The effectiveness of a weak opioid medication versus a cyclo-oxygenase-2 (COX-2) selective non-steroidal anti-inflammatory drug in treating flare-up of chronic low-back pain: results from two randomized, double-blind, 6-week studies

Decreased Analgesic Effect of Tramadol in Japanese Patients with CYP2D6 Intermediate Metabolizers after Orthopedic Surgery

Tramadol is metabolized by CYP2D6 to an active metabolite, which in turn acts as an analgesic. This study aimed to investigate the impact of CYP2D6 genotype on the analgesic effect of tramadol in clinical practice. A retrospective cohort study was performed in patients treated with tramadol for postoperative pain after arthroscopic surgery for rotator cuff injury during April 2017-March 2019. The impact of CYP2D6 genotypes on the analgesic effects was assessed by the numeric rating scale (NRS) pain scoring and analyzed by the Mann-Whitney U test. Stepwise multiple linear regression analysis was performed to identify predictive factors for the area under the time-NRS curve (NRS-AUC), which was calculated using the linear trapezoidal method. Among the 85 enrolled Japanese patients, the number of phenotypes with CYP2D6 normal metabolizer (NM) and intermediate metabolizer (IM) was n = 69 (81.1%) and n = 16 (18.9%), respectively. The NRS and NRS-AUC in the IM group were significantly higher than those in the NM group until Day 7 (p < 0.05). The multiple linear regression analysis indicated that the CYP2D6 polymorphism was a prediction factor of the high NRS-AUC levels in Days 0-7 (β = 9.52, 95% CI 1.30-17.7). In IM patients, the analgesic effect of tramadol was significantly reduced one week after orthopedic surgery in clinical practice. Therefore, dose escalation of tramadol or the use of alternative analgesic medications can be recommended for IM patients.

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).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01763-x.

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.

A Comprehensive Review of Over the Counter Treatment for Chronic Low Back Pain

PURPOSE OF THE REVIEW

Chronic low back pain (CLBP) is a major contributor to societal disease burden and years lived with disability. Nonspecific low back pain (LBP) is attributed to physical and psychosocial factors, including lifestyle factors, obesity, and depression. Mechanical low back pain occurs related to repeated trauma to or overuse of the spine, intervertebral disks, and surrounding tissues. This causes disc herniation, vertebral compression fractures, lumbar spondylosis, spondylolisthesis, and lumbosacral muscle strain.

RECENT FINDINGS

A systematic review of relevant literature was conducted. CENTRAL, MEDLINE, EMBASE, PubMed, and two clinical trials registry databases up to 24 June 2015 were included in this review. Search terms included: low back pain, over the counter, non-steroidal anti-inflammatory (NSAID), CLBP, ibuprofen, naproxen, acetaminophen, disk herniation, lumbar spondylosis, vertebral compression fractures, spondylolisthesis, and lumbosacral muscle strain. Over-the-counter analgesics are the most frequently used first-line medication for LBP, and current guidelines indicate that over-the-counter medications should be the first prescribed treatment for non-specific LBP. Current literature suggests that NSAIDs and acetaminophen as well as antidepressants, muscle relaxants, and opioids are effective treatments for CLBP. Recent randomized controlled trials also evaluate the benefit of buprenorphine, tramadol, and strong opioids such as oxycodone. This systematic review discusses current evidence pertaining to non-prescription treatment options for chronic low back pain.

Comparative safety review of current treatment options for chronic low back pain and unmet needs: a narrative review

Introduction: The healthcare expenditures in the United States are substantial for the management of refractory, chronic low back pain (CLBP). The objective of this review is to summarize and evaluate the safety profiles of different pharmacological treatment options used in the management of CLBP.Areas covered: The authors conducted a search of randomized controlled trials (RCTs) assessing the safety profiles of different pharmacological agents used in the management of CLBP. This narrative review covered corticosteroids, opioids, antidepressants, gabapentinoids, nonsteroidal anti-inflammatory drugs, muscle relaxants, anti-nerve growth factor antibodies and topical agents, as monotherapy or in combination.Expert opinion: The risk-benefit ratio of a particular treatment is a subject driving the ongoing development of pharmaceuticals. The most commonly reported AEs across all drug classes are of gastrointestinal nature, followed by neurological and skin-related. These AEs include nausea, dizziness, constipation, arthralgia, headache, dry mouth, pruritus, etc. The majority of the AEs reported are not life-threatening, although they may lower patients' quality of life, thus, affecting their compliance. One of the biggest limitations of our review stems from the paucity of safety assessments in published RCTs. Advances in our understanding of the neurobiology of pain will promote development of new therapeutic strategies.

Harms and benefits of opioids for management of non-surgical acute and chronic low back pain: a systematic review

Background

Consequences of prescription opioid use involve harms, addiction, tolerance and death. Despite routine prescription, opioids are not recommended for initial intervention by any major multidisciplinary low back pain (LBP) guideline.

Objective

Our primary purpose was to improve overall understanding of the harms and benefits associated with oral opioid interventions prescribed for treatment of acute or chronic back pain. Our second goal was to evaluate pain intensity and to compare and contrast these data with the harms. Our last objective was to evaluate conflicts of interest among the study authors and the findings.

Design/data/eligibility criteria

Studies incorporating oral prescription opioid management of non-surgical LBP were evaluated. After systematic assessment, no studies that met inclusion included participants with specifically acute LBP. Therefore, extracted data reflects only populations with subacute and chronic LBP. Data on reported harms, severe harms, pain outcomes and withdrawal rates were extracted and meta-analyses were completed for opioid versus placebo trials and opioids versus non-opioid trials.

Results

Fourteen studies met inclusion/exclusion requirements. All trials involved short-term management with limited follow-up. A high percentage of harms were identified across most studies. Opioids were not shown to be superior to other medications, and only showed superiority to placebo comparators (at cost of additional harms).

Conclusion

This review identified trends of higher harms rates and higher percentages of severe harms in opioid arms for the management of subacute and chronic LBP. The majority of trials that demonstrated benefits with opioids also had potential conflicts of interest. Lastly, non-opioid medications demonstrated statistically significant pain improvement compared with opioids. We feel that the results of the trial are supportive of current LBP guidelines and do not condone the initial use of opioids in management of subacute or chronic LBP.

