Effect of Wearing a Face Mask on Hand-to-Face Contact by Children in a Simulated School Environment: The Back-to-School COVID-19 Simulation Randomized Clinical Trial

IMPORTANCE

Wearing a face mask in school can reduce SARS-CoV-2 transmission but it may also lead to increased hand-to-face contact, which in turn could increase infection risk through self-inoculation.

OBJECTIVE

To evaluate the effect of wearing a face mask on hand-to-face contact by children while at school.

DESIGN, SETTING, AND PARTICIPANTS

This prospective randomized clinical trial randomized students from junior kindergarten to grade 12 at 2 schools in Toronto, Ontario, Canada, during August 2020 in a 1:1 ratio to either a mask or control class during a 2-day school simulation. Classes were video recorded from 4 angles to accurately capture outcomes.

INTERVENTIONS

Participants in the mask arm were instructed to bring their own mask and wear it at all times. Students assigned to control classes were not required to mask at any time (grade 4 and lower) or in the classroom where physical distancing could be maintained (grade 5 and up).

MAIN OUTCOMES AND MEASURES

The primary outcome was the number of hand-to-face contacts per student per hour on day 2 of the simulation. Secondary outcomes included hand-to-mucosa contacts and hand-to-nonmucosa contacts. A mixed Poisson regression model was used to derive rate ratios (RRs), adjusted for age and sex with a random intercept for class with bootstrapped 95% CIs.

RESULTS

A total of 174 students underwent randomization and 171 students (mask group, 50.6% male; control group, 52.4% male) attended school on day 2. The rate of hand-to-face contacts did not differ significantly between the mask and the control groups (88.2 vs 88.7 events per student per hour; RR, 1.00; 95% CI, 0.78-1.28; P = >.99). When compared with the control group, the rate of hand-to-mucosa contacts was significantly lower in the mask group (RR, 0.12; 95% CI, 0.07-0.21), while the rate of hand-to-nonmucosa contacts was higher (RR, 1.40; 95% CI, 1.08-1.82).

CONCLUSIONS AND RELEVANCE

In this clinical trial of simulated school attendance, hand-to-face contacts did not differ among students required to wear face masks vs students not required to wear face masks; however, hand-to-mucosa contracts were lower in the face mask group. This suggests that mask wearing is unlikely to increase infection risk through self-inoculation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04531254.

Le retour en classe et le port du masque pendant la pandémie de COVID-19 : le point de vue des élèves d’après une étude de simulation scolaire

Objectifs

La présente étude s’est penchée sur le point de vue des enfants relativement au retour en classe après le confinement imposé par la pandémie, sur le port du masque en classe et sur la santé mentale des enfants et des parents pendant la pandémie.

Méthodologie

La présente étude transversale a fait partie d’un exercice de simulation scolaire de deux jours au cours duquel les élèves ont été répartis au hasard entre diverses recommandations sur le port du masque. Au moyen d’analyses régression multiple, les chercheurs ont analysé le compte rendu des parents sur la santé mentale et, après la simulation, celui des élèves sur l’anxiété liée à la COVID-19 et le port du masque. Les élèves plus âgés ont participé à des groupes de travail semi-structurés pour compléter les données du questionnaire.

Résultats

Sur les 190 élèves de la présente étude, 31 % ne dépassaient pas la quatrième année et 95 % avaient hâte de rentrer en classe. La plus grande anxiété des parents ou des proches (β= 0,67; p <0,001) et leur niveau de scolarité plus bas (β=1,86; p <0,002) étaient prédicteurs d’une plus grande anxiété des enfants à l’égard de la COVID-19. Les élèves plus âgés étaient plus susceptibles de trouver le port du masque nuisible aux interactions avec leurs camarades que les plus jeunes (χ2[1]=31,16; p <0,001) et pour leur capacité à comprendre l’enseignant (χ2[1]=13,97; p <0,001). Les élèves du groupe sans masque étaient plus susceptibles de craindre de contracter la COVID-19 à l’école (χ2[1]=10,07; p <0,05) que ceux du groupe qui le portaient, et d’anticiper éprouver de la difficulté à le porter (χ2[1]=18,95; p <0,001).

Conclusions

Chez les enfants anxieux à cause de la COVID-19, l’anxiété des parents et l’information sur la COVID-19 pourraient être des cibles d’intervention. De futures recherches devraient porter sur les effets de la mise en œuvre prolongée de mesures sanitaires d’atténuation des risques sur la réussite scolaire et la santé mentale des enfants.

