Can testing clinical significance reduce false positive rates in randomized controlled trials? A snap review

Objective

The use of minimum clinically important difference in the hypothesis formulation for superiority trials is similar in principle to the concept of non-inferiority or equivalence trial. However, most clinical trials are analysed testing zero clinical difference. Since the minimum clinically important difference is pre-defined for power calculation, it is important to incorporate it in both the hypothesis testing and the interpretation of findings from clinical trials.

Results

We reviewed a set of 50 publications (25 with binary outcome, and 25 with survival time outcome). 20% of the 50 published trials that were statistically significant, were also clinically significant based on the minimum clinically important risk differences (or hazard ratio) used for their power calculations. This snap review seems to suggest that most published trials with statistically significant results were less likely to be clinically significant, which may partly explain the high false positive findings associated with findings from superiority trials. Furthermore, none of the reviewed publications explicitly used minimum clinically important difference in the interpretation of their findings. However, a systematic review is needed to critically appraise the impact of the current practice on false positive rate in published trials with significant findings.

     

Quadruple therapy with vonoprazan 20 mg daily as a first-line treatment for Helicobacter pylori infection: A single-center,open-label,noninferiority, randomized controlled trial

Background

Although vonoprazan has been proven to be a highly potent drug for Helicobacter pylori eradication, there have been no randomized trials comparing the effectiveness of regimens containing vonoprazan 20 mg daily with alternative standard strategies. We aimed to assess the efficacy, tolerance, and cost-effectiveness of quadruple therapy with vonoprazan 20 mg daily as a first-line therapy for H. pylori eradication.

Materials and Methods

We conducted a single-center, open-label, noninferiority, randomized controlled study in Zhejiang, China. Treatment-naive H. pylori-positive participants (n = 234) were randomly assigned to three groups in a 1:1:1 ratio: vonoprazan 20 mg daily with amoxicillin 1000 mg, furazolidone 100 mg and colloidal bismuth 200 mg each given twice a day for 10 days (V10) or 14 days (V14), or esomeprazole 20 mg with amoxicillin 1000 mg, furazolidone 100 mg and colloidal bismuth 200 mg each given twice a day for 14 days (E14). The primary endpoint was the eradication rates in each group. The secondary endpoints were the incidence of adverse events (AEs) and compliance.

Results

The eradication rates in the V10, V14 and E14 groups were 96.2% (89.2–99.2%), 94.9% (87.4–98.6%), and 93.6% (85.7–97.9%) in the intention-to-treat analysis, and 98.6% (92.7–100.0%), 97.4% (90.8–99.7%), and 94.8% (87.2–98.6%) in the per-protocol analysis, respectively. Quadruple therapy with vonoprazan 20 mg daily was noninferior to the esomeprazole-based regimen (Farrington and Manning test: margin 10%, significance level 2.5%). The adverse event rates were 12.8% versus 3.8% versus 6.4% in the V10, V14, and E14 groups, respectively. All regimens were well tolerated without significant differences (p = 0.096). The cost-effectiveness ratio was 1.32, 1.88, and 3.06 for the V10, V14, and E14 groups in the intention-to-treat analysis, respectively. (NCT04907747).

Conclusions

Vonoprazan (20 mg daily) was as effective as esomeprazole (20 mg twice a day) in quadruple therapies for the eradication of H. pylori, was more economical, and was well tolerated. In addition, the 10-day regimen of vonoprazan (20 mg daily) was comparable to the 14-day regimen.     

Is telephone counselling a useful addition to physician advice and nicotine replacement therapy in helping patients to stop smoking? A randomized controlled trial

BACKGROUND: The authors evaluated the incremental efficacy of telephone counselling by a nurse in addition to physician advice and nicotine replacement therapy in helping patients to stop smoking. METHODS: The trial was conducted at the University of Ottawa Heart Institute. A total of 396 volunteers who smoked 15 or more cigarettes daily were randomly assigned to either of 2 groups: usual care (control group) and usual care plus telephone counselling (intervention group); the groups were stratified by sex and degree of nicotine dependence. Usual care involved the receipt of physician advice on 3 occasions, self-help materials and 12 weeks of nicotine replacement therapy. Telephone counselling was provided by a nurse at 2, 6 and 13 weeks after the target quit date. Point-prevalent quit rates were determined at 52 weeks after the target quit date. RESULTS: The point-prevalent quit rates at 52 weeks did not differ significantly between the control and intervention groups (24.1% v. 23.4% respectively). The quit rates did not differ significantly at the secondary measurement points of 4, 12 and 26 weeks. INTERPRETATION: Brief physician assistance, along with nicotine replacement therapy, can help well-motivated smokers to quit. Three additional sessions of telephone counselling by a nurse were ineffective in increasing quit rates. This form of assistance may be useful in the absence of physician advice or when self-selected by patients.     

Can cognitive enhancers reduce the risk of falls in older people with Mild Cognitive Impairment? A protocol for a randomised controlled double blind trial

Background  

Older adults with cognitive problems have a higher risk of falls, at least twice that of cognitively normal older adults. The consequences of falls in this population are very serious: fallers with cognitive problems suffer more injuries due to falls and are approximately five times more likely to be admitted to institutional care. Although the mechanisms of increased fall risk in cognitively impaired people are not completely understood, it is known that impaired cognitive abilities can reduce attentional resource allocation while walking. Since cognitive enhancers, such as cholinesterase inhibitors, improve attention and executive function, we hypothesise that cognitive enhancers may reduce fall risk in elderly people in the early stages of cognitive decline by improving their gait and balance performance due to an enhancement in attention and executive function.     

