Meta-analysis of pain and function placebo responses in pharmacological osteoarthritis trials

Improvement in quality of life after asfotase alfa treatment in adults with pediatric-onset hypophosphatasia: data from 5 patient-reported outcome measures

Hypophosphatasia (HPP) is a rare, inherited metabolic disorder caused by deficient tissue-nonspecific alkaline phosphatase activity. This study assessed the impact of treatment with asfotase alfa on patient-reported outcomes (PROs) in adults with pediatric-onset HPP. A longitudinal, telephone-based survey was administered to eligible individuals enrolled in a patient support program. Interviews were conducted at study entry (prior to asfotase alfa initiation) and after 3, 6, and 12 mo. PROs-Patient Health Questionnaire-9 [PHQ-9], Work Productivity and Activity Impairment Questionnaire: Specific Health Problem [WPAI:SHP], Patient-Reported Outcomes Measurement Information System 29 [PROMIS-29], and Routine Assessment of Patient Index Data 3 [RAPID3]-were assessed at each time point. Appropriate statistical tests were performed to assess score changes. Among 50 enrolled patients (mean age: 46 yr [SD: 15.4]; 80% female; 94% White), 49 were evaluable at 3 mo, 44 at 6 mo, and 29 at 12 mo. By month 3, statistically significant improvements from baseline were detected in PHQ-9 scores (10.6 vs 5.8 [P < .0001]), PROMIS-29 domain scores (overall physical function: 38.0 vs 43.0 [P = .001]; anxiety: 57.5 vs 51.5 [P = .0011]; fatigue: 63.3 vs 55.3 [P < .0001]; sleep disturbances: 58.8 vs 54.3 [P = .0099]; ability to participate in social roles and activities: 42.6 vs 47.7 [P = .0012]; and pain interference: 63.8 vs 58.4 [P = .001]), and RAPID3 domain scores (functional status: 2.7 vs 1.1 [P < .0001]; pain tolerance: 6.0 vs 3.2 [P < .0001]; and global health estimate: 5.1 vs 2.7 [P < .0001]). Improvements persisted at month 12. Patients also showed improvements in WPAI:SHP domain scores at month 6 (presenteeism: 39.6% vs 14.1% [P < .0001] and work productivity loss: 41.9% vs 14.1% [P < .0001]). Treatment with asfotase alfa was associated with improved quality of life across several domains.

Clinical Assessment of Osteoarthritis Pain: Contemporary Scenario, Challenges, and Future Perspectives

The multifaceted nature of osteoarthritis (OA) pain presents a challenge in understanding and managing the condition. The diverse pain experiences, progression rates, individual responses to treatments, and complex disease mechanisms contribute to heterogeneity in the clinical studies outcomes. The lack of a standardized methodology for assessing and classifying OA pain challenges healthcare practitioners. This complicates the establishment of universally applicable protocols or standardized guidelines for treatment. This article explores the heterogeneity observed in clinical studies evaluating OA pain treatments, highlighting the necessity for refined methodologies, personalized patient categorization, and consistent outcome measures. It discusses the role of the multidimensional nature of OA pain, underlying pain mechanisms, and other contributing factors to the heterogeneity in outcome measures. Addressing these variations is crucial to establishing a more consistent framework for evidence-based treatments and advancing care of the patient with OA pain.

Contextual effects: how to, and how not to, quantify them

The importance of contextual effects and their roles in clinical care controversial. A Cochrane review published in 2010 concluded that placebo interventions lack important clinical effects overall, but that placebo interventions can influence patient-reported outcomes such as pain and nausea. However, systematic reviews published after 2010 estimated greater contextual effects than the Cochrane review, which stems from the inappropriate methods employed to quantify contextual effects. The effects of medical interventions (i.e., the total treatment effect) can be divided into three components: specific, contextual, and non-specific. We propose that the most effective method for quantifying the magnitude of contextual effects is to calculate the difference in outcome measures between a group treated with placebo and a non-treated control group. Here, we show that other methods, such as solely using the placebo control arm or calculation of a 'proportional contextual effect,' are limited and should not be applied. The aim of this study is to provide clear guidance on best practices for estimating contextual effects in clinical research.

