Associated factors and consequences of risk of bias in randomized controlled trials of yoga: A systematic review

© 2015 Cramer et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background: Bias in randomized controlled trials (RCTs) of complementary therapy interventions seems to be associated with specific factors and to potentially distort the studies' conclusions. This systematic review assessed associated factors of risk of bias and consequences for the studies' conclusions in RCTs of yoga as one of the most commonly used complementary therapies. Methods: Medline/PubMed, Scopus, IndMED and the Cochrane Library were searched through February 2014 for yoga RCTs. Risk of selection bias was assessed using the Cochrane tool and regressed to a) publication year; b) country of origin; c) journal type; and d) impact factor using multiple logistic regression analysis. Likewise, the authors' conclusions were regressed to risk of bias. Results: A total of 312 RCTs were included. Impact factor ranged from 0.0 to 39.2 (median = 1.3); 60 RCT (19.2%) had a low risk of selection bias, and 252 (80.8%) had a high or unclear risk of selection bias. Only publication year and impact factor significantly predicted low risk of bias; RCTs published after 2001 (adjusted odds ratio (OR) = 12.6; 95% confidence interval (CI) = 1.7, 94.0; p<0.001) and those published in journals with impact factor (adjusted OR = 2.6; 95%CI = 1.4, 4.9; p = 0.004) were more likely to have low risk of bias. The authors' conclusions were not associated with risk of bias. Conclusions: Risk of selection bias was generally high in RCTs of yoga; although the situation has improved since the publication of the revised CONSORT statement 2001. Pre-CONSORT RCTs and those published in journals without impact factor should be handled with increased care; although risk of bias is unlikely to distort the RCTs' conclusions

Quality of life and mental health in patients with chronic diseases who regularly practice yoga and those who do not: A case-control study

While clinical trials have shown evidence of efficacy of yoga in different chronic diseases, subjective health benefits associated with yoga practice under naturalistic conditions have not yet been investigated. The aim of this study was to investigate associations of regular yoga practice with quality of life and mental health in patients with chronic diseases. Using a case-control design, patients with chronic diseases who regularly practiced yoga were selected from a large observational study and compared to controls who did not regularly practice yoga and who were matched individually to each case on gender, main diagnosis, education, and age (within 5 years). Patients' quality of life (SF-36 questionnaire), mental health (Hospital Anxiety and Depression Scale), life satisfaction, and health satisfaction (Questionnaire for Life Satisfaction) were assessed. Patients who regularly practiced yoga (n=186) had a better general health status (P=0.012), a higher physical functioning (P=0.001), and physical component score (P=0.029) on the SF-36 than those who did not (n=186). No group differences were found for the mental scales of the SF-36, anxiety, depression, life satisfaction, or health satisfaction. In conclusion, practicing yoga under naturalistic conditions seems to be associated with increased physical health but not mental health in chronically diseased patients. © 2013 Holger Cramer et al

A systematic review and meta-analysis on the effects of yoga on weight-related outcomes

© 2016 Elsevier Inc. Introduction Overweight and obesity are among the most important modifiable risk factors for chronic diseases and premature death. The aim of this review was to systematically assess and analyze the effects of yoga on weight-related outcomes. Methods Medline/PubMed, Scopus, and the Cochrane Library were screened through March 2015 for randomized controlled trials on yoga for weight-related outcomes in the general population or overweight/obese individuals. Risk of bias was assessed using the Cochrane risk of bias tool on the following domains: selection bias, performance bias, detection bias, attrition bias, reporting bias, and other bias. Results Out of 445 records identified during literature search, 30 trials with a total of 2173 participants were included. No effects on weight, body mass index, body fat percentage or waist circumference were found. In studies with healthy adult participants an effect of yoga compared to usual care was found regarding waist/hip ratio (SMD =‐ − 1.00; 95% CI =‐ − 1.44, − 0.55; p < 0.001). In studies with overweight/obese participants only, effects relative to usual care were found for body mass index (SMD = − 0.99; 95% CI = − 1.67, − 0.31; p = 0.004). Effects however were not robust against selection bias; and publication bias could not be ruled out. No intervention-related adverse events were reported. Conclusions Despite methodological drawbacks, yoga can be preliminarily considered a safe and effective intervention to reduce body mass index in overweight or obese individuals