Trial registration number

CRD42017070914

Utilization of pain medications and its effect on quality of life, health care utilization and associated costs in individuals with chronic back pain

Purpose

Pain medications are widely prescribed to treat chronic back pain (CBP). However, the effect of using pain medications on individuals with CBP has received very little attention.

Objective

The aim of this study was to determine the patterns of pharmacological treatment in the population with CBP and assess its impact on quality of life, health care utilization and associated costs in USA.

Patients and methods

Retrospective, cross-sectional data obtained from the Medical Expenditure Panel Survey (MEPS), from 2011 to 2015, were utilized for this study. Pharmacological treatment for CBP was categorized into three mutually exclusive categories: 1) opioids only, 2) nonsteroidal anti-inflammatory drugs (NSAIDs) only, 3) opioids and NSAIDs (combination). The effect of the use of these treatments was also evaluated.

Results

A total of 5,203 individuals with CBP were identified. Of these, 2,568 (49.4%) utilized opioids only, 1,448 (27.8%) utilized NSAIDs only and 1,187 (22.8%) utilized both pain medications. Lower health-related quality-of-life scores on both the Short Form Health Survey-12 version 2 (SF-12v2) components (mental component summary score: 44.42 vs 46.67, P<0.001; physical component summary score: 35.34 vs 40.11, P<0.001) were observed for the opioid-only group compared to the NSAID-only group. In addition, individuals utilizing opioids only had greater utilization of inpatient services, office-based services, outpatient services and emergency room visits along with higher related health care costs.

Conclusion

Future researchers need to investigate the long-term risks and benefits of opioids, and policy makers should evaluate the prescribing guidelines to aim for a more patient-centered care.

Prescription Medication Use Among Community-Based U.S. Adults With Chronic Low Back Pain: A Cross-Sectional Population Based Study

Many classes of medications have been evaluated in chronic low back pain (cLBP), however their utilization in the community remains unclear. We examined patterns of prescription medication use among Americans with cLBP in a nationally representative, community-based sample. The Back Pain Survey was administered to a representative sample of U.S. adults aged 20 to 69 years (N = 5,103) during the 2009 to 2010 cycle of the National Health and Nutrition Examination Survey. cLBP was defined as self-reported pain in the area between the lower posterior margin of the ribcage and the horizontal gluteal fold on most days for at least 3 months (N = 700). Home-based interviews with pill bottle verification were used to capture commonly prescribed medications for chronic pain. Among the sample of U.S. adults with cLBP aged 20 to 69 years, 36.9% took at least 1 prescription pain medication in the past 30 days; of them, 18.8% used opioids, 9.7% nonsteroidal anti-inflammatory drugs, 8.5% muscle relaxants, and 6.9% gabapentin or pregabalin. Nonpain antidepressants and hypnotics were used by 17.8% and 4.7%, respectively. Opioids were used long-term in 76.9% of cases (median = 2 years) and were frequently coadministered with antidepressants, benzodiazepines, or hypnotics. Ninety-four percent of prescription opioids in the cLBP population were used by individuals with less than a college education. Opioids were the most widely used prescription analgesic class in community-based U.S. adults with cLBP and were often coadministered with other central nervous system-active medications. Opioid use was highly prevalent among less educated Americans with cLBP.

PERSPECTIVE

Because prescription opioid use is an issue of national concern, we examined pain-related prescription medication use in community-dwelling U.S. adults with cLBP. Opioids were the most common prescription pain medication, typically used long-term, in combination with other central nervous system-active agents, and disproportionately among individuals with less than a college education.

Alternatives to Opioids in the Pharmacologic Management of Chronic Pain Syndromes: A Narrative Review of Randomized, Controlled, and Blinded Clinical Trials

Chronic pain exerts a tremendous burden on individuals and societies. If one views chronic pain as a single disease entity, then it is the most common and costly medical condition. At present, medical professionals who treat patients in chronic pain are recommended to provide comprehensive and multidisciplinary treatments, which may include pharmacotherapy. Many providers use nonopioid medications to treat chronic pain; however, for some patients, opioid analgesics are the exclusive treatment of chronic pain. However, there is currently an epidemic of opioid use in the United States, and recent guidelines from the Centers for Disease Control (CDC) have recommended that the use of opioids for nonmalignant chronic pain be used only in certain circumstances. The goal of this review was to report the current body of evidence-based medicine gained from prospective, randomized-controlled, blinded studies on the use of nonopioid analgesics for the most common noncancer chronic pain conditions. A total of 9566 studies were obtained during literature searches, and 271 of these met inclusion for this review. Overall, while many nonopioid analgesics have been found to be effective in reducing pain for many chronic pain conditions, it is evident that the number of high-quality studies is lacking, and the effect sizes noted in many studies are not considered to be clinically significant despite statistical significance. More research is needed to determine effective and mechanism-based treatments for the chronic pain syndromes discussed in this review. Utilization of rigorous and homogeneous research methodology would likely allow for better consistency and reproducibility, which is of utmost importance in guiding evidence-based care.

Adverse events associated with medium- and long-term use of opioids for chronic non-cancer pain: an overview of Cochrane Reviews

BACKGROUND

Chronic pain is common and can be challenging to manage. Despite increased utilisation of opioids, the safety and efficacy of long-term use of these compounds for chronic non-cancer pain (CNCP) remains controversial. This overview of Cochrane Reviews complements the overview entitled 'High-dose opioids for chronic non-cancer pain: an overview of Cochrane Reviews'.

OBJECTIVES

To provide an overview of the occurrence and nature of adverse events associated with any opioid agent (any dose, frequency, or route of administration) used on a medium- or long-term basis for the treatment of CNCP in adults.

METHODS

We searched the Cochrane Database of Systematic Reviews (the Cochrane Library) Issue 3, 2017 on 8 March 2017 to identify all Cochrane Reviews of studies of medium- or long-term opioid use (2 weeks or more) for CNCP in adults aged 18 and over. We assessed the quality of the reviews using the AMSTAR criteria (Assessing the Methodological Quality of Systematic Reviews) as adapted for Cochrane Overviews. We assessed the quality of the evidence for the outcomes using the GRADE framework.

