Sample Size Calculations for Controlled Clinical Trials Using Generalized Estimating Equations (GEE)

Enhancing long-term smoking abstinence among individuals with a history of cervical intraepithelial neoplasia or cervical cancer (Project ACCESS): protocol for a randomized clinical trial

BACKGROUND

The prevalence of smoking among cervical cancer survivors is high and evidence-based smoking cessation interventions are critically needed. This paper describes the study design, methods, and data analysis plans for a randomized clinical trial (RCT) designed to evaluate the efficacy of a novel, personally tailored SMS-delivered text-based digital treatment adjuvant designed to enhance the long-term efficacy of a "Motivation And Problem-Solving" (MAPS) approach for smoking cessation among individuals with a history of cervical intraepithelial neoplasia (CIN) or cervical cancer. MAPS is a phone counseling approach designed to facilitate long-term abstinence that comprises 6 counseling calls over 12 months. The current trial is evaluating the efficacy of MAPS+, which comprises all MAPS components plus a 24-month digital treatment adjuvant. This trial represents a logical extension of our previous RCT, which compared the efficacy of MAPS to a quitline control condition and found that MAPS resulted in greater than a 2-fold increase in smoking abstinence at 12 months (i.e., 26.4% vs. 11.9%). This treatment effect was no longer significant at 18 months, suggesting that efficacy dissipated as time from the end of treatment increased. The primary aim of the current trial is to compare the efficacy of MAPS + and ST in facilitating long-term abstinence.

METHODS

Individuals who smoke and have a history of cervical cancer or CIN (N = 340) are recruited throughout Florida and randomly assigned to Standard Treatment [ST] or MAPS+. ST participants are electronically connected with the Florida Quitline. MAPS + consists of 6 proactive MAPS-based counseling calls over 12 months plus the novel, personally tailored, text message-based treatment adjuvant delivered over 24 months. All participants receive 12 weeks of combination nicotine replacement therapy (patch and lozenge) and are followed for 24 months. Participant recruitment commenced in December 2022 and is ongoing.

DISCUSSION

This study builds on promising results from our recent trial which found that MAPS was associated with substantially higher abstinence from smoking at the end of the 12-month treatment period. Finding that this low-burden, personally tailored digital treatment adjuvant improves the long-term efficacy of MAPS would have important clinical and public health implications.

TRIAL REGISTRATION

Clinical Trials Registry NCT05645146; https://clinicaltrials.gov/ct2/show/NCT05645146 ; Registered on December 9, 2022.

[A Longitudinal Study of the Reciprocal Relationship between Depression and Income among Korean Older Men and Women]

PURPOSE

This study examined the reciprocal relationships between depression and income, and gender differences in these relationships among older adults in South Korea.

METHODS

Using 2015 to 2019 of the Korea Welfare Panel Study (KoWePS), we studied 6,070 older adults (2,394 men and 3,676 women) aged 60 years over in 2015. The generalized estimating equation was employed to explore the effect of an individual income on depression and the reverse causal link-that of depression on income.

RESULTS

The study found the reciprocal relationships between income and depression. Income has a significant impact on depression. Higher-income was linked to decreased risks of the Center for Epidemiologic Studies Depression (CES-D) scores among older adults (B = -0.121, p < 0.001). Estimates of the reverse causal link show that higher CES-D scores were also linked to income reduction among Korean older adults (B = -0.007, p < 0.001). In addition, we also observed gender differences in the impact of income on depression but not in the reverse causal link. Income has more detrimental to psychological consequence for older men (B = -0.108, p < 0.001) than older women (B = -0.057, p < 0.001).

CONCLUSION

The finding implies that both psychological and social protection policies for the elderly are needed in view of gender perspective.

Retention in Community Health Screening among Taiwanese Adults: A 9-Year Prospective Cohort Study

Largely conducted in Western developed nations, research on community health screening has mainly been of limited duration. This study aims to ascertain the predictors of retention in a community health screening program, involving multiple admission cohorts over a 9-year period in Taiwan. Retention is defined as the participation in subsequent waves of health screening after being recruited for an initial screening. Data came from a prospective cohort study, named "Landseed Integrated Outreaching Neighborhood Screening (LIONS)", in Taiwan. This research retrieved 5901 community-dwelling Taiwanese adults aged 30 and over from LIONS and examined their retention in three follow-ups during 2006-2014. Generalized estimating equations were employed to evaluate retention over time as a function of social determinants, health behaviors, and health conditions. Being middle-aged, higher education, and regular exercise were positively associated with retention. Conversely, smoking, betel-nut chewing, psychiatric disorder, hypertension, type 2 diabetes mellitus, stroke, and a longer time interval since enrollment were negatively associated with retention. Furthermore, retention rates varied substantially across admission cohorts with more recent cohorts having a lower rate of retention (aOR = 0.33-0.83). Greater attention needs to be directed to retention over time and variations across admission cohorts. Additionally, those who are in either younger or older age groups and have chronic diseases or unhealthy behaviors should be targeted with greater efforts.