A systematic review and meta-analysis of qigong for the fibromyalgia syndrome

Objectives. The fibromyalgia syndrome (FMS) is a chronic condition with only few evidence-based complementary and alternative therapies available. This paper presents a systematic review and meta-analysis of the effectiveness of Qigong for fibromyalgia syndrome. Methods. The PubMed/MEDLINE, Cochrane Library, Embase, PsycINFO, and Cambase databases were screened in December 2012 to identify randomized controlled trials comparing Qigong to control interventions. Major outcome measures were pain and quality of life; and secondary outcomes included sleep quality, fatigue, depression, and safety. Standardized mean differences (SMD) and 95% confidence intervals were calculated. Results. Seven trials were located with a total of 395 FMS patients. Analyses revealed low quality evidence for short-term improvement of pain, quality of life, and sleep quality and very low quality evidence for improvement of fatigue after Qigong for FMS, when compared to usual care. No evidence was found for superiority of Qigong compared to active treatments. No serious adverse events were reported. Discussion. This systematic review found that Qigong may be a useful approach for FMS patients. According to the quality of evidence, only a weak recommendation for Qigong can be made at this point. Further high quality RCTs are required for the conclusive judgment of its long-term effects. © 2013 Romy Lauche et al

Validation of the German version of the neck disability index (NDI)

Background: The Neck Disability Index (NDI) is the most commonly used outcome measure for neck pain. This study aimed to determine the psychometric properties of a German version of the NDI. Cross-cultural translation and psychometric testing of the NDI were performed. Methods. The 10-item NDI was translated into German and administered to 558 patients with chronic unspecific neck pain (Mean age 49.9 ± 11.4 years, 76% female). The factor structure and reliability of the NDI were assessed using factor analysis, Cronbach's alpha, split-half reliability (Spearman-Brown coefficient), and intra-class correlation (ICC2,1). To determine convergent validity, pain intensity (visual analog scale; VAS), pain on movement (VAS), and quality of life (Short Form 36 Health Survey Questionnaire; SF-36) were correlated with the NDI. Correlation with range of motion and sensitivity to change were also assessed in a subsample of 49 patients. Results: The mean NDI score was 32.75 ± 13.09. Factor analysis revealed a single factor that explained 39.8% of the variance. Cronbach's alpha was 0.81; Spearman-Brown coefficient was 0.80; and intra-class correlation was 0.81 (95% confidence interval = 0.78, 0.83). Significant correlations were found for pain intensity (r = 0.22, p < 0.01), pain on movement (r = 0.39, p < 0.01), quality of life (r = -0.30 to -0.45, p < 0.01), and range of motion (r = -0.34, p = 0.02). Patients who reported global improvement of health after an exercise or yoga intervention showed a higher decrease on the NDI than patients who reported no global improvement (p < 0.01). Conclusions: The German version of the NDI has a comparable factor structure as the original version, acceptable psychometric properties, and is sensitive to change after physical activity. Neck disability is associated with other measures of neck pain. © 2014 Cramer et al.; licensee BioMed Central Ltd

Mindfulness- and acceptance-based interventions for psychosis: A Systematic Review and Meta-analysis

Background: Mindfulness- and acceptance-based interventions are increasingly studied as a potential treatment for a variety of mental conditions. Objective: To assess the effects of mindfulness- and acceptance-based interventions on psychotic symptoms and hospitalization in patients with psychosis Methods: MEDLINE/PubMed, Embase, the Cochrane Library, and PsycINFO were screened from inception through April 2015. Randomized controlled trials (RCTs) were analyzed when they assessed psychotic symptoms or hospitalization in patients with psychosis; affect, acceptance, mindfulness, and safety were defined as secondary outcomes. Results: Eight RCTs with a total of 434 patients comparing mindfulness- based (4 RCTs) or acceptancebased interventions (4 RCTs) to treatment as usual or attention control were included. Six RCTs had low risk of bias. Moderate evidence was found for short-term effects on total psychotic symptoms, positive symptoms, hospitalization rates, duration of hospitalization, and mindfulness and for long-term effects on total psychotic symptoms and duration of hospitalization. No evidence was found for effects on negative symptoms, affect, or acceptance. No serious adverse events were reported. Conclusion: Mindfulness- and acceptance- based interventions can be recommended as an additional treatment for patients with psychosis

Neck pain intensity does not predict pressure pain hyperalgesia: Re-analysis of seven randomized controlled trials

