The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
The association between negative affect and prescription opioid misuse in patients with chronic pain: the mediating role of opioid craving.
Over the past decade, considerable research has accumulated showing that chronic pain patients experiencing high levels of negative affect (NA) are at increased risk for prescription opioid misuse. The primary objective of the present study was to examine the factors that underlie the association between NA and prescription opioid misuse among patients with chronic pain. In this study, 82 patients with chronic musculoskeletal pain being prescribed opioid medication completed the Current Opioid Misuse Measure, a well-validated self-report questionnaire designed to assess prescription opioid misuse. Patients were also asked to complete self-report measures of pain intensity, NA, and opioid craving. A bootstrapped multiple mediation analysis was used to examine the mediating role of patients' pain intensity and opioid craving in the association between NA and prescription opioid misuse. Consistent with previous research, we found a significant association between NA and prescription opioid misuse. Interestingly, results revealed that opioid craving, but not pain intensity, mediated the association between NA and opioid misuse. The Discussion addresses the potential psychological and neurobiological factors that might contribute to the interrelationships among NA, opioid craving, and prescription opioid misuse in patients with pain. The clinical implications of our findings are also discussed. ⋯ Our study provides new insights into the factors that underlie the association between negative affect and prescription opioid misuse in patients with chronic pain. Our findings could have important clinical implications, particularly for patients being prescribed opioid medication, and for reducing rates of opioid misuse in patients with pain.
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Pain is a serious consequence of spinal cord injury (SCI). Our aim was to investigate the temporal aspects of different types of pain following traumatic SCI and to determine possible predictors of neuropathic pain. Prospective data on 90 patients were collected at 1, 6, and 12 months after traumatic SCI. The patients completed questionnaires on pain severity, descriptors, and impact and underwent clinical examination with bedside sensory testing. Eighty-eight patients completed the 12-month follow-up. Approximately 80% of patients reported any type of pain at all 3 time points. Neuropathic pain related to SCI increased over time, and musculoskeletal pain decreased slightly, with both being present in 59% of patients at 12 months; other neuropathic pain not related to SCI and visceral pain were present in 1 to 3%. At-level neuropathic pain present at 1 month resolved in 45% and below-level pain resolved in 33%. Early (1 month) sensory hypersensitivity (particularly cold-evoked dysesthesia) was a predictor for the development of below-level, but not at-level, SCI pain at 12 months. In conclusion, the present study demonstrates phenotypical differences between at-level and below-level SCI pain, which is important for future studies aiming to uncover underlying pain mechanisms. ⋯ The finding that early sensory hypersensitivity predicts later onset of below-level central neuropathic pain may help to identify patients at risk of developing neuropathic pain conditions after traumatic spinal cord injury. Information about onset of pain may help to identify different phenotypes in neuropathic pain conditions.
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Assessing if an individual patient has achieved clinically meaningful changes in pain intensity is a core aspect in the evaluation of pain treatments. The aim of the present study was to define minimally clinically significant differences (MCSDs) for the numerical rating scale (0-10 NRS) in adolescents with chronic pain. Data from 153 adolescents who completed an inpatient treatment were analyzed. MCSDs were defined as those cut points that yielded an optimal balance between sensitivity and specificity with regard to patients' global impression of change. The variability of the empirically defined cut points was quantified using bootstrapping. Our results show that raw changes of 1 NRS point and percent changes of 12.5% can be considered MCSDs both within the full sample and within various subsamples of patients. Applying the MCSDs developed for adults to pediatric patients yielded extremely low sensitivities; for example, only 22% of the children who described global improvement met the 50% decrease in pain criterion. Studies evaluating chronic pain treatments for adolescents should use MCSDs that are specifically developed for this group of patients. Raw changes of 1 point and 12.5% on the 0 to 10 NRS should be considered clinically meaningful. On a methodological level, we call for more systematic studies aimed at defining MCSDs that also address the variability of cut point estimates so as to foster the integration of findings. ⋯ Many studies are aimed at empirically defining cut points for clinically relevant pain using receiver operating characteristic-based methods. For the first time, we apply these methods to children and show that even when taking into account the variability of the method, cut points specific for children are needed.
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Chronic pain is influenced by biological, psychological, social, and cultural factors. The current study investigated potential roles for combinations of genetic and psychological factors in the development and/or maintenance of chronic musculoskeletal pain. An exercise-induced shoulder injury model was used, and a priori selected genetic (ADRB2, COMT, OPRM1, AVPR1 A, GCH1, and KCNS1) and psychological (anxiety, depressive symptoms, pain catastrophizing, fear of pain, and kinesiophobia) factors were included as predictors. Pain phenotypes were shoulder pain intensity (5-day average and peak reported on numerical rating scale), upper extremity disability (5-day average and peak reported on the QuickDASH), and shoulder pain duration (in days). After controlling for age, sex, and race, the genetic and psychological predictors were entered as main effects and interaction terms in separate regression models for the different pain phenotypes. Results from the recruited cohort (N = 190) indicated strong statistical evidence for interactions between the COMT diplotype and 1) pain catastrophizing for 5-day average upper extremity disability and 2) depressive symptoms for pain duration. There was moderate statistical evidence for interactions for other shoulder pain phenotypes between additional genes (ADRB2, AVPR1 A, and KCNS1) and depressive symptoms, pain catastrophizing, or kinesiophobia. These findings confirm the importance of the combined predictive ability of COMT with psychological distress and reveal other novel combinations of genetic and psychological factors that may merit additional investigation in other pain cohorts. ⋯ Interactions between genetic and psychological factors were investigated as predictors of different exercise-induced shoulder pain phenotypes. The strongest statistical evidence was for interactions between the COMT diplotype and pain catastrophizing (for upper extremity disability) or depressive symptoms (for pain duration). Other novel genetic and psychological combinations were identified that may merit further investigation.
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Comparative Study
Comparison of back pain prognostic risk stratification item sets.
Back pain outcomes may be improved and costs lowered through risk-stratified care, but relative performance of alternative item sets for predicting back pain outcomes has not been well characterized. We compared alternative prognostic item sets based on STarT Back and Chronic Pain Risk screeners in a cohort of patients initiating primary care for back pain. The STarT Back item set was brief and relied on binary responses, whereas the Chronic Pain Risk item set employed scaled responses and assessed pain persistence and diffuse pain. Patients (N = 571) were assessed soon after their initial visit and 502 (88%) were reassessed 4 months later. Items sets based on STarT Back and Chronic Pain Risk prognostic screeners, as well as a combination of items from both, were used to predict Chronic Pain Grade II-IV back pain at 4 months. The area under the receiver operating characteristic curve estimates (95% confidence intervals) were .79 (.74-.83) for items based on the STarT Back, .80 (.75-.83) for items based on Chronic Pain Risk, and .81 (.77-.85) for a composite item set. Differences in prediction were modest. Items from 2 prognostic screeners, and both combined, achieved acceptable and similar prediction of unfavorable back pain outcomes. ⋯ Given comparable predictive validity, choice among prognostic item sets should be based on clinical relevance, number of items, ease of administration, and item simplicity.