Mindfulness meditation training effects on quality of life, immune function and glutathione metabolism in service healthy female teachers: A randomized pilot clinical trial

BACKGROUND

Despite the crucial role of educators in encourage students' academic learning, addressing educator stress inside the classroom remains a significant challenge in the educational context. Mindfulness Meditation training (MM) has been recommended as an environmental enrichment strategy in schools to help teachers cope with stress and cultivating a state of awareness in daily life. Although studies have shown that MM can improve immune system dynamics the biological mechanism underlying glutathione metabolism in a healthy human is unclear.

OBJECTIVE

The purpose of this study was to determine whether MM training benefits psychological and behavioral response, immunological functions and glutathione metabolism in service healthy female teachers from public schools.

METHODS

We randomly assigned 76 teachers to an 8-week Mindfulness-Based Health Program for Educators (MBHPEduca) or Neuroscience for Education program (Neuro-Educa; active control group). Using the quality of life as our primary outcome, perceived stress, negative affectivity, and resilience as our secondary outcome, and pro-inflammatory cytokines and glutathione levels as our third outcome at baseline and post-intervention that occurred in public schools. Blood samples were collected for the measurement of three proinflammatory markers, including interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-8 (IL-8) and three GSH metabolism, including Cysteine (Cys), Homocysteine (HCys) and GSH were conducted at pre-and post-intervention, with selfreported assessments over time. Treatment effects were analyzed using generalized estimating equations (GEE) with to intention to treat.

RESULTS

We observed statistically significant improvements to the MBHP-Educa group compared to active control in perceived stress, resilience, positive and negative affect, and quality of life after 8-weeks MM (p ​< ​0.0001). Further, the MBHP-Educa group exhibited lower circulating IL-6 production accompanied by high circulating GSH, and Cys (p ​< ​0.0001). Additional analyses indicated that enhancing quality of life through mindfulness meditation training was mediated by reducing perceived stress and serum levels of IL- 6 and increasing resilience and teachers 'plasma GSH levels.

CONCLUSIONS

The present study is a pilot trial with low-power and provides preliminary evidence that mindfulness meditation training help teachers to cope with stress in the school environment with an impact on the quality of life, immune function, and glutathione metabolism.

Assessing attacks and treatment response rates among adult patients with NMOSD and MOGAD: Data from a nationwide registry in Argentina

We aimed to examine treatment interventions implemented in patients experiencing neuromyelitis optica spectrum disorders (NMOSD) attacks (frequency, types, and response).

Effectiveness of Sequential Psychological and Medication Therapies for Insomnia Disorder: A Randomized Clinical Trial

IMPORTANCE

Despite evidence of efficacious psychological and pharmacologic therapies for insomnia, there is little information about what first-line treatment should be and how best to proceed when initial treatment fails.

OBJECTIVE

To evaluate the comparative efficacy of 4 treatment sequences involving psychological and medication therapies for insomnia and examine the moderating effect of psychiatric disorders on insomnia outcomes.

DESIGN, SETTING, AND PARTICIPANTS

In a sequential multiple-assignment randomized trial, patients were assigned to first-stage therapy involving either behavioral therapy (BT; n = 104) or zolpidem (zolpidem; n = 107), and patients who did not remit received a second treatment involving either medication (zolpidem or trazodone) or psychological therapy (BT or cognitive therapy [CT]). The study took place at Institut Universitaire en Santé Mentale de Québec, Université Laval, Québec City, Québec, Canada, and at National Jewish Health, Denver, Colorado, and enrollment of patients took place from August 2012 through July 2017.

MAIN OUTCOMES AND MEASURES

The primary end points were the treatment response and remission rates, defined by the Insomnia Severity Index total score.

RESULTS

Patients included 211 adults (132 women; mean [SD] age, 45.6 [14.9] years) with a chronic insomnia disorder, including 74 patients with a comorbid anxiety or mood disorder. First-stage therapy with BT or zolpidem produced equivalent weighted percentages of responders (BT, 45.5%; zolpidem, 49.7%; OR, 1.18; 95% CI, 0.60-2.33) and remitters (BT, 38.03%; zolpidem, 30.3%; OR, 1.41; 95% CI, 0.75-2.65). Second-stage therapy produced significant increases in responders for the 2 conditions, starting with BT (BT to zolpidem, 40.6% to 62.7%; OR, 2.46; 95% CI, 1.14-5.30; BT to CT, 50.1% to 68.2%; OR, 2.09; 95% CI, 1.01-4.35) but no significant change following zolpidem treatment. Significant increase in percentage of remitters was observed in 2 of 4 therapy sequences (BT to zolpidem, 38.1% to 55.9%; OR, 2.06; 95% CI, 1.04-4.11; zolpidem to trazodone, 31.4% to 49.4%; OR, 2.13; 95% CI, 0.91-5.00). Although response/remission rates were lower among patients with psychiatric comorbidity, treatment sequences that involved BT followed by CT or zolpidem followed by trazodone yielded better outcomes for patients with comorbid insomnia. Response and remission rates were well sustained through the 12-month follow-up.

