Clinical research methodology I: introduction to randomized trials

Mind-Body Intervention for Dysfunctional Breathing in Chronic Obstructive Pulmonary Disease: Feasibility Study and Lessons Learned

Purpose: Dysfunctional breathing behaviors are prevalent in chronic obstructive pulmonary disease (COPD). Although these behaviors contribute to dyspnea, abnormal carbon dioxide (CO2) levels, and COPD exacerbations, they are modifiable. Current dyspnea treatments for COPD are suboptimal, because they do not adequately address dysfunctional breathing behaviors and anxiety together. We developed a complementary mind-body breathlessness therapy, called capnography-assisted respiratory therapy (CART), that uses real-time CO2 biofeedback at the end of exhalation (end-tidal CO2 or ETCO2), to target dysfunctional breathing habits and improve dyspnea treatment and pulmonary rehabilitation (PR) adherence in COPD. The study aim was to test the feasibility of integrating CART with a traditional, clinic-based PR program in an urban setting. Methods: We used a feasibility pre- and post-test design, with 2:1 randomization to CART+PR or control (PR-alone) groups, to test and refine CART. Multi-component CART consisted of six, 1-h weekly sessions of slow breathing and mindfulness exercises, ETCO2 biofeedback, motivational counseling, and a home program. All participants were offered twice weekly, 1-h sessions of PR over 10 weeks (up to 20 sessions). Results: Thirty-one participants with COPD were enrolled in the study. Approximately a third of participants had symptoms of psychological distress. Results showed that CART was feasible and acceptable based on 74% session completion and 91.7% homework exercise completion (n = 22). Within-group effect sizes for CART+PR were moderate to large (Cohen's d = 0.51-1.22) for reduction in resting Borg dyspnea (anticipatory anxiety) and respiratory rate, St. George's Respiratory Questionnaire (SGRQ) respiratory symptoms; and increase in Patient-Reported Outcomes Measurement Information System (PROMIS) physical function and physical activity; all p < 0.05. Conclusions: CART is a new mind-body breathing therapy that targets eucapnic breathing, interoceptive function, and self-regulated breathing to relieve dyspnea and anxiety symptoms in COPD. Study findings supported the feasibility of CART and showed preliminary signals that CART may improve exercise tolerance, reduce dyspnea, and enhance PR completion by targeting reduced dysfunctional breathing patterns (CTR No. NCT03457103).

Effectiveness of Self-assembling Peptide P11-4 Compared to Tricalcium Phosphate Fluoride Varnish in Remineralization of White Spot Lesions: A Clinical Randomized Trial

Background

Fluoride varnish with therapeutic tricalcium phosphate formulas such as Clinpro™ varnish has shown greater tendency in treating white spot lesions (WSLs) by inhibiting the progression of initial enamel lesions through the mineral exchange. The self-assembling peptide SAP₁₁-4 (Curodont Repair, CDR) works on a different scale in treating WSLs by mimicking the enamel matrix and aiming to guided enamel regeneration.

Aim

To quantitatively and qualitatively compare the effectiveness of the SAP₁₁-4 vs tricalcium posphate fluoride (TCPF) in remineralization of WSLs in young permanent teeth.

Materials and methods

Nine healthy patients were enrolled in this study. The trial was performed on 40 young permanent teeth in the initial demineralization stage. Teeth were randomly assigned to receive either TCPF (group I) or SAP₁₁-4 (group II). Lesions were assessed at pretreatment, 3, and 6 months posttreatment quantitatively per laser fluorescence DIAGNOdent pen and qualitatively through the International Caries Detection and Assessment System (ICDAS) II.

Results

The result of the current study revealed a significant quantitative and qualitative increase in remineralization of WSLs in both groups and over time intervals. However, the WSL recovery was significantly better in the self-assembling peptide group, reflecting an excellent remineralization potential of the WSLs by the SAP₁₁-4 compared to TCPF varnish.

Conclusion

Both TCPF and SAP₁₁-4 were effective in treating WSLs. However, the success of guided enamel regeneration by the SAP₁₁-4 through the biomineralization has proven superiority of this material compared to TCPF.

Clinical significance

Early detection of WSLs and minimal intervention through remineralizing agents can limit unnecessary tissue loss, further caries progression, and consequently prevent further harm to the patients.

