Pain
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Little is known about long-term pain and function outcomes among patients with chronic noncancer pain initiating chronic opioid therapy (COT). In the Middle-Aged/Seniors Chronic Opioid Therapy study of patients identified through electronic pharmacy records as initiating COT for chronic noncancer pain, we examined the relationships between level of opioid use (over the 120 days before outcome assessment) and pain and activity interference outcomes at 4- and 12-month follow-ups. Patients aged 45+ years (N = 1477) completed a baseline interview; 1311 and 1157 of these comprised the 4- and 12-month analysis samples, respectively. ⋯ A similar pattern was observed for pain intensity at 4 months and for activity interference at both time points. Better outcomes in the minimal/no use group could reflect pain improvement leading to opioid discontinuation. The similarity in outcomes of regular/higher-dose and intermittent/lower-dose opioid users suggests that intermittent and/or lower-dose use vs higher-dose use may confer risk reduction without reducing benefits.
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Multicenter Study
COMPLEXITY, COMORBIDITY AND HEALTHCARE COSTS ASSOCIATED WITH CHRONIC WIDESPREAD PAIN IN PRIMARY CARE.
The objective was to estimate the prevalence of chronic widespread pain (CWP) and compare the quality-of-life (QoL), cardiovascular risk factors, comorbidity, complexity, and health costs with the reference population. A multicenter case-control study was conducted at 3 primary care centers in Barcelona between January and December 2012: 3048 randomized patients were evaluated for CWP according to the American College of Rheumatology definition. Questionnaires on pain, QoL, disability, fatigue, anxiety, depression, and sleep quality were administered. ⋯ In conclusion, the average patient with CWP has a worse QoL and a greater burden of mental health disorders and cardiovascular risk. The average annual cost associated with CWP is nearly 3 times higher than that of patients without CWP, controlling for other clinical factors. These findings have implications for disease management and budgetary considerations.
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Sleep and pain are thought to be bidirectional related on a daily basis in adolescents with chronic pain complaints. In addition, sleep problems have been shown to predict the long-term onset of musculoskeletal pain in middle-aged adults. Yet, the long-term effects of sleep problems on pain duration and different types of pain severity in emerging adults (age: 18-25) are unknown. ⋯ This prospective effect was stronger in females than in males and was mediated by fatigue but not by symptoms of anxiety and depression or physical inactivity. Only abdominal pain had a small long-term effect on sleep problems. Our results suggest that sleep problems may be an additional target for treatment in female emerging adults with musculoskeletal pain complaints.
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Comparative Study
Quantitative sensory testing and pain-evoked cytokine reactivity: Comparison of patients with sickle cell disease to healthy matched controls.
Sickle cell disease (SCD) is an inherited blood disorder associated with significant morbidity, which includes severe episodic pain, and, often, chronic pain. Compared to healthy individuals, patients with SCD report enhanced sensitivity to thermal detection and pain thresholds and have altered inflammatory profiles, yet no studies to date have examined biomarker reactivity after laboratory-induced pain. We sought to examine this relationship in patients with SCD compared to healthy control participants. ⋯ These findings highlight the utility of laboratory pain testing methods for understanding individual differences in inflammatory cytokines. Our findings suggest amplified pain-evoked proinflammatory cytokine reactivity among patients with SCD relative to carefully matched controls. Future research is warranted to evaluate the impact of enhanced pain-related cytokine response and whether it is predictive of clinical characteristics and the frequency/severity of pain crises in patients with SCD.
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High-frequency spontaneous firing in myelinated sensory neurons plays a key role in initiating pain behaviors in several different models, including the radicular pain model in which the rat lumbar dorsal root ganglia (DRG) are locally inflamed. The sodium channel isoform NaV1.6 contributes to pain behaviors and spontaneous activity in this model. Among all isoforms in adult DRG, NaV1.6 is the main carrier of tetrodotoxin-sensitive resurgent Na currents that allow high-frequency firing. ⋯ NaVβ4 siRNA also reduced immunohistochemical NaV1.6 expression. Patch-clamp recordings of tetrodotoxin-sensitive Na currents in acutely cultured medium diameter DRG neurons showed that DRG inflammation increased transient and especially resurgent current, effects blocked by NaVβ4 siRNA. NaVβ4 may represent a more specific target for pain conditions that depend on myelinated neurons expressing NaV1.6.