CONCLUSIONS AND RELEVANCE

Behavioral therapy and zolpidem medication produced equivalent response and remission rates. Adding a second treatment produced an added value for those whose insomnia failed to remit with initial therapies.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01651442.

A randomized controlled trial of a smoking cessation self-help intervention for Spanish-speaking Hispanic/Latinx smokers: Study design and baseline characteristics

Although the current smoking prevalence among Hispanics/Latinxs (10%) is lower than in non-Hispanic whites (15%), higher prevalence is observed among certain subgroups (e.g., Puerto Rican males, 19%). Hispanic/Latinx smokers face unique challenges such as lower awareness and acceptability of nicotine replacement aids, lower prevalence of using counseling or medication, and receiving less advice to quit by their health care providers. Despite these barriers to smoking cessation, few interventions specifically targeted to Hispanic/Latinx smokers have been developed and evaluated. This paper summarizes the design, methods, analysis plan, and sample baseline characteristics of an ongoing randomized controlled trial to assess the efficacy of a Spanish-language self-help smoking cessation intervention among Hispanics/Latinxs. Current smokers who prefer health education materials in Spanish were randomized to one of two conditions. The usual care group received a standard smoking cessation booklet developed by the National Cancer Institute. The intervention group received 10 booklets, 9 pamphlets and a booklet for family and friends mailed monthly over 18 months. All participants complete self-report surveys every 6 months over 2 years. Smoking abstinence is biochemically verified at 12- and 24-month follow-up. A total of 2387 smokers were screened, 2056 were eligible and 1417 were enrolled in the study. The primary outcome is self-reported 7-day point prevalence abstinence. If the intervention is deemed efficacious, it has potential to have a large public health impact with respect to reducing smoking rates and smoking related morbidity and mortality among a large underserved minority population.

Impact of adding a video to patient education on quality of life among adults with atrial fibrillation: a randomized controlled trial

OBJECTIVE

To assess whether adding a video on atrial fibrillation (AF) to a face-to-face educational session improves quality of life (QoL), knowledge, and health resource utilization (HRU) among AF patients.

METHODS

In this parallel clinical trial, adults with AF received a face-to-face educational session on AF and were randomly allocated to watch an educational video or not. Self-reported questionnaires measured QoL (primary outcome; score 0-100), AF knowledge (score 0-25), and HRU. Data were collected before and after interventions. Within- and between-group changes were estimated by mixed models.

RESULTS

Sixty participants (age: 56 ± 13 years; men: n = 41) were allocated to watch the video after education (n = 30) or to receive education only (n = 30). Within groups over time, QoL and knowledge significantly improved. Knowledge increased by 2.3 units (95% confidence interval: 0.5-4.1) more in participants who watched the video than in others (P = 0.014). Changes in QoL and HRU were not different between groups.

CONCLUSION

Complementing education with a video on AF did not result in additional positive impacts on QoL and HRU among AF adults but led to greater improvements in AF knowledge.

PRACTICE IMPLICATIONS

The video on AF could be used as part of educational sessions to increase AF knowledge in AF patients.

Comparative impact of two continuing education activities targeted at COPD educators on educational outcomes: protocol for a non-randomized controlled study using mixed methods

Background

Therapeutic patient education (TPE) improves quality of life and reduces health care utilization among patients with chronic obstructive pulmonary disease (COPD). However, benefits from TPE might depend on the performance of the educators and training is needed to ensure the effective delivery of TPE interventions. Based on the framework by Moore et al. (J Contin Educ Health Prof 29:1-15, 2009), we will compare the impact of two continuing education (CE) activities on TPE in regard to the following educational outcomes: (1) learning, (2) self-report of competence, (3) performance of the educators, and (4) outcomes of COPD patients who will meet the newly trained educators for TPE.

Methods

We will conduct a non-randomized controlled study using mixed methods. Educators will first participate in a CE activity on TPE that will include a role-playing simulation (experimental group) or in a lecture on TPE (comparison group) and then will perform TPE in COPD patients. Among educators, we will assess: (1) learning, by measuring knowledge about TPE, and (2) self-report of competence using self-administered questionnaires before and after the activity. Then, after the CE activity, we will assess (3) educators’ performance levels in delivering TPE by rating a videotaped TPE intervention. In COPD patients who will meet the newly trained educators for TPE after either CE activity, we will assess (4) quality of life and resource utilization using interviewer-administered questionnaires, before and after TPE. Statistical analyses will compare the experimental group against the comparison group using multivariate models. Using a semi-structured interview guide, we will conduct interviews with educators and perform content analysis. Results will be integrated in order that qualitative results further explain the quantitative ones.

Discussion

To the best of our knowledge, this is the first controlled mixed methods study to compare the impact of two CE activities on TPE in regard to four educational outcomes. We believe this study will serve as a model for evaluating CE activities on TPE. Results from this study could increase educators’ performance levels in delivering effective TPE interventions, and, in turn, COPD patient outcomes.

