Power and Sample Size Calculations for Generalized Estimating Equations via Local Asymptotics

The sleep justice study - a prospective cohort study assessing sleep as a cardiometabolic risk factor after incarceration: a protocol paper

BACKGROUND

An estimated 11 million individuals are released from U.S. jails and prisons each year. Individuals with a history of incarceration have higher rates of cardiovascular disease (CVD) events and mortality compared to the general population, especially in the weeks following release from carceral facilities. Healthy sleep, associated with cardiovascular health, is an underexplored factor in the epidemiology of CVD in this population. Incarcerated people may have unique individual, environmental, and institutional policy-level reasons for being sleep deficient. The social and physical environment within carceral facilities and post-release housing may synergistically affect sleep, creating disparities in sleep and cardiovascular health. Since carceral facilities disproportionately house poor and minoritized groups, population-specific risk factors that impact sleep may also contribute to inequities in cardiovascular outcomes.

METHODS

This study is ancillary to an ongoing prospective cohort recruiting 500 individuals with known cardiovascular risk factors within three months of release from incarceration, the Justice-Involved Individuals Cardiovascular Disease Epidemiology (JUSTICE) study. The Sleep Justice study will measure sleep health among participants at baseline and six months using three validated surveys: the Pittsburgh Sleep Quality Index (PSQI), the STOP-Bang, and the Brief Index of Sleep Control. In a subsample of 100 individuals, we will assess sleep over the course of one week using wrist actigraphy, a validated objective measure of sleep that collects data on rest-activity patterns, sleep, and ambient light levels. Using this data, we will estimate and compare sleep health and its association with CVD risk factor control in individuals recently released from carceral facilities.

DISCUSSION

The incarceration of millions of poor and minoritized groups presents an urgent need to understand how incarceration affects CVD epidemiology. This study will improve our understanding of sleep health among people released from carceral facilities and its potential relationship to CVD risk factor control. Using subjective and objective measures of sleep will allow us to identify unique targets to improve sleep health and mitigate cardiovascular risk in an otherwise understudied population.

Neuroticism and Conscientiousness Moderate the Effect of Oral Medication Beliefs on Adherence of People with Mental Illness during the Pandemic

Background. After the declaration of the pandemic status in several countries, the continuity of face-to-face visits in psychiatric facilities has been delayed or even interrupted to reduce viral spread. Little is known about the personality factors associated with medication beliefs and adherence amongst individuals with mental illness during the COVID-19 pandemic. This brief report describes a preliminary naturalistic longitudinal study that explored whether the Big Five personality traits prospectively moderate the effects of medication beliefs on changes in adherence during the pandemic for a group of outpatients with psychosis or bipolar disorder. Methods. Thirteen outpatients undergoing routine face-to-face follow-up assessments during the pandemic were included (41 observations overall) and completed the Revised Italian Version of the Ten-Item Personality Inventory, the Beliefs about Medicines Questionnaire, the Morisky Medication Adherence Scale—8-item and the Beck Depression Inventory—II. Results. Participants had stronger concerns about their psychiatric medications rather than beliefs about their necessity, and adherence to medications was generally low. Participants who had more necessity beliefs than concerns had better adherence to medications. People scoring higher in Conscientiousness and Neuroticism traits and more concerned about the medication side effects had poorer adherence. Conclusions. These preliminary data suggest the importance of a careful assessment of the adherence to medications amongst people with psychosis/bipolar disorder during the pandemic. Interventions aimed to improve adherence might focus on patients’ medication beliefs and their Conscientiousness and Neuroticism personality traits.

Impact of Web-Based Cognitive Behavioral Therapy for Insomnia on Stress, Health, Mood, Cognitive, Inflammatory, and Neurodegenerative Outcomes in Rural Dementia Caregivers: Protocol for the NiteCAPP CARES and NiteCAPP SHARES Randomized Controlled Trial

BACKGROUND

Chronic insomnia affects up to 63% of family dementia caregivers. Research suggests that chronic insomnia prompts changes in central stress processing that have downstream negative effects on health and mood, as well as on cognitive, inflammatory, and neurodegenerative functioning. We hypothesize that cognitive behavioral therapy for insomnia (CBT-I) will reverse those downstream effects by improving insomnia and restoring healthy central stress processing. Rural caregivers are particularly vulnerable, but they have limited access to CBT-I; therefore, we developed an accessible digital version using community input (NiteCAPP CARES).

OBJECTIVE

This trial will evaluate the acceptability, feasibility, and short-term and long-term effects of NiteCAPP CARES on the sleep and stress mechanisms underlying poor caregiver health and functioning.

METHODS

Dyads (n=100) consisting of caregivers with chronic insomnia and their coresiding persons with dementia will be recruited from Columbia and surrounding areas in Missouri, United States. Participant dyads will be randomized to 4 weeks (plus 4 bimonthly booster sessions) of NiteCAPP CARES or a web-based sleep hygiene control (NiteCAPP SHARES). Participants will be assessed at baseline, after treatment, and 6- and 12-month follow-ups. The following assessments will be completed by caregivers: 1 week of actigraphy and daily diaries measuring sleep, Insomnia Severity Index, arousal (heart rate variability), inflammation (blood-derived biomarkers: interleukin-6 and C-reactive protein), neurodegeneration (blood-derived biomarkers: plasma amyloid beta [Aβ40 and Aβ42], total tau, and phosphorylated tau [p-tau181 and p-tau217]), cognition (Joggle battery, NIH Toolbox for Assessment of Neurological and Behavioral Function, and Cognitive Failures Questionnaire), stress and burden, health, and mood (depression and anxiety). Persons with dementia will complete 1 week of actigraphy at each time point.