Longitudinal Changes in Cardiac Structure and Function in Pediatric Kidney Transplant Recipients

BACKGROUND

Cardiovascular disease results in increased morbidity and mortality in pediatric kidney transplant recipients. Longitudinal changes in cardiac structure and function and the association with blood pressure control over time in pediatric kidney transplant recipients are unknown.

METHODS

To determine the influence of blood pressure control on cardiac changes following pediatric kidney transplant, we conducted a retrospective cohort study of children who received their first kidney transplant at the Hospital for Sick Children from 2004 to 2015. Children were followed until transfer to adult care or censoring in July 2018. Cardiac structure and function parameters were collected from clinical echocardiograms and assessed using standardized scores. Blood pressure control was determined by systolic blood pressure Z scores (above or below the 90th percentile) in combination with antihypertensive medications. A segmented mixed-effects model assessed Z scores of interventricular septum thickness, left ventricular end-diastolic dimension, and left ventricular posterior wall dimension.

RESULTS

Of 142 children included, 58% were men, mean age at transplant was 11 (±4.5) years, and average follow-up time was 4 (±3) years. All cardiac structural Z scores improved during follow-up. Interventricular septum thickness normalized at 4.0 years post-transplant. Left ventricular end-diastolic dimension normalized at 1.5 years post-transplant. Left ventricular posterior wall dimension normalized at 6.3 years post-transplant. Left ventricular mass index showed sustained improvement up to 12 years post-transplant. Individuals with uncontrolled blood pressure had increased left ventricular mass (β=2.97 [95% CI, 0.77-5.16]).

CONCLUSIONS

Cardiac structural abnormalities improve following kidney transplantation and normalize within 7 years, especially with controlled blood pressure. Strict blood pressure control is critical after pediatric kidney transplantation.

Return to school and mask-wearing in class during the COVID-19 pandemic: Student perspectives from a school simulation study

Objectives

This study examined children’s perspectives about returning to in-person school following lockdown due to the pandemic and about mask-wearing in class, as well as the mental health of children and parents during the pandemic.

Methods

This cross-sectional study was part of a 2-day school simulation exercise that randomized students to different masking recommendations. Parent-report of mental health and post-simulation child-report of COVID-19-related anxiety and mask-wearing were analyzed using descriptive and multiple regression analyses. Semi-structured focus groups were conducted with older students to supplement questionnaire data.

Results

Of 190 students in this study, 31% were in grade 4 or lower 95% looked forward to returning to in-person school. Greater child anxiety about COVID-19 was predicted by increased parent/caregiver anxiety (β=0.67; P<0.001), and lower parental educational attainment (β=1.86; P<0.002). Older students were more likely than younger students to report that mask-wearing interfered with their abilities to interact with peers (χ²(1)=31.16; P<0.001) and understand the teacher (χ²(1)=13.97; P<0.001). Students in the group that did not require masks were more likely than students in the masking group to report worries about contracting COVID-19 at school (χ²(1)=10.07; P<0.05), and anticipated difficulty wearing a mask (χ²(1)=18.95; P<0.001).

Conclusions

For children anxious about COVID-19, parental anxiety and education about COVID-19 may be targets for intervention. Future research should examine the impact of prolonged implementation of public health mitigation strategies in school on academic achievement and children’s mental health.

Impact of COVID-19 Public Health Protocols on Teachers Instructing Children and Adolescents During an In-Person Simulation

Objective

As a result of the COVID-19 pandemic, public health agencies and school boards across Canada enacted new protocols, including face masks, physical distancing and enhanced hygiene, to support the safe reopening of in-person school. This study explored the experiences and perceptions of teachers instructing children and adolescents in person during a two-day school simulation.

Method

This study was part of a large school simulation exercise conducted in Toronto, Ontario. Kindergarten to grade 12 teachers taught in classrooms with either masked students, or students who were un-masked or only masked when physical distancing was not possible. A qualitative descriptive phenomenology approach was utilized, and data were collected via virtual focus groups. Qualitative data analysis involved multiple rounds of inductive coding to generate themes.

Results

The sample included 14 teachers (92.9% female; 85.7% White), with a median of 9.5 years teaching experience. Three primary themes emerged: 1) learning to navigate public health measures, 2) needing to adapt teaching strategies and 3) striving to manage conflicting priorities. The majority of teachers reported that mask-wearing and physical distancing impacted their classroom teaching, communication and connection with students.

Conclusions

As schools transition to in-person instruction, teachers will be required to play dual roles in education and public health, with implications on safety, teaching and professional identity. Public health agencies and school boards are encouraged to engage teachers in ongoing conversations regarding in-person school planning and operations. Furthermore, evidence-based interventions, including increased teaching development programs, are recommended to support teachers during the COVID-19 pandemic.