Trial registration

The study was registered on https://clinicaltrials.gov/ (NCT02870998) on March 15, 2016.

Electronic supplementary material

The online version of this article (10.1186/s12913-018-3284-6) contains supplementary material, which is available to authorized users.

Rationale, design and pilot feasibility results of a smartphone-assisted, mindfulness-based intervention for smokers with mood disorders: Project mSMART MIND

BACKGROUND

Although individuals with psychiatric disorders are disproportionately affected by cigarette smoking, few outpatient mental health treatment facilities offer smoking cessation services. In this paper, we describe the development of a smartphone-assisted mindfulness smoking cessation intervention with contingency management (SMI-CM), as well as the design and methods of an ongoing pilot randomized controlled trial (RCT) targeting smokers receiving outpatient psychiatric treatment. We also report the results of an open-label pilot feasibility study.

METHODS

In phase 1, we developed and pilot-tested SMI-CM, which includes a smartphone intervention app that prompts participants to practice mindfulness, complete ecological momentary assessment (EMA) reports 5 times per day, and submit carbon monoxide (CO) videos twice per day. Participants earned incentives if submitted videos showed CO≤6ppm. In phase 2, smokers receiving outpatient treatment for mood disorders are randomized to receive SMI-CM or enhanced standard treatment plus non-contingent CM (EST).

RESULTS

The results from the pilot feasibility study (N=8) showed that participants practiced mindfulness an average of 3.4times/day (≥3min), completed 72.3% of prompted EMA reports, and submitted 68.0% of requested CO videos. Participants reported that the program was helpful overall (M=4.85/5) and that daily mindfulness practice was helpful for both managing mood and quitting smoking (Ms=4.50/5).

CONCLUSIONS

The results from the feasibility study indicated high levels of acceptability and satisfaction with SMI-CM. The ongoing RCT will allow evaluation of the efficacy and mechanisms of action underlying SMI-CM for improving cessation rates among smokers with mood disorders.

TEAM-UP for quality: a cluster randomized controlled trial protocol focused on preventing pressure ulcers through repositioning frequency and precipitating factors

BACKGROUND

Pressure ulcers/injuries (PrUs), a critical concern for nursing homes (NH), are responsible for chronic wounds, amputations, septic infections, and premature deaths. PrUs occur most commonly in older adults and NH residence is a risk factor for their development, with at least one of every nine U.S. NH residents experiencing a PrU and many NHs having high incidence and prevalence rates, in some instances well over 20%. PrU direct treatment costs are greater than prevention costs, making prevention-focused protocols critical. Current PrU prevention protocols recommend repositioning residents at moderate, high, and severe risk every 2 h. The advent of visco-elastic (VE) high-density foam support-surfaces over the past decade may now make it possible to extend the repositioning interval to every 3 or 4 h without increasing PrU development. The TEAM-UP (Turn Everyone And Move for Ulcer Prevention) study aims to determine: 1) whether repositioning interval can be extended for NH residents without compromising PrU incidence and 2) how changes in medical severity interact with changes in risk level and repositioning schedule to predict PrU development.

METHODS

In this proposed cluster randomized study, 9 NHs will be randomly assigned to one of three repositioning intervals (2, 3, or 4 h) for a 4-week period. Each enrolled site will use a single NH-wide repositioning interval as the standard of care for residents at low, moderate, and high risk of PrU development (N = 951) meeting the following criteria: minimum 3-day stay, without PrUs, no adhesive allergy, and using VE support surfaces (mattresses). An FDA-cleared patient monitoring system that records position/movement of these residents via individual wireless sensors will be used to visually cue staff when residents need repositioning and document compliance with repositioning protocols.

DISCUSSION

This study will advance knowledge about repositioning frequency and clinically assessed PrU risk level in relation to PrU incidence and medical severity. Outcomes of this research will contribute to future guidelines for more precise preventive nursing practices and refinement of PrU prevention guidelines.

TRIAL REGISTRATION

Clinical Trial Registration: NCT02996331 .

Impact of Adding a Decision Aid to Patient Education in Adults with Asthma: A Randomized Clinical Trial

BACKGROUND

Not providing adequate patient education interventions to asthma patients remains a major care gap. To help asthma patients and caregivers discuss inhaled controller medication use, our team has previously developed a decision aid (DA). We sought to assess whether adding this DA to education interventions improved knowledge, decisional conflict, and asthma control among adults with asthma.

METHODS

A parallel clinical trial (NCT02516449). We recruited adults with asthma, aged 18 to 65 years, prescribed inhaled controller medication to optimize asthma control. Educators randomly allocated participants either to the education + DA or to the education group. At baseline and two-month follow-up, we measured asthma knowledge (primary outcome) with a validated self-administered questionnaire (score -37 to +37). Secondary outcomes included decisional conflict and asthma control. Blinded assessors collected data. Between the two time points, the within- and between-group changes were estimated by generalized linear mixed models.