MAIN RESULTS

We included a total of 16 reviews in our overview, of which 14 presented unique quantitative data. These 14 Cochrane Reviews investigated 14 different opioid agents that were administered for time periods of two weeks or longer. The longest study was 13 months in duration, with most in the 6- to 16-week range. The quality of the included reviews was high using AMSTAR criteria, with 11 reviews meeting all 10 criteria, and 5 of the reviews meeting 9 out of 10, not scoring a point for either duplicate study selection and data extraction, or searching for articles irrespective of language and publication type. The quality of the evidence for the generic adverse event outcomes according to GRADE ranged from very low to moderate, with risk of bias and imprecision being identified for the following generic adverse event outcomes: any adverse event, any serious adverse event, and withdrawals due to adverse events. A GRADE assessment of the quality of the evidence for specific adverse events led to a downgrading to very low- to moderate-quality evidence due to risk of bias, indirectness, and imprecision.We calculated the equivalent milligrams of morphine per 24 hours for each opioid studied (buprenorphine, codeine, dextropropoxyphene, dihydrocodeine, fentanyl, hydromorphone, levorphanol, methadone, morphine, oxycodone, oxymorphone, tapentadol, tilidine, and tramadol). In the 14 Cochrane Reviews providing unique quantitative data, there were 61 studies with a total of 18,679 randomised participants; 12 of these studies had a cross-over design with two to four arms and a total of 796 participants. Based on the 14 selected Cochrane Reviews, there was a significantly increased risk of experiencing any adverse event with opioids compared to placebo (risk ratio (RR) 1.42, 95% confidence interval (CI) 1.22 to 1.66) as well as with opioids compared to a non-opioid active pharmacological comparator, with a similar risk ratio (RR 1.21, 95% CI 1.10 to 1.33). There was also a significantly increased risk of experiencing a serious adverse event with opioids compared to placebo (RR 2.75, 95% CI 2.06 to 3.67). Furthermore, we found significantly increased risk ratios with opioids compared to placebo for a number of specific adverse events: constipation, dizziness, drowsiness, fatigue, hot flushes, increased sweating, nausea, pruritus, and vomiting.There was no data on any of the following prespecified adverse events of interest in any of the included reviews in this overview of Cochrane Reviews: addiction, cognitive dysfunction, depressive symptoms or mood disturbances, hypogonadism or other endocrine dysfunction, respiratory depression, sexual dysfunction, and sleep apnoea or sleep-disordered breathing. We found no data for adverse events analysed by sex or ethnicity.

AUTHORS' CONCLUSIONS

A number of adverse events, including serious adverse events, are associated with the medium- and long-term use of opioids for CNCP. The absolute event rate for any adverse event with opioids in trials using a placebo as comparison was 78%, with an absolute event rate of 7.5% for any serious adverse event. Based on the adverse events identified, clinically relevant benefit would need to be clearly demonstrated before long-term use could be considered in people with CNCP in clinical practice. A number of adverse events that we would have expected to occur with opioid use were not reported in the included Cochrane Reviews. Going forward, we recommend more rigorous identification and reporting of all adverse events in randomised controlled trials and systematic reviews on opioid therapy. The absence of data for many adverse events represents a serious limitation of the evidence on opioids. We also recommend extending study follow-up, as a latency of onset may exist for some adverse events.

Opioid-sparing Effects of SoluMatrix Indomethacin in a Phase 3 Study in Patients With Acute Postoperative Pain

OBJECTIVES

To report the opioid-sparing effects of SoluMatrix indomethacin, developed using SoluMatrix Fine Particle Technology, in a phase 3 study in patients with acute pain following bunionectomy.

METHODS

This phase 3, placebo-controlled study randomized 462 patients with moderate-to-severe pain following bunionectomy surgery to receive SoluMatrix indomethacin 40 mg 3 times daily, SoluMatrix indomethacin 40 mg twice daily, SoluMatrix indomethacin 20 mg 3 times daily, celecoxib 400-mg loading dose followed by 200 mg twice daily, or placebo. Patients were permitted to receive opioid-containing rescue medication throughout the study. The proportion of patients who used rescue medication and the amount of rescue medication used on the first (0 to 24 h) and second (>24 to 48 h) days following initial dose of study medication, as well as time to first rescue medication use, were assessed.

RESULTS

Significantly fewer patients who received SoluMatrix indomethacin 40 or 20 mg 3 times daily used opioid-containing rescue medication on day 1 compared with those receiving placebo (P≤0.034), and fewer patients in all active treatment groups used rescue medication during the second day compared with those in the placebo group (P<0.001). All active treatment groups used significantly fewer rescue medication tablets on days 1 and 2 following randomization compared with placebo (P<0.001). The most common adverse events were nausea, postprocedural edema, and headache.

DISCUSSION

SoluMatrix indomethacin was associated with opioid-sparing effects in patients with acute postoperative pain.

[Opioids for noncancer pain in the elderly]

BACKGROUND

Opioids are increasingly used in the elderly. Side effects differ compared to other analgesics.

PURPOSE

In this review article, special aspects about using opioids for noncancer pain in older people and in geriatric patients are identified.

CURRENT SITUATION

So far randomized controlled trials for the indication of and comparison between various opioids have been performed in middle-aged patients and not exclusively in geriatric patients or elderly (> 75 years). Furthermore, the evidence for multimorbid elderly patients with respect to side effects is also very poor.

RECOMMENDATIONS

The indication for opioid therapy should be narrow. The patient and their caregivers must be provided patient information regarding opioid therapy. The principle "start low, go slow" is highly recommended. To reduce the risk of falls, longer acting opioids should be used and short acting opioids should be avoided. Everyday relevant negative effects on cognition are possible in opioid use and have to be observed. As recommended in the recently published German guideline for long-term use of opioids in noncancer pain a critical check after 3 months and in case of dosing over 120 mg morphine equivalents is advisable, especially for older patients. Liver and kidney function and drug interactions have to be taken into consideration like in every age group.