How to cite this article

Kobeissi R, Badr SBY, Osman E. Effectiveness of Self-assembling Peptide P₁₁-4 Compared to Tricalcium Phosphate Fluoride Varnish in remineralization of White Spot Lesions: A Clinical Randomized Trial. Int J Clin Pediatr Dent 2020;13(5):451-456.

Potential application of mesenchymal stem cells and their exosomes in lung injury: an emerging therapeutic option for COVID-19 patients

The COVID-19 pandemic has negatively impacted the global public health and the international economy; therefore, there is an urgent need for an effective therapy to treat COVID-19 patients. Mesenchymal stem cells (MSCs) have been proposed as an emerging therapeutic option for the SARS-CoV-2 infection. Recently, numerous clinical trials have been registered to examine the safety and efficacy of different types of MSCs and their exosomes for treating COVID-19 patients, with less published data on the mechanism of action. Although there is no approved effective therapy for COVID-19 as of yet, MSC therapies showed an improvement in the treatment of some COVID-19 patients. MSC’s therapeutic effect is displayed in their ability to reduce the cytokine storm, enhance alveolar fluid clearance, and promote epithelial and endothelial recovery; however, the safest and most effective route of MSC delivery remains unclear. The use of poorly characterized MSC products remains one of the most significant drawbacks of MSC-based therapy, which could theoretically promote the risk for thromboembolism. Optimizing the clinical-grade production of MSCs and establishing a consensus on registered clinical trials based on cell-product characterization and mode of delivery would aid in laying the foundation for a safe and effective therapy in COVID-19. In this review, we shed light on the mechanistic view of MSC therapeutic role based on preclinical and clinical studies on acute lung injury and ARDS; therefore, offering a unique correlation and applicability in COVID-19 patients. We further highlight the challenges and opportunities in the use of MSC-based therapy.

A test for treatment effects in randomized controlled trials, harnessing the power of ultrahigh dimensional big data

BACKGROUND

The randomized controlled trial (RCT) is the gold-standard research design in biomedicine. However, practical concerns often limit the sample size, n, the number of patients in a RCT. We aim to show that the power of a RCT can be increased by increasing p, the number of baseline covariates (sex, age, socio-demographic, genomic, and clinical profiles et al, of the patients) collected in the RCT (referred to as the 'dimension').

METHODS

The conventional test for treatment effects is based on testing the 'crude null' that the outcomes of the subjects are of no difference between the two arms of a RCT. We propose a 'high-dimensional test' which is based on testing the 'sharp null' that the experimental intervention has no treatment effect whatsoever, for patients of any covariate profile.

RESULTS

Using computer simulations, we show that the high-dimensional test can become very powerful in detecting treatment effects for very large p, but not so for small or moderate p. Using a real dataset, we demonstrate that the P value of the high-dimensional test decreases as the number of baseline covariates increases, though it is still not significant.

CONCLUSION

In this big-data era, pushing p of a RCT to the millions, billions, or even trillions may someday become feasible. And the high-dimensional test proposed in this study can become very powerful in detecting treatment effects.

Challenges in the design, conduct, analysis, and reporting in randomized clinical trial studies: A systematic review

Background: Randomized clinical trials have been considered as the gold standard for evaluating the effectiveness and safety of medical interventions; however, there are major barriers to their design, conduct, analysis, and reporting. They are multidisciplinary and involve different steps and face a variety of challenges that may vary from one country to another. The aim of this study was to provide a comprehensive presentation of the challenges of clinical trial studies in different steps including design, conducting, analysis, and reporting. Methods: In this study, all original articles conducted during 1991-2017 that reviewed the barriers to clinical trial studies at one of the steps of design, conducing, analysis, and reporting of the results in Medline (through PubMed), Embase, Web of Sciences, Scopus, and Google Scholar were considered. The searched keywords were as follow: challenges, barriers, and randomized clinical trial. Results: The following barriers in different steps of randomized clinical trials were identified: general barriers include insufficient knowledge and understanding of clinical research and research methodology, barriers to ethical and regulatory systems, and lack of funding. The investigator-initiated trials may face similar problems to those of sponsor-initiated trials, such as handling regulatory systems, administrative and financial issues, multiple languages, and different patient compensation approaches. The challenge related to design was poor planning. Other challenges were lack of manpower and financial resources, inappropriate statistical methods for analysis (analysis challenges), and challenges related to reporting which include selective reporting. Conclusion: Based on the results of this systematic review, the most important challenges were barriers related to handling ethical and regulatory systems, patient recruitment, and lack of budget and skilled staff for conducting clinical trials. Training to improve the quality of randomized clinical trial studies in different steps and levels was the most important recommendation in these studies.

