Pain
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Randomized Controlled Trial
Avoid or engage? Outcomes of graded exposure in youth with chronic pain using a sequential replicated single-case randomized design.
Pain-related fear is typically associated with avoidance behavior and pain-related disability in youth with chronic pain. Youth with elevated pain-related fear have attenuated treatment responses; thus, targeted treatment is highly warranted. Evidence supporting graded in vivo exposure treatment (GET) for adults with chronic pain is considerable, but just emerging for youth. ⋯ Improvements during GET Living was superior to the no-treatment randomized baseline period for avoidance, pain acceptance, and pain intensity, whereas fear and pain catastrophizing did not improve. All 5 outcomes emerged as significantly improved at 3- and 6-month follow-ups. The results of this replicated single-case experimental phase design support the effectiveness of graded exposure for youth with chronic pain and elevated pain-related fear avoidance.
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Randomized Controlled Trial
A functional polymorphism in the ABCB1 transporter predicts pharmacologic response to combination of nortriptyline and morphine in neuropathic pain patients.
Many genetic markers have been associated with variations in treatment response to analgesics, but none have been assessed in the context of combination therapies. In this study, the treatment effects of nortriptyline and morphine were tested for an association with genetic markers relevant to pain pathways. Treatment effects were determined for single and combination therapies. ⋯ The UK Biobank data set was then used to validate this genetic association. Here, patients receiving similar combination therapy (opioid + tricyclic antidepressant) carrying the C allele of rs1045642 displayed 33% fewer body pain sites than patients without that allele, suggesting better pain control. In all, our results show a robust effect of the rs1045642 polymorphism in response to chronic pain treatment with a nortriptyline + morphine combination.
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Chronic neuropathic pain (NP) is debilitating and impacts sleep health and quality of life. Treatment with gabapentinoids (GBs) has been shown to reduce pain, but its effects on sleep health have not been systematically evaluated. The objective of this systematic review and meta-analysis was to assess the relationship between GB therapy dose and duration on sleep quality, daytime somnolence, and intensity of pain in patients with NP. ⋯ Pain scores decreased significantly in patients both after 6 weeks of treatment (P < 0.001) and in trials less than 6 weeks (P = 0.017) when compared with placebo. Our data demonstrate that GBs have a positive impact on sleep health, quality of life, and pain in patients with NP syndromes. However, these benefits come at the expense of daytime somnolence.
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Drawing on advances in chronic pain metrics, a simplified Graded Chronic Pain Scale-Revised was developed to differentiate mild, bothersome, and high-impact chronic pain. Graded Chronic Pain Scale-Revised was validated among adult enrollees of 2 health plans (N = 2021). In this population, the prevalence of chronic pain (pain present most or every day, prior 3 months) was 40.5%: 15.4% with mild chronic pain (lower pain intensity and interference); 10.1% bothersome chronic pain (moderate to severe pain intensity with lower interference with life activities); and 15.0% high-impact chronic pain (sustained pain-related activity limitations). ⋯ Persons with high-impact chronic pain, relative to those with bothersome chronic pain, were more likely to have substantial activity limitations (significant differences for 4 of 5 disability indicators) and more often received long-term opioid therapy. Graded Chronic Pain Scale-Revised strongly predicted 5 activity-limitation indicators with area under receiver operating characteristic curve coefficients of 0.76 to 0.89. We conclude that the 5-item Graded Chronic Pain Scale-Revised and its scoring rules provide a brief, simple, and valid method for assessing chronic pain.
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Altered pronociceptive and antinociceptive mechanisms are often implicated in painful conditions and have been increasingly studied over the past decade. For some painful conditions, alterations are well-established, but in populations with low back pain (LBP), there remains considerable debate whether these mechanisms are altered. The present systematic review aimed to address this issue by identifying studies assessing conditioned pain modulation (CPM) and/or temporal summation of pain (TSP) in patients with LBP, comparing with either a healthy control group or using a method with reference data available. ⋯ Nonetheless, CPM was impaired in patients with LBP compared with controls (standardized mean difference = -0.44 [-0.64 to -0.23], P < 0.001), and the magnitude of this impairment was related to pain chronicity (acute/recurrent vs chronic, P = 0.003), duration (RS = -0.62, P = 0.006), and severity (RS = -0.54, P = 0.02). Temporal summation of pain was facilitated in patients with LBP compared with controls (standardized mean difference = 0.50 [0.29-0.72], P < 0.001), and the magnitude of this facilitation was weakly related to pain severity (RS= 0.41, P = 0.04) and appeared to be influenced by test modality (P < 0.001). Impaired CPM and facilitated TSP were present in patients with LBP compared with controls, although the magnitude of differences was small which may direct future research on the clinical utility.