[Opioids in chronic low back pain. A systematic review and meta-analysis of efficacy, tolerability and safety in randomized placebo-controlled studies of at least 4 weeks duration]

BACKGROUND

The efficacy and safety of opioid therapy in chronic low back pain (CLBP) is under debate. We updated a recent systematic review on the efficacy and safety of opioids in CLBP.

METHODS

We screened MEDLINE, Scopus and the Cochrane Central Register of Controlled Trials (CENTRAL) up until October 2013, as well as reference sections of original studies and systematic reviews of randomized controlled trials (RCTs) of opioids in CLBP. We included double-blind randomized placebo-controlled studies of at least 4 weeks duration. Using a random effects model, absolute risk differences (RD) were calculated for categorical data and standardized mean differences (SMD) for continuous variables.

RESULTS

We included 12 RCTs with 17 treatment arms and 4375 participants. Median study duration was 12 (4-16) weeks. Of the 17 treatment arms, seven (41.2 %) used oxycodone; four (23.6 %) tramadol; buprenorphine and oxymorphone were each used in two (11.8 %) and hydromorphone and tapentadol each in one (5.8 %). The results for studies with parallel/cross-over design were as follows (with 95 % confidence interval, CI): opioids were superior to placebo in reducing pain intensity (SMD - 0.29 [- 0.37, - 0.21], p < 0.0001; six studies with 2896 participants). Opioids were superior to placebo in 50 % pain reduction (RD 0.05 [0.01, 0.10], p = 0.01; two studies with 1492 participants; number needed to benefit (NNTB) 19 [95 % CI 10-107]). Opioids were not superior to placebo in reports of much or very much improved pain (RD 0.16 [- 0.01, 0.34], p = 0.07; two studies with 1153 participants). Opioids were superior to placebo in improving physical functioning (SMD - 0.22 [- 0.31, - 0.12], p < 0.0001; four studies with 1895 participants). Patients dropped out less frequently with opioids than with placebo due to lack of efficacy (RD - 0.10 [- 0.16, - 0.04], p = 0.001; five studies with 3168 participants; NNTB 10 [8-13]). Patients dropped out more frequently with opioids than with placebo due to adverse events (RD 0.12 [0.05, 0.19], p = 0.0007; six studies with 2910 participants; number needed to harm (NNTH) 7 [95 % CI 6-8]). There was no significant difference between opioids and placebo in terms of the frequency of serious adverse events or deaths.

CONCLUSION

Opioids were superior to placebo in terms of efficacy and inferior in terms of tolerability. Opioids and placebo did not differ in terms of safety during the study period. The conclusion on the safety of opioids compared to placebo is limited by the low number of serious adverse events and deaths. Short-term and intermediate-term opioid therapy may be considered in selected CLBP patients. The English full-text version of this article is freely available at SpringerLink (under "Supplemental").

[Recommendations of the updated LONTS guidelines. Long-term opioid therapy for chronic noncancer pain]

BACKGROUND

The regular update of the German S3 guidelines on long-term opioid therapy for chronic noncancer pain (CNCP), the"LONTS" (AWMF registration number 145/003), began in November 2013.

METHODS

The guidelines were developed by 26 scientific societies and two patient self-help organisations under the coordination of the Deutsche Schmerzgesellschaft (German Pain Society). A systematic literature search in the Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Scopus databases (up until October 2013) was performed. Levels of evidence were assigned according to the classification system of the Oxford Centre for Evidence-Based Medicine. The strength of the recommendations was established by multistep formal procedures, in order to reach a consensus according to German Association of the Medical Scientific Societies ("Arbeitsgemeinschaft der Wissenschaftlich Medizinischen Fachgesellschaften", AWMF) regulations. The guidelines were reviewed by the Drug Commission of the German Medical Association, the Austrian Pain Society and the Swiss Association for the Study of Pain.

RESULTS

Opioids are one drug-based treatment option for short- (4-12 weeks), intermediate- (13-25 weeks) and long-term (≥ 26 weeks) therapy of chronic osteoarthritis, diabetic polyneuropathy, postherpetic neuralgia and low back pain. Contraindications are primary headaches, as well as functional somatic syndromes and mental disorders with the (cardinal) symptom pain. For all other clinical presentations, a short- and long-term therapy with opioid-containing analgesics should be evaluated on an individual basis. Long-term therapy with opioid-containing analgesics is associated with relevant risks (sexual disorders, increased mortality).

CONCLUSION

Responsible application of opioid-containing analgesics requires consideration of possible indications and contraindications, as well as regular assessment of efficacy and adverse effects. Neither an uncritical increase in opioid application, nor the global rejection of opioid-containing analgesics is justified in patients with CNCP.

[Opioids in chronic noncancer pain-are opioids superior to nonopioid analgesics? A systematic review and meta-analysis of efficacy, tolerability and safety in randomized head-to-head comparisons of opioids versus nonopioid analgesics of at least four week's duration]

BACKGROUND

Some leading German pain medicine experts postulate that there is a type of chronic non-cancer pain (CNCP) with an opioid requirement. We tested whether opioids are superior to nonopioid analgesics in the management of CNCP in studies of at least 4 week's duration.

METHODS

We screened MEDLINE, Scopus and the Cochrane Central Register of Controlled Trials (CENTRAL) up until October 2013, as well as the reference sections of original studies and systematic reviews of randomised controlled trials (RCTs) of opioids in CNCP. We included double-blind RTCs comparing opioids to nonopioid analgesics of at least 4 week's duration. Relative risks differences (RD) of categorical data and standardized mean differences (SMD) of continuous variables were calculated using a random effects model.