Immunoglobulin A nephropathy is characterized by anti-commensal humoral immune responses

IgA nephropathy (IgAN) is a leading cause of kidney failure, yet little is known about the immunopathogenesis of this disease. IgAN is characterized by deposition of IgA in the kidney glomeruli, but the source and stimulus for IgA production are not known. Clinical and experimental data suggest a role for aberrant immune responses to mucosal microbiota in IgAN, and in some countries with high disease prevalence, tonsillectomy is regarded as standard-of-care therapy. To evaluate the relationship between microbiota and mucosal immune responses, we characterized the tonsil microbiota in patients with IgAN versus nonrelated household-matched control group participants and identified increased carriage of the genus Neisseria and elevated Neisseria-targeted serum IgA in IgAN patients. We reverse-translated these findings in experimental IgAN driven by BAFF overexpression in BAFF-transgenic mice rendered susceptible to Neisseria infection by introduction of a humanized CEACAM-1 transgene (B × hC-Tg). Colonization of B × hC-Tg mice with Neisseria yielded augmented levels of systemic Neisseria-specific IgA. Using a custom ELISPOT assay, we discovered anti-Neisseria–specific IgA-secreting cells within the kidneys of these mice. These findings suggest a role for cytokine-driven aberrant mucosal immune responses to oropharyngeal pathobionts, such as Neisseria, in the immunopathogenesis of IgAN. Furthermore, in the presence of excess BAFF, pathobiont-specific IgA can be produced in situ within the kidney.

Outcomes of skin cancers in pediatric solid organ transplant patients: A systematic review

BACKGROUND

The most frequently reported malignancies after solid organ transplant are cutaneous, but data on the risk in pediatric populations varies across studies.

OBJECTIVES

To perform a systematic review including reported features and outcomes of skin cancers in pediatric solid organ transplant recipients.

METHODS

EMBASE and MEDLINE were systematically searched (Prospero CRD42020201659).

RESULTS

The review summarizes data from 20 studies on 337 patients, with a median age ranging from 15.0 to 19.5 years as reported in 4 studies, who developed skin malignancies after pediatric solid organ transplantation. Median ages at transplant and skin cancer diagnosis ranged from 1.5 to 17.0 years and 15.3 to 33.5 years, respectively. Squamous cell carcinoma (SCC) was most commonly reported (218 cases), followed by basal cell carcinoma (BCC) (91 cases), melanoma (18 cases), and unspecified keratinocyte carcinomas (2 cases). The median latency period between transplantation and cancer diagnosis ranged from 2.2 to 21.0 years. Overall, 4 studies reported 17 cases of metastasis in total, and recurrence was reported in one case. Six deaths were reported in one study related to SCC and melanoma metastases. The incidence rate of skin cancer after pediatric transplantation per 100 person-years of follow-up was 2.1 based on 5 studies.

CONCLUSION

The most frequent post-transplant malignancy in pediatric organ transplant recipients was SCC.

Association of abnormal electrocardiograph metrics with prolonged recovery time in incident hemodialysis patients

BACKGROUND

Patients receiving intermittent hemodialysis have variable times of recovery to feeling better after dialysis. QT prolongation, a precursor to clinical and subclinical cardiovascular events, may contribute to delayed recovery time. We hypothesized that abnormal electrocardiographic parameters indicating perturbations in ventricular action are associated with longer recovery times thus impacting a patient-centered quality of life.

METHODS

Among 242 incident in-center hemodialysis participants from the Predictors of Arrhythmic and Cardiovascular Risk in End Stage Renal Disease (PACE) study, corrected QT interval (QTc), QRST angle and heart rate variance were measured on non-dialysis days using a standard 5-min electrocardiograph recording. Left ventricular hypertrophy (LVH) was defined using the Cornell voltage product. Recovery time was ascertained during a phone interview with a standardized validated questionnaire. Associations between QTc, QRST angle, heart rate variance, and LVH and natural log-transformed recovery time were examined using linear regression adjusted for participant characteristics and electrolytes.

RESULTS

Mean age was 55 (standard deviation 13) years, 55% were male, 72% were African American. Longer QTc interval was associated with increased recovery time (per 10 ms increase in QTc, recovery time increased by 6.2%; 95% confidence interval: 0.0-10.5). QRST angle, heart rate, heart rate variability and LVH were not significantly associated with recovery time.