RESULTS

Recruitment procedures started in February 2022. All data are expected to be collected by 2026. Full trial results are planned to be published by 2027. Secondary analyses of baseline data will be subsequently published.

CONCLUSIONS

This randomized controlled trial tests NiteCAPP CARES, a web-based CBT-I for rural caregivers. The knowledge obtained will address not only what outcomes improve but also how and why they improve and for how long, which will help us to modify NiteCAPP CARES to optimize treatment potency and support future pragmatic testing and dissemination.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04896775; https://clinicaltrials.gov/ct2/show/NCT04896775.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/37874.

GLP-1: 10-year follow-up after Roux-en-Y gastric bypass

PURPOSE

Glucagon-like peptide-1 (GLP-1) is a hormone widely studied in the short-term postoperative follow-up of Roux-en-Y gastric bypass due to its elevation and association with improvement of the glucose metabolism, but there are few studies in 10 years after RYGB follow-up with the same patient.

METHODS

Twenty morbidity obesity patients were submitted to RYGB; these patients were divided into two groups: normal glucose-tolerant morbidly obese patients (NGT) 11 patients and abnormal glucose metabolism morbidly obese patients (AGM) 9 patients. Oral glucose tolerance test (OGTT) was done during four different periods: T1 (first evaluation), T2 (pre-surgery), T3 (9 months after surgery) and T4 (10 years after surgery).

RESULTS

Groups were matched for age and gender, and as NGT and AGM had BMI of 46.31 ± 5.03 kg/m² and 50.87 ± 10.31 kg/m^2. After 10 years of RYGB, they were obesity grade I with BMI for NGT 32.45 ± 4.99 kg/m² and AGM 34.85 ± 4.46 kg/m². Plasma glucose levels decreased NGT group at T4 period had a significant reduction at 120 min after OGTT for NGT 55.49 ± 17.15 mg/dL (p˂0.001). Insulin levels changed from T1 to T4 for the NGT group. GLP-1 curves were statistically different between the NGT and AGM groups. The AGM group had a higher mean for GLP-1 secretion at T4 period and at 30 min of OGTT 63.85 ± 37.98 pmol/L when compared to NGT 50.73 ± 24.82 pmol/L with AGM > NGT with p˂0.001.

CONCLUSION

Evaluation of the same patient during 4 different periods shows that, even with weight regain, after 10-years of RYGB high levels of GLP-1 remained which can be associated with metabolic improvement especially at the NGT group.

Power for balanced linear mixed models with complex missing data processes

When designing repeated measures studies, both the amount and the pattern of missing outcome data can affect power. The chance that an observation is missing may vary across measurements, and missingness may be correlated across measurements. For example, in a physiotherapy study of patients with Parkinson's disease, increasing intermittent dropout over time yielded missing measurements of physical function. In this example, we assume data are missing completely at random, since the chance that a data point was missing appears to be unrelated to either outcomes or covariates. For data missing completely at random, we propose noncentral F power approximations for the Wald test for balanced linear mixed models with Gaussian responses. The power approximations are based on moments of missing data summary statistics. The moments were derived assuming a conditional linear missingness process. The approach provides approximate power for both complete-case analyses, which include independent sampling units where all measurements are present, and observed-case analyses, which include all independent sampling units with at least one measurement. Monte Carlo simulations demonstrate the accuracy of the method in small samples. We illustrate the utility of the method by computing power for proposed replications of the Parkinson's study.

Optimal design strategies for sibling studies with binary exposures

Sibling studies have become increasingly popular because they provide better control over confounding by unmeasured family-level risk factors than can be obtained in standard cohort studies. However, little attention has been devoted to the development of efficient design strategies for sibling studies in terms of optimizing power. We here address this issue in commonly encountered types of sibling studies, allowing for continuous and binary outcomes and varying numbers of exposed and unexposed siblings. For continuous outcomes, we show that in families with sibling pairs, optimal study power is obtained by recruiting discordant (exposed-control) pairs of siblings. More generally, balancing the exposure status within each family as evenly as possible is shown to be optimal. For binary outcomes, we elucidate how the optimal strategy depends on the variation of the binary response; as the within-family correlation increases, the optimal strategy tends toward only recruiting discordant sibling pairs (as in the case of continuous outcomes). R code for obtaining the optimal strategies is included.

The Early Determinants of Adult Health Study

This issue of the Journal features collaborative follow-up studies of two unique pregnancy cohorts recruited during 1959-1966 in the United States. Here we introduce the Early Determinants of Adult Health (EDAH) study. EDAH was designed to compare health outcomes in midlife (age 40s) for same-sex siblings discordant on birthweight for gestational age. A sufficient sample of discordant siblings could only be obtained by combining these two cohorts in a single follow-up study. All of the subsequent six papers are either based upon the EDAH sample or are related to it in various ways. For example, three papers report results from studies that significantly extended the 'core' EDAH sample to address specific questions. We first present the overall design of and rationale for the EDAH study. Then we offer a synopsis of past work with the two cohorts to provide a context for both EDAH and the related studies. Next, we describe the recruitment and assessment procedures for the core EDAH sample. This includes the process of sampling and recruitment of potential participants; a comparison of those who were assessed and not assessed based on archived data; the methods used in the adult follow-up assessment; and the characteristics at follow-up of those who were assessed. We provide online supplementary tables with much further detail. Finally, we note further work in progress on EDAH and related studies, and draw attention to the broader implications of this endeavor.