RESULTS

We included 10 RCTs with 3046 participants. Median study duration was 6 weeks (range 4-12 weeks). Five studies compared tramadol with nonsteroidal anti-inflammatory drugs (NSAIDs) in osteoarthritis pain and one trial compared tramadol to flupirtine in low back pain. Morphine was compared to antidepressants (two studies), an anticonvulsant (one study) and an antiarrhythmic (one study) in different neuropathic pain syndromes. There was no significant difference between opioids and nonopioid analgesics in pain reduction (SMD 0.03 [95 % confidence interval, CI - 0.18, 0.24]; p = 0.76). Nonopioid analgesics were superior to opioids in improving physical function (SMD 0.17 [95 % CI 0.02, 0.32]; p = 0.03). Patients dropped out due to adverse events more frequently with opioids than with nonopioid analgesics (RD 0.09 [95 % CI 0.06, 0.13]; p < 0.0001). There was no significant difference between opioids and nonopioid analgesics in terms of serious adverse events or dropout rates due to lack of efficacy.

CONCLUSION

Nonopioid analgesics are superior to opioids in terms of improvement of physical function and tolerability in short-term (4-12 weeks) therapy of neuropathic, low back and osteoarthritis pain. Our results do not support the concept of an"opioid-requiring" CNCP. The English full-text version of this article is freely available at SpringerLink (under "Supplemental").

Non-steroidal anti-inflammatory drugs for chronic low back pain

BACKGROUND

Chronic back pain is an important health problem. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used to treat people with low back pain, especially people with acute back pain. Short term NSAID use is also recommended for pain relief in people with chronic back pain. Two types of NSAIDs are available and used to treat back pain: non-selective NSAIDs and selective COX-2 NSAIDs. In 2008, a Cochrane review identified a small but significant effect from NSAIDs compared to placebo in people with chronic back pain. This is an update of the Cochrane review published in 2008 and focuses on people with chronic low back pain.

OBJECTIVES

To determine if NSAIDs are more efficacious than various comparison treatments for non-specific chronic low back pain and if so, which type of NSAID is most efficacious.

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, PubMed and two clinical trials registry databases up to 24 June 2015 for randomized controlled trials (RCTs) published in English, German or Dutch. We also screened references cited in relevant reviews.

SELECTION CRITERIA

We included RCTs (double-blind and single-blind) of NSAIDs used to treat people with chronic low back pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened trials for inclusion in this Cochrane review according to the inclusion criteria. One review author extracted the data, and a second review author checked the data. Two review authors independently evaluated the risk of bias of all included trials. If data were clinically homogeneous, we performed a meta-analysis and assessed the quality of evidence using the GRADE approach.

MAIN RESULTS

We included 13 trials in this Cochrane review. Ten studies were at 'low' risk of bias. Six studies compared NSAIDs with placebo, and included 1354 participants in total. There is low quality evidence that NSAIDs are more effective than placebo, with a mean difference in pain intensity score from baseline of -3.30 (95% CI -5.33 to -1.27) on a 0 to 100 visual analogue scale (VAS) with a median follow-up of 56 days (interquartile range (IQR) 13 to 91 days). Four studies measured disability using the Roland Morris Disability Questionnaire. There is low quality evidence that NSAIDs are more effective than placebo on disability, with a mean difference from baseline of -0.85 (95% CI -1.30 to -0.40) on a scale from 0 to 24 with a median follow-up of 84 days (IQR 42 to 105 days). All six placebo controlled studies also reported adverse events, and suggested that adverse events are not statistically significant more frequent in participants using NSAIDs compared to placebo (RR 1.04, 95% CI 0.92 to 1.17). Due to the relatively small sample size and relatively short follow-up in most included trials, it is likely that the proportion of patients experiencing an adverse event is underestimated.Two studies compared different types of non-selective NSAIDs, namely ibuprofen versus diclofenac and piroxicam versus indomethacin. The trials did not find any differences between these NSAID types, but both trials had small sample sizes. One trial reported no differences in pain intensity between treatment groups that used selective or non-selective NSAIDs. One other trial compared diflunisal with paracetamol and showed no difference in improvement from baseline on pain intensity score. One trial showed a better global improvement in favour of celecoxib versus tramadol.One included trial compared NSAIDs with 'home-based exercise'. Disability improved more in participants who did exercises versus participants receiving NSAIDs, but pain scores were similar.

AUTHORS' CONCLUSIONS

Six of the 13 included RCTs showed that NSAIDs are more effective than placebo regarding pain intensity. NSAIDs are slightly more effective than placebo regarding disability. However, the magnitude of the effects is small, and the level of evidence was low. When we only included RCTs at low risk of bias, differences in effect between NSAIDs and placebo were reduced. We identified no difference in efficacy between different NSAID types, including selective versus non-selective NSAIDs. Due to inclusion of RCTs only, the relatively small sample sizes and relatively short follow-up in most included trials, we cannot make firm statements about the occurrence of adverse events or whether NSAIDs are safe for long-term use.

The effect of journal impact factor, reporting conflicts, and reporting funding sources, on standardized effect sizes in back pain trials: a systematic review and meta-regression

BACKGROUND

Low back pain is a common and costly health complaint for which there are several moderately effective treatments. In some fields there is evidence that funder and financial conflicts are associated with trial outcomes. It is not clear whether effect sizes in back pain trials relate to journal impact factor, reporting conflicts of interest, or reporting funding.

METHODS

We performed a systematic review of English-language papers reporting randomised controlled trials of treatments for non-specific low back pain, published between 2006-2012. We modelled the relationship using 5-year journal impact factor, and categories of reported of conflicts of interest, and categories of reported funding (reported none and reported some, compared to not reporting these) using meta-regression, adjusting for sample size, and publication year. We also considered whether impact factor could be predicted by the direction of outcome, or trial sample size.

RESULTS

We could abstract data to calculate effect size in 99 of 146 trials that met our inclusion criteria. Effect size is not associated with impact factor, reporting of funding source, or reporting of conflicts of interest. However, explicitly reporting 'no trial funding' is strongly associated with larger absolute values of effect size (adjusted β=1.02 (95 % CI 0.44 to 1.59), P=0.001). Impact factor increases by 0.008 (0.004 to 0.012) per unit increase in trial sample size (P<0.001), but does not differ by reported direction of the LBP trial outcome (P=0.270).

CONCLUSIONS

The absence of associations between effect size and impact factor, reporting sources of funding, and conflicts of interest reflects positively on research and publisher conduct in the field. Strong evidence of a large association between absolute magnitude of effect size and explicit reporting of 'no funding' suggests authors of unfunded trials are likely to report larger effect sizes, notwithstanding direction. This could relate in part to quality, resources, and/or how pragmatic a trial is.

