Efficacy and safety of antidepressants for the treatment of back pain and osteoarthritis: systematic review and meta-analysis

Efficacy and safety of antidepressants for pain in older adults: A systematic review and meta-analysis

AIMS

In many countries, pain is the most common indication for use of antidepressants in older adults. We reviewed the evidence from randomized controlled trials on the efficacy and safety of antidepressants, compared to all alternatives for pain in older adults (aged ≥65 years).

METHODS

Trials published from inception to 1 February 2024, were retrieved from 13 databases. Two independent reviewers extracted data on study and participant characteristics, primary efficacy (pain scores, converted to 0-100 scale) and harms. Estimates for efficacy were pooled using a random effects model and reported as difference in means and 95% CI. Quality of included trials was assessed using the Cochrane risk of bias tool.

RESULTS

Fifteen studies (n = 1369 participants) met the inclusion criteria. The most frequently studied antidepressants were duloxetine and amitriptyline (6/15 studies each). Pain related to knee osteoarthritis was the most studied (6/15 studies). For knee osteoarthritis, antidepressants did not provide a statistically significant effect for the immediate term (0-2 weeks), (-5.6, 95% confidence interval [CI]: -11.5 to 0.3), but duloxetine provided a statistically significant, albeit a very small effect in the intermediate term, (≥6 weeks and <12 months), (-9.1, 95% CI: -11.8 to -6.4). Almost half (7/15) of the studies reported increased withdrawal of participants in the antidepressant treatment group vs. the comparator group due to adverse events.

CONCLUSIONS

For most chronic painful conditions, the benefits and harms of antidepressant medicines are unclear. This evidence is predominantly from trials with sample sizes of <100, have disclosed industry ties and classified as having unclear or high risk of bias.

Association between persistent musculoskeletal pain and incident sarcopenia in China: the mediating effect of depressive symptoms

Objective

To evaluate the association between musculoskeletal pain and incident sarcopenia and further explore the mediating effect of depressive symptoms among middle-aged and older Chinese adults.

Methods

Using the data from the China Health and Retirement Longitudinal Study 2011 and 2015, we included 12,788 participants in the cross-sectional analysis and 8,322 for the longitudinal analysis. Musculoskeletal pains located in the neck, back, waist, shoulder, arm, wrist, leg, knee, and ankle were self-reported at baseline and follow-up. The diagnosis criteria of sarcopenia was based on the Asian Working Group for Sarcopenia 2019. Multivariable logistic regression models were used to evaluate the association between musculoskeletal pain, and the Karlson-Holm-Breen (KHB) method was used to explore the mediating effect of depressive symptoms.

Results

Over the 4-year follow-up, 445 participants were identified with incident sarcopenia. In the longitudinal analysis, participants with baseline musculoskeletal pain (adjusted odds ratio (OR): 1.37, 95% confidence interval (CI): 1.07-1.76), persistent musculoskeletal pain (OR:1.68, 95%CI: 1.28-2.24), and persistent waist pain (OR:1.46, 95%CI: 1.04-2.03) were significantly associated with increased the risk of incident sarcopenia. Furthermore, depressive symptoms were found to partially mediate the association between musculoskeletal pain and incident sarcopenia.

Conclusion

Persistent musculoskeletal pain, especially in waist area, was positively associated with a higher risk of sarcopenia among the middle-aged and older Chinese. Depressive symptoms played a partial mediating role in this association.

Integrating mechanistic-based and classification-based concepts into perioperative pain management: an educational guide for acute pain physicians

Chronic pain begins with acute pain. Physicians tend to classify pain by duration (acute vs chronic) and mechanism (nociceptive, neuropathic and nociplastic). Although this taxonomy may facilitate diagnosis and documentation, such categories are to some degree arbitrary constructs, with significant overlap in terms of mechanisms and treatments. In clinical practice, there are myriad different definitions for chronic pain and a substantial portion of chronic pain involves mixed phenotypes. Classification of pain based on acuity and mechanisms informs management at all levels and constitutes a critical part of guidelines and treatment for chronic pain care. Yet specialty care is often siloed, with advances in understanding lagging years behind in some areas in which these developments should be at the forefront of clinical practice. For example, in perioperative pain management, enhanced recovery protocols are not standardized and tend to drive treatment without consideration of mechanisms, which in many cases may be incongruent with personalized medicine and mechanism-based treatment. In this educational document, we discuss mechanisms and classification of pain as it pertains to commonly performed surgical procedures. Our goal is to provide a clinical reference for the acute pain physician to facilitate pain management decision-making (both diagnosis and therapy) in the perioperative period.

Failed back surgery syndrome-terminology, etiology, prevention, evaluation, and management: a narrative review

Amid the worldwide increase in spinal surgery rates, a significant proportion of patients continue to experience refractory chronic pain, resulting in reduced quality of life and escalated healthcare demands. Failed back surgery syndrome (FBSS) is a clinical condition characterized by persistent or recurrent pain after one or more spinal surgeries. The diverse characteristics and stigmatizing descriptions of FBSS necessitate a reevaluation of its nomenclature to reflect its complexity more accurately. Accurate identification of the cause of FBSS is hampered by the complex nature of the syndrome and limitations of current diagnostic labels. Management requires a multidisciplinary approach that may include pharmacological treatment, physical therapy, psychological support, and interventional procedures, emphasizing realistic goal-setting and patient education. Further research is needed to increase our understanding, improve diagnostic accuracy, and develop more effective management strategies.

The impact of an immersive digital therapeutic tool on experimental pain: a pilot randomized within-subject experiment with an active control condition

Background

Pain is a complex and multifaced sensory and emotional experience. Virtual reality (VR) has shown promise in reducing experimental pain and chronic pain. This study examines an immersive VR environment initially designed for endometriosis patients, which demonstrated short-term analgesic effects. The research aims to determine the impact of the VR environment on experimental pain intensity and unpleasantness both during and after VR exposure (3D with binaural beats), while using an active control condition (2D with no binaural beats). Additionally, a secondary objective of the study was to identify the psychological and psychophysical factors that predict the analgesic effects of the immersive digital therapeutic tool.

Methods

The study involved twenty-one healthy individuals and used a within-subject design, comparing a VR treatment with an active control condition. Continuous heat stimulation was applied to the left forearm with a Peltier thermode. Pain ratings were collected for immediate and short-term effects.

Results

In both the VR and Control conditions, there were no significant differences in pain intensity before, during, and after exposure. However, during VR exposure, there was a significant decrease in pain unpleasantness as compared to before exposure (p < 0.001), with a 27.2% pain reduction. In the Control condition, there were no significant differences in pain unpleasantness during and after exposure. Furthermore, no psychological and psychophysical factors predicted the analgesic effects.

Discussion

The study investigated how a VR environment affected experimentally induced pain in healthy volunteers. It showed that VR reduced pain unpleasantness during exposure but had no lasting impact. The VR environment mainly influenced the emotional aspect of pain, possibly due to its inclusion of binaural beats and natural stimuli. The study suggests that the VR environment should be tested in chronic pain population with high distress levels.

Registration number clinicaltrialsgov

NCT06130267.

The challenge of pharmacotherapy for musculoskeletal pain: an overview of unmet needs

Musculoskeletal disorders are characterized by several impairments, including pain, affecting muscles, bones, joints and adjacent connective tissue, resulting in temporary or permanent functional limitations and disability. Musculoskeletal pain is particularly prevalent worldwide and greatly impacts the quality of life, social participation and economic burden. To date, several issues persist about the classification of musculoskeletal pain and its management strategies and resources. The treatment of musculoskeletal pain conditions is complex and often requires a multimodal approach, including pharmacological and non-pharmacological therapy that might be ineffective in many cases, resulting in poor patient satisfaction and controversial expectations about the potential benefits of available interventions. This manuscript provides an overview of unmet needs in managing musculoskeletal pain, particularly focusing on pharmacotherapeutic pitfalls in this context.

A Single-Session Process-Based Cognitive-Behavioral Intervention Combined with Multimodal Rehabilitation Treatment for Chronic Pain Associated with Emotional Disorders

BACKGROUND AND OBJECTIVES

Defined by chronic pain, rheumatic diseases are often co-occurring with anxiety and depression. Among the available psychological interventions, cognitive-behavioral therapies have an already-proven efficiency in these cases. However, the need to adjust their structure became ubiquitous during the post-pandemic period. Hence, the objective of this study was to investigate the impact of a single-session, process-based cognitive-behavioral intervention for patients with rheumatic conditions within an in-patient setting.

MATERIALS AND METHODS

A total of 31 participants (mean age 58.9 years) completed the single-session intervention. Assessments were conducted prior to the intervention, post-intervention and after one month.

RESULTS

Pearson's correlations, paired samples T tests and a covariance analysis based on the Linear Mixed Model were performed for exploring the relations between baseline variables and evaluating the impact of the SSI intervention. Immediately after the intervention, a significant reduction in cognitive fusion (p = 0.001, d = 1.78), experiential avoidance (p = 0.001, d = 1.4) and dysfunctional behavioral processes was observed. At the one-month evaluation, participants reported decreased pain (p = 0.001, d = 1.11), anxiety (p = 0.004, d = 0.55) and depression (p = 0.001, d = 0.72).

CONCLUSIONS

The single-session, process-based approach represents a promising intervention in healthcare contexts, as an integrative part of a multimodal rehabilitation treatment in patients with rheumatic conditions.