CONCLUSION

Longer QTc intervals are associated with longer recovery time independent of serum electrolytes. This supports a relationship between a patient's underlying arrhythmic status and time to recovery after hemodialysis. Future studies will determine if maneuvers to reduce QTc improves recovery time and quality of life of patients on hemodialysis.

Racial-ethnic differences in health-related quality of life among adults and children with glomerular disease

Introduction

Disparities in health-related quality of life (HRQOL) have been inadequately studied in patients with glomerular disease. The aim of this study was to identify relationships between race/ethnicity, socioeconomic status, disease severity, and HRQOL in an ethnically and racially diverse cohort of patients with glomerular disease.

Methods

Cure Glomerulonephropathy (CureGN) is a multinational cohort study of patients with biopsy-proven glomerular disease. Associations between race/ethnicity and HRQOL were determined by the following: 1. Missed school or work due to kidney disease; 2. Responses to Patient Reported Outcomes Measurement Information System (PROMIS) questionnaires. We adjusted for demographics, socioeconomic status, and disease characteristics using multivariable logistic and linear regression.

Results

Black and Hispanic participants had worse socioeconomic status and more severe glomerular disease than White or Asian participants. Black adults missed work or school most frequently due to kidney disease (30% versus 16-23% in the other three groups, p=0.04), and had the worst self-reported global physical health (median score 44.1 versus 48.0-48.2, p<0.001) and fatigue (53.8 versus 48.5-51.1, p=0.002), compared to other racial/ethnic groups. However, these findings were not statistically significant with adjustment for socioeconomic status and disease severity, both of which were strongly associated with HRQOL in adults. Among children, disease severity but not race/ethnicity or socioeconomic status were associated with HRQOL.

Conclusions

Among patients with glomerular disease enrolled in CureGN, the worse HRQOL reported by Black adults was attributable to lower socioeconomic status and more severe glomerular disease. No racial/ethnic differences in HRQOL were observed in children.

Trends in the epidemiology of childhood nephrotic syndrome in Africa: A systematic review

Background

Childhood nephrotic syndrome, if left untreated, leads to progressive kidney disease or death. We quantified the prevalence of steroid-sensitive nephrotic syndrome, steroid-resistant nephrotic syndrome, and histological types as the epidemiology of nephrotic syndrome in Africa remains unknown, yet impacts outcomes.

Methods

We searched MEDLINE, Embase, African Journals Online, and WHO Global Health Library for articles in any language reporting on childhood nephrotic syndrome in Africa from January 1, 1946 to July 1, 2020. Primary outcomes included steroid response, biopsy defined minimal change disease, and focal segmental glomerulosclerosis (FSGS) by both pooled and individual proportions across regions and overall.

Findings

There were 81 papers from 17 countries included. Majority of 8131 children were steroid-sensitive (64% [95% CI: 63-66%]) and the remaining were steroid-resistant (34% [95% CI: 33-35%]). Of children biopsied, pathological findings were 38% [95% CI: 36-40%] minimal change, 24% [95% CI: 22-25%] FSGS, and 38% [95% CI: 36-40%] secondary causes of nephrotic syndrome.

Interpretation

Few African countries reported on the prevalence of childhood nephrotic syndrome. Steroid-sensitive disease is more common than steroid-resistant disease although prevalence of steroid-resistant nephrotic syndrome is higher than reported globally. Pathology findings suggest minimal change and secondary causes are common. Scarcity of data in Africa prevents appropriate healthcare resource allocation to diagnose and treat this treatable childhood kidney disease to prevent poor health outcomes.

Funding

Funding was provided by the Canadian Institute for Health Research (CIHR) and the National Institute of Health (NIH) for the H3 Africa Kidney Disease Research Network. This research was undertaken, in part, from the Canada Research Chairs program.

SARS-CoV-2 antibodies in Ontario health care workers during and after the first wave of the pandemic: a cohort study

BACKGROUND

Health care workers have a critical role in the pandemic response to COVID-19 and may be at increased risk of infection. The objective of this study was to assess the seroprevalence of SARS-CoV-2 immunoglobulin G (IgG) antibodies among health care workers during and after the first wave of the pandemic.

METHODS

We conducted a prospective multicentre cohort study involving health care workers in Ontario, Canada, to detect IgG antibodies against SARS-CoV-2. Blood samples and self-reported questionnaires were obtained at enrolment, at 6 weeks and at 12 weeks. A community hospital, tertiary care pediatric hospital and a combined adult-pediatric academic health centre enrolled participants from Apr. 1 to Nov. 13, 2020. Predictors of seropositivity were evaluated using a multivariable logistic regression, adjusted for clustering by hospital site.

