Defending the rationale for the two-tailed test in clinical research

Inferential statistics for cardiothoracic surgeons: Part 3 - drawing valid conclusions from clinical data

Inferential statistics enable researchers to make predictions about a population based on sample data. This involves hypothesis testing where the null hypothesis assumes no effect, and the alternative hypothesis suggests a significant effect. Testing requires assumptions like normality and independence to be validated using tests like Shapiro-Wilk or Levene's for normality and variance. Significant findings are determined by p-values, with values under 0.05 typically indicating non-random effects. Choosing between parametric and non-parametric tests depends on data normality and variance homogeneity. Tools such as t-tests, analysis of variance (ANOVA), and their non-parametric counterparts like Mann-Whitney or Kruskal-Wallis are used based on these criteria, ensuring appropriate conclusions about clinical effects and interventions.

Study of a PST-trained voice-enabled artificial intelligence counselor for adults with emotional distress (SPEAC-2): Design and methods

BACKGROUND

Novel and scalable psychotherapies are urgently needed to address the depression and anxiety epidemic. Leveraging artificial intelligence (AI), a voice-based virtual coach named Lumen was developed to deliver problem solving treatment (PST). The first pilot trial showed promising changes in cognitive control measured by functional neuroimaging and improvements in depression and anxiety symptoms.

METHODS

To further validate Lumen in a 3-arm randomized clinical trial, 200 participants with mild-to-moderate depression and/or anxiety will be randomly assigned in a 2:1:1 ratio to receive Lumen-coached PST, human-coached PST as active treatment comparison, or a waitlist control condition where participants can receive Lumen after the trial period. Participants will be assessed at baseline and 18 weeks. The primary aim is to confirm neural target engagement by testing whether compared with waitlist controls, Lumen participants will show significantly greater improvements from baseline to 18 weeks in the a priori neural target for cognitive control, right dorsal lateral prefrontal cortex engaged by the go/nogo task (primary superiority hypothesis). A secondary hypothesis will test whether compared with human-coached PST participants, Lumen participants will show equivalent improvements (i.e., noninferiority) in the same neural target from baseline to 18 weeks. The second aim is to examine (1) treatment effects on depression and anxiety symptoms, psychosocial functioning, and quality of life outcomes, and (2) relationships of neural target engagement to these patient-reported outcomes.

CONCLUSIONS

This study offers potential to improve the reach and impact of psychotherapy, mitigating access, cost, and stigma barriers for people with depression and/or anxiety.

CLINICALTRIALS

gov #: NCT05603923.

Interpretation of clinical endpoints in trials of acute myeloid leukemia

Treatment regimens for acute myeloid leukemia (AML) have remained largely unchanged until recently. Molecular advances have opened the door to targeted therapies, many of which are in late-phase clinical trials. As new therapeutic opportunities arise, it is appropriate to review key aspects of clinical trial design, statistical interpretation of outcomes, and methods of data reporting. Complete remission and overall survival (OS) are common primary endpoints in early-phase AML clinical trials. OS and event-free survival are frequent primary endpoints in phase 3 trials. Clinical trials are designed to address the primary endpoint using prespecified α and power levels. Interpretation of additional endpoints (eg, secondary endpoints and subgroup analyses) must be viewed in light of a trial's statistical design. Furthermore, variations in reporting of endpoints must be considered in order to understand trial outcomes. Time-to-event endpoints are typically reported using Kaplan-Meier curves, which are visually informative. Statistical data derived from these curves can be complex, and a variety of factors may impact interpretation. The purpose of this review is to discuss the nuances of common AML trial endpoints and their data presentation to better inform evaluation and understanding of clinical trial data.

Brief Report on the Psychophysiological Effects of a Yoga Intervention for Chronic Stress

Abstract. This paper evaluates the results of a longitudinal investigation of the potential benefits of yoga in a nonclinical sample of chronically stressed women (N = 116). Women undertook a twice weekly, hour-long yoga class for a period of 2 months, measuring psychological and physical indicators of health periodically. Changes in both areas were compared against a wait-list control group. The reported energy expenditure between groups was estimated to be similar, which suggests that the control group engaged in physical activities other than yoga. Of the six psychological outcomes measured, we found improvements in three. Specifically, those in the practicing yoga group experienced increases in positive affect, decreases in levels of distress and stress, as well as a decrease in waist circumference and increased flexibility. No between-group differences were found in mindfulness, well-being, and negative affect. These findings are generally consistent with an emerging literature, suggesting that yoga may provide both psychological and physiological effects that extend beyond its more obvious physical benefits, and are discussed in terms of the body’s allostatic load. These results should be considered in light of this study’s limitations, which include its small sample size, lack of an “active” control group, and female-only participants.

Intracoronary autologous cardiac progenitor cell transfer in patients with hypoplastic left heart syndrome: the TICAP prospective phase 1 controlled trial

RATIONALE

Hypoplastic left heart syndrome (HLHS) remains a lethal congenital cardiac defect. Recent studies have suggested that intracoronary administration of autologous cardiosphere-derived cells (CDCs) may improve ventricular function.

OBJECTIVE

The aim of this study was to test whether intracoronary delivery of CDCs is feasible and safe in patients with hypoplastic left heart syndrome.