A randomised,double-blind,placebo-controlled clinical trial found that a novel herbal formula Urox® (Bedtime Buddy®) assisted children for the treatment of nocturnal enuresis

BackgroundNocturnal enuresis or ‘bedwetting’, is a form of night-time urinary incontinence occurring in younger children. A diagnosis can be socially disruptive and psychologically stressful for a child. The most common strategies used by parents are waking the child during the night to use the bathroom and limiting the child's water intake before going to bed.Hypothesis/PurposeTo determine if a herbal capsule formulation taken once daily can reduce incidence and frequency of nocturnal enuresis in children.Study DesignThis randomised double-blind placebo-controlled trial evaluated the efficacy of an herbal medicine product to reduce the symptoms of nocturnal enuresis. Participants, aged between 6 and 14 years of age, were recruited from the community in Australia. They were randomised via computerised random-number generation at study enrolment to receive one or two oral capsules in the morning of either Urox® (Bedtime Buddy®) or placebo. The Paediatric Quality of life (Pin-Q) was used as a quality-of-life measure and waking wet, fluid intake and urinary urgency per week were monitored.ResultsForty-one children completed the trial with an attrition rate of 16%. There were more males (64.6%) compared to females (35.4%) and the mean age was 8.6 years. Forty-one point seven percentages (41.7%) of participants had improvements in bed wetting by two months which was a highly clinically relevant effect (Cohen's D = 0.98). The primary outcome found that there was a statistically significant reduction in NE (p = 0.034; CI 0.086–2.095) and between groups using longitudinal analysis (p = 0.04, Coefficient -1.12, CI 95% -2.20 - -0.04). In the secondary outcomes, urinary urgency reduced statistically significantly for the intervention (p = 0.002; a reduction of 18.3% difference for Bedtime Buddy compared to an increase of 3.7% for the placebo).ConclusionUrox® (Bedtime Buddy®) may assist children in reducing nocturnal enuresis compared to placebo. In addition, it may assist in reducing daily incontinence and urinary urgency.     

Effects of a single administration of prostaglandin F2alpha, or a combination of prostaglandin F2alpha and prostaglandin E2, or placebo on fertility variables in dairy cows 3–5 weeks post partum, a randomized, double-blind clinical trial

In female mammals, including humans, deviations from normal androgenic or estrogenic exposure during fetal development are detrimental to subsequent adult ovarian function. Androgen deficiency, without accompanying estrogen deficit, has little apparent impact on ovarian development. Fetal estrogen deficiency, on the other hand, results in impaired oocyte and follicle development, immature and abnormal adult ovaries, and excessive ovarian stimulation from endogenous gonadotropins ultimately generating hemorrhagic follicles. Complete estrogen deficiency lasting into adulthood results in partial ovarian masculinization. Fetal androgen excess, on the other hand, mediated either by direct androgen action or following androgen aromatization to estrogen, reprograms ovarian development and reproductive neuroendocrinology to mimic that found in women with polycystic ovary syndrome: enlarged, polyfollicular, hyperandrogenic, anovulatory ovaries with accompanying LH hypersecretion. Oocyte developmental competence is also compromised. Insulin is implicated in the mechanism of both anovulation and deficient oocyte development. Fetal estrogen excess induces somewhat similar disruption of adult ovarian function to fetal androgen excess. Understanding the quality of the fetal female sex steroid hormone environment is thus becoming increasingly important in improving our knowledge of mechanisms underlying a variety of female reproductive pathologies.     

Effects of a single administration of prostaglandin F2alpha, or a combination of prostaglandin F2alpha and prostaglandin E2, or placebo on fertility variables in dairy cows 3–5 weeks post partum, a randomized, double-blind clinical trial

Background  

Delayed uterine involution has negative effects on the fertility of cows; use of prostaglandin F2alpha alone as a single treatment has not been shown to consistently improve fertility. Combined administration of PGF2alpha and PGE2 increased uterine pressure in healthy cows. We hypothesized, that the combination of both prostaglandins would accelerate uterine involution and have, therefore, a positive effect on fertility variables. In commercial dairy farming, the benefit of a single post partum combined prostaglandin treatment should be demonstrated.     

A randomized,controlled trial of interferon-β-1a (Avonex<Superscript>®</Superscript>) in patients with rheumatoid arthritis: a pilot study [ISRCTN03626626]

The objective of this study was to evaluate the safety and possible efficacy of IFN-β-1a for the treatment of patients with rheumatoid arthritis (RA). Twenty-two patients with active RA were enrolled in a phase II randomized, double-blind, placebo-controlled trial of 30 μg IFN-β-1a by weekly self-injection for 24 weeks. The primary outcome of the study was safety. Secondary outcomes included the proportion of patients achieving an American College of Rheumatology (ACR) 20 response at 24 weeks. There were no significant differences in adverse events reported in the two groups. Fewer than 20% of patients in each arm of the study achieved an ACR 20 response at 24 weeks (P = 0.71). Sixty-nine percent of patients receiving IFN-β and 67% receiving placebo terminated the study early, most of them secondary to a perceived lack of efficacy. Overall, IFN-β-1a had a safety profile similar to that of placebo. There were no significant differences in the proportion of patients achieving an ACR 20 response between the two groups.