Efficacy and safety of pulmonary application of corticosteroids in preterm infants with respiratory distress syndrome: a systematic review and meta-analysis

BACKGROUND

Systemic corticosteroids as the frontline treatment of respiratory distress syndrome (RDS) in preterm infants are associated with adverse effects on growth and neurodevelopmental outcome, but the pulmonary administration of steroids may help prevent the development of bronchopulmonary dysplasia (BPD) without these side effects.

OBJECTIVES

To evaluate the efficacy and safety of pulmonary application of corticosteroids in preterm infants with RDS.

METHODS

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, the WHO's International Clinical Trials Registry and grey literature were searched with no restriction on date and language of publication from inception to May 2016. Using a random-effect model, we pooled data from randomised controlled trials (RCTs) comparing inhaled or endotracheal corticosteroids with the standard of care, placebo or no other intervention in preterm infants with RDS.

RESULTS

We identified 873 potential citations and included 12 unique RCTs. Pulmonary corticosteroid therapy was associated with a significant reduction in the composite outcome of BPD or death (relative risk (RR) 0.85, 95% CI 0.76 to 0.96). Pulmonary application of corticosteroids significantly reduced the incidence of patent ductus arteriosus (PDA) (RR 0.82, 95% CI 0.74 to 0.92) and pneumonia (RR 0.57, 95% CI 0.35 to 0.92). There was no evidence of a significant difference regarding the risk of neurodevelopmental impairment or other side effects.

CONCLUSIONS

Pulmonary administration of corticosteroids reduces the incidence of BPD or death, pneumonia, PDA without causing any major side effects in preterm infants with RDS.

A practical blueprint to systematically study life-long health consequences of novel medically assisted reproductive treatments

In medicine, safety and efficacy are the two pillars on which the implementation of novel treatments rest. To protect the patient from unnecessary or unsafe treatments, usually, a stringent path of (pre) clinical testing is followed before a treatment is introduced into routine patient care. However, in reproductive medicine several techniques have been clinically introduced without elaborate preclinical studies. Moreover, novel reproductive techniques may harbor safety risks not only for the patients undergoing treatment, but also for the offspring conceived through these techniques. If preclinical (animal) studies were performed, efficacy and functionality the upper hand. When a new medically assisted reproduction (MAR) treatment was proven effective (i.e. if it resulted in live birth) the treatment was often rapidly implemented in the clinic. For IVF, the first study on the long-term health of IVF children was published a decade after its clinical implementation. In more recent years, prospective follow-up studies have been conducted that provided the opportunity to study the health of large groups of children derived from different reproductive techniques. Although such studies have indicated differences between children conceived through MAR and children conceived naturally, results are often difficult to interpret due to the observational nature of these studies (and the associated risk of confounding factors, e.g. subfertility of the parents), differences in definitions of clinical outcome measures, lack of uniformity in assessment protocols and heterogeneity of the underlying reasons for fertility treatment. With more novel MARs waiting at the horizon, there is a need for a framework on how to assess safety of novel reproductive techniques in a preclinical (animal) setting before they are clinically implemented. In this article, we provide a blueprint for preclinical testing of safety and health of offspring generated by novel MARs using a mouse model involving an array of tests that comprise the entire lifespan. We urge scientists to perform the proposed extensive preclinical tests for novel reproductive techniques with the goal to acquire knowledge on efficacy and the possible health effects of to-be implemented reproductive techniques to safeguard quality of novel MARs.