What a pain in the … back: a review of current treatment options with a focus on naproxen sodium

Non-specific low back pain (LBP) represents a challenging and prevalent condition that is one of the most common symptoms leading to primary care physician visits. While established guidelines recommend prioritizing non-pharmacological approaches as the primary course of action, pharmacological treatments are advised when non-pharmacological approaches are ineffective or based on patient preference. These guidelines recommend non-steroidal anti-inflammatory drugs (NSAIDs) or skeletal muscle relaxers (SMRs) as the first-line pharmacological options for acute or subacute LBP, while NSAIDs are the exclusive first-line pharmacological option for chronic LBP. Although SMRs are generally effective for acute LBP, the available evidence does not support the view that they improve functional recovery, and their comparative efficacy to NSAIDs and other analgesics remains unknown, while studies have shown them to introduce adverse events without significantly reducing LBP. Moreover, opioids continue to be widely prescribed for LBP, despite limited evidence for effectiveness and known risks of addiction and overdose. Broader use of non-opioid pharmacotherapy, including the appropriate use of OTC options, is critical to addressing the opioid crisis. The balance of evidence indicates that NSAIDs have a favorable benefit-risk profile when compared to other available pharmacological treatment options for non-specific LBP, a condition that is primarily acute in nature and well-suited for self-treatment with OTC analgesics. While clinical guidelines do not differentiate between NSAIDs, evidence indicates that OTC naproxen sodium effectively relieves pain across multiple types of pain models, and furthermore, the 14-h half-life of naproxen sodium allows sustained, all day pain relief with reduced patient pill burden as compared to shorter acting options. Choosing the most appropriate approach for managing LBP, including non-pharmacological options, should be based on the patient's condition, severity of pain, potential risks, and individual patient preference and needs.

Precision medicine analysis of heterogeneity in individual-level treatment response to amyloid beta removal in early Alzheimer's disease

INTRODUCTION

Alzheimer's disease (AD) is a neurological disorder with variability in pathology and clinical progression. AD patients may differ in individual-level benefit from amyloid beta removal therapy.

METHODS

Random forest models were applied to the EMERGE trial to create an individual-level treatment response (ITR) score which represents individual-level benefit of high-dose aducanumab relative to the placebo. This ITR score was used to test the existence of heterogeneity in treatment effect (HTE).

RESULTS

We found statistical evidence of HTE in the Clinical Dementia Rating-Sum of Boxes (CDR-SB;P =  0.034). The observed CDR-SB benefit was 0.79 points greater in the group with the top 25% of ITR score compared to the remaining 75% (P = 0.020). Of note, the highest treatment responders had lower hippocampal volume, higher plasma phosphorylated tau 181 and a shorter duration of clinical AD at baseline.

DISCUSSION

This ITR analysis provides a proof of concept for precision medicine in future AD research and drug development.

HIGHLIGHTS

Emerging trials have shown a population-level benefit from amyloid beta (Aβ) removal in slowing cognitive decline in early Alzheimer's disease (AD). This work demonstrates significant heterogeneity of individual-level treatment effect of aducanumab in early AD. The greatest clinical responders to Aβ removal therapy have a pattern of more severe neurodegenerative process.

Comparative Efficacy and Safety of Antidepressants for Patients with Chronic Back Pain: A Network Meta-Analysis

Various antidepressants have introduced in clinical practice for pain management, but it is important to understand how to properly use them. We therefore performed a systematic review and network meta-analysis to compare and rank the efficacy and safety of antidepressants for patients with chronic back pain. We identified eligible randomized controlled trials (RCTs) that investigated the efficacy and safety of antidepressants for chronic back pain from PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov, searching from inception to May 2023. Six categories of antidepressants for the treatment of chronic back pain were included, and the surface under the cumulative ranking probabilities was applied to rank the treatment strategies. Overall, we selected 19 RCTs recruiting 2903 patients for the meta-analysis. Tricyclic antidepressants presented the best relative effects for relief in pain score (surface under the cumulative ranking, 84.4%). The results of pairwise comparison analyses found the use of serotonin-noradrenaline reuptake inhibitors (SNRIs) significantly reduced pain score and low disability score compared with placebo, irrespective of treatment duration. Noradrenaline-dopamine reuptake inhibitors (relative risk [RR], 2.80; 95% confidence interval [CI], 1.30-6.03; P = .008) and SNRIs (RR, 1.17; 95% CI, 1.07-1.27; P < .001) significantly increased the risk of adverse events. SNRIs were associated with an increased risk of withdrawal due to adverse events (RR, 2.37; 95% CI, 1.64-3.43; P < .001). This study found that antidepressants are more efficacious than placebos for treating chronic back pain, and tricyclic antidepressants are the most likely medications that lead to pain relief.

Central Sensitization and Pain: Pathophysiologic and Clinical Insights

Central sensitization is an increased responsiveness of nociceptive neurons in the central nervous system to their normal or subthreshold afferent input.

AIM

To explain how the notion of central sensitization has changed our understanding of pain conditions, discuss how this knowledge can be used to improve the management of pain, and highlight knowledge gaps that future research needs to address.

METHODS

Overview of definitions, assessment methods, and clinical implications.

RESULTS

Human pain models, and functional and molecular imaging have provided converging evidence that central sensitization occurs and is clinically relevant. Measures to assess central sensitization in patients are available; however, their ability to discriminate sensitization of central from peripheral neurons is unclear. Treatments that attenuate central sensitization are available, but the limited understanding of molecular and functional mechanisms hampers the development of target-specific treatments. The origin of central sensitization in human pain conditions that are not associated with tissue damage remains unclear.

CONCLUSION

The knowledge of central sensitization has revolutionized our neurobiological understanding of pain. Despite the limitations of clinical assessment in identifying central sensitization, it is appropriate to use the available tools to guide clinical decisions towards treatments that attenuate central sensitization. Future research that elucidates the causes, molecular and functional mechanisms of central sensitization would provide crucial progress towards the development of treatments that target specific mechanisms of central sensitization.

What are Brazilian orthopaedists' views on the diagnosis and treatment of patients with chronic nonspecific low back pain? A qualitative investigation

BACKGROUND

Orthopaedists are often the first point of contact for patients who present with low back pain (LBP) and chronic LBP in Brazil.

AIM

To explore the views of orthopaedists on therapeutic approaches for chronic non-specific low back pain (CNLBP) with a view to gain insights into aspects of clinical practice considered important to them.

METHODS

A qualitative design underpinned by interpretivism was employed. Participants were (n = 13) orthopaedists with experience in treating patients with CNLBP. Following the pilot interviews, semi-structured interviews were conducted, audio-recorded, transcribed and de-identified. Interview data were thematically analysed.

RESULTS

Four themes were identified. (1) Biophysical aspects are important and predominate, but sometimes their relevance can be unclear; (2) Psychosocial aspects and lifestyle factors influence the therapeutic approach; (3) Treatment of CNLBP - including medication, physical activity, surgery and other invasive procedures and other therapeutic modalities; and (4) Nuances of clinical practice - "it goes beyond medicine".

CONCLUSION

Brazilian orthopaedists value identifying the biophysical cause(s) of chronic low back pain. Psychological factors were often discussed secondary to biophysical aspects, whereas social aspects were rarely mentioned. Orthopaedists highlighted their difficulties in navigating patients' emotions and reassuring patients without referrals to imaging tests. Orthopaedists may benefit from training that targets communication and other relational aspects of care in order to work with people who present with CNLBP.

Impact of mental health components on the development of back pain in young adults with adolescent idiopathic scoliosis

BACKGROUND

Back pain occurs commonly in adults and is multifactorial in nature. This study aimed to assess the prevalence and intensity of back pain during young adulthood in subjects with adolescent idiopathic scoliosis (AIS), as well as factors that may be associated with its prognosis.

METHODS

Subjects with AIS aged 20-39 treated conservatively were included in this study. Patient-reported outcome measures in adulthood involved episodes of back pain, and scales of self-image, depression, anxiety, and stress. Additionally, pain, self-image, and mental health scores were retrieved at the first clinic consultation. Occurrence of back pain was defined as a numeric pain rating scale ≥ 6.

RESULTS

101 participants were enrolled. The prevalence of back pain in the lifetime, past 12 months, past 6 months, past 1 month, past 7 days, and past 24 h were 37%, 35%, 31%, 27%, 23%, and 20%, respectively. Male, self-image, and depression were significant associated factors for the development of back pain at all time points. Furthermore, the analyses of the initial presentation of participants have shown that participants with back pain in adulthood were characterised by poor self-image and mental health during their adolescence.

CONCLUSION

The present study addressed the natural history of back pain in young adults with conservatively treated AIS. Psychological makeup has been shown to constitute the development of back pain and is strongly hinted as an early sign of having back pain in adulthood among subjects with AIS.

General practitioners' decision-making process to prescribe pain medicines for low back pain: a qualitative study

BACKGROUND

Pain medicines are widely prescribed by general practitioners (GPs) when managing people with low back pain (LBP), but little is known about what drives decisions to prescribe these medicines.

OBJECTIVES

The aim of this study was to investigate what influences GPs' decision to prescribe pain medicines for LBP.

DESIGN

Qualitative study with in-depth interviews.

SETTING

Australian primary care.

PARTICIPANTS

We interviewed 25 GPs practising in Australia experienced in managing LBP (mean (SD) age 53.4 (9.1) years, mean (SD) years of experience: 24.6 (9.3), 36% female). GPs were provided three vignettes describing common LBP presentations (acute exacerbation of chronic LBP, subacute sciatica and chronic LBP) and were asked to think aloud how they would manage the cases described in the vignettes.

DATA ANALYSIS

We summarised GP's choices of pain medicines for each vignette using content analysis and used framework analysis to investigate factors that affected GP's decision-making.

RESULTS

GPs more commonly prescribed opioid analgesics. Anticonvulsants and antidepressants were also commonly prescribed depending on the presentation described in the vignette. GP participants made decisions about what pain medicines to prescribe for LBP largely based on previous experiences, including their own personal experiences of LBP, rather than guidelines. The choice of pain medicine was influenced by a range of clinical factors, more commonly the patient's pathoanatomical diagnosis. While many adhered to principles of judicious use of pain medicines, polypharmacy scenarios were also common. Concerns about drug-seeking behaviour, adverse effects, stigma around opioid analgesics and pressure from regulators also shaped their decision-making process.

