Efficient estimation for left-truncated competing risks regression for case-cohort studies.

The case-cohort study design provides a cost-effective study design for a large cohort study with competing risk outcomes. The proportional subdistribution hazards model is widely used to estimate direct covariate effects on the cumulative incidence function for competing risk data. In biomedical studies, left truncation often occurs and brings extra challenges to the analysis. Existing inverse probability weighting methods for case-cohort studies with competing risk data not only have not addressed left truncation, but also are inefficient in regression parameter estimation for fully observed covariates. We propose an augmented inverse probability-weighted estimating equation for left-truncated competing risk data to address these limitations of the current literature. We further propose a more efficient estimator when extra information from the other causes is available. The proposed estimators are consistent and asymptotically normally distributed. Simulation studies show that the proposed estimator is unbiased and leads to estimation efficiency gain in the regression parameter estimation. We analyze the Atherosclerosis Risk in Communities study data using the proposed methods.

Risk of diabetes and cardiovascular diseases in women with vaginal bleeding before 20 gestational weeks: Danish population-based cohort study.

BACKGROUND: Women's reproductive health is associated with cardiovascular morbidity. However, an association of vaginal bleeding (VB) in pregnancy with diabetes and cardiovascular outcomes has scarcely been investigated. METHODS: We conducted a population-based cohort study in Denmark (1994-2018). Using nationwide registries, among 903 327 women we identified 1 901 725 pregnancies: 39 265 ended in childbirth and were affected by VB; 1 389 285 ended in childbirth and were unaffected by VB; 333 785 ended in a termination, and 139 390 ended in a miscarriage. The outcomes were diabetes types 1 and 2, hypertension, ischaemic heart disease including myocardial infarction, atrial fibrillation or flutter, heart failure and ischaemic and haemorrhagic stroke. We computed incidence rates and hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for age, calendar year of pregnancy end, morbidities and reproductive and socioeconomic factors, using inverse probability of treatment-weighted Cox proportional hazards regression. RESULTS: In analyses of VB-affected vs VB-unaffected pregnancies, aHRs were 1.15 (1.03-1.28) for diabetes type 1, 1.19 (1.13-1.26) for diabetes type 2, 1.19 (1.14-1.25) for hypertension, 1.26 (1.16-1.37) for ischaemic heart disease, 1.21 (1.03-1.42) for myocardial infarction, 1.32 (1.14-1.51) for atrial fibrillation or flutter and 1.23 (0.99-1.52) for heart failure. aHRs were 1.41 (1.26-1.57) and 1.46 (1.23-1.72) for ischaemic and haemorrhagic stroke, respectively. When contrasting VB-affected pregnancies with terminations, aHRs were up to 1.3-fold increased for diabetes and hypertension; however, when contrasting VB-affected pregnancies with miscarriages, estimates were below or close to the null value. CONCLUSIONS: Women's risks of diabetes and cardiovascular outcomes later in life were increased following VB-affected vs VB-unaffected pregnancy or termination, but not following VB-affected pregnancy vs miscarriage.

The Study of Muscle, Mobility and Aging (SOMMA): A Unique Cohort Study About the Cellular Biology of Aging and Age-related Loss of Mobility.

BACKGROUND: The Study of Muscle, Mobility and Aging (SOMMA) aims to understand the biological basis of many facets of human aging, with a focus on mobility decline, by creating a unique platform of data, tissues, and images. METHODS: The multidisciplinary SOMMA team includes 2 clinical centers (University of Pittsburgh and Wake Forest University), a biorepository (Translational Research Institute at Advent Health), and the San Francisco Coordinating Center (California Pacific Medical Center Research Institute). Enrollees were age ≥70 years, able to walk ≥0.6 m/s (4 m); able to complete 400 m walk, free of life-threatening disease, and had no contraindications to magnetic resonance or tissue collection. Participants are followed with 6-month phone contacts and annual in-person exams. At baseline, SOMMA collected biospecimens (muscle and adipose tissue, blood, urine, fecal samples); a variety of questionnaires; physical and cognitive assessments; whole-body imaging (magnetic resonance and computed tomography); accelerometry; and cardiopulmonary exercise testing. Primary outcomes include change in walking speed, change in fitness, and objective mobility disability (able to walk 400 m in 15 minutes and change in 400 m speed). Incident events, including hospitalizations, cancer diagnoses, fractures, and mortality are collected and centrally adjudicated by study physicians. RESULTS: SOMMA exceeded its goals by enrolling 879 participants, despite being slowed by the COVID-19 pandemic: 59.2% women; mean age 76.3 ± 5.0 years (range 70-94); mean walking speed 1.04 ± 0.20 m/s; 15.8% identify as other than Non-Hispanic White. Over 97% had data for key measurements. CONCLUSIONS: SOMMA will provide the foundation for discoveries in the biology of human aging and mobility.

Patient Recruitment Into a Multicenter Clinical Cohort Linking Electronic Health Records From 5 Health Systems: Cross-sectional Analysis.

