Mechanisms and direction of allocation bias in randomised clinical trials

Prehabilitation programs for individuals with cancer: a systematic review of randomized-controlled trials

BACKGROUND

Prehabilitation programs focusing on exercise training as the main component are known as a promising alternative for improving patients' outcomes before cancer surgery. This systematic review determined the benefits and harms of prehabilitation programs compared with usual care for individuals with cancer.

METHODS

We searched CENTRAL, MEDLINE, and EMBASE from inception to June 2022, and hand searched clinical trial registries. We included randomized-controlled trials (RCTs) in adults, survivors of any type of cancer, that compared prehabilitation programs that had exercise training as the major component with usual care or other active interventions. Outcome measures were health-related quality of life (HRQL), muscular strength, postoperative complications, average length of stay (ALOS), handgrip strength, and physical activity levels. Two reviewers independently screened the studies, extracted data, and assessed the risk of bias and the certainty of the evidence.

RESULTS

Twenty-five RCTs (2682 participants) published between 2010 and 2022 met our inclusion criteria. Colorectal and lung cancers were the most common diagnoses. The studies had methodological concerns regarding outcome measurement, selective reporting, and attrition. Five prehabilitation programs were compared to usual care (rehabilitation): combined training, aerobic training, respiratory muscle training plus aerobic training, respiratory muscle training plus resistance training, and pelvic floor training. The studies provided no clear evidence of an effect between groups. We assessed the overall certainty of the evidence as very low, downgraded due to serious study limitations and imprecision.

CONCLUSION

Prehabilitation programs focusing on exercise training may have an effect on adults with cancer, but the evidence is very uncertain. We have very little confidence in the results and the true effect is likely to be substantially different from these. Further research is needed before we can draw a more certain conclusion.

SYSTEMATIC REVIEW REGISTRATION

CRD42019125658.

Daily consumption of γ-oryzanol-fortified canola oil, compared with unfortified canola and sunflower oils, resulted in a better improvement of certain cardiometabolic biomarkers of adult subjects with type 2 diabetes: a randomized controlled clinical trial

BACKGROUND

This study was undertaken to examine the effects of daily consumption of γ-oryzanol (ORZ)-fortified canola oil, as compared with plain canola and sunflower oils, on certain cardiometabolic indicators.

METHODS

Ninety-two adult subjects from both sexes with T2D were randomly assigned to one of the three groups to receive: (a) ORZ-fortified canola oil (Group 1; n1 = 30); (b) unfortified canola oil (Group 2; n2 = 32); or (c) sunflower oil (Group 3; n3 = 30) for 12 weeks. The participants were instructed to use only the given oils for all cooking (but frying) purposes. Anthropometric, dietary and biochemical assessments were done initially and finally.

RESULTS

Though body mass index (BMI) significantly decreased in all three groups, only in Groups 1 and 2 waist circumference (WC) showed a significant decrement (-2.6 ± 0.1 and -2.2 ± 0.1 cm in Groups 1 and 2 respectively, p < 0.001 for both) which was accompanied by a significant reduction of blood pressure just in Group 1. Fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) showed a significant decrease only in ORZ-fortified canola oil group (-7.7 ± 0.4 mg/dL, p = 0.039 and -0.7 ± 0.1%, p < 0.001, respectively). However, insulin resistance, as judged by HOMA-IR, did not change significantly. In addition, serum triglyceride (TG) concentrations decreased in all three groups but only in ORZ-fortified canola oil was this decrement statistically significant (-17.9 ± 2.1 mg/dL, p = 0.005). Other components of serum lipid profile did not change significantly in either group.

CONCLUSIONS

Consumption of either sunflower or canola oils for 12 weeks improved certain studied biomarkers. However, only ORZ-fortified canola oil resulted in a significant decrease of blood pressure, WC, FBG, HbA1c and TG. These findings can help both clinicians and public health authorities for dietary recommendations to subjects with T2D and presumably the whole community.

TRIAL REGISTRATION

number at clinicaltrials.gov (NCT05271045).

Effects of resistance training on C-reactive protein in menopausal and postmenopausal women: a systematic review and meta-analysis of randomized controlled trials

IMPORTANCE

Menopause is a biological stage associated with increased cardiovascular morbidity and mortality due to changes in sex hormone levels.