Opioids for low back pain

Back pain affects most adults, causes disability for some, and is a common reason for seeking healthcare. In the United States, opioid prescription for low back pain has increased, and opioids are now the most commonly prescribed drug class. More than half of regular opioid users report back pain. Rates of opioid prescribing in the US and Canada are two to three times higher than in most European countries. The analgesic efficacy of opioids for acute back pain is inferred from evidence in other acute pain conditions. Opioids do not seem to expedite return to work in injured workers or improve functional outcomes of acute back pain in primary care. For chronic back pain, systematic reviews find scant evidence of efficacy. Randomized controlled trials have high dropout rates, brief duration (four months or less), and highly selected patients. Opioids seem to have short term analgesic efficacy for chronic back pain, but benefits for function are less clear. The magnitude of pain relief across chronic non-cancer pain conditions is about 30%. Given the brevity of randomized controlled trials, the long term effectiveness and safety of opioids are unknown. Loss of long term efficacy could result from drug tolerance and emergence of hyperalgesia. Complications of opioid use include addiction and overdose related mortality, which have risen in parallel with prescription rates. Common short term side effects are constipation, nausea, sedation, and increased risk of falls and fractures. Longer term side effects may include depression and sexual dysfunction. Screening for high risk patients, treatment agreements, and urine testing have not reduced overall rates of opioid prescribing, misuse, or overdose. Newer strategies for reducing risks include more selective prescription of opioids and lower doses; use of prescription monitoring programs; avoidance of co-prescription with sedative hypnotics; and reformulations that make drugs more difficult to snort, smoke, or inject.

Substantive review of the literature of medication treatment of chronic low back pain among adults

PURPOSE

Pain can be debilitating, and it is often inadequately treated, particularly among patients with chronic low back pain (CLBP). CLBP has a substantial economic impact, as it affects an individual's ability to perform activities of daily living and maintain employment. This study aims to review original studies related to the evidence-based management of patients with CLBP to develop an algorithm for prescribing medications and recommending other treatment modalities for patients with CLBP.

DATA SOURCES

An electronic search of PubMed, CINAHL, and the Cochrane Database was conducted to identify studies related to the evidence-based management of CLBP that were performed between 2003 and 2012. The following keywords were used: low back pain, back pain, chronic back pain, medication management, and adjunct therapy. The selected articles were specific to CLBP, medication-based management, and additional treatment options, such as adjunct therapies.

CONCLUSIONS

The collected data revealed that there are a number of approaches to the management of CLBP. Medication regimens are frequently used and widely available, but alternative treatment modalities can also be effective.

IMPLICATIONS FOR PRACTICE

Providers should encourage patients to explore a variety of treatment modalities that can provide pain relief and improve functionality and overall well-being.

Opioids compared with placebo or other treatments for chronic low back pain: an update of the Cochrane Review

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To assess the efficacy of opioids in adults with chronic low back pain (CLBP).

SUMMARY OF BACKGROUND DATA

Opioids for CLBP has increased dramatically. However, the benefits and risks remain unclear.

METHODS

We updated a 2007 Cochrane Review through October 2012 of randomized controlled trials from multiple databases. Use of noninjectable opioids in CLBP for at least 4 weeks was compared with placebo or other treatments; comparisons with different opioids were excluded. Outcomes included pain and function using standardized mean difference (SMD) or risk ratios with 95% confidence intervals (CIs), and absolute risk difference with 95% CI for adverse effects. Study quality was evaluated using Grading of Recommendations Assessment, Development, and Evaluation criteria.

RESULTS

Fifteen trials (5540 participants), including twelve new, met the criteria. Tramadol was better than placebo for pain (SMD, -0.55; 95% CI, -0.66 to -0.44) and function (SMD, -0.18; 95% CI, -0.29 to -0.07). Compared with placebo, transdermal buprenorphine decreased pain (SMD, -2.47; 95% CI, -2.69 to -2.25), but not function (SMD, -0.14; 95% CI, -0.53 to 0.25). Strong opioids (morphine, hydromorphone, oxycodone, oxymorphone, and tapentadol), were better than placebo for pain (SMD, -0.43; 95% CI, -0.52 to -0.33) and function (SMD, -0.26; 95% CI, -0.37 to -0.15). One trial demonstrated little difference with tramadol compared with celecoxib for pain relief. Two trials (272 participants) found no difference between opioids and antidepressants for pain or function. Reviewed trials had low to moderate quality, high drop-out rates, short duration, and limited interpretability of functional improvement. No serious adverse effects, risks (addiction or overdose), or complications (sleep apnea, opioid-induced hyperalgesia, hypogonadism) were reported.

CONCLUSION

There is evidence of short-term efficacy (moderate for pain and small for function) of opioids to treat CLBP compared with placebo. The effectiveness and safety of long-term opioid therapy for treatment of CLBP remains unproven.

Opioids compared to placebo or other treatments for chronic low-back pain

BACKGROUND

The use of opioids in the long-term management of chronic low-back pain (CLBP) has increased dramatically. Despite this trend, the benefits and risks of these medications remain unclear. This review is an update of a Cochrane review first published in 2007.

OBJECTIVES

To determine the efficacy of opioids in adults with CLBP.

SEARCH METHODS

We electronically searched the Cochrane Back Review Group's Specialized Register, CENTRAL, CINAHL and PsycINFO, MEDLINE, and EMBASE from January 2006 to October 2012. We checked the reference lists of these trials and other relevant systematic reviews for potential trials for inclusion.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that assessed the use of opioids (as monotherapy or in combination with other therapies) in adults with CLBP that were at least four weeks in duration. We included trials that compared non-injectable opioids to placebo or other treatments. We excluded trials that compared different opioids only.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias and extracted data onto a pre-designed form. We pooled results using Review Manager (RevMan) 5.2. We reported on pain and function outcomes using standardized mean difference (SMD) or risk ratios with 95% confidence intervals (95% CI). We used absolute risk difference (RD) with 95% CI to report adverse effects.