A modern multimodal pain protocol eliminates the need for opioids for most patients following total knee arthroplasty: results from a retrospective comparative cohort study

PURPOSE

Modern multimodal analgesia has been shown to significantly reduce opioid use following total knee arthroplasty (TKA). This study was conducted to determine if changing TKA discharge opioid prescriptions from automatic to upon request resulted in more opioid free recoveries without compromising pain control.

METHODS

Between December 2019 and August 2021, an orthopedic surgeon performed 144 primary unilateral TKAs; patients received the same multimodal analgesia protocol except for postoperative opioid prescribing. The first consecutively-treated cohort automatically received an opioid prescription following discharge (automatic group) and the second cohort received opioid prescriptions only upon request (upon request group). Opioid prescription data were derived from a prescription monitoring program and patient-reported outcomes (PROs) were collected preoperatively and at 2 and 12 weeks postoperatively.

RESULTS

A higher percentage of the upon request group was opioid free 3 months after TKA compared with the automatic group (55.6% vs 4.3%, p < 0.0001) without compromising pain or function. Among opioid-naïve patients, 72% in the upon request group were opioid free after TKA compared with 5.4% in the automatic group. Opioid prescribing was not significantly reduced among opioid-experienced patients regardless of the pain protocol.

CONCLUSION

Requiring patients to request opioid prescriptions following TKA resulted in a higher rate of opioid free TKA, especially among opioid-naïve patients, without increasing pain compared with offering all patients an initial opioid prescription.

LEVEL OF EVIDENCE

Level III.

Osteoarthritis today: Lost in translation?

Osteoarthritis (OA) is a highly prevalent joint disease that is associated with pain, loss of function, and high direct and indirect economic costs. The current therapeutic options are inadequate, providing only a moderate symptom relief without the possibility of disease modification. While treatment options and personalized medicines are increasing for many complex diseases, OA drug development has been impeded by the advanced state of disease at the time of diagnosis and intervention, heterogeneity in both symptoms and rates of progression, and a lack of validated biomarkers and relevant outcome measures. This review article summarizes the OA landscape, including therapies in development as potential OA treatments, potential biomarkers undergoing evaluation by the US Food and Drug Administration, and a summary of current OA treatment guidelines, with a particular focus on the knee OA.

A Novel Mobile App-based Neuromuscular Electrical Stimulation Therapy for the Management of Knee Osteoarthritis: Results From an Extension Study of a Randomized, Double-blind, Sham-controlled, Multicenter Trial

Mobile app-based neuromuscular electrical stimulation (NMES) is a promising treatment of knee osteoarthritis as previously demonstrated in a 12-week, randomized, double-blind, sham-controlled, multicenter trial (parent study).

A Randomized Controlled Trial of Thai Medicinal Plant-4 Cream versus Diclofenac Gel in the Management of Symptomatic Osteoarthritis of the Knee

Background

Osteoarthritis of the knee is a common degenerative musculoskeletal condition. Thai Medicinal Plant-4 (TMP-4) cream is made up of Garcinia mangostana peel, Sesamum indicum seeds, Glycine max (L.) Merr. seeds, and Centella asiatica leaves, all of which have anti-inflammatory and analgesic properties. The present study aimed at determining the efficacy and safety of TMP-4 cream versus diclofenac gel in the treatment of symptomatic osteoarthritis of the knee.

Methods

A randomized-controlled trial was conducted to assess knee pain on a scale of 100 mm Visual Analog Scale (VAS) and other key metrics, including VAS knee stiffness, a modified 10-step stair climb test, a timed up and go test, the Knee Injury and Osteoarthritis Outcome Score, and safety outcomes, following administration of either TMP-4 cream or diclofenac gel for 4 weeks.

Results

A total of 199 patients with moderate knee pain intensity were randomly assigned to either TMP-4 cream or diclofenac gel (allocation ratio 1 : 1). The mean changes of VAS knee pain in the TMP-4 cream and diclofenac gel groups were −31.68 ± 14.18 mm and −31.09 ± 12.41 mm, respectively, (mean difference = −0.58, 95% confidence interval = −4.37–3.20, P=0.761). The upper limit of 95% confidence interval for the comparison between TMP-4 cream and diclofenac gel was within the predefined margin of 7 mm for noninferiority. The safety was comparable between the two interventions.

Conclusions

TMP-4 cream was noninferior to diclofenac gel in relieving osteoarthritic knee pain and may be considered as an alternative therapeutic option in the treatment of symptomatic osteoarthritis of the knee.