Nomogram predicting the risk of recurrence after curative-intent resection of primary non-metastatic gastrointestinal neuroendocrine tumors: An analysis of the U.S. Neuroendocrine Tumor Study Group

BACKGROUND

The risk of recurrence after resection of non-metastatic gastro-entero-pancreatic neuroendocrine tumors (GEP-NET) is poorly defined. We developed/validated a nomogram to predict risk of recurrence after curative-intent resection.

METHODS

A training set to develop the nomogram and test set for validation were identified. The predictive ability of the nomogram was assessed using c-indices.

RESULTS

Among 1477 patients, 673 (46%) were included in the training set and 804 (54%) in y the test set. On multivariable analysis, Ki-67, tumor size, nodal status, and invasion of adjacent organs were independent predictors of DFS. The risk of death increased by 8% for each percentage increase in the Ki-67 index (HR 1.08, 95% CI, 1.05-1.10; P < 0.001). GEP-NET invading adjacent organs had a HR of 1.65 (95% CI, 1.03-2.65; P = 0.038), similar to tumors ≥3 cm (HR 1.67, 95% CI, 1.11-2.51; P = 0.014). Patients with 1-3 positive nodes and patients with >3 positive nodes had a HR of 1.81 (95% CI, 1.12-2.87; P = 0.014) and 2.51 (95% CI, 1.50-4.24; P < 0.001), respectively. The nomogram demonstrated good ability to predict risk of recurrence (c-index: training set, 0.739; test set, 0.718).

CONCLUSION

The nomogram was able to predict the risk of recurrence and can be easily applied in the clinical setting.

Improved stratification of ALS clinical trials using predicted survival

Introduction

In small trials, randomization can fail, leading to differences in patient characteristics across treatment arms, a risk that can be reduced by stratifying using key confounders. In ALS trials, riluzole use (RU) and bulbar onset (BO) have been used for stratification. We hypothesized that randomization could be improved by using a multifactorial prognostic score of predicted survival as a single stratifier.

Methods

We defined a randomization failure as a significant difference between treatment arms on a characteristic. We compared randomization failure rates when stratifying for RU and BO (“traditional stratification”) to failure rates when stratifying for predicted survival using a predictive algorithm. We simulated virtual trials using the PRO‐ACT database without application of a treatment effect to assess balance between cohorts. We performed 100 randomizations using each stratification method – traditional and algorithmic. We applied these stratification schemes to a randomization simulation with a treatment effect using survival as the endpoint and evaluated sample size and power.

Results

Stratification by predicted survival met with fewer failures than traditional stratification. Stratifying predicted survival into tertiles performed best. Stratification by predicted survival was validated with an external dataset, the placebo arm from the BENEFIT‐ALS trial. Importantly, we demonstrated a substantial decrease in sample size required to reach statistical power.

Conclusions

Stratifying randomization based on predicted survival using a machine learning algorithm is more likely to maintain balance between trial arms than traditional stratification methods. The methodology described here can translate to smaller, more efficient clinical trials for numerous neurological diseases.

Contrast media-induced nephropathy: how has Italy contributed in the past 30 years? A systematic review

Background and objective

The use of contrast media in Italy has exponentially increased in the past 3 decades. However, it is unknown whether there has been an increase in clinical research evaluating the risks associated with contrast media usage, especially regarding contrast-induced nephropathy. To fill this gap in knowledge, we performed a systematic review.

Study eligibility criteria

Meta-analyses, observational studies, and clinical trials assessing contrast media-induced nephropathy as the safety outcome, in which at least one author was affiliated with an Italian university/health care structure, were eligble.

Data sources

Ovid MEDLINE, Ovid Embase, Cochrane Methodology Register, and Web of Science were screened.

Participants

Men and women exposed to contrast media.

Results

In total, 60 original articles were retrieved with an incremental trend between 1990 and 2017. Cohort studies were the most common study design represented. In total, 45 of 60 (75.0%) studies were monocenter studies and 41 of 60 (68.3%) received no funding. In all, 91.7% of studies disclosed no conflicts of interest and 81.7% had no external collaboration. Most of the studies provided a level of evidence of III-2 (32/60; 53.3%) and II (23/60; 38.3%). In total, 50 of 60 studies (83.3%) were published in a scientific journal ranked in the first quartile of their subject area.