OBJECTIVE

This systematic review aimed to investigate the benefits and harms of RT in menopausal and postmenopausal women.

EVIDENCE REVIEW

We searched PubMed, Embase, CENTRAL, Scopus, and Web of Science from inception to 2021, and clinical trial registries. Randomized controlled trials (RCT) in menopausal and postmenopausal women that compared women undergoing RT programs with a control group were included. The primary outcomes were C-reactive protein level and adverse events; and, the secondary outcomes were lipid profile and waist circumference. Two reviewers independently selected the studies, extracted data, and assessed the completeness of RT programs, risk of bias, and quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation approach (GRADE). A random-effects model was used. Statistical significance was set at P < 0.05.

FINDINGS

Twelve RCTs published from 2012 to 2020 met the inclusion criteria (n = 482). Four follow-up periods were assessed. RT caused reductions in C-reactive protein levels compared to those in the control group in postmenopausal women in the short- to long-term follow-up (mean difference, -0.47 mg/dL; 95% confidence interval, -0.66 to -0.29; P < 0.00001). Furthermore, RT may reduce C-reactive protein levels even at moderate and moderate-to-high intensity ( P < 0.0001 and P = 0.0005, respectively). Similar findings were found for lipid profiles in the short- to long-term follow-up ( P < 0.05). RT may have had little to no effect on waist circumference. The certainty of the body of evidence was assessed as very low and downgraded owing to serious study limitations, inconsistency, imprecision, and publication bias.

CONCLUSIONS AND RELEVANCE

There was very low-quality evidence supporting the benefits of RT compared with control for C-reactive protein levels and lipid profile. No benefits were found for the outcome of waist circumference in postmenopausal women with different comorbidities or risk factors. Safety data were scarce. We have little confidence in the results, and the true effect is likely to be substantially different. Further well-conducted and well-reported RCTs are warranted to strengthen the evidence.

PROTOCOL REGISTRATION

PROSPERO CRD42020213125.

Reevaluating the Use of Sound Therapy for Tinnitus Management: Perspectives on Relevant Systematic Reviews

PURPOSE

Tinnitus is a highly prevalent condition that can severely reduce health functioning. In spite of extant clinical practice guidelines (CPGs), implementation of these CPGs is relatively uncommon. As a result, patients seeking professional services for tinnitus often have no assurance of receiving evidence-based care. The purpose of this tutorial was to clarify the evidence for sound therapy so that it may be included in future CPGs for tinnitus.

METHOD

"Best clinical evidence" is obtained from high-quality systematic reviews, which are generally considered the highest level of evidence. Our review of recent, comprehensive, high-quality systematic reviews of interventions for tinnitus concludes that cognitive behavioral therapy is the only effective intervention, though the strength of evidence was generally rated as low in these reviews. Although trials of sound therapy for tinnitus have been included in these reviews, they have been rated as having high risk of bias (RoB) and not included in syntheses or rated as insufficient strength of evidence.

RESULTS

Conclusions from these and other reviews have influenced recommendations made in CPGs for tinnitus. These conclusions, however, can make it appear that an intervention for tinnitus is not effective, even if the opposite is true. We contend that the strict inclusion criteria for these reviews are counterproductive and have the effect of obscuring decades of evidence demonstrating the clinical effectiveness of sound therapies for tinnitus. Ultimately, this process has resulted in many patients not receiving sound therapy, despite what should be sufficient evidence that this is an effective form of intervention.

CONCLUSION

If we rely on systematic reviews using contemporary RoB assessment criteria for studies published prior to these reporting guidelines, then we risk excluding important conclusions regarding interventions that could help patients in need.

A systematic review and meta-analysis of the effects of Hibiscus sabdariffa on blood pressure and cardiometabolic markers

Context

Hibiscus sabdariffa (hibiscus) has been proposed to affect cardiovascular risk factors.

Objective

To review the evidence for the effectiveness of hibiscus in modulating cardiovascular disease risk markers, compared with pharmacologic, nutritional, or placebo treatments.

Data Sources

A systematic search of the Web of Science, Cochrane, Ovid (MEDLINE, Embase, AMED), and Scopus databases identified reports published up to June 2021 on randomized controlled trials using hibiscus as an intervention for lipid profiles, blood pressure (BP), and fasting plasma glucose levels in adult populations.

