Blinded sample size recalculation in multiple composite population designs with normal data and baseline adjustments

The increasing interest in subpopulation analysis has led to the development of various new trial designs and analysis methods in the fields of personalized medicine and targeted therapies. In this paper, subpopulations are defined in terms of an accumulation of disjoint population subsets and will therefore be called composite populations. The proposed trial design is applicable to any set of composite populations, considering normally distributed endpoints and random baseline covariates. Treatment effects for composite populations are tested by combining p-values, calculated on the subset levels, using the inverse normal combination function to generate test statistics for those composite populations while the closed testing procedure accounts for multiple testing. Critical boundaries for intersection hypothesis tests are derived using multivariate normal distributions, reflecting the joint distribution of composite population test statistics given no treatment effect exists. For sample size calculation and sample size, recalculation multivariate normal distributions are derived which describe the joint distribution of composite population test statistics under an assumed alternative hypothesis. Simulations demonstrate the absence of any practical relevant inflation of the type I error rate. The target power after sample size recalculation is typically met or close to being met.

Factors influencing sleep quality in the intensive care unit: a descriptive pilot study in Korea

BACKGROUND

As sleep disturbances are common in the intensive care unit (ICU), this study assessed the sleep quality in the ICU and identified barriers to sleep.

METHODS

Patients admitted to the ICUs of a tertiary hospital between June 2022 and December 2022 who were not mechanically ventilated at enrollment were included. The quality of sleep (QoS) at home was assessed on a visual analog scale as part of an eight-item survey, while the QoS in the ICU was evaluated using the Korean version of the Richards-Campbell Sleep Questionnaire (K-RCSQ). Good QoS was defined by a score of ≥50.

RESULTS

Of the 30 patients in the study, 19 reported a QoS score <50. The Spearman correlation coefficient showed no meaningful relationship between the QoS at home and the overall K-RCSQ QoS score in the ICU (r=0.16, P=0.40). The most common barriers to sleep were physical discomfort (43%), being awoken for procedures (43%), and feeling unwell (37%); environmental factors including noise (30%) and light (13%) were also identified sources of sleep disruption. Physical discomfort (median [interquartile range]: 32 [28.0-38.0] vs. 69 [42.0-80.0], P=0.004), being awoken for procedures (36 [20.0-48.0] vs. 54 [36.0-80.0], P=0.04), and feeling unwell (31 [18.0-42.0] vs. 54 [40.0-76.0], P=0.01) were associated with lower K-RCSQ scores.

CONCLUSIONS

In the ICU, physical discomfort, patient care interactions, and feeling unwell were identified as barriers to sleep.

Who needs what (features) when? Personalizing engagement with data-driven self-management to improve health equity

OBJECTIVES

To examine the feasibility of promoting engagement with data-driven self-management of health among individuals from minoritized medically underserved communities by tailoring the design of self-management interventions to individuals' type of motivation and regulation in accordance with the Self-Determination Theory.

METHODS

Fifty-three individuals with type 2 diabetes from an impoverished minority community were randomly assigned to four different versions of an mHealth app for data-driven self-management with the focus on nutrition, Platano; each version was tailored to a specific type of motivation and regulation within the SDT self-determination continuum. These versions included financial rewards (external regulation), feedback from expert registered dietitians (RDF, introjected regulation), self-assessment of attainment of one's nutritional goals (SA, identified regulation), and personalized meal-time nutrition decision support with post-meal blood glucose forecasts (FORC, integrated regulation). We used qualitative interviews to examine interaction between participants' experiences with the app and their motivation type (internal-external).

RESULTS

As hypothesized, we found a clear interaction between the type of motivation and Platano features that users responded to and benefited from. For example, those with more internal motivation reported more positive experience with SA and FORC than those with more external motivation. However, we also found that Platano features that aimed to specifically address the needs of individuals with external regulation did not create the desired experience. We attribute this to a mismatch in emphasis on informational versus emotional support, particularly evident in RDF. In addition, we found that for participants recruited from an economically disadvantaged community, internal factors, such as motivation and regulation, interacted with external factors, most notably with limited health literacy and limited access to resources.