RESULTS

Among the 1062 health care workers participating, the median age was 40 years, and 834 (78.5%) were female. Overall, 57 (5.4%) were seropositive at any time point (2.5% when participants with prior infection confirmed by polymerase chain reaction testing were excluded). Seroprevalence was higher among those who had a known unprotected exposure to a patient with COVID-19 (p < 0.001) and those who had been contacted by public health because of a nonhospital exposure (p = 0.003). Providing direct care to patients with COVID-19 or working on a unit with a COVID-19 outbreak was not associated with higher seroprevalence. In multivariable logistic regression, presence of symptomatic contacts in the household was the strongest predictor of seropositivity (adjusted odds ratio 7.15, 95% confidence interval 5.42-9.41).

INTERPRETATION

Health care workers exposed to household risk factors were more likely to be seropositive than those not exposed, highlighting the need to emphasize the importance of public health measures both inside and outside of the hospital.

Long-Term Kidney Outcomes Following Dialysis-Treated Childhood Acute Kidney Injury: A Population-Based Cohort Study

BACKGROUND

AKI is common during pediatric hospitalizations and associated with adverse short-term outcomes. However, long-term outcomes among survivors of pediatric AKI who received dialysis remain uncertain.

METHODS

To determine the long-term risk of kidney failure (defined as receipt of chronic dialysis or kidney transplant) or death over a 22-year period for pediatric survivors of dialysis-treated AKI, we used province-wide health administrative databases to perform a retrospective cohort study of all neonates and children (aged 0-18 years) hospitalized in Ontario, Canada, from April 1, 1996, to March 31, 2017, who survived a dialysis-treated AKI episode. Each AKI survivor was matched to four hospitalized pediatric comparators without dialysis-treated AKI, on the basis of age, sex, and admission year. We reported the incidence of each outcome and performed Cox proportional hazards regression analyses, adjusting for relevant covariates.

RESULTS

We identified 1688 pediatric dialysis-treated AKI survivors (median age 5 years) and 6752 matched comparators. Among AKI survivors, 53.7% underwent mechanical ventilation and 33.6% had cardiac surgery. During a median 9.6-year follow-up, AKI survivors were at significantly increased risk of a composite outcome of kidney failure or death versus comparators. Death occurred in 113 (6.7%) AKI survivors, 44 (2.6%) developed kidney failure, 174 (12.1%) developed hypertension, 213 (13.1%) developed CKD, and 237 (14.0%) had subsequent AKI. AKI survivors had significantly higher risks of developing CKD and hypertension versus comparators. Risks were greatest in the first year after discharge and gradually decreased over time.

CONCLUSIONS

Survivors of pediatric dialysis-treated AKI are at higher long-term risks of kidney failure, death, CKD, and hypertension, compared with a matched hospitalized cohort.

Frailty, Age, and Postdialysis Recovery Time in a Population New to Hemodialysis

Background

Frailty, a phenotype characterized by decreased physiologic reserve and the inability to recover following confrontation with a stressor like hemodialysis, may help identify which patients on incident hemodialysis will experience longer postdialysis recovery times. Recovery time is associated with downstream outcomes, including quality of life and mortality. We characterized postdialysis recovery times among patients new to hemodialysis and quantified the association between frailty and hemodialysis recovery time.

Methods

Among 285 patients on hemodialysis enrolled in the Predictors of Arrhythmic and Cardiovascular Risk in End Stage Renal Disease (PACE) study, frailty was measured using the Fried phenotype. Self-reported recovery time was obtained by telephone interview. We estimated the association of frailty (intermediately frail and frail versus nonfrail) and postdialysis recovery time using adjusted negative binomial regression.

Results

Median time between dialysis initiation and study enrollment was 3.4 months (IQR, 2.7-4.9), and that between initiation and recovery time assessment was 11 months (IQR, 9.3-15). Mean age was 55 years, 24% were >65 years, and 73% were Black; 72% of individuals recovered in ≤1 hour, 20% recovered in 1-6 hours, 5% required 6-12 hours to recover, and <5% required >12 hours to recover. Those with intermediate frailty, frailty, and age ≤65 years had 2.56-fold (95% CI, 1.45 to 4.52), 1.72-fold (95% CI, 1.03 to 2.89), and 2.35-fold (95% CI, 1.44 to 3.85) risks, respectively, of longer recovery time independent of demographic characteristics, comorbidity, and dialysis-related factors.