CONCLUSIONS

We identified several aspects of decision-making that help explain the current profile of pain medicines prescribed for LBP by GPs. Themes identified by our study could inform future implementation strategies to improve the quality use of medicines for LBP.

Between guidelines and clinical trials: evidence-based advice on the pharmacological management of non-specific chronic low back pain

The pharmacological management of nonspecific chronic low back pain (NCLBP) aims to restore patients' daily activities and improve their quality of life. The management of NCLBP is not well codified and extremely heterogeneous, and residual symptoms are common. Pharmacological management should be considered as co-adjuvant to non-pharmacological therapy, and should be guided by the symptoms reported by the patients. Depending on the individual severity of NCLPB, pharmacological management may range from nonopioid to opioid analgesics. It is important to identify patients with generalized sensory hypersensitivity, who may benefit from dedicated therapy. This article provides an evidence-based overview of the principles of pharmacological management of NCLPB.

Effects of elastic kinesiology taping on shoulder proprioception: a systematic review

BACKGROUND

Shoulder injuries are associated with proprioceptive deficits. Elastic kinesiology tape (KT) is used for treating musculoskeletal disorders, including shoulder injuries, as it arguably improves proprioception.

OBJECTIVE

To synthesize the evidence on the effects of elastic KT on proprioception in healthy and pathological shoulders.

METHODS

Four databases (PubMed, WoS, CINAHL, SPORTDiscus) were searched for studies that investigated the effects of elastic KT on shoulder proprioception. Outcome measures were active joint position sense (AJPS), passive joint position sense (PJPS), kinesthesia, sense of force (SoF), and sense of velocity (SoV). Risk of bias (RoB) was assessed using the Cochrane Collaboration RoB tool for randomized controlled trials (RCTs), and the ROBINS-1 for non-RCTs, while the certainty of evidence was determined using GRADE.

RESULTS

Eight studies (5 RCTs, 3 non-RCTs) were included, yielding 187 shoulders (102 healthy and 85 pathological shoulders). RoB ranged from low (2 studies), moderate (5 studies), to high (1 study). Elastic KT has a mixed effect on AJPS of healthy shoulders (n=79) (low certainty). Elastic KT improves AJPS (subacromial pain syndrome and rotator cuff tendinopathy, n=52) and PJPS (chronic hemiparetic shoulders, n=13) among pathological shoulders (very low certainty). Elastic KT has no effect on kinesthesia among individuals with subacromial pain syndrome (n=30) (very low certainty).

CONCLUSION

There is very low to low certainty of evidence that elastic KT enhances shoulder AJPS and PJPS. The aggregate of evidence is currently so low that any recommendation on the effectiveness of elastic KT on shoulder proprioception remains speculative.

Antidepressants for pain management in adults with chronic pain: a network meta-analysis

BACKGROUND

Chronic pain is common in adults, and often has a detrimental impact upon physical ability, well-being, and quality of life. Previous reviews have shown that certain antidepressants may be effective in reducing pain with some benefit in improving patients' global impression of change for certain chronic pain conditions. However, there has not been a network meta-analysis (NMA) examining all antidepressants across all chronic pain conditions.

OBJECTIVES

To assess the comparative efficacy and safety of antidepressants for adults with chronic pain (except headache).

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS, AMED and PsycINFO databases, and clinical trials registries, for randomised controlled trials (RCTs) of antidepressants for chronic pain conditions in January 2022.

SELECTION CRITERIA

We included RCTs that examined antidepressants for chronic pain against any comparator. If the comparator was placebo, another medication, another antidepressant, or the same antidepressant at different doses, then we required the study to be double-blind. We included RCTs with active comparators that were unable to be double-blinded (e.g. psychotherapy) but rated them as high risk of bias. We excluded RCTs where the follow-up was less than two weeks and those with fewer than 10 participants in each arm.  DATA COLLECTION AND ANALYSIS: Two review authors separately screened, data extracted, and judged risk of bias. We synthesised the data using Bayesian NMA and pairwise meta-analyses for each outcome and ranked the antidepressants in terms of their effectiveness using the surface under the cumulative ranking curve (SUCRA). We primarily used Confidence in Meta-Analysis (CINeMA) and Risk of Bias due to Missing Evidence in Network meta-analysis (ROB-MEN) to assess the certainty of the evidence. Where it was not possible to use CINeMA and ROB-MEN due to the complexity of the networks, we used GRADE to assess the certainty of the evidence. Our primary outcomes were substantial (50%) pain relief, pain intensity, mood, and adverse events. Our secondary outcomes were moderate pain relief (30%), physical function, sleep, quality of life, Patient Global Impression of Change (PGIC), serious adverse events, and withdrawal.

MAIN RESULTS

This review and NMA included 176 studies with a total of 28,664 participants. The majority of studies were placebo-controlled (83), and parallel-armed (141). The most common pain conditions examined were fibromyalgia (59 studies); neuropathic pain (49 studies) and musculoskeletal pain (40 studies). The average length of RCTs was 10 weeks. Seven studies provided no useable data and were omitted from the NMA. The majority of studies measured short-term outcomes only and excluded people with low mood and other mental health conditions. Across efficacy outcomes, duloxetine was consistently the highest-ranked antidepressant with moderate- to high-certainty evidence. In duloxetine studies, standard dose was equally efficacious as high dose for the majority of outcomes. Milnacipran was often ranked as the next most efficacious antidepressant, although the certainty of evidence was lower than that of duloxetine. There was insufficient evidence to draw robust conclusions for the efficacy and safety of any other antidepressant for chronic pain.  Primary efficacy outcomes Duloxetine standard dose (60 mg) showed a small to moderate effect for substantial pain relief (odds ratio (OR) 1.91, 95% confidence interval (CI) 1.69 to 2.17; 16 studies, 4490 participants; moderate-certainty evidence) and continuous pain intensity (standardised mean difference (SMD) -0.31, 95% CI -0.39 to -0.24; 18 studies, 4959 participants; moderate-certainty evidence). For pain intensity, milnacipran standard dose (100 mg) also showed a small effect (SMD -0.22, 95% CI -0.39 to 0.06; 4 studies, 1866 participants; moderate-certainty evidence). Mirtazapine (30 mg) had a moderate effect on mood (SMD -0.5, 95% CI -0.78 to -0.22; 1 study, 406 participants; low-certainty evidence), while duloxetine showed a small effect (SMD -0.16, 95% CI -0.22 to -0.1; 26 studies, 7952 participants; moderate-certainty evidence); however it is important to note that most studies excluded participants with mental health conditions, and so average anxiety and depression scores tended to be in the 'normal' or 'subclinical' ranges at baseline already. Secondary efficacy outcomes Across all secondary efficacy outcomes (moderate pain relief, physical function, sleep, quality of life, and PGIC), duloxetine and milnacipran were the highest-ranked antidepressants with moderate-certainty evidence, although effects were small. For both duloxetine and milnacipran, standard doses were as efficacious as high doses. Safety There was very low-certainty evidence for all safety outcomes (adverse events, serious adverse events, and withdrawal) across all antidepressants. We cannot draw any reliable conclusions from the NMAs for these outcomes.

AUTHORS' CONCLUSIONS

Our review and NMAs show that despite studies investigating 25 different antidepressants, the only antidepressant we are certain about for the treatment of chronic pain is duloxetine. Duloxetine was moderately efficacious across all outcomes at standard dose. There is also promising evidence for milnacipran, although further high-quality research is needed to be confident in these conclusions. Evidence for all other antidepressants was low certainty. As RCTs excluded people with low mood, we were unable to establish the effects of antidepressants for people with chronic pain and depression. There is currently no reliable evidence for the long-term efficacy of any antidepressant, and no reliable evidence for the safety of antidepressants for chronic pain at any time point.

Surgical versus non-surgical treatment for sciatica: systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To investigate the effectiveness and safety of surgery compared with non-surgical treatment for sciatica.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, CINAHL, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and the World Health Organisation International Clinical Trials Registry Platform from database inception to June 2022.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials comparing any surgical treatment with non-surgical treatment, epidural steroid injections, or placebo or sham surgery, in people with sciatica of any duration due to lumbar disc herniation (diagnosed by radiological imaging).

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data. Leg pain and disability were the primary outcomes. Adverse events, back pain, quality of life, and satisfaction with treatment were the secondary outcomes. Pain and disability scores were converted to a scale of 0 (no pain or disability) to 100 (worst pain or disability). Data were pooled using a random effects model. Risk of bias was assessed with the Cochrane Collaboration's tool and certainty of evidence with the grading of recommendations assessment, development, and evaluation (GRADE) framework. Follow-up times were into immediate term (≤six weeks), short term (>six weeks and ≤three months), medium term (>three and <12 months), and long term (at 12 months).

RESULTS

24 trials were included, half of these investigated the effectiveness of discectomy compared with non-surgical treatment or epidural steroid injections (1711 participants). Very low to low certainty evidence showed that discectomy, compared with non-surgical treatment, reduced leg pain: the effect size was moderate at immediate term (mean difference -12.1 (95% confidence interval -23.6 to -0.5)) and short term (-11.7 (-18.6 to -4.7)), and small at medium term (-6.5 (-11.0 to -2.1)). Negligible effects were noted at long term (-2.3 (-4.5 to -0.2)). For disability, small, negligible, or no effects were found. A similar effect on leg pain was found when comparing discectomy with epidural steroid injections. For disability, a moderate effect was found at short term, but no effect was observed at medium and long term. The risk of any adverse events was similar between discectomy and non-surgical treatment (risk ratio 1.34 (95% confidence interval 0.91 to 1.98)).