BACKGROUND: There is growing interest in identifying and recruiting research participants from health systems using electronic health records (EHRs). However, few studies have described the practical aspects of the recruitment process or compared electronic recruitment methods to in-person recruitment, particularly across health systems. OBJECTIVE: The objective of this study was to describe the steps and efficiency of the recruitment process and participant characteristics by recruitment strategy. METHODS: EHR-based eligibility criteria included being an adult patient engaged in outpatient primary or bariatric surgery care at one of 5 health systems in the PaTH Clinical Research Network and having ≥2 weight measurements and 1 height measurement recorded in their EHR within the last 5 years. Recruitment strategies varied by site and included one or more of the following methods: (1) in-person recruitment by study staff from clinical sites, (2) US postal mail recruitment letters, (3) secure email, and (4) direct EHR recruitment through secure patient web portals. We used descriptive statistics to evaluate participant characteristics and proportion of patients recruited (ie, efficiency) by modality. RESULTS: The total number of eligible patients from the 5 health systems was 5,051,187. Of these, 40,048 (0.8%) were invited to enter an EHR-based cohort study and 1085 were enrolled. Recruitment efficiency was highest for in-person recruitment (33.5%), followed by electronic messaging (2.9%), including email (2.9%) and EHR patient portal messages (2.9%). Overall, 779 (65.7%) patients were enrolled through electronic messaging, which also showed greater rates of recruitment of Black patients compared with the other strategies. CONCLUSIONS: We recruited a total of 1085 patients from primary care and bariatric surgery settings using 4 recruitment strategies. The recruitment efficiency was 2.9% for email and EHR patient portals, with the majority of participants recruited electronically. This study can inform the design of future research studies using EHR-based recruitment.

The effect of a hand hygiene program featuring tailored religion-relevant interventions on healthcare workers' hand rubbing compliance and beliefs in the United Arab Emirates: A cohort study.

BACKGROUND: Hand hygiene with ABHR is more effective, time-saving and skin-friendly than traditional handwashing. However, alcohol-based hand rub (ABHR) use can be an obstacle for specific religions. The study aimed to test the effect of a modified hand hygiene program featuring religion-relevant, culturally-specific interventions on compliance and beliefs about ABHR use. METHODS: A cohort study design was employed between August and November 2017 at a large tertiary hospital in the United Arab Emirates. Hand hygiene audit data and a cross-sectional survey were used to measure the impact of the modified hand hygiene program on compliance with, and beliefs about, ABHR use. RESULTS: The intervention group had higher mean compliance with overt (p = 0.002) and covert (p = 0.04) ABHR use post-intervention, and higher mean compliance with overt ABHR use (p = 0.002) than the control group. The intervention group had more positive religious beliefs (p = 0.01) about ABHR use than the control group. CONCLUSION: Implementing a hand hygiene program featuring tailored religion-relevant interventions in a culturally appropriate way had a positive effect on compliance with, and beliefs about, ABHR use.

Rationale and design of three observational, prospective cohort studies including biobanking to evaluate and improve diagnostics, management strategies and risk stratification in venous thromboembolism: the VTEval Project.

INTRODUCTION: Venous thromboembolism (VTE) with its two manifestations deep vein thrombosis (DVT) and pulmonary embolism (PE) is a major public health problem. The VTEval Project aims to investigate numerous research questions on diagnosis, clinical management, treatment and prognosis of VTE, which have remained uncertain to date. METHODS AND ANALYSIS: The VTEval Project consists of three observational, prospective cohort studies on VTE comprising cohorts of individuals with a clinical suspicion of acute PE (with or without DVT), with a clinical suspicion of acute DVT (without symptomatic PE) and with an incidental diagnosis of VTE (PE or DVT). The VTEval Project expects to enrol a total of approximately 2000 individuals with subsequent active and passive follow-up investigations over a time period of 5 years per participant. Time points for active follow-up investigations are at months 3, 6, 12, 24 and 36 after diagnosis (depending on the disease cohort); passive follow-up investigations via registry offices and the cancer registry are performed 48 and 60 months after diagnosis for all participants. Primary short-term outcome is defined by overall mortality (PE-related death and all other causes of death), primary long-term outcome by symptomatic VTE (PE-related death, recurrence of non-fatal PE or DVT). The VTEval Project includes three 'all-comer' studies and involves the standardised acquisition of high-quality data, covering the systematic assessment of VTE including symptoms, risk profile, psychosocial, environmental and lifestyle factors as well as clinical and subclinical disease, and it builds up a large state-of-the-art biorepository containing various materials from serial blood samplings. ETHICS AND DISSEMINATION: The VTEval Project has been approved by the local data safety commissioner and the responsible ethics committee (reference no. 837.320.12 (8421-F)). Trial results will be published in peer-reviewed journals and presented at national and international scientific meetings. TRIAL REGISTRATION NUMBER: NCT02156401.