Randomized controlled trials

Author(s):  
Sube Banerjee ◽  
Rod S. Taylor ◽  
Jennifer Hellier

This chapter on randomized controlled trials (RCTs) considers some of the key factors in the design, conduct, analysis, and interpretation of RCTs. The chapter provides an overview of what constitutes an RCT and why they are needed. The chapter also provides an overview of the major practical elements of the design and conduct of RCTs, including undertaking a background review of literature, the need for formulation of a clear primary hypothesis and objective, selection and definition of the study population, collecting outcomes at baseline and follow-up, and appropriate methods of statistical analysis and inference. The chapter concludes with a consideration of the need for clinical trial units, complex interventions, and alternative RCT designs.

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiao-Li Chen ◽  
Bei-Lei Zhang ◽  
Chang Meng ◽  
Hui-Bin Huang ◽  
Bin Du

Abstract Objective Conservative oxygen strategy is recommended in acute illness while its benefit in ICU patients remains controversial. Therefore, we sought to conduct a systematic review and meta-analysis to examine such oxygen strategies’ effect and safety in ICU patients. Methods We searched PubMed, Embase, and the Cochrane database from inception to Feb 15, 2021. Randomized controlled trials (RCTs) that compared a conservative oxygen strategy to a conventional strategy in critically ill patients were included. Results were expressed as mean difference (MD) and risk ratio (RR) with a 95% confidence interval (CI). The primary outcome was the longest follow-up mortality. Heterogeneity, sensitivity analysis, and publication bias were also investigated to test the robustness of the primary outcome. Results We included seven trials with a total of 5265 patients. In general, the conventional group had significantly higher SpO2 or PaO2 than that in the conservative group. No statistically significant differences were found in the longest follow-up mortality (RR, 1.03; 95% CI, 0.97–1.10; I2=18%; P=0.34) between the two oxygen strategies when pooling studies enrolling subjects with various degrees of hypoxemia. Further sensitivity analysis showed that ICU patients with mild-to-moderate hypoxemia (PaO2/FiO2 >100 mmHg) had significantly lower mortality (RR, 1.24; 95% CI, 1.05–1.46; I2=0%; P=0.01) when receiving conservative oxygen therapy. These findings were also confirmed in other study periods. Additional, secondary outcomes of the duration of mechanical ventilation, the length of stay in the ICU and hospital, change in sequential organ failure assessment score, and adverse events were comparable between the two strategies. Conclusions Our findings indicate that conservative oxygen therapy strategy did not improve the prognosis of the overall ICU patients. The subgroup of ICU patients with mild to moderate hypoxemia might obtain prognosis benefit from such a strategy without affecting other critical clinical results.


2021 ◽  
Author(s):  
Ji-Guo Yu ◽  
Jing Wang ◽  
Yi Xiang

Background: Vitrectomy with internal limiting membrane (ILM) peeling is an effective surgical procedure for the treatment of macular holes (MHs). However, there is a possibility of poor postoperative anatomical closure with conventional ILM peeling for MHs larger than 400 μm. Therefore, a novel inverted ILM flap technique was developed for such cases. Objectives: This meta-analysis study was performed to evaluate and compare the anatomical and visual outcomes of the inverted ILM flap technique and ILM peeling in large MHs. Methods: The Cochrane Library, PubMed, and Embase databases were searched to identify randomized controlled trials (RCTs). The trial eligibility and risk of bias were assessed according to Cochrane review methods. The primary outcome measures included MH closure rate and postoperative visual acuity (VA). Subgroup analysis of postoperative VA based on follow-up time was also conducted. Pooled odds ratios (ORs), weighted mean difference (WMD), and 95% confidence intervals (CIs) were calculated. Statistical analysis was performed using RevMan 5.3 software. Results: Five RCTs with a total of 155 eyes in the inverted ILM flap group and 161 eyes in the ILM peeling group were included in this meta-analysis. Statistical meta-analysis revealed that the overall MH closure rate in the inverted ILM flap group was significantly higher than that in the ILM peeling group (OR, 3.10; 95% CI, 1.25 to 7.66; P = 0.01). The postoperative VA was significantly better in the inverted ILM flap group than ILM peeling group (WMD, -0.14; 95% CI, -0.21 to -0.07; P = 0.0002). The subgroup meta-analysis indicated that the postoperative VA was significantly better in the inverted ILM flap group than ILM peeling group (WMD, -0.17; 95% CI, -0.26 to -0.08; P = 0.0004) at the 3-month follow-up. However, no significant difference was observed between the two groups at the 6-month follow-up (WMD, -0.09; 95% CI, -0.20 to 0.02; P = 0.10). Conclusions: Vitrectomy with inverted ILM flap technique showed a higher anatomical closure rate as well as visual gain—although only in the short-term as no difference in visual recovery was found at the 6-month follow-up—than did ILM peeling in large MHs. The inverted ILM flap technique should be considered as a preferred and routine procedure for the treatment of patients with MHs larger than 400 µm.