CONCLUSION

Very low to low certainty evidence suggests that discectomy was superior to non-surgical treatment or epidural steroid injections in reducing leg pain and disability in people with sciatica with a surgical indication, but the benefits declined over time. Discectomy might be an option for people with sciatica who feel that the rapid relief offered by discectomy outweighs the risks and costs associated with surgery.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021269997.

Associations between chronic pain, anxiety, and depression among adults in the United States

OBJECTIVE

The objective of the study was to determine the associations of depression and anxiety with chronic pain among U.S. adults.

SETTING

Nationally representative cross-sectional survey analysis.

METHODS

The National Health Interview Survey for 2019 was analyzed with respect to the chronic pain module and embedded depression and anxiety scales (PHQ-8 and GAD-7). Univariate associations between the presence of chronic pain and depression and anxiety scores were determined. Similarly, associations between the presence of chronic pain and the adults' treating with medications for depression and anxiety were also determined. Odds ratios, adjusted for age and sex, were computed for these associations.

RESULTS

Among 244.6 million sampled U.S. adults, 50.2 million (95% confidence interval, 48.2-52.2 million) reported chronic pain (20.5%, [19.9%-21.2%] of the population). Adults with chronic pain had elevated severity of depressive symptoms (PHQ-8 categories: none/minimal: 57.6%, mild: 22.3%, moderate: 11.4%, and severe: 8.7%) versus those without chronic pain (87.6%, 8.8%, 2.3%, and 1.2%; p < 0.001). Adults with chronic pain had elevated severity of anxiety symptoms (GAD-7 categories: none/minimal: 66.4%, mild: 17.1%, moderate: 8.5%, severe: 8.0%) versus those without chronic pain (89.0%, 7.5%, 2.1%, and 1.4%; p < 0.001). 22.4% and 24.5% of chronic pain sufferers were taking medication for depression and anxiety versus 6.6% and 8.5% of those without chronic pain, respectively (both p < 0.001). Adjusted odds ratios for the association of chronic pain with increasing severity of depression or anxiety and taking a depression or anxiety medication were 6.32 (5.82-6.85), 5.63 (5.15-6.15), 3.98 (3.63-4.37), and 3.42 (3.12-3.75), respectively.

CONCLUSIONS

The presence of chronic pain in adults associated with significantly higher severity scores for both anxiety and depression as measured by validated surveys in a nationally representative sample. The same is true for the association between chronic pain and an adult taking medication for depression and/or anxiety. These data highlight the impact of chronic pain has on psychological well-being within the general population.

A Shared Genetic Signature for Common Chronic Pain Conditions and its Impact on Biopsychosocial Traits

The multiple comorbidities & dimensions of chronic pain present a formidable challenge in disentangling its aetiology. Here, we performed genome-wide association studies of 8 chronic pain types using UK Biobank data (N =4,037-79,089 cases; N = 239,125 controls), followed by bivariate linkage disequilibrium-score regression and latent causal variable analyses to determine (respectively) their genetic correlations and genetic causal proportion (GCP) parameters with 1,492 other complex traits. We report evidence of a shared genetic signature across chronic pain types as their genetic correlations and GCP directions were broadly consistent across an array of biopsychosocial traits. Across 5,942 significant genetic correlations, 570 trait pairs could be explained by a causal association (|GCP| >0.6; 5% false discovery rate), including 82 traits affected by pain while 410 contributed to an increased risk of chronic pain (cf. 78 with a decreased risk) such as certain somatic pathologies (eg, musculoskeletal), psychiatric traits (eg, depression), socioeconomic factors (eg, occupation) and medical comorbidities (eg, cardiovascular disease). This data-driven phenome-wide association analysis has demonstrated a novel and efficient strategy for identifying genetically supported risk & protective traits to enhance the design of interventional trials targeting underlying causal factors and accelerate the development of more effective treatments with broader clinical utility. PERSPECTIVE: Through large-scale phenome-wide association analyses of >1,400 biopsychosocial traits, this article provides evidence for a shared genetic signature across 8 common chronic pain types. It lays the foundation for further translational studies focused on identifying causal genetic variants and pathophysiological pathways to develop novel diagnostic & therapeutic technologies and strategies.

Diagnosis and Management of Neuropathic Pain in Spine Diseases

Neuropathic pain is generally defined as a non-physiological pain experience caused by damage to the nervous system. It can occur spontaneously, as a reaction to a given stimulus, or independently of its action, leading to unusual pain sensations usually referred to as firing, burning or throbbing. In the course of spine disorders, pain symptoms commonly occur. According to available epidemiological studies, a neuropathic component of pain is often present in patients with spinal diseases, with a frequency ranging from 36% to 55% of patients. Distinguishing between chronic nociceptive pain and neuropathic pain very often remains a challenge. Consequently, neuropathic pain is often underdiagnosed in patients with spinal diseases. In reference to current guidelines for the treatment of neuropathic pain, gabapentin, serotonin and norepinephrine reuptake inhibitors and tricyclic antidepressants constitute first-line therapeutic agents. However, long-term pharmacologic treatment often leads to developing tolerance and resistance to used medications. Therefore, in recent years, a plethora of therapeutic methods for neuropathic pain have been developed and investigated to improve clinical outcomes. In this review, we briefly summarized current knowledge about the pathophysiology and diagnosis of neuropathic pain. Moreover, we described the most effective treatment approaches for neuropathic pain and discussed their relevance in the treatment of spinal pain.

Presence of depression and anxiety with distinct patterns of pharmacological treatments before the diagnosis of chronic fatigue syndrome: a population-based study in Taiwan

OBJECTIVE

An increased prevalence of psychiatric comorbidities (including depression and anxiety disorder) has been observed among patients with chronic fatigue syndrome (CFS). However, few studies have examined the presence of depression and anxiety disorder before the diagnosis of CFS. This study aimed to clarify the preexisting comorbidities and treatments associated with patients with subsequent CFS diagnosis in a population-based cohort in Taiwan.

METHODS

An analysis utilizing the National Health Insurance Research Database of Taiwan was conducted. Participants included were 6303 patients with CFS newly diagnosed between 2000 and 2010 and 6303 age-/sex-matched controls.

RESULTS

Compared with the control group, the CFS group had a higher prevalence of depression and anxiety disorder before the diagnosis of CFS. Sampled patients who took specific types of antidepressants, namely, selective serotonin reuptake inhibitors (adjusted odds ratio [aOR] = 1.21, 95% confidence interval [CI] 1.04-1.39), serotonin antagonists and reuptake inhibitors (SARI; aOR = 1.87, 95% CI 1.59-2.19), and tricyclic antidepressants (aOR = 1.46, 95% CI 1.09-1.95), had an increased risk of CFS. CFS risk was also higher among participants taking benzodiazepine, muscle relaxants, and analgesic drugs. A sub-group analysis revealed that SARI use was related to an increased risk of CFS in the depression, anxiety disorder, male, and female groups. In the depression and anxiety disorder groups, analgesic drug use was associated with an increased CFS risk. Nonpharmacological treatment administration differed between men and women.

CONCLUSION

This population-based retrospective cohort study revealed an increased risk of CFS among populations with preexisting depression and anxiety disorder, especially those taking SARI and analgesic drugs.

The slow de-implementation of non-evidence-based treatments in low back pain hospital care-Trends in treatments using Dutch hospital register data from 1991 to 2018

BACKGROUND

Low back pain (LBP) is the leading cause of disability worldwide and has an excessive societal burden. Accumulating evidence has shown that some medical approaches such as imaging in absence of clear indications, medication and some invasive treatments may contribute to the problem rather than alleviating it.

OBJECTIVES

To determine the extent of de-implementation of non-evidence-based hospital treatments for LBP care in the Netherlands in the last three decades.

METHODS

Using a register-based population-level observational study with Dutch hospital data, providing a nearly complete coverage of hospital admissions in the Netherlands in 1991-2018, we assessed five frequently applied non-evidence-based hospital treatments for LBP. Time trends in treatment use (absolute and per 100,000 inhabitants) were plotted and analysed using Poisson regression.

RESULTS

The use of bed rest for non-specific LBP and hernia nuclei pulposi, and discectomy for spinal stenosis decreased 91%, 81% and 86% since the availability of evidence/guidelines, respectively. De-implementation, beyond 84%, was reached after 18 and 17 years for bed rest for non-specific LBP and discectomy respectively, while it was not reached after 28 years for bed rest for hernia nuclei pulposi. For spinal fusion and invasive pain treatment, there was an initial increase followed by a reduction. Overall, these treatments reduced by 85% and 75%, respectively.

CONCLUSIONS

In the Netherlands, de-implementation of five non-recommended hospital LBP treatments, if at all, took several decades. Although de-implementation was substantial, slow de-implementation has likely resulted in considerable waste of resources and avoidable harm to many patients in Dutch hospitals.

SIGNIFICANCE

Medically intensive approaches to low-back pain care contribute to the high societal burden of this disease. There have been calls to avoid such care. Using Dutch hospital data, we showed that de-implementation of five non-recommended hospital low-back pain treatments, if at all, took several decades (i.e. ≥17 years) after availability of evidence and guidelines. Slow de-implementation has likely resulted in considerable waste of resources and avoidable harm to hospital patients; better ways for de-implementation of non-evidence-based care are needed.

How effective are physiotherapy interventions in treating people with sciatica? A systematic review and meta-analysis

PURPOSE

Physiotherapy interventions are prescribed as first-line treatment for people with sciatica; however, their effectiveness remains controversial. The purpose of this systematic review was to establish the short-, medium- and long-term effectiveness of physiotherapy interventions compared to control interventions for people with clinically diagnosed sciatica.