Ayurveda in Knee Osteoarthritis-Secondary Analyses of a Randomized Controlled Trial

Background: Ayurveda is widely practiced in South Asia in the treatment of osteoarthritis (OA). The aim of these secondary data analyses were to identify the most relevant variables for treatment response and group differences between Ayurvedic therapy compared to conventional therapy in knee OA patients. Methods: A total of 151 patients (Ayurveda n = 77, conventional care n = 74) were analyzed according to the intention-to-treat principle in a randomized controlled trial. Different statistical approaches including generalized linear models, a radial basis function (RBF) network, exhausted CHAID, classification and regression trees (CART), and C5.0 with adaptive boosting were applied. Results: The RBF network implicated that the therapy arm and the baseline values of the WOMAC Index subscales might be the most important variables for the significant between-group differences of the WOMAC Index from baseline to 12 weeks in favor of Ayurveda. The intake of nutritional supplements in the Ayurveda group did not seem to be a significant factor in changes in the WOMAC Index. Ayurveda patients with functional limitations > 60 points and pain > 25 points at baseline showed the greatest improvements in the WOMAC Index from baseline to 12 weeks (mean value 107.8 ± 27.4). A C5.0 model with nine predictors had a predictive accuracy of 89.4% for a change in the WOMAC Index after 12 weeks > 10. With adaptive boosting, the accuracy rose to 98%. Conclusions: These secondary analyses suggested that therapeutic effects cannot be explained by the therapies themselves alone, although they were the most important factors in the applied models.

A Novel Mobile App-Based Neuromuscular Electrical Stimulation Therapy for Improvement of Knee Pain, Stiffness, and Function in Knee Osteoarthritis: A Randomized Trial

Background

Knee osteoarthritis (OA) is a widespread and debilitating disease that continues to plague patients. Over the past decade, neuromuscular electrical stimulation (NMES) therapy has shown promise in alleviating knee OA-related symptoms. This study sought to evaluate the efficacy and safety of a home-based NMES therapy for reduction of pain, stiffness, and function associated with knee OA.

Material and methods

A randomized, sham-controlled, double-blind, multicenter trial was conducted with 12-week follow-up in 156 knee OA patients receiving either home-based NMES therapy or a modified low-voltage NMES therapy. Outcome measures including knee pain, stiffness, and functionality were collected at baseline through week 12 after the therapy. The primary endpoint was the percentage change from baseline (PCFB) in the Visual Analog Scale (VAS) pain for a patient-nominated physical activity. Secondary endpoints included VAS for general knee pain, Western Ontario and McMaster Universities Osteoarthritis Index, Knee Injury and Osteoarthritis Outcome Score Joint Replacement, and isometric quadriceps strength test.

Results

A clinically meaningful reduction for VAS Nominated Activity was higher in the per-protocol treatment-compliant NMES group than that in the sham low-voltage NMES group at week 12 (PCFB of 42.8% vs 38.6%, P = .562). This was similarly true for the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale (PCFBs of 36.8% vs 26.6%, P = .038). Similar trends and reductions of pain were observed for VAS General, Knee Injury and Osteoarthritis Outcome Score Joint Replacement Pain subscale, and isometric quadriceps strength.

Conclusion

Home-based NMES treatment resulted in a clinically meaningful reduction of knee pain, stiffness, and knee functional improvements at week 12 compared with sham NMES treatment.

Autologous Fat Grafting as Treatment of Postmastectomy Pain Syndrome: A Randomized Controlled Trial

BACKGROUND

Postmastectomy pain syndrome is a common and disabling side effect of breast cancer treatment. Medical treatment seems to be insufficient for a considerable proportion of patients. Fat grafting has shown promise in relieving pain from postmastectomy pain syndrome, but no randomized clinical trial comparing fat grafting to a sham operation has been performed to date. The authors' objective was to compare the effect of fat grafting compared to a sham operation for treating postmastectomy pain syndrome.

METHODS

The authors conducted a single-center, double-blind, randomized clinical trial with two arms between October of 2017 and September of 2020. The authors assessed four patients suffering from postmastectomy pain syndrome for inclusion. The intervention group received scar-releasing rigottomy and fat grafting to the area of pain. The control group received scar-releasing rigottomy and a placebo of saline solution. The primary outcome was the degree of pain measured using the Numerical Rating Scale. The secondary outcomes were the degree and quality of neuropathic pain (Neuropathic Pain Symptom Inventory) and quality of life (36-Item Short-Form Health Survey). Follow-up was 6 months.