RESULTS

Fifty-one participants (response rate: 53%; age: 44 ± 13 years; women: n = 32) were randomized either to the education + DA group (n = 26) or to the education group (n = 25), and included in statistical analyses. Between baseline and follow-up, mean [95% CI] knowledge scores increased from 21.5 [19.9-23.2] to 25.1 [23.1-27.0] in the education + DA group (P = 0.0002) and from 24.0 [22.3-25.7] to 26.0 [24.0-28.0] in the education group (P = 0.0298). In both of the groups, decisional conflict and asthma control improved. There were no differences between groups.

CONCLUSIONS

Education improved knowledge, decisional conflict, and asthma control whether the DA was added or not.

Optimal design of longitudinal data analysis using generalized estimating equation models

Longitudinal studies are often applied in biomedical research and clinical trials to evaluate the treatment effect. The association pattern within the subject must be considered in both sample size calculation and the analysis. One of the most important approaches to analyze such a study is the generalized estimating equation (GEE) proposed by Liang and Zeger, in which "working correlation structure" is introduced and the association pattern within the subject depends on a vector of association parameters denoted by ρ. The explicit sample size formulas for two-group comparison in linear and logistic regression models are obtained based on the GEE method by Liu and Liang. For cluster randomized trials (CRTs), researchers proposed the optimal sample sizes at both the cluster and individual level as a function of sampling costs and the intracluster correlation coefficient (ICC). In these approaches, the optimal sample sizes depend strongly on the ICC. However, the ICC is usually unknown for CRTs and multicenter trials. To overcome this shortcoming, Van Breukelen et al. consider a range of possible ICC values identified from literature reviews and present Maximin designs (MMDs) based on relative efficiency (RE) and efficiency under budget and cost constraints. In this paper, the optimal sample size and number of repeated measurements using GEE models with an exchangeable working correlation matrix is proposed under the considerations of fixed budget, where "optimal" refers to maximum power for a given sampling budget. The equations of sample size and number of repeated measurements for a known parameter value ρ are derived and a straightforward algorithm for unknown ρ is developed. Applications in practice are discussed. We also discuss the existence of the optimal design when an AR(1) working correlation matrix is assumed. Our proposed method can be extended under the scenarios when the true and working correlation matrix are different.

Sequential psychological and pharmacological therapies for comorbid and primary insomnia: study protocol for a randomized controlled trial

BACKGROUND

Chronic insomnia is a prevalent disorder associated with significant psychosocial, health, and economic impacts. Cognitive behavioral therapies (CBTs) and benzodiazepine receptor agonist (BzRA) medications are the most widely supported therapeutic approaches for insomnia management. However, few investigations have directly compared their relative and combined benefits, and even fewer have tested the benefits of sequential treatment for those who do not respond to initial insomnia therapy. Moreover, insomnia treatment studies have been limited by small, highly screened study samples, fixed-dose, and fixed-agent pharmacotherapy strategies that do not represent usual clinical practices. This study will address these limitations.

METHODS/DESIGN

This is a two-site randomized controlled trial, which will enroll 224 adults who meet the criteria for a chronic insomnia disorder with or without comorbid psychiatric disorders. Prospective participants will complete clinical assessments and polysomnography and then will be randomly assigned to first-stage therapy involving either behavioral therapy (BT) or zolpidem. Treatment outcomes will be assessed after 6 weeks, and treatment remitters will be followed for the next 12 months on maintenance therapy. Those not achieving remission will be offered randomization to a second, 6-week treatment, again involving either pharmacotherapy (zolpidem or trazodone) or psychological therapy (BT or cognitive therapy (CT)). All participants will be re-evaluated 12 weeks after the protocol initiation and at 3-, 6-, 9-, and 12-month follow-ups. Insomnia remission, defined categorically as a score < 8 on the Insomnia Severity Index, a patient-reported outcome, will serve as the primary endpoint for treatment comparisons. Secondary outcomes will include sleep parameters derived from daily sleep diaries and from polysomnography, subjective measures of fatigue, mood, quality of life, and functional impairments; and measures of adverse events; dropout rates; and treatment acceptability. Centrally trained therapists will administer therapies according to manualized, albeit flexible, treatment algorithms.

DISCUSSION

This clinical trial will provide new information about optimal treatment sequencing and will have direct implication for the development of clinical guidelines for managing chronic insomnia with and without comorbid psychiatric conditions.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01651442 , Protocol version 4, 20 April 2011, registered 26 June 2012.