METHODS AND RESULTS

Between January 5, 2011, and January 16, 2012, 14 patients (1.8±1.5 years) were prospectively assigned to receive intracoronary infusion of autologous CDCs 33.4±8.1 days after staged procedures (n=7), followed by 7 controls with standard palliation alone. The primary end point was to assess the safety, and the secondary end point included the preliminary efficacy to verify the right ventricular ejection fraction improvements between baseline and 3 months. Manufacturing and intracoronary delivery of CDCs were feasible, and no serious adverse events were reported within the 18-month follow-up. Patients treated with CDCs showed right ventricular ejection fraction improvement from baseline to 3-month follow-up (46.9%±4.6% to 52.1%±2.4%; P=0.008). Compared with controls at 18 months, cardiac MRI analysis of CDC-treated patients showed a higher right ventricular ejection fraction (31.5%±6.8% versus 40.4%±7.6%; P=0.049), improved somatic growth (P=0.0005), reduced heart failure status (P=0.003), and lower incidence of coil occlusion for collaterals (P=0.007).

CONCLUSIONS

Intracoronary infusion of autologous CDCs seems to be feasible and safe in children with hypoplastic left heart syndrome after staged surgery. Large phase 2 trials are warranted to examine the potential effects of cardiac function improvements and the long-term benefits of clinical outcomes.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01273857.

The reversal of cardiology practices: interventions that were tried in vain

Medical reversal happens when new trials-better powered, designed or controlled than predecessors--contradict current standard of care. The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial and CAST study are notable examples of investigations that overturned current practice by demonstrating that these interventions offered no survival benefits. In this mini-review, we summarize our experience reviewing a decade of original articles in the New England Journal of Medicine with an eye towards investigations that reversed cardiology practice. From the management of arrhythmias to lipids to percutaneous coronary intervention (PCI) and finally, hemodynamics, reversals in the cardiology literature cover a broad set of practices. These reversals are instructive in that many of the therapies overturned were widely adopted and based on either sound physiologic reasoning or observational trials.

Exact one-sided confidence bounds for the risk ratio in 2 x 2 tables with structural zero

This paper examines exact one-sided confidence limits for the risk ratio in a 2 x 2 table with structural zero. Starting with four approximate lower and upper limits, we adjust each using the algorithm of Buehler (1957) to arrive at lower (upper) limits that have exact coverage properties and are as large (small) as possible subject to coverage, as well as an ordering, constraint. Different Buehler limits are compared by their mean size, since all are exact in their coverage. Buehler limits based on the signed root likelihood ratio statistic are found to have the best performance and recommended for practical use.

Home-based exercise improves functional performance and quality of life in women with diastolic heart failure

BACKGROUND

Diastolic heart failure (DHF) is common in older women. There have been no clinical trials that have identified therapies to improve symptoms in these patients. A total of 32 women with New York Heart Association class II and III DHF (left ventricular ejection fraction >45% and symptoms of dyspnea or fatigue) were randomized into a 12-week home-based, low-to-moderate intensity (40% and 60%, respectively) exercise and education program (intervention) or education only program (control). Methods and results The intervention group improved in the 6-minute walk test from 840 +/- 366 ft to 1043 +/- 317 ft versus 824 +/- 367 ft to 732 +/- 408 ft in the control group (P =.002). Quality of life also improved in the intervention group compared with the control group as measured by the Living with Heart Failure Questionnaire (41 +/- 26 to 24 +/- 18 vs 27 +/- 18 to 28 +/- 22 at 12 weeks, P =.002; 24 +/- 18 to 19 +/- 18 vs 28 +/- 22 to 32 +/- 27 at the 3-month follow-up, P =.014) and the Geriatric Depression Scale (6 +/- 4 to 4 +/- 4 vs 5 +/- 3 to 7 +/- 5 at 12 weeks, P =.012; 4 +/- 4 to 4 +/- 4 vs 7 +/- 5 to 7 +/- 5 at the 3-month follow-up, P =.009).

CONCLUSIONS

Women with DHF exhibit significant comorbidities and physical limitations. Home-based, low-to-moderate intensity exercise, in addition to education, is an effective strategy for improving the functional capacity and quality of life in women with DHF. Further study is needed to assess the long-term effect of exercise on clinical outcomes.

[Smoking among a cohort of Spanish university graduates. The SUN Project]

OBJECTIVE

The objective of this study was to assess the association between employment, educational level, marital status, and smoking in a large cohort of Spanish university graduates (3- and 5-year degrees), with a predominance of health professionals.

METHODS

A cross-sectional analysis of the baseline data of the first 7,508 participants in the follow-up study of the University of Navarre (SUN Project) was performed. The subjects were classified according to their smoking status. Independent variables were: employment, marital status, highest educational level attained, number of children, alcohol consumption (g/day), body mass index, and age. In the multivariate analysis, 3 non-conditional logistic regression models were built using the following outcomes: a) smokers vs never-smokers plus ex-smokers; b) smokers vs never-smokers; c) smokers of 15 or more cigarettes a day vs smokers of less than 15 cigarettes a day plus never-smokers and ex-smokers.

RESULTS

Among men, no association was found between employment and smoking status in any of the comparisons. In contrast, among women, being a nurse was associated with a higher prevalence of smoking. The prevalence of current smokers among nurses was 48.5%. Female students were also more likely to smoke and had a higher risk of being heavy smokers (OR = 1.81; 95% CI, 1.28-2.57). A lower prevalence of smoking was found among participants of both sexes who had completed a doctorate.

CONCLUSIONS

Among a large Spanish collective with higher education, the prevalence of smoking was higher in women with a shorter college degree. The prevalence of smoking among nurses was higher than the average among women graduates, which is a cause for concern.