RESULTS

Thirty-five participants completed follow-up: 18 participants in the intervention group and 17 in the control group. The authors detected no statistically significant changes in average and maximum pain or neuropathic pain. Regarding quality of life, the control group reported a statistically significant improvement in emotional problem parameters, whereas the intervention group reported a deterioration. The authors observed no serious adverse effects.

CONCLUSION

The authors did not find evidence to support that fat grafting is superior to a placebo when treating postmastectomy pain syndrome.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, I.

Responsiveness of an activity tracker as a measurement tool in a knee osteoarthritis clinical trial (ACTIVe-OA study)

BACKGROUND

In osteoarthritis (OA) clinical trials, reliable and responsive outcome measures to document physical and functional improvements are limited.

OBJECTIVE

This study aimed to assess whether the use of an activity tracker in an OA clinical trial is a responsive measurement tool. Secondary objectives assessed feasibility and validity.

METHODS

We recruited 65 participants in a prospective cohort study nested in a placebo-controlled clinical trial of platelet-rich plasma injection in knee OA. Participants wore an activity tracker (Fitbit Flex 2), and a smartphone was preloaded with a mobile application (OApp) designed to monitor load rates as a surrogate of knee loading. Participants used the systems for 7 days at baseline and for 7 days before the 2-month follow-up assessment. Effect size (ES) and standardised response mean (SRM) were calculated for change in step count and knee loading rate and regularly used knee OA outcome measures. Correlation coefficients (r) were calculated to examine the strength of the association between outcome measures.

RESULTS

Step count showed a trivial ES and SRM and mean knee loading rate measurements a moderate ES and SRM. We found a weak but significant correlation between change in mean steps per day and global improvement overall (r = 0.28) and Western Western Ontario and McMaster Universities Osteoarthritis Index function (r = -0.28). Compliance was high with the activity trackers.

CONCLUSIONS

Despite good feasibility, this study did not show significant responsiveness or validity of the activity trackers as compared with currently recommended outcome measures in OA clinical trials. The main challenge is the lack of a gold standard outcome measure to validate against, and because of the complex interplay between pain and measured function, a lack of correlation does not necessarily represent a failed validation in this context. Australian New Zealand Clinical Trials Registry: ACTRN12617000853347. This trial is a substudy of the "Platelet-rich plasma as a symptom-and disease-modifying treatment for knee osteoarthritis - the RESTORE trial".

Osteoarthritis: Current Molecular Biomarkers and the Way Forward

The ultimate hope of researchers and patients is a pathway to development of treatments for osteoarthritis to modify the disease process in addition to the symptoms. However, development of disease modifying drugs requires objective endpoints such as measures of joint structure, joint tissue homeostasis and/or joint survival-measures such as provided by imaging biomarkers, molecular biomarkers and joint replacement frequency, respectively. Although biomarkers supporting investigational drug use and drug approval include surrogate endpoints that may not necessarily reflect or directly correlate with the clinical outcome of interest, a formal biomarker qualification process currently exists that is a rigorous three stage process that yields biomarker approvals (or denials) for specific contexts of use. From a cost perspective, biochemical biomarkers are the 'ones to beat'; however, even well-validated biomarkers may not cross the translation gaps for eventual use in healthcare unless they offer an advantage in terms of cost per quality adjusted life year. This review summarizes the case FOR and AGAINST biomarkers in drug development and highlights the current data for a subset of biomarkers in the osteoarthritis research field informing on cartilage homeostasis, joint inflammation and altered subchondral bone remodeling.

The clinical and cost effectiveness of splints for thumb base osteoarthritis: a randomized controlled clinical trial

OBJECTIVES

To investigate the clinical effectiveness, efficacy and cost effectiveness of splints (orthoses) in people with symptomatic basal thumb joint OA (BTOA).