© 2014 The Authors. Objectives: To determine factors, including pain intensity, associated with pressure pain sensitivity in chronic non-specific neck pain and with changes after therapeutic interventions. Methods: This re-analysis used pooled data from 7 randomized controlled clinical trials. Pressure pain thresholds were assessed at the hand and at the site of maximal pain in the neck region before and after different non-pharmacological interventions. Age, gender, neck pain intensity and duration, mental health, expectancy and time interval between measurements were used to determine factors influencing pressure pain thresholds as well as pressure pain threshold changes. Results: A total of 346 patients (77 males, 269 females, mean age 52.6 years (standard deviation 12.0 years)) were included in study, 306 of whom provided a complete data-set for analysis. Pressure pain thresholds at the neck area or the hand did not correlate with pain intensity. Changes in pressure pain thresholds correlated with time between measurements, indicating time-sensitive changes. Discussion: No coherent correlations between pressure pain thresholds and pain intensity were found. Further research is needed to evaluate the relationship between pain intensity and pressure pain thresholds before its use as a valid substitute of pain rating can be supported. Until then, the results of trials with respect to using pressure pain thresholds as an outcome variable must be interpreted with care

Yoga for multiple sclerosis: A systematic review and meta-analysis

© 2014 Cramer et al. While yoga seems to be effective in a number of neuropsychiatric disorders, the evidence of efficacy in multiple sclerosis remains unclear. The aim of this review was to systematically assess and meta-analyze the available data on efficacy and safety of yoga in patients with multiple sclerosis. Medline/PubMed, Scopus, the Cochrane Central Register of Controlled Trials, PsycINFO, CAM-Quest, CAMbase, and IndMED were searched through March 2014. Randomized controlled trials (RCTs) of yoga for patients with multiple sclerosis were included if they assessed health-related quality of life, fatigue, and/or mobility. Mood, cognitive function, and safety were defined as secondary outcome measures. Risk of bias was assessed using the Cochrane tool. Seven RCTs with a total of 670 patients were included. Evidence for short-term effects of yoga compared to usual care were found for fatigue (standardized mean difference [SMD] = 20.52; 95% confidence intervals (CI) = 21.02 to 20.02; p = 0.04; heterogeneity: I2 = 60%; Chi2 = 7.43; p = 0.06) and mood (SMD = 20.55; 95%CI = 20.96 to 20.13; p = 0.01; heterogeneity: I2 = 0%; Chi2 = 1.25; p = 0.53), but not for health-related quality of life, muscle function, or cognitive function. The effects on fatigue and mood were not robust against bias. No short-term or longer term effects of yoga compared to exercise were found. Yoga was not associated with serious adverse events. In conclusion, since no methodological sound evidence was found, no recommendation can be made regarding yoga as a routine intervention for patients with multiple sclerosis. Yoga might be considered a treatment option for patients who are not adherent to recommended exercise regimens

Effect of Yoga in the Therapy of Irritable Bowel Syndrome: A Systematic Review

© 2016 AGA Institute Background & Aims This review aims to systematically survey the effects of yoga on symptoms of irritable bowel syndrome (IBS), pain, quality of life, mood, stress, and safety in patients with IBS. Methods MEDLINE/Pubmed, Scopus, the Cochrane Library, CAM-QUEST, CAMbase, and IndMED were screened through November 2015. Randomized controlled trials comparing yoga with usual care, nonpharmacologic, or pharmacologic interventions were analyzed for patients with IBS. Primary outcomes included gastrointestinal symptoms, quality of life, and pain. Anxiety, mood, and safety were defined as secondary outcomes. Risk of bias was assessed according to the Cochrane Collaboration recommendations. Results Six randomized controlled trials with a total of 273 patients were included in the qualitative analysis. There was evidence for a beneficial effect of a yogic intervention over conventional treatment in IBS, with significantly decreased bowel symptoms, IBS severity, and anxiety. Furthermore, there were significant improvements in quality of life, global improvement, and physical functioning after yoga compared with no treatment. Two randomized controlled trials reported safety data stating that no adverse events occurred. Overall, risk of bias of the included studies was unclear. Conclusions The findings of this systematic review suggest that yoga might be a feasible and safe adjunctive treatment for people with IBS. Nevertheless, no recommendation can be made regarding yoga as a routine intervention for patients with IBS because of major flaws in study methods. More research is needed with respect to a high-quality study design and consensus in clinical outcome measurements in IBS. ClinicalTrials.gov number, NCT02721836

Yoga for improving health-related quality of life, mental health and cancer-related symptoms in women diagnosed with breast cancer