Conclusions

In adults new to hemodialysis, frailty was independently associated with prolonged postdialysis recovery. Future studies should assess the effect of frailty-targeted interventions on recovery time to improve clinical outcomes.

International Society of Nephrology Global Kidney Health Atlas: structures, organization, and services for the management of kidney failure in North America and the Caribbean

The International Society of Nephrology established the Global Kidney Health Atlas project to define the global capacity for kidney replacement therapy and conservative kidney care, and this second iteration was to describe the availability, accessibility, quality, and affordability of kidney failure (KF) care worldwide. This report presents results for the International Society of Nephrology North America and the Caribbean region. Relative to other regions, the North America and Caribbean region had better infrastructure and funding for health care and more health care workers relative to the population. Various essential medicines were also more available and accessible. There was substantial variation in the prevalence of treated KF in the region, ranging from 137.4 per million population (pmp) in Jamaica to 2196 pmp in the United States. A mix of public and private funding systems cover costs for nondialysis chronic kidney disease care in 60% of countries and for dialysis in 70% of countries. Although the median number of nephrologists is 18.1 (interquartile range, 15.3-29.5) pmp, which is approximately twice the global median of 9.9 (interquartile range, 1.2-22.7) pmp, some countries reported shortages of other health care workers. Dialysis was available in all countries, but peritoneal dialysis was underutilized and unavailable in Barbados, Cayman Islands, and Turks and Caicos. Kidney transplantation was primarily available in Canada and the United States. Economic factors were the major barriers to optimal KF care in the Caribbean countries, and few countries in the region have chronic kidney disease-specific national health care policies. To address regional gaps in KF care delivery, efforts should be directed toward augmenting the workforce, improving the monitoring and reporting of kidney replacement therapy indicators, and implementing noncommunicable disease and chronic kidney disease-specific policies in all countries.

Functional outcomes of sleep predict cardiovascular intermediary outcomes and all-cause mortality in incident hemodialysis patients

STUDY OBJECTIVES

Patients with end-stage kidney disease (ESKD) commonly experience sleep disturbances. Sleep disturbance has been inconsistently associated with mortality risk in hemodialysis patients, but the burden of symptoms from sleep disturbances has emerged as a marker that may shed light on these discrepancies and guide treatment decisions. This study examines whether functional outcomes of sleep are associated with increased risk of intermediary CV outcomes or mortality among adults initiating hemodialysis.

METHODS

In 228 participants enrolled in the Predictors of Arrhythmic and Cardiovascular risk in ESRD (PACE) study, the Functional Outcomes of Sleep Questionnaire-10 (FOSQ-10), which assesses functional outcomes of daytime sleepiness, was administered within 6 months of enrollment. Intermediary CV outcomes included QTc [ms], heart rate variance [ms²], left ventricular mass index [g/m², LVMI], and left ventricular hypertrophy [LVH]. The association of FOSQ-10 score with all-cause mortality was examined using proportional hazards regression. Results: Mean age was 55 years, median BMI was 28 kg/m² (IQR 24,33), with 70% African Americans. Median FOSQ-10 score was 19.7 (IQR: 17.1,20.0). A 10% lower FOSQ-10 score was associated with increased mortality risk (HR 1.09, 95%CI 1.01-1.18). Lower FOSQ-10 scores were associated with longer QTc duration and lower heart rate variance, but not LVMI or LVH.

CONCLUSIONS

In adults initiating dialysis, sleep-related functional impairment is common and is associated with intermediary cardiovascular disease measures and increased mortality risk. Future studies should assess the impact of screening for sleep disturbances in ESKD patients to identify individuals at increased risk for cardiovascular complications and death.

Identification of Novel Biomarkers and Pathways for Coronary Artery Calcification in Nondiabetic Patients on Hemodialysis Using Metabolomic Profiling

BACKGROUND

A better understanding of the pathophysiology involving coronary artery calcification (CAC) in patients on hemodialysis (HD) will help to develop new therapies. We sought to identify the differences in metabolomics profiles between patients on HD with and without CAC.

METHODS

In this case-control study, nested within a cohort of 568 incident patients on HD, the cases were patients without diabetes with a CAC score >100 (n=51), and controls were patients without diabetes with a CAC score of zero (n=48). We measured 452 serum metabolites in each participant. Metabolites and pathway scores were compared using Mann-Whitney U tests, partial least squares-discriminant analyses, and pathway enrichment analyses.