CONCLUSIONS

The study suggests feasibility of using SDT to tailor design of mHealth interventions for promoting data-driven self-management to individuals' motivation and regulation. However, further research is needed to better align design solutions with different levels of self-determination continuum, to incorporate stronger emphasis on emotional support for individuals with external regulation, and to address unique needs and challenges of underserved communities, with particular attention to limited health literacy and access to resources.

Traditional healers working with primary care and mental health for early intervention in psychosis in young persons: protocol for the feasibility cluster randomised controlled trial

OBJECTIVES

In low/middle-income countries (LMICs), more than half of patients with first-episode psychosis initially seek treatment from traditional and religious healers as their first care. This contributes to an excessively long duration of untreated psychosis (DUP). There is a need for culturally appropriate interventions to involve traditional and spiritual healers to work collaboratively with primary care practitioners and psychiatrists through task-shifting for early detection, referral and treatment of first episode of psychosis.

METHODS

To prevent the consequences of long DUP in adolescents in LMICs, we aim to develop and pilot test a culturally appropriate and context-bespoke intervention. Traditional HEalers working with primary care and mental Health for early interventiOn in Psychosis in young pErsons (THE HOPE) will be developed using ethnographic and qualitative methods with traditional healers and caregivers. We will conduct a randomised controlled cluster feasibility trial with a nested qualitative study to assess study recruitment and acceptability of the intervention. Ninety-three union councils in district Peshawar, Pakistan will be randomised and allocated using a 1:1 ratio to either intervention arm (THE HOPE) or enhanced treatment as usual and stratified by urban/rural setting. Data on feasibility outcomes will be collected at baseline and follow-up. Patients, carers, clinicians and policymakers will be interviewed to ascertain their views about the intervention. The decision to proceed to the phase III trial will be based on prespecified stop-go criteria.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from Keele University Ethical Review Panel (ref: MH210177), Khyber Medical University Ethical Review Board (ref: DIR/KMU-EB/IG/001005) and National Bioethics Committee Pakistan (ref no. 4-87/NBC-840/22/621). The results of THE HOPE feasibility trial will be reported in peer-reviewed journals and academic conferences and disseminated to local stakeholders and policymakers.

TRIAL REGISTRATION NUMBER

ISRCTN75347421.

"I'm Too Old for That": The Role of Ageism and Sexual Dysfunctional Beliefs in Sexual Health in a Sample of Heterosexual and LGB Older Adults: A Pilot Study

The role of ageism (i.e., discrimination against individuals or groups on the basis of their age), in particular toward the sexuality of the elderly, remains, to date, an overlooked issue. A few studies have suggested that ageistic stereotypes can negatively affect older adults' sexual health. No data are available, in particular, about differences among heterosexual and LGB (lesbian, gay, and bisexual) populations. The present study aimed to investigate differences in perceived ageism and related dysfunctional beliefs in a sample of heterosexual (n = 104) and LGB (n = 103) older adults (aged 55 or older; mean age 66.5) and their impact on sexual health and satisfaction. LGB individuals reported higher rates of masturbation and sexual intercourse and an increased quality of sexual activity as compared to heterosexuals. In addition, no differences between the groups emerged as regards perceived ageism and dysfunctional beliefs toward ageing. In conclusion, LGB individuals perceived more ageism toward sexuality than their counterparts; however, heterosexuals were more likely to have dysfunctional beliefs toward sexuality in ageing. The study findings highlight the significance of examining sexual orientation to understand experiences of sexuality in ageing of the growing older population. Renewed socio-educational efforts based on these data are clearly needed.

