When inferiority meets non-inferiority: implications for interim analyses

Is mechanical bowel preparation necessary to reduce surgical site infection following colon surgery? Protocol for a multicentre Canadian randomized controlled trial

AIM

There is significant practice variation with respect to the use of bowel preparation to reduce surgical site infection (SSI) following colon surgery. Although intravenous antibiotics + mechanical bowel preparation + oral antibiotics (IVA + MBP + OA) has been shown to be superior to IVA + MBP and IVA, there are insufficient high-quality data from randomized controlled trails (RCTs) that directly compare these options. This is an important question, because if IVA + OA has similar effectiveness to IVA + MBP + OA, mechanical bowel preparation can be safely omitted, and the associated side effects avoided. The aim of this work is to compare rates of SSI following IVA + OA + MBP (MBP) versus IVA + OA (OA) for elective colon surgery.

METHOD

This is a multicentre, parallel, two-arm, noninferiority RCT comparing IVA + OA + MBP versus IVA + OA. The primary outcome is the overall rate of SSI 30 days following surgery. Secondary outcomes are length of stay and 30-day emergency room visit and readmission rates. The planned sample size is 1062 subjects with four participating high-volume centres. Overall SSI rates 30 days following surgery between the treatment groups will be compared using a general linear model. Secondary outcomes will be analysed with linear regression for continuous outcomes, logistic regression for binary outcomes and modified Poisson regression for count data.

CONCLUSION

It is expected that IVA + OA will work similarly to IVA + MBP + OA and that this work will provide definitive evidence showing that MBP is not necessary to reduce SSI. This is highly relevant to both patients and physicians as it will have the potential to significantly change practice and outcomes following colon surgery in Canada and beyond.

Pivmecillinam with Amoxicillin/Clavulanic acid as step down oral therapy in febrile Urinary Tract Infections caused by ESBL-producing Enterobacterales (PACUTI)

BACKGROUND

Oral treatment alternatives for febrile urinary tract infections are limited in the era of increasing antimicrobial resistance. We aim to evaluate if the combination of pivmecillinam and amoxicillin/clavulanic acid is non-inferior to current alternatives for step-down therapy in adult patients with febrile urinary tract infection.

METHODS

We plan to perform an investigator-initiated non-inferiority trial. Adult hospitalised patients treated with 1-5 days of intravenous antibiotics for acute febrile urinary tract infection caused by extended spectrum beta-lactamase (ESBL) producing Enterobacterales will be randomised 1:1 to either control (7-10 days of either oral ciprofloxacin 500 mg twice daily or oral trimethoprim-sulfamethoxazole 800 mg/160 mg twice daily or intravenous ertapenem 1 g once daily, depending on sex, drug allergy, glomerular filtration rate and susceptibility testing) or intervention (10 days of pivmecillinam 400 mg three times daily and amoxicillin/clavulanic acid 500/125 mg three times daily). The primary outcome will be clinical cure 10 days (+/- 2 days) after antibiotic treatment completion. Clinical cure is defined as being alive with absence of fever and return to non-infected baseline of urinary tract symptoms without additional antibiotic treatment or re-hospitalisation (for urinary tract infection) based on a centralised allocation-blinded structured telephone interview. We plan to recruit 330 patients to achieve 90% power based on a sample size simulation analysis using a two-group comparison, one-sided alpha of 2.5%, an absolute non-inferiority margin of 10% and expecting 93% clinical cure rate and 10% loss to follow-up. The primary endpoint will be analysed using generalised estimated equations and reported as risk difference for both intention-to-treat and per protocol populations. Patients are planned to be recruited from at least 10 centres in Sweden from 2023 to 2026.

DISCUSSION

If the combination of pivmecillinam and amoxicillin/clavulanic acid is found to be non-inferior to the control drugs there are potential benefits in terms of tolerability, frequency of interactions, outpatient treatment, side effects, nosocomial infections and drive for further antimicrobial resistance compared to existing drugs.

TRIAL REGISTRATION

NCT05224401. Registered on February 4, 2022.

Aspirin Discontinuation at 24 to 28 Weeks' Gestation in Pregnancies at High Risk of Preterm Preeclampsia: A Randomized Clinical Trial

Importance

Aspirin reduces the incidence of preterm preeclampsia by 62% in pregnant individuals at high risk of preeclampsia. However, aspirin might be associated with an increased risk of peripartum bleeding, which could be mitigated by discontinuing aspirin before term (37 weeks of gestation) and by an accurate selection of individuals at higher risk of preeclampsia in the first trimester of pregnancy.