Data Extraction

Seventeen chronic trials were included. Quantitative data were examined using a random effects meta-analysis and meta-regression with trial sequential analysis to account for type I and type II errors.

Data Analysis

Hibiscus exerted stronger effects on systolic BP (−7.10 mmHg [95%CI, −13.00, −1.20]; I² = 95%; P = 0.02) than placebo, with the magnitude of reduction greatest in those with elevated BP at baseline. Hibiscus induced reductions to BP similar to that resulting from medication (systolic BP reduction, 2.13 mmHg [95%CI, −2.81, 7.06], I² = 91%, P = 0.40; diastolic BP reduction, 1.10 mmHg [95%CI, −1.55, 3.74], I² = 91%, P = 0.42). Hibiscus also significantly lowered levels of low-density lipoprotein compared with other teas and placebo (−6.76 mg/dL [95%CI, −13.45, −0.07]; I² = 64%; P = 0.05).

Conclusions

Regular consumption of hibiscus could confer reduced cardiovascular disease risk. More studies are warranted to establish an effective dose response and treatment duration.

Systematic Review Registration

PROSPERO registration no. CRD42020167295

Corticosteroid injection or dry needling for musculoskeletal pain and disability? A systematic review and GRADE evidence synthesis

Background

Corticosteroid injection and dry needling have been used in the treatment of musculoskeletal conditions, but it is unclear which intervention is the most effective. The purpose of this study was to compare the effects of corticosteroid injection and dry needling for musculoskeletal conditions at short-, medium-, and long-term follow-up.

Methods

Electronic databases were searched up to 31 October 2021. Two researchers independently screened titles, abstracts and full-text articles. Randomized clinical trials (RCTs) that investigated the effectiveness of dry needling compared to corticosteroid injection in patients over 18 years with a musculoskeletal condition were included in the review. The studies had to report pain and/or disability as outcome. Risk of bias was assessed by using the revised Cochrane Collaboration tool (RoB 2.0). Quality of evidence was evaluated by using the GRADE approach.

Results

Six studies were included (n = 384 participants). Four musculoskeletal conditions were investigated. There is very low-quality evidence that CSI is superior to DN for reducing heel pain (plantar fasciitis) and lateral elbow pain at short- and medium-term follow-up, but not for myofascial pain and greater trochanteric pain. There is very low-quality evidence that DN is more effective than CSI at long-term follow-up for reducing pain in people with plantar fasciitis and lateral epicondylitis. Very low-certainty evidence shows that there is no difference between DN and CSI for disability at short-term follow-up. One study showed that CSI is superior to DN at medium-term follow-up and another observed that DN is superior to CSI for reducing disability at long-term.

Conclusions

There are no differences between DN and CSI in pain or disability for myofascial pain and greater trochanteric pain syndrome. Very-low certainty evidence suggests that CSI is superior to DN at shorter follow-up periods, whereas DN seems to be more effective than CSI at longer follow-up durations for improving pain in plantar fasciitis and lateral epicondylitis. Large RCTs with higher methodological quality are needed in order to draw more incisive conclusions.

PROSPERO registration number

CRD42020148650.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12998-021-00408-y.

Key concepts in clinical epidemiology: addressing and reporting sources of bias in randomized controlled trials

Randomized controlled trials are widely considered the most robust design for evaluating the effects of clinical interventions. While generalisability is often limited, randomization aims to ensure that effects observed are genuine. However, there are common sources of bias, even in well-conducted trials, that pose a threat to this interpretation. The revised Cochrane risk-of-bias tool for trials (RoB 2) distinguishes five domains of bias that can affect the results of trials stemming from (1) the randomization process, (2) deviations from intended interventions, (3) missing outcome data, (4) outcome measurement, and (5) reporting of findings. We use RoB 2 as a framework for recommendations to help researchers mitigate these sources of bias and ensure transparency in reporting so that users of research are aware of them.

