting interpretations. We analyzed data from 315 participants who participated in previous clinical trials (65 with chronic Achilles tendinopathy; 250 with fibromyalgia) to establish an MCIC for movement pain. A composite movement pain score was defined as the average pain (Numeric Rating Scale: 0-10) during 2 clinically relevant activities. The change in movement pain was calculated as the change in movement pain from pre-intervention to post-intervention. A Global Scale (GS: 1-7) was completed after the intervention on perceived change in health status. Participants were dichotomized into non-responders (GS ≥4) and responders (GS <3). Receiver operating characteristic curves were calculated to determine threshold values and corresponding sensitivity and specificity. We used the Euclidean method to determine the optimal threshold point of the Receiver operating characteristic curve to determine the MCIC. The MCIC for raw change in movement pain was 1.1 (95% confidence interval [CI]: .9-1.6) with a sensitivity of .83 (95% CI: .75-.92) and specificity of .79 (95% CI: .72-.86). For percent change in movement pain the MCIC was 27% (95% CI: 10-44%) with a sensitivity of .79 (95% CI: .70-.88) and a specificity of .82 (95% CI: .72-.90). Establishing an MCIC for movement pain will improve interpretations in clinical practice and research. PERSPECTIVE: A minimal clinically important change (MCIC) of 1.1- points (95% CI: .9-1.6) for movement pain discriminates between responders and non-responders to rehabilitation. This MCIC provides context for interpreting the meaningfulness of improvement in pain specific to movement tasks.

Personal factors and baseline function in patients undergoing non-operative management for chronic hip-related groin pain: a cross-sectional study

Aim

Little is known about the relationship between personal factors and perception of hip-related function among patients with chronic hip-related groin pain (HRGP) seeking non-operative management. This analysis was performed to determine if depressive symptoms, central sensitisation, movement evoked pain (MEP), pressure hypersensitivity and activity level were associated with patients' perception of hip-related function, represented by the International Hip Outcome Tool (iHOT-33).

Methods

This cross-sectional study used baseline data from a pilot randomised clinical trial. Participants had anterior hip symptoms for at least 3 of the past 12 months reproduced on examination. Depressive symptoms, central sensitisation and activity level were quantified with self-report questionnaires. MEP was assessed during step down and squat. Pain pressure threshold (PPT) was used to assess pressure hypersensitivity. Statistical analysis was performed to assess bivariate association between variables and independent association of variables with iHOT-33.

Results

Data from 33 participants (aged 18-40 years) with HRGP were analysed. Greater depressive symptoms (rs=-0.48, p=0.005), higher MEP during step down (rs=-0.36, p=0.040) and squat (rs=-0.39, p=0.024), and greater central sensitisation (rs=-0.33, p=0.058) were associated with lower (worse) iHOT-33 scores. Greater depressive symptoms (β=-0.47, 95% CI -0.76 to -0.17; p=0.003) and higher MEP during squat (β=-0.38, 95% CI -0.68 to -0.08; p=0.014) accounted for 37% of variability in iHOT-33. After adjusting for depressive symptoms and MEP, PPT, central sensitisation symptoms and activity level were not associated iHOT-33.

Conclusions

In patients with HRGP seeking non-operative management, greater depressive symptoms and MEP are independently associated with worse self-perceived hip function.

Trial registration number

NCT03959319.

Reflections from the OARSI 2022 clinical trials symposium: The pain of OA-Deconstruction of pain and patient-reported outcome measures for the benefit of patients and clinical trial design

OBJECTIVE

Osteoarthritis (OA) drug development is hampered by a number of challenges. One of the main challenges is the apparent discordance between pain and structure, which has had a significant impact on drug development programs and has led to hesitance among stakeholders. Since 2017, the Clinical Trials Symposium (CTS) has been hosted under the Osteoarthritis Research Society International (OARSI) leadership. OARSI and the CTS steering committee yearly invite and encourage discussions on selected special subject matter between regulators, drug developers, clinicians, clinical researchers, biomarker specialists, and basic scientists to progress drug development in the OA field.