Objective

To determine whether aspirin discontinuation in pregnant individuals with normal soluble fms-like tyrosine kinase-1 to placental growth factor (sFlt-1:PlGF) ratio between 24 and 28 weeks of gestation was noninferior to aspirin continuation to prevent preterm preeclampsia.

Design, Setting, and Participants

Multicenter, open-label, randomized, phase 3, noninferiority trial conducted in 9 maternity hospitals across Spain. Pregnant individuals (n = 968) at high risk of preeclampsia during the first-trimester screening and an sFlt-1:PlGF ratio of 38 or less at 24 to 28 weeks of gestation were recruited between August 20, 2019, and September 15, 2021; of those, 936 were analyzed (intervention: n = 473; control: n = 463). Follow-up was until delivery for all participants.

Interventions

Enrolled patients were randomly assigned in a 1:1 ratio to aspirin discontinuation (intervention group) or aspirin continuation until 36 weeks of gestation (control group).

Main Outcomes and Measures

Noninferiority was met if the higher 95% CI for the difference in preterm preeclampsia incidences between groups was less than 1.9%.

Results

Among the 936 participants, the mean (SD) age was 32.4 (5.8) years; 3.4% were Black and 93% were White. The incidence of preterm preeclampsia was 1.48% (7/473) in the intervention group and 1.73% (8/463) in the control group (absolute difference, -0.25% [95% CI, -1.86% to 1.36%]), indicating noninferiority.

Conclusions and Relevance

Aspirin discontinuation at 24 to 28 weeks of gestation was noninferior to aspirin continuation for preventing preterm preeclampsia in pregnant individuals at high risk of preeclampsia and a normal sFlt-1:PlGF ratio.

Trial Registration

ClinicalTrials.gov Identifier: NCT03741179 and ClinicalTrialsRegister.eu Identifier: 2018-000811-26.

Parallel-group, randomised, controlled, non-inferiority trial of high-flow nasal cannula versus non-invasive ventilation for emergency patients with acute cardiogenic pulmonary oedema: study protocol

INTRODUCTION

High-flow nasal cannula (HFNC) is an innovative oxygen-delivering technique, which has been shown to effectively decrease the intubation risk in patients with hypoxaemic respiratory failure of various aetiologies compared with conventional oxygen therapy. Also, it has proved to be non-inferior to non-invasive positive pressure ventilation (NIPPV) in patients with hypoxaemic respiratory failure primarily due to pneumonia. Evidence on its benefits compared with NIPPV, which is the standard of care for patients with acute cardiogenic pulmonary oedema (ACPE) with hypoxaemic respiratory distress, is limited. Therefore, we planned this study to investigate the effects of HFNC compared with NIPPV for emergency patients with ACPE.

METHODS AND ANALYSIS

In this single-centred, non-blinded, parallel-group, randomised, controlled, non-inferiority trial, we will randomly allocate 240 patients visiting the emergency department with ACPE in a 1:1 ratio to receive either HFNC or NIPPV for at least 4 hours using computer-generated mixed-block randomisation concealed by sealed opaque envelopes. The primary outcome is the intubation rate in 72 hours after randomisation. The main secondary outcomes are intolerance rate, mortality rate and treatment failure rate (a composite of intolerance, intubation and mortality). The outcome assessors and data analysts will be blinded to the intervention. These categorical outcomes will be analysed by calculating the risk ratio. Interim analyses evaluating the primary outcome will be performed after half of the expected sample size are recruited.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Siriraj Institutional Review Board (study ID: Si 271/2021). It has been granted the Siriraj Research and Development Fund. All participants or their authorised third parties will provide written informed consent prior to trial inclusion. The study results will be published in a peer-reviewed international journal and presented at national and international scientific conferences.

TRIAL REGISTRATION NUMBER

TCTR20210413001.

Hybrid cardiac rehabilitation trial (HYCARET): protocol of a randomised, multicentre, non-inferiority trial in South America

INTRODUCTION

Cardiac rehabilitation (CR) programmes are well established, and their effectiveness and cost-effectiveness are proven. In spite of this, CR remains underused, especially in lower-resource settings such as Latin America. There is an urgent need to create more accessible CR delivery models to reach all patients in need. This trial aims to evaluate if the prevention of recurrent cardiovascular events is not inferior in a hybrid CR programme compared with a standard programme.