Rationale and design of a patient-centered medical home intervention for patients with end-stage renal disease on hemodialysis

In the U.S., more than 400,000 individuals with end-stage renal disease (ESRD) require hemodialysis (HD) for renal replacement therapy. ESRD patients experience a high burden of morbidity, mortality, resource utilization, and poor quality of life (QOL). Under current care models, ESRD patients receive fragmented care from multiple providers at multiple locations. The Patient-Centered Medical Home (PCMH) is a team approach, providing coordinated care across the healthcare continuum. While this model has shown some early benefits for complex chronic diseases such as diabetes, it has not been applied to HD patients. This study is a non-randomized quasi-experimental intervention trial implementing a Patient-Centered Medical Home for Kidney Disease (PCMH-KD). The PCMH-KD extends the existing dialysis care team (comprised of a nephrologist, dialysis nurse, dialysis technician, social worker, and dietitian) by adding a general internist, pharmacist, nurse coordinator, and a community health worker, all of whom will see the patients together, and separately, as needed. The primary goal is to implement a comprehensive, multidisciplinary care team to improve care coordination, quality of life, and healthcare use for HD patients. Approximately 240 patients will be recruited from two sites; a non-profit university-affiliated dialysis center and an independent for-profit dialysis center. Outcomes include (i) patient-reported outcomes, including QOL and satisfaction; (ii) clinical outcomes, including blood pressure and diet; (iii) healthcare use, including emergency room visits and hospitalizations; and (iv) staff perceptions. Given the significant burden that patients with ESRD on HD experience, enhanced care coordination provides an opportunity to reduce this burden and improve QOL.

Impact of extracardiac vascular disease on vein graft failure and outcomes after coronary artery bypass surgery

BACKGROUND

While extracardiac vascular disease (ECVD), defined as a history of peripheral vascular disease (PVD) or cerebrovascular disease (CBVD), is common in patients undergoing coronary artery bypass graft (CABG) surgery, there are limited data available on the association between ECVD, vein graft failure (VGF), and clinical outcomes.

METHODS

Using data from the Project of Ex-vivo Vein Graft Engineering via Transfection IV (PREVENTIV) trial (n = 3,014), 1-year angiographic follow-up and 5-year clinical outcomes (death, myocardial infarction, and revascularization) were determined in patients with and without ECVD. Logistic regression was used to assess risk of VGF. Generalized estimating equations methods were used to account for correlations in a graft-level analysis. Kaplan-Meier estimates and Cox hazards regression were used to compare clinical outcomes. We similarly explored the association of the individual components CBVD and PVD with both VGF and clinical outcomes in an additive model.

RESULTS

Patients with ECVD (n = 634, 21%) were older, more commonly female, and had more comorbidities, lower use of internal thoracic artery grafting, and overall worse graft quality than patients without ECVD. VGF rates tended to be higher (patient-level: odds ratio [OR]: 1.23, 95% confidence interval [CI] 0.96 to 1.58, p = 0.099; graft-level: OR: 1.23, 95% CI: 1.00 to 1.53, p = 0.053) in patients with ECVD. VGF rates were significantly higher among CBVD patients (OR: 1.42, 95% CI: 1.03 to 1.97, p = 0.035; graft-level: OR: 1.40, 95% CI: 1.06 to 1.85, p = 0.019). Patients with ECVD had a higher risk of death, myocardial infarction, or revascularization 5 years after CABG surgery (hazard ratio [HR]: 2.96, 95% CI: 2.02 to 4.35, p < 0.001). This relationship was driven by the subset of patients with PVD (HR = 3.32, 95% CI: 2.16 to 5.09, p < 0.001) and not by those with CBVD (HR = 1.10, 95% CI: 0.88 to 1.37, p = 0.40).

CONCLUSIONS

ECVD is common among patients undergoing CABG surgery and is associated with similar short-term but increasingly worse long-term clinical outcomes. This higher risk may be partly, but not exclusively, due to higher rates of VGF among these patients.

A randomized, double-blind comparison of licorice versus sugar-water gargle for prevention of postoperative sore throat and postextubation coughing

BACKGROUND

One small study suggests that gargling with licorice before induction of anesthesia reduces the risk of postoperative sore throat. Double-lumen tubes are large and thus especially likely to provoke sore throats. We therefore tested the hypothesis that preoperative gargling with licorice solution prevents postoperative sore throat and postextubation coughing in patients intubated with double-lumen tubes.

METHODS

We enrolled 236 patients having elective thoracic surgery who required intubation with a double-lumen endotracheal tube. Patients were randomly assigned to gargle 5 minutes before induction of anesthesia for 1 minute with: (1) Extractum Liquiritiae Fluidum (licorice 0.5 g); or (2) Sirupus Simplex (sugar 5 g); each diluted in 30 mL water. Sore throat and postextubation coughing were evaluated 30 minutes, 90 minutes, and 4 hours after arrival in the postanesthesia care unit, and the first postoperative morning using an 11-point Likert scale by an investigator blinded to treatment.

RESULTS

The incidence of postoperative sore throat was significantly reduced in patients who gargled with licorice rather than sugar-water: 19% and 36% at 30 minutes, 10% and 35% at 1.5 hours, and 21% and 45% at 4 hours, respectively. The corresponding estimated treatment effects (relative risks) were 0.54 (95% CI, 0.30-0.99, licorice versus sugar-water; P = 0.005), 0.31 (0.14-0.68) (P < 0.001), and 0.48 (0.28-0.83) (P < 0.001).

CONCLUSION

Licorice gargling halved the incidence of sore throat. Preinduction gargling with licorice appears to be a simple way to prevent a common and bothersome complication.