2015 ◽  
Vol 8 (8) ◽  
pp. 74 ◽  
Author(s):  
Maryam Kardan-Souraki ◽  
Zeinab Hamzehgardeshi ◽  
Ismail Asadpour ◽  
Reza Ali Mohammadpour ◽  
Soghra Khani

<p><strong>BACKGROUND:</strong> Lack of intimacy is currently the main concern rather than main concern of the experts in psychology and counseling. It is considered as one of the most important causes for divorce and as such to improve marital intimacy a great number of interventions have been proposed in the literature. Intimacy training and counseling make the couples take effective and successful steps to increase marital intimacy. No study has reviewed the interventions promoting marital intimacy after marriage. Thus, this review study aimed to classify the articles investigating the impact of interventional programs on marital intimacy after marriage.</p><p><strong>SEARCH METHODS:</strong> In April 2015, we performed a general search in Google Scholar search engines, and then we did an advanced search the databases of Science Direct, ProQuest, SID, Magiran, Irandoc, Pubmed, Scopus, <a href="http://www.cochranelibrary.com/">Cochrane Library</a>, and Psych info; Cumulative Index to Nursing and Allied Health Literature (CINAHL). Also, lists of the references of the relevant articles were reviewed for additional citations. Using Medical Subject Headings (MESH) keywords: Intervention (Clinical Trials, Non-Randomized Controlled Trials, Randomized Controlled Trials, Education), intimacy, marital (Marriage) and selected related articles to the study objective were from 1995 to April 2015. Clinical trials that evaluated one or more behavioral interventions to improve marital intimacy were reviewed in the study.</p><p><strong>MAIN RESULTS:</strong> 39 trials met the inclusion criteria. Eleven interventions had follow-up, and 28 interventions lacked follow-up. The quality evidence for 22 interventions was low, for 15 interventions moderate, and for one intervention was considered high. Findings from studies were categorized in 11 categories as the intimacy promoting interventions in dimensions of emotional, psychological, physical, sexual, temporal, communicational, social and recreational, aesthetic, spiritual, intellectual intimacy, and total intimacy.</p><p><strong>AUTHORS’ CONCLUSIONS:</strong> Improving and promoting communication, problem solving, self-disclosure and empathic response skills and sexual education and counseling in the form of cognitive-behavioral techniques and based on religious and cultural context of each society, an effective step can be taken to enhance marital intimacy and strengthen family bonds and stability. Health care providers should consider which interventions are appropriate to the couple characteristics and their relationships.</p>


2021 ◽  
Vol 51 (14) ◽  
pp. 2321-2336
Author(s):  
Alice Lannes ◽  
Eric Bui ◽  
Catherine Arnaud ◽  
Jean-Philippe Raynaud ◽  
Alexis Revet

