Pain
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Many analgesics inadequately address the psychiatric comorbidities of chronic and persistent pain, but there is no standard preclinical model of pain-altered behavior to support the development of new therapies. To explore this conflicting and inconclusive literature, we conducted a focused systematic review and meta-analysis on the effect of complete Freund adjuvant-induced (CFA) rodent hind paw inflammation on multiple classical indicators of exploratory behavior, stress coping, and naturalistic behavior. Our primary objective was to define CFA's effect on assays including, but not limited to, the elevated plus maze and forced swim test. ⋯ Complete Freund adjuvant modestly but significantly decreased exploratory behavior, significantly increased passive stress coping in the tail suspension test but not the forced swim test, and significantly decreased preference for sucrose and naturally rewarding activity. Subgroup analyses revealed significant differences between species and animal sourcing. Based on the evidence provided here, we conclude future studies should focus on CFA's effect on natural rewards and naturalistic behaviors.
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In recent years, long-term prescribing and use of strong opioids for chronic noncancer pain (CNCP) has increased in high-income countries. Yet existing uncertainties, controversies, and differing recommendations make the rationale for prolonged opioid use in CNCP unclear. This systematic review and meta-analyses compared the efficacy, safety, and tolerability of strong opioids with placebo or nonopioid therapy in CNCP, with a special focus on chronic low back pain (CLBP). ⋯ Very low to low certainty findings suggest that 4 to 15 weeks (short or intermediate term) opioid therapy in CLBP (compared with placebo) may cause clinically relevant reductions in pain but also more gastrointestinal and nervous system adverse events, with likely no effect on disability. By contrast, long-term opioid therapy (≥6 months) in CNCP may not be superior to nonopioids in improving pain or disability or pain-related function but seems to be associated with more adverse events, opioid abuse or dependence, and possibly an increase in all-cause mortality. Our findings also underline the importance and need for well-designed trials assessing long-term efficacy and safety of opioids for CNCP and CLBP.
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Yoga is frequently used for back pain relief. However, the evidence was judged to be of only low to moderate certainty. To assess the efficacy and safety of yoga in patients with low back pain, a meta-analysis was performed. ⋯ Compared with passive control, yoga was associated with short-term improvements in pain intensity (15 RCTs; mean difference [MD] = -0.74 points on a numeric rating scale; 95% confidence interval [CI] = -1.04 to -0.44; standardized mean difference [SMD] = -0.37 95% CI = -0.52 to -0.22), pain-related disability (15 RCTs; MD = -2.28; 95% CI = -3.30 to -1.26; SMD = -0.38 95% CI = -0.55 to -0.21), mental health (7 RCTs; MD = 1.70; 95% CI = 0.20-3.20; SMD = 0.17 95% CI = 0.02-0.32), and physical functioning (9 RCTs; MD = 2.80; 95% CI = 1.00-4.70; SMD = 0.28 95% CI = 0.10-0.47). Except for mental health, all effects were sustained long-term. Compared with an active comparator, yoga was not associated with any significant differences in short-term or long-term outcomes.
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Persistent postsurgical pain (PPSP) is a common and often disabling postoperative morbidity, but many questions remain about factors associated with PPSP. This systematic review and meta-analysis aimed to identify preoperative, intraoperative, and postoperative factors associated with PPSP after gynecological surgeries, namely, hysterectomy and cesarean section, and urological surgeries, namely, prostatectomy and donor nephrectomy. Overall, 18 gynecological surgery studies, 4 prostatectomy studies, and 2 donor nephrectomy studies met the review criteria, providing data that could be meta-analyzed. ⋯ Persistent postsurgical pain after gynecological and urological surgeries is common. This systematic review identified important factors associated with cesarean section and hysterectomy that can help identify women who are at high risk of PPSP. More high-quality studies with consistent methodology are needed to understand the factors associated with PPSP risk, particularly for surgeries such as prostatectomy and nephrectomy.
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Meta Analysis
Different routes of administration in chronic migraine prevention lead to different placebo responses: a meta-analysis.
Placebo response is a powerful determinant of health outcomes in several disorders. Meta-analysis of clinical trials in pain conditions shows that it can contribute up to 75% of the overall treatment effect. Placebo response deriving from different routes of administration is poorly understood in primary headaches' pharmacological prevention. ⋯ Administration route affects placebo responses in CM preventive treatment. Elucidating the underlying mechanisms that mediate a placebo response in migraine treatment is beneficial to clinical practice and drug development, especially when comparing drugs with different routes of administration, with the effect of application to the head being superior to the other routes in this study. In our study the placebo response accounted for approximately 75% of the therapeutic gain in the treatment of CM.