Blinded Sample Size Recalculation in Longitudinal Clinical Trials Using Generalized Estimating Equations

In clinical trials in which outcomes are measured repeatedly during the follow-up phase, data analysis is frequently performed using generalized estimating equations (GEEs). Sample size calculation is then especially challenging since in addition to the treatment effect, the intrasubject correlation and the variability of the model error term have to be specified. In this article, the authors investigated by Monte Carlo simulations whether a blinded midcourse estimation of these quantities in an internal pilot study design is feasible in such trials and whether nominal type I and type II error rates are preserved when the estimates are used for sample size recalculation. The actual type I error rates of the blinded sample size recalculation procedure turned out to agree well with the nominal levels. Furthermore, the simulated power was observed to be near the target value as long as the sample size of the internal pilot study was sufficiently high and the bound effects induced by the range of the correlation were limited. The proposed procedure is a helpful tool to achieve robustness of the power with respect to initial misspecifications in the planning stage in clinical trials analyzed by GEE.

There is no relationship between academic achievement and body mass index among fourth-grade, predominantly African-American children

School-based initiatives to combat childhood obesity may use academic performance to measure success. This cross-sectional study investigated the relationship between academic achievement and body mass index percentile, socioeconomic status (SES), and race by linking existing datasets that are not routinely linked. Data from a school-based project (with National Institutes of Health funding) concerning dietary recall accuracy were linked with data from the state's Department of Education through the state's Office of Research and Statistics. Data were available on 1,504 fourth-grade, predominantly African-American children from 18 schools total in one district in South Carolina during the 2004-2005, 2005-2006, and 2006-2007 school years. School staff administered standardized tests in English, math, social studies, and science. Researchers measured children's weight and height. Children were categorized as low-SES, medium-SES, or high-SES based on eligibility for free, reduced-price, or full-price school meals, respectively. Results from marginal regression analyses for each sex for the four academic subjects, separately and combined, showed that test scores were not related to body mass index percentile, but were positively related to SES (P values <0.0001), and were related to race, with lower scores for African-American children than children of other races (P values <0.0039). Cost-efficient opportunities exist to create longitudinal data sets to investigate relationships between academic performance and obesity across kindergarten through 12th-grade children. State agencies can house body mass index data in state-based central repositories where staff can use globally unique identifiers and link data across agencies. Results from such studies could potentially change the way school administrators view nutrition and physical education.

Allergies in high-risk schoolchildren after early intervention with cow's milk protein hydrolysates: 10-year results from the German Infant Nutritional Intervention (GINI) study

BACKGROUND

The long-term effect of nutritional intervention with hydrolysate infant formulas on allergic manifestations in high-risk children is uncertain.

OBJECTIVE

We sought to investigate the effect of hydrolysate infant formulas on allergic phenotypes in children with family history of allergies at school age.

METHODS

We analyzed data from participants of the prospective German Infant Nutritional Intervention study after 10 years of follow-up. At birth, children were randomly assigned to receive, for the first 4 months, one of 4 blinded formulas as breast milk substitute, if necessary: partially hydrolyzed whey formula (pHF-W), extensively hydrolyzed whey formula (eHF-W), extensively hydrolyzed casein formula (eHF-C), or standard cow's milk formula. Outcomes were parent-reported, physician-diagnosed allergic diseases. Log-binomial regression models were used for statistical analysis.

RESULTS

The relative risk for the cumulative incidence of any allergic disease in the intention-to-treat analysis (n = 2252) was 0.87 (95% CI, 0.77-0.99) for pHF-W, 0.94 (95% CI, 0.83-1.07) for eHF-W, and 0.83 (95% CI, 0.72-0.95) for eHF-C compared with standard cow's milk formula. The corresponding figures for atopic eczema/dermatits (AD) were 0.82 (95% CI, 0.68-1.00), 0.91 (95% CI, 0.76-1.10), and 0.72 (95% CI, 0.58-0.88), respectively. In the per-protocol analysis (n = 988) effects were stronger. The period prevalence of AD at 7 to 10 years was significantly reduced with eHF-C in this analysis, but there was no preventive effect on asthma or allergic rhinitis.

CONCLUSION

The significant preventive effect on the cumulative incidence of allergic diseases, particularly AD, with pHF-W and eHF-C persisted until 10 years without rebound, whereas eHF-W showed no significant risk reduction. There is insufficient evidence of ongoing preventive activity at 7 to 10 years of age.

Rapid sample size calculations for a defined likelihood ratio test-based power in mixed-effects models

Efficient power calculation methods have previously been suggested for Wald test-based inference in mixed-effects models but the only available alternative for Likelihood ratio test-based hypothesis testing has been to perform computer-intensive multiple simulations and re-estimations. The proposed Monte Carlo Mapped Power (MCMP) method is based on the use of the difference in individual objective function values (ΔiOFV) derived from a large dataset simulated from a full model and subsequently re-estimated with the full and reduced models. The ΔiOFV is sampled and summed (∑ΔiOFVs) for each study at each sample size of interest to study, and the percentage of ∑ΔiOFVs greater than the significance criterion is taken as the power. The power versus sample size relationship established via the MCMP method was compared to traditional assessment of model-based power for six different pharmacokinetic and pharmacodynamic models and designs. In each case, 1,000 simulated datasets were analysed with the full and reduced models. There was concordance in power between the traditional and MCMP methods such that for 90% power, the difference in required sample size was in most investigated cases less than 10%. The MCMP method was able to provide relevant power information for a representative pharmacometric model at less than 1% of the run-time of an SSE. The suggested MCMP method provides a fast and accurate prediction of the power and sample size relationship.