A Systematic Review Comparing Experimental Design of Animal and Human Methotrexate Efficacy Studies for Rheumatoid Arthritis: Lessons for the Translational Value of Animal Studies

Simple Summary

If we want to use animal studies to predict what will happen if we give a drug to humans, it makes sense to perform the animal studies as similarly to human studies as possible. For example, if animal tests of a drug only look at the effect of injecting the drug in young healthy animals, we cannot expect the results to be similar in human tests giving tablets to older patients who may have other diseases besides the one for which they receive the drug. We did an in-depth analysis of how 147 animal and 512 human studies of the drug methotrexate for rheumatoid arthritis were performed. Important differences were present, for example, animal studies used more males, while rheumatoid arthritis occurs more in females. We calculated the human-equivalent age of the animals, and they were on average younger than humans. Many studies did not fully report the way the experiments were performed. In spite of these differences, the drug methotrexate works well against rheumatoid arthritis in animal models and humans. Further (literature) research is still needed; we do not yet understand when we can reliably predict human effects from animal studies.

Abstract

Increased awareness and understanding of current practices in translational research is required for informed decision making in drug development. This paper describes a systematic review of methotrexate for rheumatoid arthritis, comparing trial design between 147 animal and 512 human studies. Animal studies generally included fewer subjects than human studies, and less frequently reported randomisation and blinding. In relation to life span, study duration was comparable for animals and humans, but included animals were younger than included humans. Animal studies often comprised males only (61%), human studies always included females (98% included both sexes). Power calculations were poorly reported in both samples. Analyses of human studies more frequently comprised Chi-square tests, those of animal studies more frequently reported analyses of variance. Administration route was more variable, and more frequently reported in animal than human studies. Erythrocyte sedimentation rate and c-reactive protein were analysed more frequently in human than in animal studies. To conclude, experimental designs for animal and human studies are not optimally aligned. However, methotrexate is effective in treating rheumatoid arthritis in animal models and humans. Further evaluation of the available evidence in other research fields is needed to increase the understanding of translational success before we can optimise translational strategies.

Gastroesophageal Reflux Disease and Probiotics: A Systematic Review

Probiotic is little known for its benefits on upper gastrointestinal health. The objective of this systematic review was to examine the efficacy of probiotics in alleviating the frequency and severity of symptoms in gastroesophageal reflux disease (GERD) in the general adult population. The PubMed and Web of Science databases were searched for prospective studies on GERD, heartburn, regurgitation, and dyspepsia, without any limitation on sample size. The Jadad scale was used to evaluate the quality of randomized controlled trials. In total, 13 prospective studies that were published in 12 articles were included in the analysis and scored per the Jadad scale as high- (five studies), medium- (two), and low- (six) quality. One article reported on two probiotic groups; thus, 14 comparisons were included in the selected studies, of which 11 (79%) reported positive benefits of probiotics on symptoms of GERD. Five out of 11 positive outcomes (45%) noted benefits on reflux symptoms: three noted reduced regurgitation; improvements in reflux or heartburn were seen in one study; five (45%) saw improvements in dyspepsia symptoms; and nine (81%) saw improvements in other upper gastrointestinal symptoms, such as nausea (three studies), abdominal pain (five), and gas-related symptoms (four), such as belching, gurgling, and burping. In conclusion, probiotic use can be beneficial for GERD symptoms, such as regurgitation and heartburn. However, proper placebo-controlled, randomized, and double-blinded clinical trials with a sufficient number of participants are warranted to confirm its efficacy in alleviating these symptoms. Further, interventions with longer durations and an intermediate analysis of endpoints should be considered to determine the proper therapeutic window.

Clowning in children undergoing potentially anxiety-provoking procedures: a systematic review and meta-analysis

BACKGROUND

The operation areas of clowns in the medical context are multifaceted. Clowning in children undergoing surgery has been shown to be able to lessen children's anxiety. Hence, our aim was to assess the effectiveness of clowning on anxiety in children undergoing potentially anxiety-provoking procedures.

METHODS

We searched MEDLINE, CENTRAL, and EMBASE for randomized controlled trials (RCTs) in December 2018. The primary outcome was children's anxiety. We used the Cochrane risk of bias tool to assess risk of bias of the included studies.

RESULTS

We found eleven RCTs including 733 children. Their risk of bias was relatively high. Children undergoing clowning were significantly less anxious in preoperative time compared to parental presence or no intervention (mean difference (MD) - 7.16; 95% CI - 10.58, - 3.75) and in operation, induction, or patient room (MD - 20.45; 95% CI - 35.54, - 5.37), but not during mask application or physician examination (MD 2.33; 95% CI - 4.82, 9.48). Compared with midazolam, children's anxiety was significantly lower in preoperative time (MD - 7.60; 95% CI - 11.73, - 3.47), but not in the induction room (MD - 9.63; 95% CI - 21.04, 1.77).