METHODS

This systematic review was registered on PROSPERO CRD42018103900. Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL (EBSCO), Embase, PEDro, PubMed, Scopus and grey literature were searched from inception to January 2021 without language restrictions. Inclusion criteria were randomised controlled trials evaluating physiotherapy interventions compared to a control intervention in people with clinical or imaging diagnosis of sciatica. Primary outcome measures were pain and disability. Study selection and data extraction were performed by two independent reviewers with consensus reached by discussion or third-party arbitration if required. Risk of bias was assessed independently by two reviewers using the Cochrane Risk of Bias tool with third-party consensus if required. Meta-analyses and sensitivity analyses were performed with random effects models using Revman v5.4. Subgroup analyses were undertaken to examine the effectiveness of physiotherapy interventions compared to minimal (e.g. advice only) or substantial control interventions (e.g. surgery).

RESULTS

Three thousand nine hundred and fifty eight records were identified, of which 18 trials were included, with a total number of 2699 participants. All trials had a high or unclear risk of bias. Meta-analysis of trials for the outcome of pain showed no difference in the short (SMD - 0.34 [95%CI - 1.05, 0.37] p = 0.34, I² = 98%), medium (SMD 0.15 [95%CI - 0.09, 0.38], p = 0.22, I²= 80%) or long term (SMD 0.09 [95%CI - 0.18, 0.36], p = 0.51, I²= 82%). For disability there was no difference in the short (SMD - 0.00 [95%CI - 0.36, 0.35], p = 0.98, I² = 92%, medium (SMD 0.25 [95%CI - 0.04, 0.55] p = 0.09, I² = 87%), or long term (SMD 0.26 [95%CI - 0.16, 0.68] p = 0.22, I² = 92%) between physiotherapy and control interventions. Subgroup analysis of studies comparing physiotherapy with minimal intervention favoured physiotherapy for pain at the long-term time points. Large confidence intervals and high heterogeneity indicate substantial uncertainly surrounding these estimates. Many trials evaluating physiotherapy intervention compared to substantial intervention did not use contemporary physiotherapy interventions.

CONCLUSION

Based on currently available, mostly high risk of bias and highly heterogeneous data, there is inadequate evidence to make clinical recommendations on the effectiveness of physiotherapy interventions for people with clinically diagnosed sciatica. Future studies should aim to reduce clinical heterogeneity and to use contemporary physiotherapy interventions.

Efficacy, safety, and tolerability of antidepressants for pain in adults: overview of systematic reviews

OBJECTIVE

To provide a comprehensive overview of the efficacy, safety, and tolerability of antidepressants for pain according to condition.

DESIGN

Overview of systematic reviews.

DATA SOURCES

PubMed, Embase, PsycINFO, and the Cochrane Central Register of Controlled Trials from inception to 20 June 2022.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Systematic reviews comparing any antidepressant with placebo for any pain condition in adults.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently extracted data. The main outcome measure was pain; for headache disorders it was frequency of headaches. Continuous pain outcomes were converted into a scale of 0 (no pain) to 100 (worst pain) and were presented as mean differences (95% confidence intervals). Dichotomous outcomes were presented as risk ratios (95% confidence intervals). Data were extracted from the time point closest to the end of treatment. When end of treatment was too variable across trials in a review, data were extracted from the outcome or time point with the largest number of trials and participants. Secondary outcomes were safety and tolerability (withdrawals because of adverse events). Findings were classified from each comparison as efficacious, not efficacious, or inconclusive. Certainty of evidence was assessed with the grading of recommendations assessment, development, and evaluation framework.

RESULTS

26 reviews (156 unique trials and >25 000 participants) were included. These reviews reported on the efficacy of eight antidepressant classes covering 22 pain conditions (42 distinct comparisons). No review provided high certainty evidence on the efficacy of antidepressants for pain for any condition. 11 comparisons (nine conditions) were found where antidepressants were efficacious, four with moderate certainty evidence: serotonin-norepinephrine reuptake inhibitors (SNRIs) for back pain (mean difference -5.3, 95% confidence interval -7.3 to -3.3), postoperative pain (-7.3, -12.9 to -1.7), neuropathic pain (-6.8, -8.7 to -4.8), and fibromyalgia (risk ratio 1.4, 95% confidence interval 1.3 to 1.6). For the other 31 comparisons, antidepressants were either not efficacious (five comparisons) or the evidence was inconclusive (26 comparisons).

CONCLUSIONS

Evidence of efficacy of antidepressants was found in 11 of the 42 comparisons included in this overview of systematic reviews-seven of the 11 comparisons investigated the efficacy of SNRIs. For the other 31 comparisons, antidepressants were either inefficacious or evidence on efficacy was inconclusive. The findings suggest that a more nuanced approach is needed when prescribing antidepressants for pain conditions.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022311073.

MANIFESTATIONS AND TREATMENT OF LOWER BACK PAIN SYNDROME IN WARTIME

OBJECTIVE

The aim: To improve treatment of patients with lower back pain through identification of pathogenetic factors in its formation.

PATIENTS AND METHODS

Materials and methods: The early results of treatment of 84 patients with lower back pain (main group) were analysed. Patients of the main group were divided into two subgroups: one group involved patients with mental disorders, the other - patients not suffering from such disorders (the Spielberger-Hanin Anxiety Test used). The patients of the main group with mental disorders (49 patients) were administered with epidural steroid injections and antidepressants. The patients with no mental disorders (35 patients) were administered with epidural steroid injections only. The control group involved 36 patients with lower back pain who did not undergo any psychological testing and were administered with epidural steroid injections only. The Visual Analog Scale (VAS) and the Oswestry Disability Index questionnaire were used to assess pain syndrome. The assessment was carried out twice: in the pre-operative period and in three months after the treatment.

RESULTS

Results: A significant difference in the early treatment results between the main and control groups was established according to both the Visual Analog Scale and the Oswestry Disability Index in favour of the main group patients, who were differentiated by pathogenetic factors of the pain syndrome formation.

CONCLUSION

Conclusions: Lower back pain syndrome necessitates clarification of its components in order to develop pathogenically based treatment.

Chronic Pain and Psychiatric Conditions

Introduction

Chronic pain is a common condition with high socioeconomic and public health burden. A wide range of psychiatric conditions are often comorbid with chronic pain and chronic pain conditions, negatively impacting successful treatment of either condition. The psychiatric condition receiving most attention in the past with regard to chronic pain comorbidity has been major depressive disorder, despite the fact that many other psychiatric conditions also demonstrate epidemiological and genetic overlap with chronic pain. Further understanding potential mechanisms involved in psychiatric and chronic pain comorbidity could lead to new treatment strategies both for each type of disorder in isolation and in scenarios of comorbidity.

Methods

This article provides an overview of relationships between DSM-5 psychiatric diagnoses and chronic pain, with particular focus on PTSD, ADHD, and BPD, disorders which are less commonly studied in conjunction with chronic pain. We also discuss potential mechanisms that may drive comorbidity, and present new findings on the genetic overlap of chronic pain and ADHD, and chronic pain and BPD using linkage disequilibrium score regression analyses.

Results

Almost all psychiatric conditions listed in the DSM-5 are associated with increased rates of chronic pain. ADHD and BPD are significantly genetically correlated with chronic pain. Psychiatric conditions aside from major depression are often under-researched with respect to their relationship with chronic pain.

Conclusion

Further understanding relationships between psychiatric conditions other than major depression (such as ADHD, BPD, and PTSD as exemplified here) and chronic pain can positively impact understanding of these disorders, and treatment of both psychiatric conditions and chronic pain.

Assessment and nonsurgical management of low back pain: a narrative review

Low back pain (LBP) is a common condition that affects people of all ages and income levels worldwide. The etiology of LBP may be mechanical, neuropathic, systemic, referred visceral, or secondary to other causes. Despite numerous studies, the diagnosis and management of LBP remain challenging due to the complex biomechanics of the spine and confounding factors, such as trivial degenerative imaging findings irrelevant to symptoms and psychological and emotional factors. However, it is imperative to identify the crucial signs ("red flags") indicating a serious underlying condition. While many recent guidelines emphasize non-pharmacologic management approaches, such as education, reassurance, and physical and psychological care, as the first option, LBP patients in many countries, including South Korea, are prescribed medications. Multidisciplinary rehabilitation combined with prudent use of medications is required in patients unresponsive to first-line therapy. The development of practical guidelines apposite for South Korea is needed with multidisciplinary discussion.

OA-Pain-Sense: Machine Learning Prediction of Hip and Knee Osteoarthritis Pain from IMU Data

Joint pain is a prominent symptom of Hip and Knee Osteoarthritis (OA), impairing patients’ movements and affecting the joint mechanics of walking. Self-report questionnaires are currently the gold standard for Hip OA and Knee OA pain assessment, presenting several problems, including the fact that older individuals often fail to provide accurate self-pain reports. Passive methods to assess pain are desirable. This study aims to explore the feasibility of OA-Pain-Sense, a passive, automatic Machine Learning-based approach that predicts patients’ self-reported pain levels using SpatioTemporal Gait features extracted from the accelerometer signal gathered from an anterior-posterior wearable sensor. To mitigate inter-subject variability, we investigated two types of data rescaling: subject-level and dataset-level. We explored six different binary machine learning classification models for discriminating pain in patients with Hip OA or Knee OA from healthy controls. In rigorous evaluation, OA-Pain-Sense achieved an average accuracy of 86.79% using the Decision Tree and 83.57% using Support Vector Machine classifiers for distinguishing Hip OA and Knee OA patients from healthy subjects, respectively. Our results demonstrate that OA-Pain-Sense is feasible, paving the way for the development of a pain assessment algorithm that can support clinical decision-making and be used on any wearable device, such as smartphones.

Rescaling pain intensity measures for meta-analyses of analgesic medicines for low back pain appears justified: an empirical examination from randomised trials

OBJECTIVE

Meta-analyses of analgesic medicines for low back pain often rescale measures of pain intensity to use mean difference (MD) instead of standardised mean difference for pooled estimates. Although this improves clinical interpretability, it is not clear whether this method is justified. Our study evaluated the justification for this method.