Compliance to Multidisciplinary Lifestyle Intervention Decreases Blood Pressure in Patients with Resistant Hypertension: A Cross-Sectional Pilot Study

Hypertension is a common chronic medical condition. Treatment is not satisfactory in a significant proportion of patients with primary hypertension, despite the concurrent use of three or more medications with different mechanisms of action. Such treatment-resistant hypertension is a clinical challenge associated with poor prognosis and needs further investigation. The efficacy of lifestyle changes has not been established yet in patients with resistant hypertension, and educational efforts appear clinically irrelevant in patients who must achieve behavioral changes without supervision. A 6-month multidisciplinary pilot intervention enrolled 50 patients with established resistant hypertension. The aims were: (1) to examine whether intensive and supervised lifestyle changes contribute to decreasing blood pressure in this condition, and (2) to identify which components affect compliance and feasibility. The program provided intensive changes in nutrition, physical exercise, and control of sleep disturbances supervised by nutritionists, physiotherapists, and psychologists. Nurses and pharmacists followed up on adherence to the antihypertensive medication. The primary outcome was 24 h blood pressure control. Data in patients with full compliance (n = 30) indicate that lifestyle modifications in resistant hypertension significantly reduced 24 h both systolic and diastolic blood pressure (p < 0.01), body mass index (p < 0.01), medication burden (p = 0.04), improving physical fitness, and cardiovascular risk markers such as heart rate (p = 0.01) and augmentation index (p = 0.02). The adherence to the intervention was moderate, with an attrition rate of 12%. A modified version reducing visits and explorations will likely improve compliance and can be used to assess the long-term maintenance of these benefits in managing resistant hypertension by diverse healthcare providers.

Tandem Breastfeeding and Human Milk Macronutrients: A Prospective Observational Study

BACKGROUND

Tandem breastfeeding is defined as two or more offspring of different ages who are breastfed by their mother at the same time. Breastfeeding during pregnancy and tandem breastfeeding have not been widely investigated.

RESEARCH AIM

To determine the influence of tandem breastfeeding on the macronutrient content of human milk.

METHODS

This longitudinal study used a prospective and a retrospective group. Human milk samples from tandem-breastfeeding participants (n = 18) were compared to samples from non-tandem-breastfeeding participants (n = 31). Samples were collected during the last month of pregnancy (pregnancy milk), 72 hr after birth (colostrum) and 14-60 days post-delivery (mature milk). Macronutrients were measured by mid-infrared spectroscopy.

RESULTS

Fat content in pregnancy milk was lower than in mature milk (p < .01). Protein content was higher in pregnancy milk than in colostrum and mature milk (p < .01 and p < .001, respectively). Inversely, carbohydrate content in pregnancy milk was lower than in colostrum and mature milk (p = .02 and p < .01, respectively). Fat and energy contents in pregnancy milk of tandem-breastfeeding participants were lower than in mature milk of non-tandem-breastfeeding participants (p < .001 and p < .01, respectively), and protein content was higher than in mature milk (p < .001). Carbohydrate content in colostrum and mature milk of tandem-breastfeeding participants was higher than that of non-tandem-breastfeeding participants (p < .001 for both).

CONCLUSION

Human milk produced during pregnancy had different macronutrient content than human milk produced after delivery. Colostrum and mature milk of tandem-breastfeeding participants were similar to human milk produced by non-tandem-breastfeeding participants, with the exception of carbohydrate content.

The efficacy of transbronchial indocyanine green instillation for fluorescent-guided wedge resection

 

OBJECTIVES

The purpose of this study was to investigate the feasibility of lung wedge resection by combining 3-dimensional (3D) image analysis with transbronchial indocyanine green (ICG) instillation, in order to delineate the intended area for resection.