MAIN RESULTS

We included 15 trials (5540 participants). Tramadol was examined in five trials (1378 participants); it was found to be better than placebo for pain (SMD -0.55, 95% CI -0.66 to -0.44; low quality evidence) and function (SMD -0.18, 95% CI -0.29 to -0.07; moderate quality evidence). Transdermal buprenorphine (two trials, 653 participants) may make little difference for pain (SMD -2.47, 95%CI -2.69 to -2.25; very low quality evidence), but no difference compared to placebo for function (SMD -0.14, 95%CI -0.53 to 0.25; very low quality evidence). Strong opioids (morphine, hydromorphone, oxycodone, oxymorphone, and tapentadol), examined in six trials (1887 participants), were better than placebo for pain (SMD -0.43, 95%CI -0.52 to -0.33; moderate quality evidence) and function (SMD -0.26, 95% CI -0.37 to -0.15; moderate quality evidence). One trial (1583 participants) demonstrated that tramadol may make little difference compared to celecoxib (RR 0.82, 95% CI 0.76 to 0.90; very low quality evidence) for pain relief. Two trials (272 participants) found no difference between opioids and antidepressants for either pain (SMD 0.21, 95% CI -0.03 to 0.45; very low quality evidence), or function (SMD -0.11, 95% -0.63 to 0.42; very low quality evidence). The included trials in this review had high drop-out rates, were of short duration, and had limited interpretability of functional improvement. They did not report any serious adverse effects, risks (addiction or overdose), or complications (sleep apnea, opioid-induced hyperalgesia, hypogonadism). In general, the effect sizes were medium for pain and small for function.

AUTHORS' CONCLUSIONS

There is some evidence (very low to moderate quality) for short-term efficacy (for both pain and function) of opioids to treat CLBP compared to placebo. The very few trials that compared opioids to non-steroidal anti-inflammatory drugs (NSAIDs) or antidepressants did not show any differences regarding pain and function. The initiation of a trial of opioids for long-term management should be done with extreme caution, especially after a comprehensive assessment of potential risks. There are no placebo-RCTs supporting the effectiveness and safety of long-term opioid therapy for treatment of CLBP.

Efficacy and safety of tanezumab versus naproxen in the treatment of chronic low back pain

Tanezumab is a humanized monoclonal antibody that specifically inhibits nerve growth factor as a treatment for chronic pain. This phase IIB study investigated the efficacy and safety of tanezumab for chronic low back pain vs placebo and naproxen. Patients (N=1347) received intravenous tanezumab (5, 10, or 20mg every 8weeks), naproxen (500mg twice daily), or placebo. The primary efficacy end point was mean change in daily average low back pain intensity (LBPI) from baseline to week 16. Secondary end points included mean change from baseline to week 16 in the Roland Morris Disability Questionnaire and Patient's Global Assessment (PGA) of low back pain. Tanezumab 10 and 20mg had similar efficacy profiles and significantly improved LBPI, Roland Morris Disability Questionnaire, and PGA scores vs both placebo and naproxen (P⩽.05). Tanezumab 5mg provided improvement of PGA scores vs placebo (P⩽.05), and naproxen resulted in significant improvement of LBPI vs placebo (P⩽.05). Adverse event incidence was comparable across tanezumab doses but higher than with placebo or naproxen. Arthralgia, pain in extremity, headache, and paresthesia were the most commonly reported adverse events by tanezumab-treated patients. The most frequently reported adverse events resulting in discontinuation of tanezumab treatment were arthralgia and paresthesia; the highest frequency was observed with tanezumab 20mg (both 1.4%). Serious adverse event incidence was similar across treatments. In conclusion, tanezumab provided significantly greater improvement in pain, function, and global scores vs placebo and naproxen in patients with chronic low back pain.

A review of pharmacotherapy for chronic low back pain with considerations for sports medicine

Up to 30% of athletes experience low back pain (LBP) depending on sport type, sex, training intensity and frequency, and technique. United States clinical guidelines define back pain as chronic if it persists for ≥ 12 weeks, and subacute if it persists 4 to < 12 weeks. Certain sports injuries are likely to lead to chronic pain. Persistent or chronic symptoms are frequently associated with degenerative lumbar disc disease or spondylolytic stress lesions. Exercise therapy is widely used and is the most conservative form of treatment for chronic LBP (cLBP). Pharmacotherapies for cLBP include acetaminophen, nonsteroidal anti-inflammatory drugs, and opioids. Acetaminophen is a well-tolerated first-line pharmacotherapy, but high-dose, long-term use is associated with hepatic toxicity. Nonsteroidal anti-inflammatory drugs can be an effective second-line option if acetaminophen proves inadequate but they have well-known risks of gastrointestinal, cardiovascular, and other systemic adverse effects that increase with patient age, dose amount, and duration of use. The serotonin-norepinephrine reuptake inhibitor, duloxetine, has demonstrated modest efficacy and is associated with systematic adverse events, including serotonin syndrome, which can be dose related or result from interaction with other analgesics. Opioids may be an effective choice for moderate to severe pain but also have significant risks of adverse events and carry a substantial risk of addiction and abuse. Because the course of cLBP may be protracted, patients may require treatment over years or decades, and it is critical that the risk/benefit profiles of pharmacotherapies are closely evaluated to ensure that short- and long-term treatments are optimized for each patient. This article reviews the clinical evidence and the guideline recommendations for pharmacotherapy of cLBP.

Efficacy and safety of flupirtine modified release for the management of moderate to severe chronic low back pain: results of SUPREME, a prospective randomized, double-blind, placebo- and active-controlled parallel-group phase IV study

OBJECTIVE

To demonstrate non-inferior/superior efficacy of flupirtine modified release (MR) compared with tramadol/placebo for the management of moderate to severe chronic low back pain (LBP).

RESEARCH DESIGN

Randomized, double-blind, active-/placebo-controlled double-dummy multicenter study, performed in 31 German study centers. LBP patients (n = 363) with moderate pain intensity were randomized 1:1:1 to receive flupirtine MR 400 mg, tramadol extended release (ER) 200 mg, or matching placebo (each given OD in the evening) over 4 weeks.