METHODS

We identified randomised clinical trials of analgesic medicines for adults with low back pain that used two scales with different ranges to measure the same construct of pain intensity. We transformed all data to a 0-100 scale, then compared between-group estimates across pairs of scales with different ranges.

RESULTS

Twelve trials were included. Overall, differences in means between pain intensity measures that were rescaled to a common 0-100 scale appeared to be small and randomly distributed. For one study that measured pain intensity on a 0-100 scale and a 0-10 scale; when rescaled to 0-100, the difference in MD between the scales was 0.8 points out of 100. For three studies that measured pain intensity on a 0-10 scale and 0-3 scale; when rescaled to 0-100, the average difference in MD between the scales was 0.2 points out of 100 (range 5.5 points lower to 2.7 points higher). For two studies that measured pain intensity on a 0-100 scale and a 0-3 scale; when rescaled to 0-100, the average difference in MD between the scales was 0.7 points out of 100 (range 6.2 points lower to 12.1 points higher). Finally, for six studies that measured pain intensity on a 0-100 scale and a 0-4 scale; when rescaled to 0-100, the average difference in MD between the scales was 0.7 points (range 5.4 points lower to 8.3 points higher).

CONCLUSION

Rescaling pain intensity measures may be justified in meta-analyses of analgesic medicines for low back pain. Systematic reviewers may consider this method to improve clinical interpretability and enable more data to be included.

STUDY REGISTRATION/DATA AVAILABILITY

Open Science Framework (osf.io/8rq7f).

Glutamatergic systems in neuropathic pain and emerging non-opioid therapies

Neuropathic pain, a disease of the somatosensory nervous system, afflicts many individuals and adequate management with current pharmacotherapies remains elusive. The glutamatergic system of neurons, receptors and transporters are intimately involved in pain but, to date, there have been few drugs developed that therapeutically modulate this system. Glutamate transporters, or excitatory amino acid transporters (EAATs), remove excess glutamate around pain transmitting neurons to decrease nociception suggesting that the modulation of glutamate transporters may represent a novel approach to the treatment of pain. This review highlights and summarizes (1) the physiology of the glutamatergic system in neuropathic pain, (2) the preclinical evidence for dysregulation of glutamate transport in animal pain models, and (3) emerging novel therapies that modulate glutamate transporters. Successful drug discovery requires continuous focus on basic and translational methods to fully elucidate the etiologies of this disease to enable the development of targeted therapies. Increasing the efficacy of astrocytic EAATs may serve as a new way to successfully treat those suffering from this devastating disease.

Antidepressants for hip and knee osteoarthritis

BACKGROUND

Although pain is common in osteoarthritis, most people fail to achieve adequate analgesia. Increasing acknowledgement of the contribution of pain sensitisation has resulted in the investigation of medications affecting pain processing with central effects. Antidepressants contribute to pain management in other conditions where pain sensitisation is present.

OBJECTIVES

To assess the benefits and harms of antidepressants for the treatment of symptomatic knee and hip osteoarthritis in adults.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search was January 2021.

SELECTION CRITERIA

We included randomised controlled trials of adults with osteoarthritis that compared use of antidepressants to placebo or alternative comparator. We included trials that focused on efficacy (pain and function), treatment-related adverse effects and had documentation regarding discontinuation of participants. We excluded trials of less than six weeks of duration or had participants with concurrent mental health disorders.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Major outcomes were pain; responder rate; physical function; quality of life; and proportion of participants who withdrew due to adverse events, experienced any adverse events or had serious adverse events. Minor outcomes were proportion meeting the OARSI (Osteoarthritis Research Society International) Response Criteria, radiographic joint structure changes and proportion of participants who dropped out of the study for any reason. We used GRADE to assess certainty of evidence.

MAIN RESULTS

Nine trials (2122 participants) met the inclusion criteria. Seven trials examined only knee osteoarthritis. Two also included participants with hip osteoarthritis. All trials compared antidepressants to placebo, with or without non-steroidal anti-inflammatory drugs. Trial sizes were 36 to 388 participants. Most participants were female, with mean ages of 54.5 to 65.9 years. Trial durations were 8 to 16 weeks. Six trials examined duloxetine. We combined data from nine trials in meta-analyses for knee and hip osteoarthritis. One trial was at low risk of bias in all domains. Five trials were at risk of attrition and reporting bias. High-certainty evidence found that antidepressants resulted in a clinically unimportant improvement in pain compared to placebo. Mean reduction in pain (0 to 10 scale, 0 = no pain) was 1.7 points with placebo and 2.3 points with antidepressants (mean difference (MD) -0.59, 95% confidence interval (CI) -0.88 to -0.31; 9 trials, 2122 participants). Clinical response was defined as achieving a 50% or greater reduction in 24-hour mean pain. High-certainty evidence demonstrated that 45% of participants receiving antidepressants had a clinical response compared to 28.6% receiving placebo (RR 1.55, 95% CI 1.32 to 1.82; 6 RCTs, 1904 participants). This corresponded to an absolute improvement in pain of 16% more responders with antidepressants (8.9% more to 26% more) and a number needed to treat for an additional beneficial effect (NNTB) of 6 (95% CI 4 to 11). High-certainty evidence showed that the mean improvement in function (on 0 to 100 Western Ontario and McMaster Universities Arthritis Index, 0 = best function) was 10.51 points with placebo and 16.16 points with antidepressants (MD -5.65 points, 95% CI -7.08 to -4.23; 6 RCTs, 1909 participants). This demonstrates a small, clinically unimportant response. Moderate-certainty evidence (downgraded for imprecision) showed that quality of life measured using the EuroQol 5-Dimension scale (-0.11 to 1.0, 1.0 = perfect health) improved by 0.07 points with placebo and 0.11 points with antidepressants (MD 0.04, 95% CI 0.01 to 0.07; 3 RCTs, 815 participants). This is clinically unimportant. High-certainty evidence showed that total adverse events increased in the antidepressant group (64%) compared to the placebo group (49%) (RR 1.27, 95% CI 1.15 to 1.41; 9 RCTs, 2102 participants). The number needed to treat for an additional harmful outcome (NNTH) was 7 (95% CI 5 to 11). Low-certainty evidence (downgraded twice for imprecision for very low numbers of events) found no evidence of a difference in serious adverse events between groups (RR 0.94, 95% CI 0.46 to 1.94; 9 RCTs, 2101 participants). The NNTH was 1000.  Moderate-certainty evidence (downgraded for imprecision) showed that 11% of participants receiving antidepressants withdrew from trials due to an adverse event compared to 5% receiving placebo (RR 2.15, 95% CI 1.56 to 2.97; 6 RCTs, 1977 participants). The NNTH was 17 (95% CI 10 to 35).

AUTHORS' CONCLUSIONS

There is high-certainty evidence that use of antidepressants for knee osteoarthritis leads to a non-clinically important improvement in mean pain and function. However, a small number of people will have a 50% or greater important improvement in pain and function. This finding was consistent across all trials. Pain in osteoarthritis may be due to a variety of causes that differ between individuals. It may be that the cause of pain that responds to this therapy is only present in a small number of people. There is moderate-certainty evidence that antidepressants have a small positive effect on quality of life with heterogeneity between trials. High-certainty evidence indicates antidepressants result in more adverse events and moderate-certainty evidence indicates more withdrawal due to adverse events. There was little to no difference in serious adverse events (low-certainty evidence due to low numbers of events). This suggests that if antidepressants were being considered, there needs to be careful patient selection to optimise clinical benefit given the known propensity for adverse events with antidepressant use. Future trials should include alternative antidepressant agents or phenotyping of pain in people with osteoarthritis, or both.

Systemic corticosteroids for radicular and non-radicular low back pain

BACKGROUND

Corticosteroids are medications with anti-inflammatory and immunosuppressant properties. Systemic corticosteroids administered through the oral, intravenous, or intramuscular routes have been used to treat various types of low back pain, including radicular back pain (not due to spinal stenosis), non-radicular back pain, and spinal stenosis. However, there is uncertainty about the benefits and harms of systemic corticosteroids for low back pain.

OBJECTIVES

To evaluate the benefits and harms of systemic corticosteroids versus placebo or no corticosteroid for radicular low back pain, non-radicular low back pain, and symptomatic spinal stenosis in adults.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was September 2021.

SELECTION CRITERIA

We included randomized and quasi-randomized trials in adults of systematic corticosteroids versus placebo or no corticosteroid.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. The major outcomes were pain, function, need for surgery, serious adverse effect, and presence of hyperglycemia. The minor outcomes were quality of life, successful outcomes, non-serious adverse events, and withdrawal due to adverse events. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

Thirteen trials (1047 participants) met the inclusion criteria. Nine trials included participants with radicular low back pain, two trial with low back pain, and two trials with spinal stenosis. All trials blinded participants to receipt of systemic corticosteroids. Seven trials were at low risk of bias, five at unclear risk, and one at high risk of selection bias. Two trials were at high risk of attrition bias. Doses and duration of systemic corticosteroid therapy varied. Radicular low back pain For radicular low back pain, moderate-certainty evidence indicated that systemic corticosteroids probably slightly decrease pain versus placebo at short-term follow-up (mean difference (MD) 0.56 points better, 95% confidence interval (CI) 1.08 to 0.04 on a 0 to 10 scale) and may slightly increase the likelihood of experiencing improvement in pain at short-term follow-up (risk ratio (RR) 1.21, 95% CI 0.88 to 1.66; absolute effect 5% better (95% CI 5% worse to 15% better). Systemic corticosteroids may not improve function at short-term follow-up (standardized mean difference (SMD) 0.14 better; range 0.49 better to 0.21 worse) and probably increase the likelihood of improvement in function at short-term follow-up (RR 1.52, 95% CI 1.22 to 1.91; absolute effect 19% better, 95% CI 8% better to 30% better). Systemic corticosteroids were associated with greater improvement in function versus placebo at long-term follow-up (MD -7.40, 95% CI -12.55 to -2.25 on the 0 to 100 Oswestry Disability Index) and greater likelihood of functional improvement (RR 1.29, 95% CI 1.06 to 1.56), based on a single trial. There was no difference in likelihood of surgery (RR 1.00, 95% CI 0.68 to 1.47). Evidence indicated that systemic corticosteroids (administered as a single dose or as a short course of therapy) are not associated with increased risk of any adverse event, serious adverse events, withdrawal due to adverse events, or hyperglycemia, but estimates were imprecise as some trials did not report harms, and harms reporting was suboptimal in trials that did provide data. Limitations included variability across trials in interventions (e.g. corticosteroid used, dose and duration of treatment), clinical settings, and participants (e.g. duration of symptoms, methods for diagnosis); limited utility of subgroup analyses due to small numbers of trials; methodologic limitations or suboptimal reporting of methods by some trials; and too few trials to formally assess for publication bias using graphical or statistical tests for small sample effects. Non-radicular low back pain Evidence on systemic corticosteroids versus placebo for non-radicular pain was limited and suggested that systemic corticosteroids may be associated with slightly worse short-term pain but slightly better function. Spinal stenosis For spinal stenosis, limited evidence indicated that systemic corticosteroids are probably no more effective than placebo for short-term pain or function.