METHODS

From December 2017 to July 2020, 28 patients undergoing wedge resection (17 primary lung cancers, 11 metastatic lung tumours) were enrolled, and fluorescence-guided wedge resection was attempted. Virtual sublobar resections were created preoperatively for each patient using a 3D Image Analyzer. Surgical margins were measured in each sublobar resection simulation in order to select the most optimal surgical resection area. After transbronchial instillation of ICG, near-infrared thoracoscopic visualization allowed matching of the intended area for resection to the virtual sublobar resection area. To investigate the effectiveness of ICG instillation, the clarity of the ICG-florescent border was evaluated, and the distance from the true tumour to the surgical margins was compared to that of simulation.

RESULTS

Mean tumour diameter was 12.4 ± 4.3 mm. The entire targeted tumour was included in resected specimens of all patients (100% success rate). The shortest distances to the surgical margin via 3D simulation and by actual measurement of the specimen were11.4 ± 5.4 and 12.2 ± 4.1 mm, respectively (P = 0.285) and were well correlated (R2 = 0.437). While all specimens had negative malignant cells at the surgical margins, one loco-regional recurrence was observed secondary to the dissemination of neuroendocrine carcinoma.

CONCLUSIONS

ICG-guided lung wedge resection after transbronchial ICG instillation and preoperative 3D image analysis allow for adequate negative surgical margins, providing decreased risk of local recurrence.

Determining sample size for progression criteria for pragmatic pilot RCTs: the hypothesis test strikes back!

Background

The current CONSORT guidelines for reporting pilot trials do not recommend hypothesis testing of clinical outcomes on the basis that a pilot trial is under-powered to detect such differences and this is the aim of the main trial. It states that primary evaluation should focus on descriptive analysis of feasibility/process outcomes (e.g. recruitment, adherence, treatment fidelity). Whilst the argument for not testing clinical outcomes is justifiable, the same does not necessarily apply to feasibility/process outcomes, where differences may be large and detectable with small samples. Moreover, there remains much ambiguity around sample size for pilot trials.

Methods

Many pilot trials adopt a ‘traffic light’ system for evaluating progression to the main trial determined by a set of criteria set up a priori. We construct a hypothesis testing approach for binary feasibility outcomes focused around this system that tests against being in the RED zone (unacceptable outcome) based on an expectation of being in the GREEN zone (acceptable outcome) and choose the sample size to give high power to reject being in the RED zone if the GREEN zone holds true. Pilot point estimates falling in the RED zone will be statistically non-significant and in the GREEN zone will be significant; the AMBER zone designates potentially acceptable outcome and statistical tests may be significant or non-significant.

Results

For example, in relation to treatment fidelity, if we assume the upper boundary of the RED zone is 50% and the lower boundary of the GREEN zone is 75% (designating unacceptable and acceptable treatment fidelity, respectively), the sample size required for analysis given 90% power and one-sided 5% alpha would be around n = 34 (intervention group alone). Observed treatment fidelity in the range of 0–17 participants (0–50%) will fall into the RED zone and be statistically non-significant, 18–25 (51–74%) fall into AMBER and may or may not be significant and 26–34 (75–100%) fall into GREEN and will be significant indicating acceptable fidelity.

Discussion

In general, several key process outcomes are assessed for progression to a main trial; a composite approach would require appraising the rules of progression across all these outcomes. This methodology provides a formal framework for hypothesis testing and sample size indication around process outcome evaluation for pilot RCTs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00770-x.

Effects of a peer co-facilitated educational programme for parents of children with ADHD: a feasibility randomised controlled trial protocol

INTRODUCTION

Significant numbers of children with attention deficit hyperactivity disorder (ADHD) display problems that cause multiple disabilities, deficits and handicaps that interfere with social relationships, development and school achievement. They may have multiple problems, which strain family dynamics and influence the child's treatment. Parent activation, described as parents' knowledge, skills and confidence in dealing with their child's health and healthcare, has been shown to be an important factor in improving health outcomes. Research suggests that parents need edification to learn skills crucial to the treatment and management of their children's healthcare. Promoting positive parenting techniques may reduce negative parenting factors in families. This study aims to assess the acceptability, feasibility and estimated sample size of a randomised controlled trial (RCT) comparing an ADHD peer co-led educational programme added to treatment as usual (TAU).