METHOD

The main topic for the 2022 OARSI CTS was to elucidate the many facets of pain in OA and to enable a discussion between regulators (Food and Drug Administration (FDA) and the European Medicines Agency (EMA)) and drug developers to clarify outcomes and study designs for OA drug development.

RESULTS

Signs or symptoms indicative of nociceptive pain occur in 50-70% of OA patients, neuropathic-like pain in 15-30% of patients, and nociplastic pain in 15-50% of patients. Weight-bearing knee pain is associated with bone marrow lesions and effusions. There are currently no simple objective functional tests whose improvements correlate with patient perceptions.

CONCLUSIONS

The CTS participants, in collaboration with the FDA and EMA, raised several suggestions that they consider key to future clinical trials in OA including the need for more precise differentiation of pain symptoms and mechanisms, and methods to reduce placebo responses in OA trials.

CE: Overcoming Movement-Evoked Pain to Facilitate Postoperative Recovery

ABSTRACT

Severe postoperative movement-evoked pain (MEP) can be immobilizing, instilling in patients the fear that further activity will produce unbearable pain. This impedes healing and restoration of function while also extending time to recovery. Therefore, it is critical to manage MEP effectively through timely evaluation and comprehensive care planning. This article builds on recent calls to standardize testing of MEP to inform care planning in a way that both reduces pain and improves functioning. Subsequent reassessment of MEP can guide the refinement of therapy. Although this approach may seem intuitive, it challenges common practices that focus too heavily on pain intensity, resulting in overtreating, undertreating, or not treating pain, while ignoring the risks of immobility and the importance of movement for improving functional capacity. The authors propose a multifaceted approach to overcoming MEP that nurse clinicians, educators, researchers, and compliance professionals can use to enhance the quality and safety of nursing practice.

Study Protocol Modeling Evoked Pain in Older African Americans With Knee Osteoarthritis

BACKGROUND

African American (AA) older adults with knee osteoarthritis experience more severe chronic pain and advanced physical disability. One of the most prominent stimuli that provokes knee pain is movement. Research suggests that, compared to Whites, AAs report significantly higher movement-evoked pain (MEP) in the knee. However, little is known about the biopsychosocial-behavioral mechanisms underlying MEP.

OBJECTIVES

The aim of the study was to present a study protocol to (a) characterize the biopsychosocial-behavioral mechanisms that predict MEP in AAs with knee osteoarthritis and (b) develop a targeted, mechanism-based self-management intervention to reduce MEP and maximize movement.

METHODS

An observational, mixed-methods cohort study will enroll 90 AA/Black adults (ages 55-90 years) to understand intraindividual and interindividual effects on MEP. Participants will complete assessments of MEP, function and gait, biopsychosocial-behavioral questionnaires, quantitative sensory testing, and 7-day ecological momentary assessments of pain and related symptoms. For the qualitative phase, focus groups will be conducted to co-construct a mechanism-based pain self-management intervention.

RESULTS

We will develop phenotypes of MEP based on biopsychosocial-behavioral predictors and correlate measures of MEP with function. Our central hypothesis is that higher levels of MEP will predict lower self-reported function and poorer performance on functional tasks and that multiple biopsychosocial and behavioral factors will be associated with MEP and function. Predictors may serve as risk or protective factors for MEP and physical function. In targeting the biopsychosocial-behavioral mechanisms of MEP, we anticipate that older AAs may request that intervention components include culturally tailored self-management education, movement/physical activity training, treatment decision-making skills, coaching, spirituality, and social/kinship support.

CONCLUSION

Osteoarthritis is now the single most common cause of disability, mobility limitations, and persistent pain in older adults-especially AA older adults. To our knowledge, this will be the first study to systematically phenotype MEP in an older racial minority population with knee osteoarthritis and will be relevant for reducing knee pain and improving function.