CONCLUSIONS

Clowning seems to lower children's anxiety, but because of the increased risk of bias of included studies and the very low quality of evidence, these results should be considered with caution.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016039045.

Bias in clinical trials into the effects of complementary and alternative medicine therapies on hemodialysis patients

Background:

Chronic renal failure is among the major health challenges in the world. Many clinical trials have been conducted to assess the effects of complementary and alternative therapies on hemodialysis-related outcomes. However, a number of biases may affect the results of these studies.

Aims:

This study aimed to assess biases in randomized clinical trials into the effects of complementary and alternative therapies on hemodialysis patients.

Settings and Design:

A critical review on clinical trials into the effects of complementary and alternative therapies therapies on hemodialysis patients.

Materials and Methods:

This study was conducted on 114 randomized clinical trials which had been published in 2012–2017 into the effects of complementary and alternative therapies on hemodialysis patients. The Cochrane Risk of Bias Tool was employed to assess biases in the included trials. The collected data were presented using the measures of descriptive statistics, namely absolute and relative frequencies.

Results:

Among 114 included trials, 71.05% (81 trials) had used low bias methods for random sequence generation, while 60.52% (69 trials) had provided no clear information about allocation concealment. Moreover, respecting blinding, 57.89% of trials (66 trials) were low bias. Around 60.52% of trials (69 trials) had no attrition between randomization and final follow-up assessment and 84.21% (96 trials) had apparently reported all intended outcomes.

Conclusions:

This study shows that 50% of randomized clinical trials into the effects of complementary and alternative therapies on hemodialysis patients have low bias. Yet, quality improvement is still needed to produce more conclusive evidence.

Applying a systems approach to thyroid physiology: Looking at the whole with a mitochondrial perspective instead of judging single TSH values or why we should know more about mitochondria to understand metabolism

Classical thinking in endocrine physiology squeezes our diagnostic handling into a simple negative feedback mechanism with a controller and a controlled variable. In the case of the thyroid this is reduced to TSH and fT3 and fT4, respectively. The setting of this tight notion has no free space for any additions. In this paper we want to challenge this model of limited application by proposing a construct based on a systems approach departing from two basic considerations. In first place since the majority of cases of thyroid disease develop and appear during life it has to be considered as an acquired condition. In the second place, our experience with the reversibility of morphological changes makes the autoimmune theory inconsistent.

While medical complexity can expand into the era of OMICS as well as into one where manipulations with the use of knock-outs and -ins are common in science, we have preferred to maintain a simple and practical approach. We will describe the interactions of iron, magnesium, zinc, selenium and coenzyme Q10 with the thyroid axis. The discourse will be then brought into the context of ovarian function, i.e. steroid hormone production. Finally the same elemental players will be presented in relation to the basic mitochondrial machinery that supports the endocrine.

We propose that an intact mitochondrial function can guard the normal endocrine function of both the thyroid as well as of the ovarian axis. The basic elements required for this function appear to be magnesium and iron. In the case of the thyroid, magnesium-ATP acts in iodine uptake and the heme protein peroxidase in thyroid hormone synthesis. A similar biochemical process is found in steroid synthesis with cholesterol uptake being the initial energy-dependent step and later the heme protein ferredoxin 1 which is required for steroid synthesis. Magnesium plays a central role in determining the clinical picture associated with thyroid disease and is also involved in maintaining fertility. With the aid of 3D sonography patients needing selenium and/or coenzyme Q10 can be easily identified. By this we firmly believe that physicians should know more about basic biochemistry and the way it fits into mitochondrial function in order to understand metabolism. Contemplating only TSH is highly reductionistic.

Outline

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Author's profiles and motivation for this analysis

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The philosophical alternatives in science and medicine

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Reductionism vs. systems approach in clinical thyroid disease guidelines

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The entry into complexity: the involvement of the musculoskeletal system

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Integrating East and West: teachings from Chinese Medicine and from evidence based medicine (EBM)

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Can a mathematical model represent complexity in the daily thyroid practice?

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How effective is thyroxine treatment?

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Resolving the situation of residual symptoms in treated patients with thyroid disease

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Importance of iron, zinc and magnesium in relation to thyroid function

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Putting together new concepts related to thyroid function for a systems approach

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Expanding our model into general aspects of medicine