Conclusion

There was an increased number of studies evaluating contrast-induced nephropathy in Italy during the last three decades. These studies covered procedures to prevent contrast-induced nephropathy or aimed to identify risk factors, biomarkers, and scores, and their related prognosis.

Endoscopic ultrasound-guided hepaticogastrostomy versus percutaneous transhepatic drainage for malignant biliary obstruction after failed endoscopic retrograde cholangiopancreatography: a retrospective expertise-based study from two centers

BACKGROUND

Percutaneous transhepatic biliary drainage (PTBD) is widely performed as a salvage procedure in patients with unresectable malignant obstruction of the common bile duct (CBD) after failed endoscopic retrograde cholangiopancreatography (ERCP) or in case of surgically altered anatomy. Endoscopic ultrasound-guided hepaticogastrostomy (EU-HGS) is a more recently introduced alternative to relieve malignant obstructive jaundice. The aim of this prospective observational study was to compare the outcome, efficacy and adverse events of EU-HGS and PTBD.

METHODS

From April 2012 to August 2015, consecutive patients with malignant CBD obstruction who underwent EU-HGS or PTBD in two tertiary-care referral centers were included. The primary endpoint was the clinical success rate. Secondary endpoints were technical success, overall survival, procedure-related adverse events, incidence of adverse events, and reintervention rate.

RESULTS

A total of 51 patients (EU-HGS, n = 31; PTBD, n = 20) were included. Median survival was 71 days (range 25-75th percentile; 30-95) for the EU-HGS group and 78 days (range 25-75th percentile; 42-108) for the PTBD group (p = 0.99). Technical success was achieved in all patients in both groups. Clinical success was achieved in 25 (86%) of 31 patients in the EU-HGS group and in 15 (83%) of 20 patients in the PTBD group (p = 0.88). There was no difference in adverse events rates between the two groups (EU-HGS: 16%; PTBD: 10%) (p = 0.69). Four deaths within 1 month (two hemorrhagic and two septic) were considered procedure related (two in the EU-HGS group and two in the PTBD group). Overall reintervention rate was significantly lower after EU-HGS (n = 2) than after PTBD (n = 21) (p = 0.0001). Length of hospital stay was shorter after EU-HGS (8 days versus 15 days; p = 0.002).

CONCLUSIONS

EU-HGS can be an effective and safe mini invasive-procedure alternative to PTBD, with similar success and adverse-event rates, but with lower rates of reintervention and length of hospitalization.

Effect of nonsurgical periodontal therapy verses oral hygiene instructions on type 2 diabetes subjects with chronic periodontitis: a randomised clinical trial

Background

40 subjects with type 2 diabetes and moderate to severe CP were randomly distributed to groups receiving either NSPT or OHI. Periodontal parameters, glycosylated haemoglobin (HbA1c) and high-sensitivity C-reactive protein (hs-CRP) were evaluated at baseline, 2- and 3-months intervals.

Methods

40 subjects with type 2 diabetes and moderate to severe CP were randomly distributed to groups receiving either NSPT or OHI. Periodontal parameters, glycosylated haemoglobin (HbA1c) and high-sensitivity C-reactive protein (hs-CRP) were evaluated at baseline, 2- and 3-months intervals.

Results

15 subjects from NSPT group and 17 from OHI group completed the study. The difference in plaque index (PI) between NSPT and OHI groups were significant at 2 months recall (p = 0.013). There was no significant difference between NSPT and OHI group for all other clinical periodontal parameters, HbA1c and CRP levels. At 3 months post-therapy, periodontal parameters improved significantly in both groups with sites with probing pocket depth (PPD) < 4 mm reported as 98 ± 1.8% in NSPT group and 92 ± 14.9% in OHI group. Mean PPD and mean probing attachment loss (PAL) within the NSPT group reduced significantly from baseline (2.56 ± 0.57 mm, 3.35 ± 0.83 mm) to final visit (1.94 ± 0.26 mm, 2.92 ± 0.72 mm) (p = 0.003, p < 0.001). For OHI group, improvements in mean PPD and mean PAL were also seen from baseline (2.29 ± 0.69 mm, 2.79 ± 0.96 mm) to final visit (2.09 ± 0.72 mm, 2.62 ± 0.97 mm) (p < 0.001 for both). Similarly, HbA1c levels decreased in both groups with NSPT group recording statistically significant reduction (p = 0.038). Participants who demonstrated ≥ 50% reduction in PPD showed significant reductions of HbA1c and hs-CRP levels (p = 0.004 and p = 0.012).