AUTHORS' CONCLUSIONS

Systemic corticosteroids appear to be slightly effective at improving short-term pain and function in people with radicular low back pain not due to spinal stenosis, and might slightly improve long-term function. The effects of systemic corticosteroids in people with non-radicular low back pain are unclear and systemic corticosteroids are probably ineffective for spinal stenosis. A single dose or short course of systemic corticosteroids for low back pain does not appear to cause serious harms, but evidence is limited.

Weight-centric treatment of depression and chronic pain

Background

Depression and chronic pain are two major chronic non-communicable diseases (CNCD). Considering the bidirectional relationship between obesity and CNCD, it is of the utmost importance to understand the effect of medications utilized to treat these diseases on body weight.

Methods

This is a clinical review on the effect of medications for depression and chronic pain on body weight. We searched PubMed, Scopus, MEDLINE, and Google Scholar databases for studies on the topic from January 1, 1950 to April 1, 2022 in English language. Additionally, we present expert opinions in the fields of obesity, depression and chronic pain, providing a weight-centric approach to treat depression and chronic pain.

Results

Several antidepressant and chronic pain medications are associated with weight gain. Selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, tricyclic antidepressants, monoamine oxidases, mirtazapine and trazodone are common antidepressants that can increase body weight while bupropion is significantly associated with weight loss. Gabapentin and pregabalin are common chronic pain medications that are linked to weight gain. On the other hand, topiramate is associated with significant weight loss. Obesity, depression and chronic pain experts recommend avoiding medications that can increase body weight if another effective alternative is available.

Conclusion

By shifting prescribing practices toward a weight-conscious approach (i.e., switching from weight gain medications to weight loss/neutral), it is possible to mitigate the incidence of drug-induced weight gain.

Causal associations of iron status and back pain risk: A Mendelian randomization study

Background

Observational studies have previously suggested a link between iron status makers and back pain. We conducted a two-sample Mendelian randomization (MR) study to determine the putative causal relationship between systemic iron status and back pain.

Materials and methods

In this MR study, a genome-wide association study (GWAS) involving 48,972 individuals was used to identify genetic instruments highly associated with systemic iron status. The outcome data (back pain) were derived from the Neale Lab consortium's summary data from the UK Biobank (85,221 cases and 336,650 controls). With the inverse variance weighted (IVW) method as the main analysis, conservative analyses (selecting SNPs with concordant change of iron status biomarkers) and liberal analyses (selecting SNPs with genome-wide significant association with each iron status biomarker) were carried out. For sensitivity analyses, the MR-Egger, MR-Egger intercept, weighted median, weighted mode, and MR based on a Bayesian model averaging approaches were used. The Cochran's Q-test was used to detect heterogeneity.

Results

Back pain was associated with genetically instrumented serum iron (OR = 1.01; 95% CI = 1.00-1.02, p = 0.01), ferritin (OR = 1.02; 95% CI = 1.00-1.04, p = 0.02), and transferrin saturation (OR = 1.01; 95% CI = 1.00-1.01, p = 0.01). Furthermore, there was no evidence of a link between transferrin and the risk of back pain (OR = 0.99, 95% CI = 0.98-1.00, p = 0.08). The sensitivity analyses and Cochran's Q-test indicated that no pleiotropy or heterogeneity was detected (all p > 0.05).

Conclusion

We provided potential genetic evidences for the causal associations of iron status with increased incidence of back pain. However, the evidences were weakened due to the low power. Further larger MR studies or RCTs are needed to investigate small effects.

Chronic-Exposure Low-Frequency Magnetic Fields (Magnetotherapy and Magnetic Stimulation) Influence Serum Serotonin Concentrations in Patients with Low Back Pain-Clinical Observation Study

(1) Background: The influence of serotonin on many regulatory mechanisms has not been sufficiently studied. The use of a physical method, assuming the possibility of its action on increasing the concentration of serotonin, may be the direction of therapy limiting the number of antidepressants used. The aim of the research was to study the effects of low-frequency magnetic fields of different characteristics on the circadian profile of serotonin in men with low back pain. (2) Methods: 16 men with back pain syndrome participated in the study. The patients were divided into two groups. In group 1, magnetotherapy (2.9 mT, 40 Hz, square wave, bipolar) was applied at 10.00 a.m. In group 2, the M2P2 magnetic stimulation program of the Viofor JPS device was used. Treatments in each group lasted 3 weeks, 5 days each, with breaks for Saturday and Sunday. The daily serotonin profile was determined the day before the exposure and the day after the last treatment. Blood samples (at night with red light) were collected at 8:00, 12:00, 16:00, 24:00, and 4:00. The patients did not suffer from any chronic or acute disease and were not taking any medications. (3) Results: In group 1, a significant increase in serotonin concentration was observed after 15 treatments at 4:00. In group 2, a significant increase in serotonin concentration was observed at 8:00 after the end of the treatments. In comparison between magnetotherapy and magnetic stimulation, the time points at which differences appeared after the application of serotonin occurred due to the increase in its concentrations after the application of magnetic stimulation. (4) Conclusions: Magnetotherapy and magnetic stimulation, acting in a similar way, increase the concentration of serotonin. Weak magnetic fields work similarly to the stronger ones used in TMS. It is possible to use them in the treatment of mental disorders or other diseases with low serotonin concentrations.

Medications for Treating Low Back Pain in Adults. Evidence for the Use of Paracetamol, Opioids, Nonsteroidal Anti-inflammatories, Muscle Relaxants, Antibiotics, and Antidepressants: An Overview for Musculoskeletal Clinicians

BACKGROUND

Because pharmacological therapies may play an important role in managing musculoskeletal pain, the appropriate use of medicines for common conditions like low back pain (LBP) is critical. New evidence on the effects and safety of paracetamol, nonsteroidal anti-inflammatory drugs (NSAIDs), opioid analgesics, muscle relaxants, antibiotics, and antidepressants for LBP warrants an updated overview for musculoskeletal clinicians on this topic.

CLINICAL QUESTION

How effective and safe are paracetamol, NSAIDs, opioid analgesics, muscle relaxants, antibiotics, and antidepressants compared with placebo for treating LBP?

KEY RESULTS

For acute LBP (<12 weeks), muscle relaxants and NSAIDs may be superior to placebo for reducing pain, but the effects of opioids, antibiotics, and antidepressants are unknown. Paracetamol provides no additional benefit for acute LBP. For chronic LBP (>12 weeks), NSAIDs, antidepressants, and opioids may be superior to placebo for reducing pain, but opioids have an established profile of harms. Antibiotics may also reduce pain for people with chronic LBP with Modic type 1 changes, although the risks may outweigh their benefits. The effects of paracetamol and muscle relaxants for chronic LBP were unclear.

CLINICAL APPLICATION

NSAIDs may have a role in managing acute and chronic LBP, with cautious use in people who may be at greater risk of experiencing adverse events. Paracetamol, opioid analgesics, antibiotics, muscle relaxants, and antidepressants should only be prescribed following a discussion between the treating clinician and the patient, considering the risks and possible benefits, and after or in conjunction with recommended nonpharmacological strategies for improving LBP. J Orthop Sports Phys Ther 2022;52(7):425-431. Epub: 18 May 2022. doi:10.2519/jospt.2022.10788.

Trends in Prescriptions for Non-opioid Pain Medications Among U.S. Adults With Moderate or Severe Pain, 2014-2018

As opioid prescribing has declined, it is unclear how the landscape of prescription pain treatment across the U.S. has changed. We used nationally-representative data from the Medical Expenditure Health Survey, 2014 to 2018 to examine trends in prescriptions for opioid and non-opioid pain medications, including acetaminophen, non-steroidal anti-inflammatory drugs, gabapentinoids, and antidepressants among U.S. adults with self-reported pain. Overall, from 2014 to 2018, the percentage of participants receiving a prescription for opioids declined, (38.8% vs 32.8%), remained stable for non-steroidal anti-inflammatory drugs (26.8% vs 27.7%), and increased for acetaminophen (1.6% vs 2.3%), antidepressants (9.6% vs 12.0%) and gabapentinoids (13.2% vs 19.0%). In this period, the adjusted odds of receiving an opioid prescription decreased (aOR = .93, 95% CI = .90-.96), while the adjusted odds of receiving antidepressant, gabapentinoid and acetaminophen prescriptions increased (antidepressants: aOR = 1.08, 95% CI = 1.03-1.13 gabapentinoids: aOR = 1.11, 95% CI = 1.06-1.17; acetaminophen: aOR = 1.10, 95% CI: 1.02-1.20). Secondary analyses stratifiying within the 2014 to 2016 and 2016 to 2018 periods revealed particular increases in prescriptions for gabapentinoids (aOR = 1.13, 95% CI = 1.05-1.21) and antidepressants (aOR = 1.23, 95% CI = 1.12-1.35) since 2016. PERSPECTIVE: These data demonstrate that physicians are increasingly turning to CDC-recommended non-opioid medications for pain management, particularly antidepressants and gabapentinoids. However, evidence for these medications' efficacy in treating numerous common pain conditions, including low back pain, remains limited.