© 2017 The Cochrane Collaboration. Background: Breast cancer is the cancer most frequently diagnosed in women worldwide. Even though survival rates are continually increasing, breast cancer is often associated with long-term psychological distress, chronic pain, fatigue and impaired quality of life. Yoga comprises advice for an ethical lifestyle, spiritual practice, physical activity, breathing exercises and meditation. It is a complementary therapy that is commonly recommended for breast cancer-related impairments and has been shown to improve physical and mental health in people with different cancer types. Objectives: To assess effects of yoga on health-related quality of life, mental health and cancer-related symptoms among women with a diagnosis of breast cancer who are receiving active treatment or have completed treatment. Search methods: We searched the Cochrane Breast Cancer Specialised Register, MEDLINE (via PubMed), Embase, the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1), Indexing of Indian Medical Journals (IndMED), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) search portal and Clinicaltrials.gov on 29 January 2016. We also searched reference lists of identified relevant trials or reviews, as well as conference proceedings of the International Congress on Complementary Medicine Research (ICCMR), the European Congress for Integrative Medicine (ECIM) and the American Society of Clinical Oncology (ASCO). We applied no language restrictions. Selection criteria: Randomised controlled trials were eligible when they (1) compared yoga interventions versus no therapy or versus any other active therapy in women with a diagnosis of non-metastatic or metastatic breast cancer, and (2) assessed at least one of the primary outcomes on patient-reported instruments, including health-related quality of life, depression, anxiety, fatigue or sleep disturbances. Data collection and analysis: Two review authors independently collected data on methods and results. We expressed outcomes as standardised mean differences (SMDs) with 95% confidence intervals (CIs) and conducted random-effects model meta-analyses. We assessed potential risk of publication bias through visual analysis of funnel plot symmetry and heterogeneity between studies by using the Chi2 test and the I2 statistic. We conducted subgroup analyses for current treatment status, time since diagnosis, stage of cancer and type of yoga intervention. Main results: We included 24 studies with a total of 2166 participants, 23 of which provided data for meta-analysis. Thirteen studies had low risk of selection bias, five studies reported adequate blinding of outcome assessment and 15 studies had low risk of attrition bias. Seventeen studies that compared yoga versus no therapy provided moderate-quality evidence showing that yoga improved health-related quality of life (pooled SMD 0.22, 95% CI 0.04 to 0.40; 10 studies, 675 participants), reduced fatigue (pooled SMD -0.48, 95% CI -0.75 to -0.20; 11 studies, 883 participants) and reduced sleep disturbances in the short term (pooled SMD -0.25, 95% CI -0.40 to -0.09; six studies, 657 participants). The funnel plot for health-related quality of life was asymmetrical, favouring no therapy, and the funnel plot for fatigue was roughly symmetrical. This hints at overall low risk of publication bias. Yoga did not appear to reduce depression (pooled SMD -0.13, 95% CI -0.31 to 0.05; seven studies, 496 participants; low-quality evidence) or anxiety (pooled SMD -0.53, 95% CI -1.10 to 0.04; six studies, 346 participants; very low-quality evidence) in the short term and had no medium-term effects on health-related quality of life (pooled SMD 0.10, 95% CI -0.23 to 0.42; two studies, 146 participants; low-quality evidence) or fatigue (pooled SMD -0.04, 95% CI -0.36 to 0.29; two studies, 146 participants; low-quality evidence). Investigators reported no serious adverse events. Four studies that compared yoga versus psychosocial/educational interventions provided moderate-quality evidence indicating that yoga can reduce depression (pooled SMD -2.29, 95% CI -3.97 to -0.61; four studies, 226 participants), anxiety (pooled SMD -2.21, 95% CI -3.90 to -0.52; three studies, 195 participants) and fatigue (pooled SMD -0.90, 95% CI -1.31 to -0.50; two studies, 106 participants) in the short term. Very low-quality evidence showed no short-term effects on health-related quality of life (pooled SMD 0.81, 95% CI -0.50 to 2.12; two studies, 153 participants) or sleep disturbances (pooled SMD -0.21, 95% CI -0.76 to 0.34; two studies, 119 participants). No trial adequately reported safety-related data. Three studies that compared yoga versus exercise presented very low-quality evidence showing no short-term effects on health-related quality of life (pooled SMD -0.04, 95% CI -0.30 to 0.23; three studies, 233 participants) or fatigue (pooled SMD -0.21, 95% CI -0.66 to 0.25; three studies, 233 participants); no trial provided safety-related data. Authors' conclusions: Moderate-quality evidence supports the recommendation of yoga as a supportive intervention for improving health-related quality of life and reducing fatigue and sleep disturbances when compared with no therapy, as well as for reducing depression, anxiety and fatigue, when compared with psychosocial/educational interventions. Very low-quality evidence suggests that yoga might be as effective as other exercise interventions and might be used as an alternative to other exercise programmes