Efficacy of an Andrographis paniculata composition for the relief of rheumatoid arthritis symptoms: a prospective randomized placebo-controlled trial

Andrographis paniculata (Burm. f.) Wall ex Nees (Acanthaceae) possesses anti-inflammatory effects, attributed to the main constituent andrographolide proposed as alternative in the treatment of autoimmune disease. A prospective, randomized, double blind, and placebo-controlled study in patients with rheumatoid arthritis (RA) was performed. Tablets (Paractin) made of an extract of A. paniculata (30% total andrographolides) were administered three times a day for 14 weeks, after a 2-week washout period to 60 patients with active RA. The primary outcomes were pain intensity measured using a horizontal visual analog pain scale (VAPS). In addition, ACR, EULAR, and SF36 clinical parameters were recorded. The intensity of joint pain decreased in the active vs placebo group at the end of treatment, although these differences were not statistically significant. A significant diminishing for week in tender joint -0.13 95% confidence interval (CI; -0.22 to 0.06; p = 0.001), number of swollen joints -0.15 95%CI (-0.29 to -0.02; p = 0.02), total grade of swollen joint -0.27 95%CI (-0.48 to -0.07; p = 0.010), number of tender joints -0.25 95%CI (-0.48 to -0.02; p = 0.033), total grade of swollen joints -0.27 95%CI (-0.48 to -0.07; p = 0.01), total grade of tender joints -0.47 95%CI (-0.77 to -0.17; p = 0.002) and HAQ -0.52 95%CI (-0.82 to -0.21; p < 0.001) and SF36 0.02 95%CI (0.01 to 0.02; p < 0.001) health questionnaires was observed within the group with the active drug. Moreover, it was associated to a reduction of rheumatoid factor, IgA, and C4. These findings suggest that A. paniculata could be a useful "natural complement" in the treatment of AR; however, a larger trial and a more extended period of treatment is necessary in order to corroborate these results.

Are there sex differences in the predictive validity of DSM-IV ADHD among younger children?

We assessed the predictive validity of attention-deficit/hyperactivity disorder (ADHD) in 20 girls and 98 boys who met the Diagnostic and Statistical Manual for Mental Disorders (4th ed., American Psychiatric Association, 1994) criteria for ADHD at 4 to 6 years of age compared to 24 female and 102 male comparison children. Over the next 8 years, both girls and boys who met criteria for ADHD in Year 1 exhibited more ADHD symptoms and impairment than same-sex comparison children. Effect sizes were consistently large, indicating that the diagnosis of ADHD at 4 to 6 years of age has predictive validity for both sexes. Both girls and boys with ADHD in Year 1 also exhibited higher levels of symptoms of conduct disorder, major depression, and anxiety disorders in early adolescence than same-sex comparison children, controlling levels of the same symptoms in Year 1. This indicates both substantial homotypic and heterotypic continuity for ADHD in both sexes, but significant interactions with time indicated that childhood ADHD predicts more steeply rising symptoms of anxiety and depression during early adolescence in girls than in boys.

Analysis of clustered data in multicentre trauma studies

INTRODUCTION

In order to design multicentre studies an estimate of the correlation of the observations within each centre is necessary. A standard measure of the correlation between observations within each centre is the Intraclass Correlation Coefficient (ICC).

METHOD

We used the National Trauma Data Bank (NTDB). By 2004, 448 trauma centres (including 110 level I and 123 level II trauma centres) from 43 states and US territories contributed over 1.2 million records to the NTDB. Data of patients directly transported from the scene of injury to level I or II trauma centres were used to calculate the ICC of in-hospital trauma fatality and emergency department (ED) shock rate.

RESULTS

The ICCs of ED shock and in-hospital fatality rate were 0.010 (95% confidence interval (CI): 0.003-0.018) and 0.039 (95% CI: 0.028-0.050), respectively. The ICC of shock in the ED was the highest for penetrating injuries (0.017, 95% CI: 0.003-0.032) and the lowest for women (0.008, 95% CI: 0.002-0.013) although the observed difference between men and women was not statistically significant. The ICC of trauma fatality was the highest for penetrating injuries (0.073, 95% CI: 0.047-0.098), and the lowest for blunt injuries (0.029, 95% CI: 0.020-0.037).

DISCUSSION

Although the calculated ICCs might seem so small as to be ignored, the required sample size in studies with exclusively exposed or non-exposed clusters depends on the ICC and the average number of subjects within clusters. Therefore, investigators should be aware of the influence that these ICCs might have on sample size and power of their studies.