Infrapatellar Fat Pad-Synovial Membrane Anatomo-Fuctional Unit: Microscopic Basis for Piezo1/2 Mechanosensors Involvement in Osteoarthritis Pain

The Infrapatellar Fat Pad (IFP) is a fibro-adipose tissue of the knee recently reconsidered as part of a single anatomo-functional unit (AFU) together with the synovial membrane (SM). Several evidence support the role of this unit in the mechanisms that trigger and perpetuate the onset and progression of osteoarthritis (OA) disease. Additionally, the contribution of IFP-SM AFU in OA-associated pain has also been supposed, but this assumption still needs to be fully elucidated. Within this context, the recent discovery of the mechanoceptive Piezo ion channels (i.e., Piezo1 and Piezo2) in mammals and consciousness on their role in mediating both mechanoceptive and inflammatory stimuli could shed some light on knee OA pain, as well as on the process leading from acute to chronic nociceptive responses. For this purpose, the IFP-SM AFUs of both healthy donors (non-OA IFP-SM AFUs, n = 10) and OA patients (OA IFP-SM AFUs, n = 10) were processed by histology and immunohistochemistry. After the attribution of a histopathological score to IFP-SM AFUs to confirm intrinsic differences between the two groups, the specimens were investigated for the expression and localization/distribution pattern of the mechanosensors Piezo1 and Piezo2. In addition, the presence of monocytes/macrophages (CD68), peripheral nerve endings (PGP9.5) and neoangiogenesis signs (YAP1) was evaluated for a broad tissue characterization. The study results lead to a better description of the IFP-SM AFU microscopic features in both healthy and pathological conditions, highlighting peculiar differences in the study cohort. Specifically, immunopositivity towards Piezo1/2, CD68 and YAP1 markers was detected at vessels level in the OA- IFP-SM AFUs compartments, differently from the non-OA-group. A correlation with pain was also inferred, paving the way for the identification of new and effective molecules in OA management.

Pharmacotherapy for Spine-Related Pain in Older Adults

As the population ages, spine-related pain is increasingly common in older adults. While medications play an important role in pain management, their use has limitations in geriatric patients due to reduced liver and renal function, comorbid medical problems, and polypharmacy. This review will assess the evidence basis for medications used for spine-related pain in older adults, with a focus on drug metabolism and adverse drug reactions. A PubMed/OVID search crossing common spine, neck, and back pain terms with key words for older adults and geriatrics was combined with common drug classes and common drug names and limited to clinical trials and age over 65 years. The results were then reviewed with identification of commonly used drugs and drug categories: nonsteroidal anti-inflammatories (NSAIDs), acetaminophen, corticosteroids, gabapentin and pregabalin, antispastic and antispasmodic muscle relaxants, tricyclic antidepressants (TCAs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tramadol, and opioids. Collectively, 138 double-blind, placebo-controlled trials were the focus of the review. The review found a variable contribution of high-quality studies examining the efficacy of medications for spine pain primarily in the geriatric population. There was strong evidence for NSAID use with adjustments for gastrointestinal and renal risk factors. Gabapentin and pregabalin had mixed evidence for neuropathic pain. SNRIs had good evidence for neuropathic pain and a more favorable safety profile than TCAs. Tramadol had some evidence in older patients, but more so in persons aged < 65 years. Rational therapeutic choices based on geriatric spine pain diagnosis are helpful, such as NSAIDs and acetaminophen for arthritic and myofascial-based pain, gabapentinoids or duloxetine for neuropathic and radicular pain, antispastic agents for myofascial-based pain, and combination therapy for mixed etiologies. Tramadol can be well tolerated in older patients, but has risks of cognitive and classic opioid side effects. Otherwise, opioids are typically avoided in the treatment of spine-related pain in older adults due to their morbidity and mortality risk and are reserved for refractory severe pain. Whenever possible, beneficial geriatric spine pain pharmacotherapy should employ the lowest therapeutic doses with consideration of polypharmacy, potentially decreased renal and hepatic metabolism, and co-morbid medical disorders.

The Effectiveness of Duloxetine for Knee Osteoarthritis: An Overview of Systematic Reviews

Background: Knee osteoarthritis (KOA) has become a public health problem. Several systematic reviews (SRs) have reported that duloxetine may be an effective treatment for improving pain and depressive symptoms in patients with KOA.

Aim: To evaluate the available results and provide scientific evidence for the efficacy and safety of duloxetine for KOA.

Methods: A comprehensive search strategy was conducted across eight databases from inception to 31 December 2021. Two researchers independently selected eligible studies, collected data and evaluated those included SRs’ quality. For assessing methodological quality, the Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR 2) was employed. Risk of Bias in Systematic Reviews (ROBIS) was used to assess the risk of bias. Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) was utilized for assessing reporting quality. In addition, the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to determine primary outcome indicators’ evidence quality.

Results: Totally 6 SRs were contained in this overview. After assessment based on AMSTAR 2, ROBIS, and PRISMA, unsatisfactory results in terms of methodological quality, risk of bias as well as reporting quality, were obtained. Limitations included a search of grey literature, the reasons for selecting the study type, an excluded study list and the specific reasons, reporting bias assessment, and reporting of potential sources of conflict of interest. According to the GRADE results, the evidence quality was high in 0, moderate in 5, low in 19, and very low in 36. Limitations were the most commonly downgraded factor, followed by publication bias and inconsistency.

Conclusion: Duloxetine may be an effective treatment for improving pain and depressive symptoms in KOA patients with acceptable adverse events. However, due to the low quality of the available evidence, the original study design and the quality of evidence from SRs should be further improved, so as to provide strong scientific evidence for definitive conclusions.

Systematic Review Registration: PROSPERO; (http://www.crd.york.ac.uk/PROSPERO/), identifier (CRD42021289823).

Transcriptional and cellular signatures of cortical morphometric remodelling in chronic pain

ABSTRACT

Chronic pain is a highly debilitating and difficult to treat condition, which affects the structure of the brain. Although the development of chronic pain is moderately heritable, how disease-related alterations at the microscopic genetic architecture drive macroscopic brain abnormalities is currently largely unknown. Here, we examined alterations in morphometric similarity (MS) and applied an integrative imaging transcriptomics approach to identify transcriptional and cellular correlates of these MS changes, in 3 independent small cohorts of patients with distinct chronic pain syndromes (knee osteoarthritis, low back pain, and fibromyalgia) and age-matched and sex-matched pain-free controls. We uncover a novel pattern of cortical MS remodelling involving mostly small-to-medium MS increases in the insula and limbic cortex (none of these changes survived stringent false discovery rate correction for the number of regions tested). This pattern of changes is different from that observed in patients with major depression and cuts across the boundaries of specific pain syndromes. By leveraging transcriptomic data from Allen Human Brain Atlas, we show that cortical MS remodelling in chronic pain spatially correlates with the brain-wide expression of genes related to pain and broadly involved in the glial immune response and neuronal plasticity. Our findings bridge levels to connect genes, cell classes, and biological pathways to in vivo imaging correlates of chronic pain. Although correlational, our data suggest that cortical remodelling in chronic pain might be shaped by multiple elements of the cellular architecture of the brain and identifies several pathways that could be prioritized in future genetic association or drug development studies.

Systematic review of guideline-recommended medications prescribed for treatment of low back pain

OBJECTIVE

To identify and descriptively compare medication recommendations among low back pain (LBP) clinical practice guidelines (CPG).

METHODS

We searched PubMed, Cochrane Database of Systematic Review, Index to Chiropractic Literature, AMED, CINAHL, and PEDro to identify CPGs that described the management of mechanical LBP in the prior five years. Two investigators independently screened titles and abstracts and potentially relevant full text were considered for eligibility. Four investigators independently applied the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument for critical appraisal. Data were extracted for pharmaceutical intervention, the strength of recommendation, and appropriateness for the duration of LBP.

RESULTS

316 citations were identified, 50 full-text articles were assessed, and nine guidelines with global representation met the eligibility criteria. These CPGs addressed pharmacological treatments with or without non-pharmacological treatments. All CPGS focused on the management of acute, chronic, or unspecified duration of LBP. The mean overall AGREE II score was 89.3% (SD 3.5%). The lowest domain mean score was for applicability, 80.4% (SD 5.2%), and the highest was Scope and Purpose, 94.0% (SD 2.4%). There were ten classifications of medications described in the included CPGs: acetaminophen, antibiotics, anticonvulsants, antidepressants, benzodiazepines, non-steroidal anti-inflammatory drugs (NSAIDs), opioids, oral corticosteroids, skeletal muscle relaxants (SMRs), and atypical opioids.

CONCLUSIONS

Nine CPGs, included ten medication classes for the management of LBP. NSAIDs were the most frequently recommended medication for the treatment of both acute and chronic LBP as a first line pharmacological therapy. Acetaminophen and SMRs were inconsistently recommended for acute LBP. Meanwhile, with less consensus among CPGs, acetaminophen and antidepressants were proposed as second-choice therapies for chronic LBP. There was significant heterogeneity of recommendations within many medication classes, although oral corticosteroids, benzodiazepines, anticonvulsants, and antibiotics were not recommended by any CPGs for acute or chronic LBP.