METHOD AND ANALYSIS

A non-inferiority, pragmatic, multicentre, parallel (1:1), prospective, randomised and open with blinded endpoint assessment clinical trial will be conducted. 308 patients with coronary artery disease will be recruited consecutively. Participants will be randomised to hybrid or standard rehabilitation programme. The hybrid CR programme includes 10 supervised exercise sessions and individualised lifestyle counselling by a physiotherapist, with a transition after 4-6 weeks to unsupervised delivery via text messages and phone calls. The standard CR consists of 18-22 supervised exercise sessions, as well as group education sessions about lifestyle. Intervention in both groups is between 8 and 12 weeks. The primary outcome is a composite of cardiovascular mortality and hospitalisations due to cardiovascular causes. Secondary outcomes are health-related quality of life, exercise capacity, muscle strength, heart-healthy behaviour, return-to-work, cardiovascular risk factor, adherence, and exercise-related adverse events. The outcomes will be measured at the end of intervention, at 6 months and at 12 months follow-up from recruitment. The primary outcome will be tracked through the end of the trial. Per-protocol and intention-to-treat analysis will be undertaken.Cox regression model will be used to compare primary outcome among study groups.

ETHICS AND DISSEMINATION

Ethics committees at the sponsor institution and each centre where participants will be recruited approved the study protocol and the Informed Consent. Research findings will be published in peer-reviewed journals; additionally, results will be disseminated among region stakeholders.

TRIAL REGISTRATION NUMBER

NCT03881150; Pre-results.

DATE AND VERSION

01 October 2019.

Oral fosfomycin versus ciprofloxacin in women with E.coli febrile urinary tract infection, a double-blind placebo-controlled randomized controlled non-inferiority trial (FORECAST)

Background

Febrile Urinary Tract Infection (FUTI) is frequently treated initially with intravenous antibiotics, followed by oral antibiotics guided by clinical response and bacterial susceptibility patterns. Due to increasing infection rates with multiresistant Enterobacteriaceae, antibiotic options for stepdown treatment decline and patients more frequently require continued intravenous antibiotic treatment for FUTI. Fosfomycin is an antibiotic with high bactericidal activity against Escherichia coli and current resistance rates are low in most countries. Oral Fosfomycin-Trometamol 3000 mg (FT) reaches appropriate antibiotic concentrations in urine and blood and is considered safe. As such, it is a potential alternative for stepdown treatment.

Methods

The FORECAST study (Fosfomycin Randomized controlled trial for E.coli urinary tract infections as Alternative Stepdown Treatment) is a randomized, double-blind, double-dummy, non-inferiority trial in which 240 patients will be randomly allocated to a stepdown treatment with FT or ciprofloxacin (standard of care) for FUTI, caused by Escherichia coli with in vitro susceptibility to both antibiotics. The study population consists of consenting female patients (≥18 years) with community acquired E. coli FUTI. After intravenous antibiotic treatment during at least 48 (but less than 120) hours, and if eligibility criteria for iv-oral switch are met, patients receive either FT (3 g every 24 h) or ciprofloxacin (500 mg every 12 h) for a total antibiotic duration of 10 days. The primary endpoint is clinical cure (resolution of symptoms) 6–10 days post-treatment. Secondary endpoints are microbiological cure 6–10 days post-treatment, clinical cure, mortality, ICU admittance, relapse, reinfection, readmission, additional antibiotic use for UTI, early study discontinuation, adverse events, days of hospitalization and days of absenteeism within 30–35 days post-treatment. The sample size is based on achieving non-inferiority on the primary endpoint, applying a non-inferiority margin of 10%, a two-sided p-value of < 0.05 and a power of 80%.

Discussion

The study aims to demonstrate non-inferiority of oral fosfomycin, compared to oral ciprofloxacin, in the stepdown treatment of E. coli FUTI.

Trial registration

Registered at the Nederlands trial register (Dutch trial register) on 4-10-2017. Trial registration number: NTR6449. Secondary ID (national authority): NL60186.041.17.

Extended antibiotic therapy versus placebo after laparoscopic cholecystectomy for mild and moderate acute calculous cholecystitis: A randomized double-blind clinical trial

BACKGROUND

Acute calculous cholecystitis (ACC) is the most common complication of cholelithiasis. Laparoscopic cholecystectomy (LC) is the gold standard treatment in mild and moderate forms. Currently there is consensus for the use of antibiotics in the preoperative phase of ACC. However, the need for antibiotic therapy after surgery remains undefined with a low level of scientific evidence.