AbstractChildren with parents suffering from a psychiatric disorder are at higher risk for developing a mental disorder themselves. This systematic review and meta-analysis of randomized controlled trials aims to evaluate the efficacy of psychosocial interventions to prevent negative mental health outcomes in the offspring of parents with mental illness. Eight electronic databases, grey literature and a journal hand-search identified 14 095 randomized controlled trials with no backward limit to June 2021. Outcomes in children included incidence of mental disorders (same or different from parental ones) and internalizing and externalizing symptoms at post-test, short-term and long-term follow-up. Relative risks and standardized mean differences (SMD) for symptom severity were generated using random-effect meta-analyses. Twenty trials were selected (pooled n = 2689 children). The main therapeutic approaches found were cognitive-behavioural therapy and psychoeducation. A significant effect of interventions on the incidence of mental disorders in children was found with a risk reduction of almost 50% [combined relative risk = 0.53, 95% confidence interval (CI) 0.34–0.84]. Interventions also had a small but significant effect on internalizing symptoms at post-test (SMD = −0.25, 95% CI −0.37 to −0.14) and short-term follow-up (−0.20, 95% CI −0.37 to −0.03). For externalizing symptoms, a decreasing slope was observed at post-test follow-up, without reaching the significance level (−0.11, 95% CI −0.27 to 0.04). Preventive interventions targeting the offspring of parents with mental disorders showed not only a significant reduction of the incidence of mental illness in children, but also a diminution of internalizing symptoms in the year following the intervention.


2020 ◽  
Author(s):  
Daniel Dickerson ◽  
Jennifer Parker ◽  
Carrie Johnson ◽  
Ryan A. Brown ◽  
Elizabeth D'Amico

Abstract Background: Although the majority of American Indians/Alaska Natives (AI/ANs) reside in urban areas, there are very few randomized controlled trials (RCTs) analyzing culturally centered substance use prevention interventions for this population. Methods: We describe methods employed to recruit and retain urban AI/AN adolescents into a RCT, which was focused on testing the potential benefits of a substance use prevention intervention for this population. We also report challenges encountered in recruitment and retention of participants and strategies employed addressing these challenges. Data collection occurred from August 2014 to October 2017. Results: We partnered with two community-based organizations in different cities in California. We utilized AI/AN recruiters from communities, placed flyers in community-based organizations, and asked organizations to post flyers on their web and social media sites. We also offered gift cards for participants. Our initial recruitment and retention model was moderately successful; however, we encountered five main challenges: 1) transportation, 2) increasing trust and interest, 3) adding research sites, 4) getting the word out about the project, and 5) getting youth to complete follow-up surveys. Strategies employed to overcome transportation challenges included shortening the number of sessions, offering sessions on both weekends and weekdays, and increasing bus tokens and transportation options. We hired more staff from AI/AN communities, added more research sites from our previously established relationships, and were more pro-active in getting the word out on the project in AI/AN communities. We also utilized more field tracking, and emailed and mailed survey invitations to reach more participants for their follow-up surveys. Because of our efforts, we were nearly able to reach our initial recruitment and retention goals. Conclusions: By identifying challenges and employing culturally appropriate strategies, we were able to collect valuable data on the potential effectiveness of a substance use prevention intervention for urban AI/AN adolescents. Findings from this study assist toward the development of potentially successful strategies to successfully recruit and retain urban AI/AN adolescents in RCTs.


Stroke ◽  
2021 ◽  
Vol 52 (1) ◽  
pp. 366-372
Author(s):  
Mark I. Boulos ◽  
Laavanya Dharmakulaseelan ◽  
Devin L. Brown ◽  
Richard H. Swartz

Few randomized controlled trials have evaluated the effectiveness of continuous positive airway pressure (CPAP) in reducing recurrent vascular events and mortality in poststroke obstructive sleep apnea (OSA). To date, results have been mixed, most studies were underpowered and definitive conclusions are not available. Using lessons learned from prior negative trials in stroke, we reappraise prior randomized controlled trials that examined the use of CPAP in treating poststroke OSA and propose the following considerations: (1) Intervention-based changes, such as ensuring that patients are using CPAP for at least 4 hours per night (eg, through use of improvements in CPAP technology that make it easier for patients to use), as well as considering alternative treatment strategies for poststroke OSA; (2) Population-based changes (ie, including stroke patients with severe and symptomatic OSA and CPAP noncompliers); and (3) Changes to timing of intervention and follow-up (ie, early initiation of CPAP therapy within the first 48 hours of stroke and long-term follow-up calculated in accordance with sample size to ensure adequate power). Given the burden of vascular morbidity and mortality in stroke patients with OSA, there is a strong need to learn from past negative trials and explore innovative stroke prevention strategies to improve stroke-free survival.