RESULTS

Compared with controls, cases were older (64±13 versus 42±12 years) and were less likely to be Black (51% versus 94%). We identified three metabolites in bile-acid synthesis (chenodeoxycholic, deoxycholic, and glycolithocholic acids) and one pathway (arginine/proline metabolism). After adjusting for demographics, higher levels of chenodeoxycholic, deoxycholic, and glycolithocholic acids were associated with higher odds of having CAC; comparing the third with the first tertile of each bile acid, the OR was 6.34 (95% CI, 1.12 to 36.06), 6.73 (95% CI, 1.20 to 37.82), and 8.53 (95% CI, 1.50 to 48.49), respectively. These associations were no longer significant after further adjustment for coronary artery disease and medication use. Per 1 unit higher in the first principal component score, arginine/proline metabolism was associated with CAC after adjusting for demographics (OR, 1.83; 95% CI, 1.06 to 3.15), and the association remained significant with additional adjustments for statin use (OR, 1.84; 95% CI, 1.04 to 3.27).

CONCLUSIONS

Among patients on HD without diabetes mellitus, chenodeoxycholic, deoxycholic, and glycolithocholic acids may be potential biomarkers for CAC, and arginine/proline metabolism is a plausible mechanism to study for CAC. These findings need to be confirmed in future studies.

APOL1 Risk Variants and Subclinical Cardiovascular Disease in Incident Hemodialysis Patients

Introduction

To better understand the impact of APOL1 risk variants in end-stage renal disease (ESRD) we evaluated associations of APOL1 risk variants with subclinical cardiovascular disease (CVD) and mortality among African Americans initiating hemodialysis and enrolled in the Predictors of Arrhythmic and Cardiovascular Risk in ESRD cohort study.

Methods

We modeled associations of APOL1 risk status (high = 2; low = 0/1 risk alleles) with baseline subclinical CVD (left ventricular [LV] hypertrophy; LV mass; ejection fraction; coronary artery calcification [CAC]; pulse wave velocity [PWV]) using logistic and linear regression and all-cause or cardiovascular mortality using Cox models, adjusting for age, sex, and ancestry. In sensitivity analyses, we further adjusted for systolic blood pressure and Charlson Comorbidity Index.

Results

Of 267 African American participants successfully genotyped for APOL1, 27% were high-risk carriers, 41% were women, and mean age was 53 years. At baseline, APOL1 high- versus low-risk status was independently associated with 50% and 53% lower odds of LV hypertrophy and CAC, respectively, and 10.7% lower LV mass. These associations were robust to further adjustment for comorbidities but not systolic blood pressure. APOL1 risk status was not associated with all-cause or cardiovascular mortality (mean follow-up 2.5 years).

Conclusion

Among African American patients with incident hemodialysis, APOL1 high-risk status was associated with better subclinical measures of CVD but not mortality.

Associations of Serum Calciprotein Particle Size and Transformation Time With Arterial Calcification, Arterial Stiffness, and Mortality in Incident Hemodialysis Patients

RATIONALE & OBJECTIVE

Characteristics of the transformation of primary to secondary calciprotein particles (CPPs) in serum, including the size of secondary CPP (CPP2) aggregates and the time of transformation (T₅₀), may be markers for arterial calcification in patients undergoing hemodialysis (HD). We examined the associations of CPP2 aggregate size and T₅₀ with arterial calcification in incident HD patients.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Incident HD patients (n=402with available CPP2 measures and n=388with available T₅₀ measures) from the Predictors of Arrhythmic and Cardiovascular Risk in End-Stage Renal Disease (PACE) Study PREDICTORS: Serum CPP2 size and T₅₀ at baseline.

OUTCOMES

Primary outcomes were baseline coronary artery and thoracic aorta calcifications. Exploratory outcomes included baseline arterial stiffness, measured by pulse wave velocity (PWV) and ankle brachial index, and longitudinally, repeat measures of PWV and all-cause mortality.

ANALYTICAL APPROACH

Tobit regression, multiple linear regression, Poisson regression, linear mixed-effects regression, and Cox proportional hazards regression.

RESULTS

Mean age was 55±13 years, 41% were women, 71% were Black, and 57% had diabetes mellitus. Baseline CPP2 size and T₅₀ were correlated with baseline fetuin A level (r=-0.59 for CPP2 and 0.44 for T₅₀; P<0.001 for both), but neither was associated with baseline measures of arterial calcification or arterial stiffness. Baseline CPP2 size and T₅₀ were not associated with repeat measures of PWV. During a median follow-up of 3.5 (IQR, 1.7-6.2) years, larger CPP2 was associated with higher risk for mortality (HR, 1.17 [95% CI, 1.05-1.31] per 100nm larger CPP2 size) after adjusting for demographics and comorbid conditions, but there was no association between baseline T₅₀ and risk for mortality.