METHODS

The CHART (Cholecystectomy Antibiotic Randomised Trial) study is a single-center, prospective, double blind, and randomized trial. Patients with mild to moderate ACC operated by LC were randomly assigned to receive antibiotic (amoxicillin/clavulanic acid) or placebo treatment for 5 consecutive days. The primary endpoint was postoperative infectious complications. Secondary endpoints were as follows: (1) duration of hospital stay, (2) readmissions, (3) reintervention, and (4) overall mortality.

RESULTS

In the per-protocol analysis, 6 of 104 patients (5.8%) in the placebo arm and 6 of 91 patients (6.6%) in the antibiotic arm developed postoperative infectious complications (absolute difference 0.82 (95% confidence interval, -5.96 to 7.61, P = .81). The median hospital stay was 3 days. There was no mortality. There were no differences regarding readmissions and reoperations between the 2 groups.

CONCLUSION

Although this trial failed to show noninferiority of postoperative placebo compared to antibiotic treatment after LC for mild and moderate ACC within a noninferiority margin of 5%, the use of antibiotics in the postoperative period does not seem justified, because it was not associated with a decrease in the incidence of infectious and other types of morbidity in the present study.

A randomised controlled trial to compare the safety, effectiveness and cost-effectiveness of doxycycline (200 mg/day) with that of oral prednisolone (0.5 mg/kg/day) for initial treatment of bullous pemphigoid: the Bullous Pemphigoid Steroids and Tetracyclines (BLISTER) trial

BACKGROUND

Bullous pemphigoid (BP) is an autoimmune blistering skin disorder with increased morbidity and mortality in the elderly.

OBJECTIVES

To evaluate the effectiveness, safety and cost-effectiveness of a strategy of initiating BP treatment with oral doxycycline or oral prednisolone. We hypothesised that starting treatment with doxycycline gives acceptable short-term blister control while conferring long-term safety advantages over starting treatment with oral prednisolone.

DESIGN

Pragmatic multicentre two-armed parallel-group randomised controlled trial with an economic evaluation.

SETTING

A total of 54 dermatology secondary care centres in the UK and seven in Germany.

PARTICIPANTS

Adults with BP [three or more blisters at two sites and positive direct and/or indirect immunofluorescence (immunoglobulin G and/or complement component 3 immunofluorescence at the dermal-epidermal junction)] and able to give informed consent.

INTERVENTIONS

Participants were allocated using online randomisation to initial doxycycline treatment (200 mg/day) or prednisolone (0.5 mg/kg/day). Up to 30 g/week of potent topical corticosteroids was permitted for weeks 1-3. After 6 weeks, clinicians could switch treatments or alter the prednisolone dose as per normal practice.

MAIN OUTCOME MEASURES

Primary outcomes: (1) the proportion of participants with three or fewer blisters at 6 weeks (investigator blinded) and (2) the proportion with severe, life-threatening and fatal treatment-related events at 52 weeks. A regression model was used in the analysis adjusting for baseline disease severity, age and Karnofsky score, with missing data imputed. Secondary outcomes included the effectiveness of blister control after 6 weeks, relapses, related adverse events and quality of life. The economic evaluation involved bivariate regression of costs and quality-adjusted life-years (QALYs) from a NHS perspective.

RESULTS

In total, 132 patients were randomised to doxycycline and 121 to prednisolone. The mean patient age was 77.7 years and baseline severity was as follows: mild 31.6% (three to nine blisters), moderate 39.1% (10-30 blisters) and severe 29.3% (> 30 blisters). For those starting on doxycycline, 83 out of 112 (74.1%) had three or fewer blisters at 6 weeks, whereas for those starting on prednisolone 92 out of 101 (91.1%) had three or fewer blisters at 6 weeks, an adjusted difference of 18.6% in favour of prednisolone [90% confidence interval (CI) 11.1% to 26.1%], using a modified intention-to-treat (mITT) analysis. Per-protocol analysis showed similar results: 74.4% compared with 92.3%, an adjusted difference of 18.7% (90% CI 9.8% to 27.6%). The rate of related severe, life-threatening and fatal events at 52 weeks was 18.2% for those started on doxycycline and 36.6% for those started on prednisolone (mITT analysis), an adjusted difference of 19.0% (95% CI 7.9% to 30.1%; p = 0.001) in favour of doxycycline. Secondary outcomes showed consistent findings. There was no significant difference in costs or QALYs per patient at 1 year between doxycycline-initiated therapy and prednisolone-initiated therapy (incremental cost of doxycycline-initiated therapy £959, 95% CI -£24 to £1941; incremental QALYs of doxycycline-initiated therapy -0.024, 95% CI -0.088 to 0.041). Using a willingness-to-pay criterion of < £20,000 per QALY gained, the net monetary benefit associated with doxycycline-initiated therapy was negative but imprecise (-£1432, 95% CI -£3094 to £230).