METHODS

A pragmatic, multicentre parallel group randomized controlled trial at 17 National Health Service (NHS) hospital departments recruited adults with symptomatic BTOA and at least moderate hand pain and dysfunction. We randomized participants (1:1:1) using a computer-based minimization system to one of three treatment groups: a therapist supported self-management programme (SSM), a therapist supported self-management programme plus a verum thumb splint (SSM+S), or a therapist supported self-management programme plus a placebo thumb splint (SSM+PS). Participants were blinded to group allocation, received 90 min therapy over 8 weeks and were followed up for 12 weeks from baseline. Australian/Canadian (AUSCAN) hand pain at 8 weeks was the primary outcome, using intention to treat analysis. We calculated costs of treatment.

RESULTS

We randomized 349 participants to SSM (n = 116), SSM+S (n = 116) or SSM+PS (n = 117) and 292 (84%) provided AUSCAN Osteoarthritis Hand Index hand pain scores at the primary end point (8 weeks). All groups improved, with no mean treatment difference between groups: SSM+S vs SSM -0.5 (95% CI: -1.4, 0.4), P = 0.255; SSM+PS vs SSM -0.1 (95% CI: -1.0, 0.8), P = 0.829; and SSM+S vs SSM+PS -0.4 (95% CI: -1.4, 0.5), P = 0.378. The average 12-week costs were: SSM £586; SSM+S £738; and SSM+PS £685.

CONCLUSION

There was no additional benefit of adding a thumb splint to a high-quality evidence-based, supported self-management programme for thumb OA delivered by therapists.

TRIAL REGISTRATION

ISRCTN 54744256 (http://www.isrctn.com/ISRCTN54744256).

Choice of control group treatments in hand osteoarthritis trials: A systematic review and meta-analysis

OBJECTIVES

To assess how patient characteristics and study design influence the effectiveness of control interventions in hand OA trials.

METHODS

The study protocol was registered in PROSPERO (CRD42020163473). Two authors independently searched four electronic databases from their inception to December 31, 2019. Randomized and non-randomized controlled hand OA trials were included if pain intensity was assessed using a validated scale. We allocated control groups into one of the following: placebo, add-on treatment, no treatment, or active treatment. The standardized mean differences (d) of pain, as well as subjective function and hand strength, were pooled with 95% confidence intervals (CI) and 90% prediction intervals using random-effects models. Meta-regression and post-hoc subgroup analyses were performed to investigate which factors potentially impacted placebo analgesia and between-study heterogeneity.

RESULTS

Thirty-one placebo, 11 add-on, 12 no-treatment, and 10 active-treatment controls were included in meta-analyses. Effective pain relief was observed in placebo (d = -0.50, 95% CI -0.63 to -0.37), add-on (d = -0.35, 95% CI -0.59 to -0.12), and active-treatment (d = -0.92, 95% CI -1.35 to -0.48) groups. In subjective function, these treatments had smaller but beneficial effects; hand strength, contrastingly, was not improved. Placebo effects were larger when flare designs were used (d = -0.96) and more homogeneous when minimum pain thresholds were set (d = -0.46, 90% prediction intervals -0.79 to -0.14).

CONCLUSION

Placebo, add-on, and active control treatments were more effective than the no treatment control in relieving hand pain and improving subjective function. By choosing minimum pain thresholds and flare requirements at patient enrollment, moderate pain relief may be replicated among control participants in future randomized placebo-controlled trials.

Pentosan polysulfate sodium for Ross River virus-induced arthralgia: a phase 2a, randomized, double-blind, placebo-controlled study

Background

Alphaviruses, such as Ross River (RRV) and chikungunya virus (CHIKV), cause significant global morbidity, with outbreaks of crippling joint inflammation and pain, leaving patients incapacitated for months to years. With no available vaccine or specific therapeutic for any alphaviral disease, and a growing economic and public health burden, there is a serious need for the development of specific therapies.

Methods

This study evaluated the safety and efficacy of pentosan polysulfate sodium (PPS) in subjects with RRV-induced arthralgia in a double-blind, placebo-controlled trial. Twenty subjects were randomized 2:1 to subcutaneous PPS (2 mg/kg) or placebo (sodium chloride 0.9%) twice weekly for 6 weeks. Safety evaluation included physical examination, concomitant medications, and laboratory findings. Efficacy assessments included change from baseline in joint function (hand grip strength and RAPID3) and quality of life (SF-36) at Days 15, 29, 39 and 81 after treatment initiation. Inflammatory and cartilage degradation biomarkers were exploratory endpoints.