LIMITATIONS

Possible imprecision in assays, small sample size, limited generalizability to incident HD populations with different racial composition, and residual confounding.

CONCLUSIONS

In incident HD patients, neither CPP2 size nor T₅₀ was associated with prevalent arterial calcification and stiffness. Larger CPP2 was associated with risk for mortality, but this finding needs to be confirmed in future studies.

Calcification Biomarkers, Subclinical Vascular Disease, and Mortality Among Multiethnic Dialysis Patients

Introduction

Vascular calcification and stiffness are associated with higher mortality and cardiovascular disease in hemodialysis patients, but the underlying mechanism is not well elucidated and previous studies have been contradictory. We sought to determine the association of circulating calcification biomarkers with calcification, stiffness, and mortality in a multiethnic incident dialysis population.

Methods

Among 391 incident hemodialysis participants enrolled in the Predictors of Arrhythmic and Cardiovascular Risk in End Stage Renal Disease (PACE) study, we examined the cross-sectional associations of baseline fibroblast growth factor 23 (FGF23), desphospho-uncarboxylated matrix Gla protein (dp-ucMGP), fetuin-A, and osteoprotegerin (OPG) according to total coronary artery calcium score (CAC, using the Agatston calcification criteria) at baseline, vascular stiffness (pulse wave velocity [PWV]) over 4 study visits, and all-cause mortality.

Results

Patients' mean age was 55 years; 40% were female, 72% were African American, and 58% had diabetes. Higher OPG and FGF23 were associated with a 1.09-fold (per 5-pmol/l increase in OPG; 95% confidence interval [CI]: 1.01-1.17) and 1.12-fold (per increase of 100 log RU/ml in FGF23; 95% CI: 1.02‒1.34) higher prevalence of CAC, independent of demographics, comorbidities, dialysis factors, and serum klotho levels. Higher OPG was associated with higher baseline PWV. Higher FGF23 was associated with lower PWV over follow-up. dp-ucMGP and fetuin-A were not associated with either CAC or vascular stiffness. After adjustment, circulating biomarkers were not associated with mortality risk.

Conclusion

Several circulating calcification biomarkers were only modestly associated with subclinical cardiovascular disease in an incident multiethnic hemodialysis population; none were associated with mortality. Understanding whether these associations persist in larger, diverse hemodialysis populations is warranted before planning trials.

Incidence and Risk Factors of Obesity in Childhood Solid-Organ Transplant Recipients

BACKGROUND

Obesity is a significant public health concern; however, the incidence post solid-organ transplantation is not well reported.

METHODS

This study determined the incidence and risk factors of obesity among pediatric solid-organ transplant recipients (heart, lung, liver, kidney, multiorgan) at The Hospital for Sick Children (2002-2011), excluding prevalent obesity. Follow-up occurred from transplantation until development of obesity, last follow-up, or end of study. Incidence of obesity was determined overall, by baseline body mass index, and organ group. Risk factors were assessed using Cox proportional-hazards regression.

RESULTS

Among 410 (55% male) children, median transplant age was 8.9 (interquartile range [IQR]: 1.0-14.5) years. Median follow-up time was 3.6 (IQR: 1.5-6.4) years. Incidence of obesity was 65.2 (95% confidence interval [CI]: 52.7-80.4) per 1000 person-years. Overweight recipients had a higher incidence, 190.4 (95% CI: 114.8-315.8) per 1000 person-years, than nonoverweight recipients, 56.1 (95% CI: 44.3-71.1). Cumulative incidence of obesity 5-years posttransplant was 24.1%. Kidney relative to heart recipients had the highest risk (3.13 adjusted hazard ratio [aHR]; 95% CI: 1.53-6.40) for obesity. Lung and liver recipients had similar rates to heart recipients. Those with higher baseline body mass index (z-score; 1.72 aHR; 95% CI: 1.39-2.14), overweight status (2.63 HR; 95% CI: 1.71-4.04), and younger transplant age (y; 1.18 aHR; 95% CI: 1.12-1.25) were at highest risk of obesity. Higher cumulative steroid dosage (per 10 mg/kg) was associated with increased risk of obesity after adjustment.

CONCLUSIONS

Among all transplanted children at The Hospital for Sick Children, 25% developed obesity within 5-years posttransplant. Kidney recipients, younger children, those overweight at transplant, and those with higher cumulative steroid use (per 10 mg/kg) were at greatest risk. Early screening and intervention for obesity are important preventative strategies.