CONCLUSIONS

A strategy of starting BP patients on doxycycline is non-inferior to standard treatment with oral prednisolone for short-term blister control and considerably safer in the long term. The limitations of the trial were the wide non-inferiority margin, the moderate dropout rate and that serious adverse event collection was unblinded. Future work might include inducing remission with topical or oral corticosteroids and then randomising to doxycycline or prednisolone for maintenance.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN13704604.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 10. See the NIHR Journals Library website for further project information.

Rectal indomethacin alone versus indomethacin and prophylactic pancreatic stent placement for preventing pancreatitis after ERCP: study protocol for a randomized controlled trial

Background

The combination of prophylactic pancreatic stent placement (PSP) – a temporary plastic stent placed in the pancreatic duct – and rectal non-steroidal anti-inflammatory drugs (NSAIDs) is recommended for preventing post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) in high-risk cases. Preliminary data, however, suggest that PSP may be unnecessary if rectal NSAIDs are administered. Given the costs and potential risks of PSP, we aim to determine whether rectal indomethacin obviates the need for pancreatic stent placement in patients undergoing high-risk ERCP.

Methods/Design

The SVI (Stent vs. Indomethacin) trial is a comparative effectiveness, multicenter, randomized, double-blind, non-inferiority study of rectal indomethacin alone versus the combination of rectal indomethacin and PSP for preventing PEP in high-risk cases. One thousand four hundred and thirty subjects undergoing high-risk ERCP, in whom PSP is planned solely for PEP prevention, will be randomized to indomethacin alone or combination therapy. Those who are aware of study group assignment, including the endoscopist, will not be involved in the post-procedure care of the patient for at least 48 hours. Subjects will be assessed for PEP and its severity by a panel of independent and blinded adjudicators. Indomethacin alone will be declared non-inferior to combination therapy if the two-sided 95 % upper confidence bound of the treatment difference is less than 5 % between the two groups. Biological specimens will be obtained from trial participants and centrally banked.

Discussion

The SVI trial is designed to determine whether PSP remains necessary in the era of NSAIDs pharmacoprevention. The associated bio-repository will establish the groundwork for important scientific breakthrough.

Trial registration

NCT02476279, registered June 2015.

A randomized controlled trial to compare the safety and effectiveness of doxycycline (200 mg daily) with oral prednisolone (0.5 mg kg(-1) daily) for initial treatment of bullous pemphigoid: a protocol for the Bullous Pemphigoid Steroids and Tetracyclines (BLISTER) Trial

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune blistering disease in older people, and is associated with significant morbidity and mortality. Oral corticosteroids are usually effective but the side-effects are thought to contribute to the high morbidity and mortality rate. Treatment with oral tetracyclines may be effective but high-quality, randomized controlled trials (RCTs) are needed to confirm this.

OBJECTIVES

To compare the effectiveness and safety of two strategies for treating BP.

METHODS

This is a two-arm, parallel group, 52-week RCT comparing doxycycline with prednisolone for initial treatment of BP. Dose is fixed for the initial 6 weeks of treatment (doxycycline 200 mg daily; prednisolone 0.5 mg kg(-1) daily), after which it can be adjusted according to need. A total of 256 patients with BP will be recruited in the U.K. and Germany.

RESULTS

The primary outcomes are: (i) effectiveness (assessor-blinded blister count at 6 weeks) and (ii) safety [proportion of patients experiencing ≥ grade 3 adverse events (i.e. severe, life: threatening or fatal) related to trial medication during the year of follow-up]. Primary effectiveness analysis will be an assessment of whether doxycycline can be considered noninferior to prednisolone after 6 weeks of treatment. Primary safety analysis is a superiority analysis at 12 months. Secondary outcomes include longer-term assessment of effectiveness, relapse rates, the proportion of patients experiencing any grade of adverse events related to treatment, quality of life and cost-effectiveness.

CONCLUSIONS

The trial will provide good evidence for whether the strategy of starting BP treatment with doxycycline is a useful alternative to prednisolone.