2020 ◽  
Vol 7 ◽  
Author(s):  
Tamanna Chibber ◽  
Adrian Baranchuk

The coexistence of atrial fibrillation and heart failure significantly increases the risk of all-cause mortality and heart failure hospitalizations. Sex-related differences in all patients undergoing atrial fibrillation catheter ablation include the referral of fewer women for catheter ablation (15–25%), older age of women at ablation, and higher risk of post-ablation recurrence of atrial fibrillation. We searched the existing literature for sex-related differences in patients undergoing atrial fibrillation catheter ablation with a focus on heart failure. Randomized controlled trials assessing atrial fibrillation catheter ablation in patients with heart failure have demonstrated a significant reduction in all-cause mortality and heart failure hospitalizations. Within the eight existing randomized controlled trials on heart failure with reduced ejection fraction, women composed a small proportion of the study population. Only two studies (CASTLE-AF and AATAC-HF) specifically assessed the effect of gender on outcome and showed no difference in post-ablation outcomes. Registry data-based studies assessing sex-related differences in atrial fibrillation catheter ablation in heart failure reveal that women are half as likely as men to undergo ablation. Conflicting data exist on the interaction of gender and heart failure as they may affect peri-ablation and post-ablation long-term outcomes such as atrial fibrillation recurrence or heart failure hospitalizations. In conclusion, existing studies provide insight into the gender-based differences in patients undergoing catheter ablation for atrial fibrillation as it pertains to heart failure. Further prospective studies with higher proportions of female participants are required to accurately determine gender-based differences in this population.


2020 ◽  
Vol 4 (s1) ◽  
pp. 138-138
Author(s):  
Obumneke A Amadi

OBJECTIVES/GOALS: The aim was to examine whether nicotine patch was more effective in encouraging abstinence from cigarettes smoking compared to placebo. METHODS/STUDY POPULATION: Randomized controlled trials involving the general teenage age group smokers who were current smokers-“smoked less than 100 cigarettes over their lifetime and smoked at the time of the interview. Databases were searched for relevant studies reported in English that employed a randomized design published since 2000. Two authors extracted data and assessed quality. The primary outcomes and prioritization were continuous abstinence at 3, 6 and 12-month follow-up or more for the number of patients who responded to treatment, defined as a reduction/abstinence. Heterogeneity between studies did not preclude combined analyses of the data. RESULTS/ANTICIPATED RESULTS: 4 of 266 publications were included. Four studies reported positive effects on smoking cessation at end of treatment: (1) nicotine patches improved continuous abstinence at 6 weeks – 9 weeks months; (2) nicotine patch improved continuous abstinence at 3 to 6 months; (3) nicotine patches improved continuous abstinence 6 and 12 months; (4) nicotine patches improved continuous abstinence at 6 months – 12 and 24 months (5). All studies showed, continuous abstinence at follow up differed in percentage between groups both at 6 weeks through 24 months, with NRT (Nicotine patch) intervention groups achieving higher rates in most of the studies compared to placebo intervention group. Conclusions: NRT intervention methods seem to increase smoking abstinence in those treated for smoking cessation. Further and larger sample size studies are required to make stronger the base of evidence. DISCUSSION/SIGNIFICANCE OF IMPACT: Four randomized controlled trials investigating the effectiveness of smoking cessation interventions, for teenagers who smoke cigarettes were identified for inclusion in this review. Four of the studies reported significant effects on smoking cessation, providing evidence of effectiveness of NRT (nicotine patch), behavioral support and combinations of the two, although not all trials intervention treatments found an effect. The four studies reported important intervention effects at both the short and long follow-ups required: 6 weeks up to the 24 months, thereby, providing stronger evidence to support the effectiveness of NRT intervention on smoking cessation. All studies showed some evidence of improved smoking abstinence outcomes. The four studies had in common that the smoking cessation interventions provided a combination of intent to treat prevention, and of all the clinical trials none of them suggested a negative effect of smoking cessation treatment on substance use outcomes using NRT. However, the studies used reliable methods and reported their cases properly, but the small number of studies reviewed for the systematic review makes the conclusion about the effectiveness of these interventions uncertain. The papers visibly stated how the trials protected against bias, as indicated by the Yes (low risk). No (high risk) and U as “unclear risk.” All four studies conducted a random sequence generation of participants enrolled into the study sample.


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