The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
Exploring what factors mediate treatment effect: Example of the STarT Back study high-risk intervention.
Interventions developed to improve disability outcomes for low back pain (LBP) often show only small effects. Mediation analysis was used to investigate what led to the effectiveness of the STarT Back trial, a large primary care-based trial that treated patients consulting with LBP according to their risk of a poor outcome. The high-risk subgroup, randomized to receive either psychologically-informed physiotherapy (n = 93) or current best care (n = 45), was investigated to explore pain-related distress and pain intensity as potential mediators of the relationship between treatment allocation and change in disability. ⋯ Outcome was measured using the Roland-Morris Disability Questionnaire. Change in pain-related distress and pain intensity were found to have a significant mediating effect of .25 (standardized estimate, bootstrapped 95% confidence interval, .09-.39) on the relationship between treatment group allocation and change in disability outcome. This study adds to the evidence base of treatment mediation studies in pain research and the role of distress in influencing disability outcome in those with complex LBP.
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Barriers to clinical trial recruitment can delay study completion, potentially resulting in increased costs and an unrepresentative sample. In the current study of 150 participants with chronic pain, we used a computerized adaptive choice-based conjoint survey that included 8 characteristics that may affect enrollment in pharmacologic pain treatment trials (ie, treatment allocation, frequency of pain ratings, treatment administration method, current medications, number of study visits, availability of evening and weekend visits, invasiveness of laboratory procedures, payment). ⋯ The fourth most important characteristic was number of study visits (13%), with participants preferring fewer in-person visits and more phone contacts. Understanding the preferences of potential participants is an important step toward enhancing enrollment in pain treatment trials.
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Catastrophizing is a potent psychological modulator of pain across several chronic pain populations; yet despite evidence that patients with sickle cell disease (SCD) catastrophize more than patients with other chronic pain conditions, previous research indicates that catastrophizing is not related to sickle cell pain after controlling for relevant covariates such as depression. Recent research suggests that pain-related catastrophizing should be assessed across pain contexts (eg, dispositional and situational). In this study, we measured disease-specific, general non-disease-related, and situational catastrophizing and assessed the relationship between these contextual dimensions of catastrophizing and laboratory and clinical pain among patients with SCD. ⋯ SCD-specific and non-SCD catastrophizing were associated with clinical pain outcomes, and situational catastrophizing with markers of central sensitization and laboratory pain. Further examination of the time course of laboratory responses revealed that increases in situational catastrophizing were associated with subsequent increases in laboratory pain sensitivity. Taken together, results show the relevance of catastrophizing in understanding pain in SCD, and suggest that context-specific anchors may be beneficial in predicting different aspects of the pain experience (eg, chronic pain, pain sensitization).
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The current study examined the relationship between perceived injustice and attentional bias (AB) toward pain among individuals with chronic low back pain asked to perform and appraise the pain and difficulty of a standardized set of common physical activities. A pictorial dot-probe task assessed AB toward pain stimuli (ie, pain faces cueing pain), after which participants performed the physical tasks. Participants also rated face stimuli in terms of pain, sadness, and anger expression. ⋯ Exploratory analyses indicated that participants with higher levels of perceived injustice rated stimulus faces as sadder and angrier; no such differences emerged for pain ratings. To our knowledge, this is the first study to examine the association between perceived injustice and AB toward pain, as well as perceived injustice and in vivo appraisals of common physical activity. Results extend existing literature and suggest that attentional and potential interpretive bias should be considered in future research.
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Chronic pain is prevalent in children/adolescents and contributes to high rates of healthcare utilization. Research suggests injustice perceptions about pain are important in adult patients and a possible treatment focus. We conducted a preliminary evaluation of the psychometric properties of the Injustice Experiences Questionnaire (IEQ) and the relationship between injustice perceptions, pain, and functioning in chronic pain patients (N = 139, mean age = 15 years, 72% female) presenting to a pediatric pain clinic. ⋯ Additionally, perceived injustice remained significantly associated with pain intensity, functional disability, emotional functioning, social functioning, and school functioning after accounting for relevant demographic and clinical factors. This is the first study to suggest that injustice perceptions are important in the experience of pediatric chronic pain patients. Future studies should more thoroughly examine the psychometric properties of the IEQ in children/adolescents and elucidate the causal nature of these relationships, which will inform treatment efforts to improve pediatric pain care.