CLINICAL TRIAL REGISTRATION

EudraCT 2009-013268-38.

MAIN OUTCOME MEASURES

Primary endpoint was change from baseline in the LBP intensity index (LBPIX; 11-point NRS) at week 4; last observation carried forward was used to impute missing scores.

RESULTS

Least square (LS) mean ± SD LBPIX changes from baseline at week 4 were clinically significant for all three treatment groups of the intent-to-treat (ITT) and the per-protocol (PP) population (n = 326/276): placebo (n = 110/96): -1.81 ± 1.65/-1.77 ± 1.59; flupirtine MR (n = 109/95): -2.23 ± 1.73/-2.28 ± 1.68; and tramadol ER (n = 107/85): -1.92 ± 1.84/2.03 ± 1.83 (p < 0.001 for each). ITT/PP treatment effects for flupirtine MR were non-inferior when compared with tramadol ER and superior when compared with placebo (p = 0.003/0.033). Significantly more ITT patients treated with flupirtine MR (59.6/37.6 showed a ≥30/50% LBPIX relief in comparison to placebo (46.4/24.6%; p vs. flupirtine MR: 0.049/0.037). Treatment contrasts for tramadol failed to reach significance vs. placebo. Within the safety population (n = 355), flupirtine MR (n = 119) was associated with a significantly lower incidence of treatment emergent AEs (TEAEs; 21.0%) and TEAE-related study discontinuations (3.4%) than tramadol ER (n = 116; 34.5/12.0%; p = 0.039/0.017) and exhibited an overall safety/tolerability profile non-inferior to placebo (n = 120; 15.8/3.3%; p = ns for each). Major limitations of this study were the short treatment duration, the comparison of different drug classes and the lack of a titration phase.

CONCLUSIONS

The analgesic efficacy of flupirtine MR 400 mg OD was comparable to that of tramadol ER 200 mg OD and superior to that of placebo.

A review of the efficacy, safety, and cost-effectiveness of COX-2 inhibitors for Africa and the Middle East region

Despite an increasingly sophisticated understanding of pain mechanisms, acute and chronic pain remain undertreated throughout the world. This situation reflects the large gap that exists between evidence and practice in pain management and is typified by inappropriate use of nonsteroidal anti-inflammatory drugs (NSAIDs). The scientific evidence around these drugs continues to expand at a high rate, yet physicians are often unaware of best practice. To address this gap among physicians in Africa and the Middle East, an Expert Panel meeting was convened with representatives from the region. The principal objective of the meeting was to review the latest guidelines on the management of acute and chronic pain and to review the efficacy, safety, and cost-effectiveness of cyclooxygenase-2 (COX-2) inhibitors in these settings. The main outcome of this review process was a number of consensus statements concerning the definitions of acute and chronic pain, and the efficacy, safety and cost-effectiveness of traditional nonselective NSAIDs (nsNSAIDs) and selective COX-2 inhibitors (coxibs). The panel agreed that nsNSAIDs and coxibs are effective analgesics with similar efficacy for acute pain; for chronic musculoskeletal pain, NSAIDs are significantly more effective than either placebo or paracetamol. Coxibs offer important safety advantages over nsNSAIDs, including gastrointestinal safety and preservation of platelet function; notably, the cardiovascular safety of coxibs has been the subject of much recent debate. Furthermore, the panel agreed there is substantial evidence to indicate that cost savings can be achieved by using celecoxib in patients at moderate to high risk of gastrointestinal adverse events, even in countries with moderate healthcare expenditures.

Immunosuppressive effects of opioids--clinical relevance

Opioid-induced immunosuppression has been demonstrated in cell culture experiments and in animal models. This is in striking contrast to the paucity of confirmatory studies in humans. This review describes the basic pharmacokinetics and -dynamics of opioid use in patients. It summarizes the major findings on opioid use and infectious complications in intensive care unit (ICU) patients, in patients with acute or chronic non-malignant pain, and in intravenous drug users (IDU). The limitations of studies in each area are discussed. For example, ethical concerns may complicate randomized placebo-controlled trials (RCT) in acute postoperative pain and for a large part of ICU patients. Importantly, most studies in patients with chronic (non-malignant) pain only inadequately report infectious complications in relation to opioid use since their incidence is usually not considered to be drug related. Infectious complications in IDUs are very frequent but cannot easily be distinguished from risk behavior or risk environment. In summary, convincing clinical evidence is lacking that opioids per se increase the rate of infectious complications in most patient categories. From a clinical standpoint, important unresolved issues are i) selection of relevant animal models, ii) opioid selection and discontinuation, and iii) the role of coexisting diseases and concomitant other medications.

Further Qualification of a Therapeutic Responder Index for Patients with Chronic Low Back Pain

Objective.

Previously, a preliminary patient responder index (RI) in chronic low back pain (CLBP) was developed and validated in 5 placebo-controlled clinical trials. The resulting RI was a > 30% improvement in CLBP and patient global assessment (PGA), and no worsening (< 20%) in the Roland Morris Disability Questionnaire (RMDQ) total score. Our objective was to provide further characterization of the preliminary RI in a trial with an active control.

Methods.

Data from a 6-week randomized, double-blind study of celecoxib compared to tramadol hydrochloride was analyzed to determine differences by treatment group on the CLBP RI and its components, to compare the CLBP RI with each of its individual components, and to reanalyze the original cutoff points for the responder criteria.

Results.

Of the celecoxib arm, 50.7%, and of the tramadol hydrochloride arm, 43.7% were classified as responders under the CLBP RI (p = 0.043). The PGA is the most important component in the RI (45% of the sample failed to reach the > 30% improvement criteria on the PGA compared to 34% on the low back pain visual analog scale and only 11% on the RMDQ. The agreement among the CLBP RI with each of its 3 components was largest for the PGA component (κ coefficient 0.849) and smallest for the RMDQ component (κ coefficient 0.207).

Conclusion.

The RI appears to be particularly sensitive to the cutoff point used for improvement in the PGA component. Further testing of the index in trials with other active comparators is required to gain a fuller understanding of its performance.