Conclusion

NSPT significantly reduced PI at 2 months post-therapy as compared to OHI. Both NSPT and OHI demonstrated improvements in other clinical parameters as well as HbA1c and CRP levels.

Trial registration

ClinicalTrials.gov: NCT01951547.

Quantifying the exact allocation ratios in randomized clinical trials with biased coin randomization

The biased coin randomization approach is frequently adopted in randomized clinical trials to control the balance in overall treatment assignments. In this article, an algorithm is developed to theoretically determine the exact allocation ratios for all the patients that will be enrolled in a randomized clinical trial with biased coin randomization based on the order in which they are randomized. Our results show that the exact allocation ratios can significantly deviate from the ratio as specified for the trial, which poses challenges to the enrollment of the trial and to the interpretation of the results. In order to maintain a constant allocation ratio throughout the trial, a modification of the widely adopted permuted block randomization is proposed, which is shown to achieve better balance for not only the overall treatment assignments but also the baseline stratification variables that are desired to be balanced at the end of the trial.

Evidence from the scene: paramedic perspectives on involvement in out-of-hospital research

STUDY OBJECTIVE

In the context of calls to develop better systems for out-of-hospital clinical research, we seek to understand paramedics' perceptions of involvement in research and the barriers and facilitators to that involvement.

METHODS

This was a qualitative study using semistructured focus groups with 58 United Kingdom paramedics and interviews with 30 US firefighter-paramedics. The study focused on out-of-hospital research (trials of out-of-hospital treatment for stroke), whereby paramedics identified potential study subjects or obtained consent and administered study treatment in the field. Data were analyzed with a thematic and discourse approach.

RESULTS

Three key themes emerged as significant facilitators and barriers to paramedic involvement in research: patient benefit, professional identity and responsibility, and time. Paramedics showed willingness and capacity to engage in research but also some reticence because of the perceived sacrifice of autonomy and challenge to their identity. Paramedics work in a time-sensitive environment and were concerned that research would increase time taken in the field.

CONCLUSION

Awareness of these perspectives will help with development of out-of-hospital research protocols and potentially facilitate greater participation.

Balancing multiple baseline characteristics in randomized clinical trials

It is of vital importance to the success of a randomized clinical trial to maintain the balance of baseline characteristics (covariates) that could potentially confound the outcomes of the trial. Various randomization methods have been proposed to increase the likelihood of having balanced covariates at the end of a trial, most of which only apply to categorical covariates. An optimization approach to maintaining the balance of multiple covariates in randomized clinical trials is proposed, which is applicable to both continuous and categorical covariates and allows the covariates to be ranked according to their clinical importance as perceived by the clinical trial practitioners. Simulation results show that the proposed algorithm significantly outperforms the standard randomization approach via flipping an unbiased coin. The proposed randomization method can be easily implemented and generalized for cases where there are multiple treatment arms with equal or unequal randomization probabilities.

IRINI: random group allocation of multiple prognostic factors

Statistically sound experimental design in pharmacology studies ensures that the known prognostic factors, if any, are equally represented across investigational groups to avoid bias and imbalance which could render the experiment invalid or lead to false conclusions. Complete randomization can be effective to reduce bias in the created groups especially in large sample size situations. However, in small studies which involve only few treatment subjects, as in preclinical trials, there is a high chance of imbalance. The effects of this imbalance may be removed through covariate analysis or prevented with stratified randomization, however small studies limit the number of covariates to be analyzed this way. The problem is accentuated when there are multiple baseline covariates with varying scales and magnitudes to be considered in the randomization, and creating a balanced solution becomes a combinatorial challenge. Our method, IRINI, uses an optimization technique to achieve treatment to subject group allocation across multiple prognostic factors concurrently. It ensures that the created groups are equal in size and statistically comparable in terms of mean and variance. This method is a novel application of genetic algorithms to solve the allocation problem and simultaneously ensure quality, speed of the results and randomness of the process. Results from preclinical trials demonstrate the effectiveness of the method.