Research design considerations for randomized controlled trials of spinal cord stimulation for pain: Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials/Institute of Neuromodulation/International Neuromodulation Society recommendations

ABSTRACT

Spinal cord stimulation (SCS) is an interventional nonpharmacologic treatment used for chronic pain and other indications. Methods for evaluating the safety and efficacy of SCS have evolved from uncontrolled and retrospective studies to prospective randomized controlled trials (RCTs). Although randomization overcomes certain types of bias, additional challenges to the validity of RCTs of SCS include blinding, choice of control groups, nonspecific effects of treatment variables (eg, paresthesia, device programming and recharging, psychological support, and rehabilitative techniques), and safety considerations. To address these challenges, 3 professional societies (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials, Institute of Neuromodulation, and International Neuromodulation Society) convened a meeting to develop consensus recommendations on the design, conduct, analysis, and interpretation of RCTs of SCS for chronic pain. This article summarizes the results of this meeting. Highlights of our recommendations include disclosing all funding source and potential conflicts; incorporating mechanistic objectives when possible; avoiding noninferiority designs without internal demonstration of assay sensitivity; achieving and documenting double-blinding whenever possible; documenting investigator and site experience; keeping all information provided to patients balanced with respect to expectation of benefit; disclosing all information provided to patients, including verbal scripts; using placebo/sham controls when possible; capturing a complete set of outcome assessments; accounting for ancillary pharmacologic and nonpharmacologic treatments in a clear manner; providing a complete description of intended and actual programming interactions; making a prospective ascertainment of SCS-specific safety outcomes; training patients and researchers on appropriate expectations, outcome assessments, and other key aspects of study performance; and providing transparent and complete reporting of results according to applicable reporting guidelines.

Certainty in ascending sensory signals - The unexplored driver of analgesic placebo response

Previous frameworks have failed to adequately explain the observed correlation between within-subject variability in pain reporting and analgesic placebo response. These relationships have been observed in both clinical and experimental setups. Within-subject variability of clinical pain scores is traditionally assessed based on daily pain diaries collected during the pre-intervention stage. Experimental variability can be assessed by the Focused Analgesia Selection Test (FAST), which calculates the relationship between noxious stimuli administrated at various intensities and pain reports. The variability, either clinical or experimental, has been shown to predict the placebo response. In explaining the placebo response, Bayesian Brain Hypothesis (BBH) posits that pain perception (posterior), is composed of certainty (precision) of expectations (priors due to belief or conditioning) and incoming sensory information (likelihood), with the bulk of research focused on the precision of priors. Virtually all placebo analgesia research has focused on the priors and their certainty, rather than on the certainty of the likelihood, mainly because it cannot be assessed directly. We propose that the within-subject variability, as encapsulated by the FAST, is a proxy for certainty in (or, precision of) ascending sensory signals, and our results suggest that it could not only be assessed, but also manipulated. If true, our hypothesis will facilitate new lines of research and could potentially promote precision analgesic medicine by use of variability of pain scores as a diagnostic method to identify pain patients who will benefit from specific treatments.

A deeper look at pain variability and its relationship with the placebo response: results from a randomized, double-blind, placebo-controlled clinical trial of naproxen in osteoarthritis of the knee

Previous studies have shown a robust correlation between variability of clinical pain scores and responsiveness to placebo (but not active drug) in pain studies, but explanations for these relationships are lacking. We investigated this further by assessing relationship between the Focused Analgesia Selection Test (FAST), a psychophysical method that quantifies pain reporting variability in response to experimental stimuli, variability of daily clinical pain scores as captured using diary, and response to treatment in the context of a randomized controlled crossover trial of naproxen vs placebo in knee osteoarthritis. Evoked pain using the Staircase-Evoked Pain Procedure served as the primary efficacy endpoint. Variability of daily pain scores and the FAST were assessed at baseline. Fifty-five subjects completed the study and were included in the analyses. Our results indicated a statistically significant, moderate linear relationship between variability of clinical and experimental pain reports (r = -0.416, P = 0.004). Both correlated with the placebo response (r = 0.393, P = 0.004; r =-0.371, P = 0.009; respectively), but only the FAST predicted the treatment difference between naproxen and placebo, as demonstrated both in a regression model (P = 0.002, Beta = 0.456, t = 3.342) and in a receiver operating characteristic curve (0.721) analysis. Our results extend previous findings to include a correlation between experimental pain variability and the placebo response and suggest that experimental pain variability is a better predictor of patients who respond preferentially to drug over placebo. A theoretical model unifying these observations is proposed, and practical implications are discussed.