METHODS AND ANALYSIS

Using a randomised waitlist controlled trial, parents of children aged 6-12 years newly diagnosed with ADHD, and referred to a child mental health outpatient clinic in Mid-Norway, will receive TAU concomitant with a peer co-facilitated parental engagement educational programme (n=25). Parents in the control group will receive TAU, and the educational programme treatment within a waitlist period of 3-6 months (n=25). Parent activation, satisfaction, well-being, quality of life and treatment adherence, will be assessed at baseline (T0), 2 weeks (T1) pre-post intervention (T2, T3) and at 3 months follow-up (T4). Shared decision making, parents preferred role in health-related decisions and involvement, parent-reported symptoms of ADHD and child's overall level of functioning will be assessed at T0 and T4. Such data will be used to calculate the required sample size for a full-scale RCT.

ETHICS AND DISSEMINATION

Approval was obtained from the Regional Committee for Medicine and Health Research Ethics in Mid-Norway (ref: 2018/1196). The findings of this study are expected to provide valuable knowledge about how to optimise family education and management of ADHD and will be disseminated through presentations at conferences and publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04010851.

General concepts in biostatistics and clinical epidemiology: Experimental studies with randomized clinical trial design

In experimental studies, researchers apply an intervention to a group of study participants and analyze the effects over a future or prospective timeline. The prospective nature of these types of studies allows for the determination of causal relationships, but the interventions they are based on require rigorous bioethical evaluation, approval from an ethics committee, and registration of the study protocol prior to implementation. Experimental research includes clinical and preclinical testing of a novel intervention or therapy at different phases of development. The main objective of clinical trials is to evaluate an interventions efficacy and safety. Conventional clinical trials are blinded, randomized, and controlled, meaning that participants are randomly assigned to either the study intervention group or a comparator (a control group exposed to a placebo intervention or another non-placebo or active interventionor not exposed to any intervention) to reduce selection and confounding biases, and researchers are also unaware of the type of intervention being applied. Intention-to-treat analysis (inclusion of all originally randomized subjects) should be done to avoid the effects of attrition (dropout) and crossover (variance in the exposure or treatment over time). A quasi-experimental design and external controls may also be used. Metrics used to measure the magnitude of effects include relative risk, absolute and relative risk reductions, and numbers needed to treat and harm. Confounding factors are controlled by randomization. Other types of bias to consider are selection, performance, detection, and reporting. This review is the fifth of a methodological series on general concepts in biostatistics and clinical epidemiology developed by the Chair of Scientific Research Methodology at the School of Medicine, University of Valparaíso, Chile. It describes general theoretical concepts related to randomized clinical trials and other experimental studies in humans, including fundamental elements, historical development, bioethical issues, structure, design, association measures, biases, and reporting guidelines. Factors that should be considered in the execution and evaluation of a clinical trial are also covered.

Clinical trials with nested subgroups: Analysis, sample size determination and internal pilot studies

The importance of subgroup analyses has been increasing due to a growing interest in personalized medicine and targeted therapies. Considering designs with multiple nested subgroups and a continuous endpoint, we develop methods for the analysis and sample size determination. First, we consider the joint distribution of standardized test statistics that correspond to each (sub)population. We derive multivariate exact distributions where possible, providing approximations otherwise. Based on these results, we present sample size calculation procedures. Uncertainties about nuisance parameters which are needed for sample size calculations make the study prone to misspecifications. We discuss how a sample size review can be performed in order to make the study more robust. To this end, we implement an internal pilot study design where the variances and prevalences of the subgroups are reestimated in a blinded fashion and the sample size is recalculated accordingly. Simulations show that the procedures presented here do not inflate the type I error significantly and maintain the prespecified power as long as the sample size of the smallest subgroup is not too small. We pay special attention to the case of small sample sizes and attain a lower boundary for the size of the internal pilot study.