Results

PPS was well tolerated, with a similar proportion of subjects reporting at least one treatment-emergent adverse event (TEAE) in the treatment and placebo groups. Injection site reactions were the most common TEAE and occurred more frequently in the PPS group. Dominant hand grip strength and SF-36 scores improved with PPS at all time points assessed, with hand grip strength improvement of 6.99 kg (p = 0.0189) higher than placebo at Day 15. PPS showed significant improvements versus placebo in adjusted mean relative change from baseline for RAPID3 Pain (p = 0.0197) and Total (p = 0.0101) scores at Day 15. At the conclusion of the study overall joint symptoms, assessed by RAPID3, showed near remission in 61.5% of PPS subjects versus 14.3% of placebo subjects. Additionally, PPS treatment improved COMP, CTX-II, CCL1, CXCL12, CXCL16 and CCL17 biomarker levels versus placebo.

Conclusions

Overall, the improvements in strength and joint symptoms warrant further evaluation of PPS as a specific treatment for RRV-induced and other forms of arthritis.

Trial registration

This trial is registered at the Australian New Zealand Clinical Trials Registry #ACTRN12617000893303.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04123-w.

Osteoarthritis year in review 2020: epidemiology & therapy

This personal choice of research themes and highlights from within the past year (1 May 2019 to 14 April 2020) spans descriptive, analytical-observational, and intervention studies. Descriptive estimates of the burden of osteoarthritis continue to underscore its position as a leading cause of disability worldwide, but whose burden is often felt greatest among disadvantaged and marginalised communities. Many of the major drivers of that burden are known but epidemiological studies continue the important work of elaborating on their timing, dose, specificity, and reversibility and placing them within an appropriate multi-level framework. A similar process of elaboration is seen also in studies (re-)estimating the relative benefits and risks of existing interventions, in some cases helping to identify low-value care, unwarranted variation, and initiating processes of deprescribing and decommissioning. Such research need not engender therapeutic nihilism. Our review closes by highlighting some emerging evidence on the efficacy and safety of novel therapeutic interventions and with a selective roll-call of methodological and meta-research in OA illustrating the continued commitment to improving research quality.

Wearable Devices: Current Status and Opportunities in Pain Assessment and Management

INTRODUCTION

We investigated the possibilities and opportunities for using wearable devices that measure physical activity and physiometric signals in conjunction with ecological momentary assessment (EMA) data to improve the assessment and treatment of pain.

METHODS

We considered studies with cross-sectional and longitudinal designs as well as interventional or observational studies correlating pain scores with measures derived from wearable devices. A search was also performed on studies that investigated physical activity and physiometric signals among patients with pain.

RESULTS

Few studies have assessed the possibility of incorporating wearable devices as objective tools for contextualizing pain and physical function in free-living environments. Of the studies that have been conducted, most focus solely on physical activity and functional outcomes as measured by a wearable accelerometer. Several studies report promising correlations between pain scores and signals derived from wearable devices, objectively measured physical activity, and physical function. In addition, there is a known association between physiologic signals that can be measured by wearable devices and pain, though studies using wearable devices to measure these signals and associate them with pain in free-living environments are limited.

CONCLUSION

There exists a great opportunity to study the complex interplay between physiometric signals, physical function, and pain in a real-time fashion in free-living environments. The literature supports the hypothesis that wearable devices can be used to develop reproducible biosignals that correlate with pain. The combination of wearable devices and EMA will likely lead to the development of clinically meaningful endpoints that will transform how we understand and treat pain patients.

Estimating contextual effect in nonpharmacological therapies for pain in knee osteoarthritis: a systematic analytic review

OBJECTIVE

Conduct a systematic review and use meta-analytic techniques to estimate the proportion of total treatment effect that can be attributable to contextual effects (PCE) in adults receiving nonpharmacological, nonsurgical (NPNS) treatments for knee osteoarthritis (OA).

DESIGN

We reviewed the published literature to identify five frequently studied NPNS treatments for knee OA: exercise, acupuncture, ultrasound, laser, and transcutaneous electrical nerve stimulation (TENS). We searched for randomized controlled trials (RCTs) of these treatments and abstracted pre- and post-intervention pain scores for groups receiving placebo and active treatments. For each study we calculated the PCE by dividing the change in pain in the placebo group by the change in pain in the active treatment group. We log transformed the PCE measure and pooled across studies using a random effects model.

RESULTS

We identified 25 studies for analysis and clustered the RCTs into two groups: acupuncture and topical energy modalities (TEM). 13 acupuncture studies included 1,653 subjects and 12 TEM studies included 572 subjects. The combined PCE was 0.61 (95% CI 0.46-0.80) for acupuncture and 0.69 (95% CI 0.54-0.88) for TEM.

CONCLUSION

Our findings suggest that about 61% and 69% of the total treatment effect experienced by subjects receiving acupuncture and TEM treatments, respectively, for knee OA pain may be explained by contextual effects. Contextual effects may include the placebo effect, changes attributable to natural history, and effects of co-therapies. These data highlight the important role of contextual effects in the response to NPNS OA treatments.

Clinical Efficacy and Safety of Yellow Oil Formulations 3 and 4 versus Indomethacin Solution in Patients with Symptomatic Osteoarthritis of the Knee: A Randomized Controlled Trial

Background

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) are widely prescribed for the treatment of symptomatic osteoarthritis (OA) of the knee. However, searching for alternatives such as locally available medicinal herbs to manage OA knee pain remains of clinical value. The objective of the present study was to evaluate the efficacy and safety of two yellow oil formulations in patients with OA of the knee.

Methods

This prospective, randomized, single-blind, active-controlled, noninferiority study enrolled 102 patients with OA of the knee. Eligible patients were randomly assigned to apply either yellow oil formulation 3 (YOF3), yellow oil formulation 4 (YOF4), or indomethacin solution (INDO) topically four times daily for four weeks. Outcomes were assessed on a biweekly basis. The primary efficacy outcome measure was a 100 mm visual analog scale (VAS) of pain, while secondary endpoints included knee function, physical performance assessments, and safety parameters. Modified intention-to-treat and per-protocol analyses were applied. Assessment of noninferiority was done with a prespecified margin of 10 mm for VAS pain.

Results

Of 102 patients enrolled, 86 completed the study: 29/34 in the YOF3 group, 25/34 in the YOF4 group, and 32/34 in the INDO group. The absolute reduction in VAS pain at the final evaluation was −25.06 ± 13.91, −18.50 ± 16.06, and −23.38 ± 10.05 mm in the YOF3, YOF4, and INDO groups, respectively (p=0.169). Only YOF3 was found to be noninferior to INDO. Other efficacy outcomes were significantly improved in all three groups. All the interventions were well tolerated; no skin rash was observed in any of the three groups.

Conclusions

YOF3 was shown to be noninferior to INDO in relieving knee pain and should be considered an alternative for the treatment of symptomatic OA of the knee. Further research into the mechanism of action of YOF3 and its long-term efficacy and safety is required.

Placebo Responses and Placebo Effects in Functional Gastrointestinal Disorders

Much has been written about the placebo effects in functional gastrointestinal disorders (FGD), especially in irritable bowel syndrome (IBS), driven by the early hypothesis that in randomized controlled trials (RCTs) of IBS, the placebo effect might be specifically high and thus, corrupts the efficacy of novel drugs developed for this condition. This narrative review is based on a specific search method, a database (www.jips.online) developed since 2004 containing more than 4,500 papers (data papers, meta-analyses, systematic reviews, reviews) pertinent to the topic placebo effects/placebo response. Three central questions-deducted from the body of current literature-are addressed to explore the evidence behind this hypothesis: What is the size placebo effect in FGD, especially in IBS, and is it different from the placebo effect seen in other gastrointestinal disorders? Is the placebo effect in FGD different from other functional, non-intestinal disorders, e.g. in other pain syndromes? Is the placebo effect in FGD related to placebo effects seen in psychiatry, e.g. in depression, anxiety disorders, and alike? Following this discussion, a fourth question is raised as the result of the three: What are the consequences of this for future drug trials in FGD? In summary it is concluded that, contrary to common belief and discussion, the placebo effect seen in RCT in FGD is not specifically high and extraordinary as compared to other comparable (i.e. functional) disorders. It shares less than expected commonalities with the placebo effect in psychiatry, and very few predictors have yet been identified that determine its effect size, especially some that are driven by design features of the studies. Current practice of RCT in IBS seems to limit and control the placebo effect quite well, and future trial practice, e.g. head-to-head trial, still offers options to maintain this control, even in the absence of placebos used.