Technology engagement is associated with higher perceived physical well-being in stroke patients prescribed smartwatches for atrial fibrillation detection

Background

Increasing ownership of smartphones among Americans provides an opportunity to use these technologies to manage medical conditions. We examine the influence of baseline smartwatch ownership on changes in self-reported anxiety, patient engagement, and health-related quality of life when prescribed smartwatch for AF detection.

Method

We performed a post-hoc secondary analysis of the Pulsewatch study (NCT03761394), a clinical trial in which 120 participants were randomized to receive a smartwatch-smartphone app dyad and ECG patch monitor compared to an ECG patch monitor alone to establish the accuracy of the smartwatch-smartphone app dyad for detection of AF. At baseline, 14 days, and 44 days, participants completed the Generalized Anxiety Disorder-7 survey, the Health Survey SF-12, and the Consumer Health Activation Index. Mixed-effects linear regression models using repeated measures with anxiety, patient activation, physical and mental health status as outcomes were used to examine their association with smartwatch ownership at baseline.

Results

Ninety-six participants, primarily White with high income and tertiary education, were randomized to receive a study smartwatch-smartphone dyad. Twenty-four (25%) participants previously owned a smartwatch. Compared to those who did not previously own a smartwatch, smartwatch owners reported significant greater increase in their self-reported physical health (β = 5.07, P < 0.05), no differences in anxiety (β = 0.92, P = 0.33), mental health (β = -2.42, P = 0.16), or patient activation (β = 1.86, P = 0.54).

Conclusions

Participants who own a smartwatch at baseline reported a greater positive change in self-reported physical health, but not in anxiety, patient activation, or self-reported mental health over the study period.

Self-reported efficacy in patient-physician interaction in relation to anxiety, patient activation, and health-related quality of life among stroke survivors

BACKGROUND

Early detection of AF is critical for stroke prevention. Several commercially available smartwatches are FDA cleared for AF detection. However, little is known about how patient-physician relationships affect patients' anxiety, activation, and health-related quality of life when prescribed smartwatch for AF detection.

METHODS

Data were used from the Pulsewatch study (NCT03761394), which randomized adults (>50 years) with no contraindication to anticoagulation and a CHA2DS2-VASc risk score ≥2 to receive a smartwatch-smartphone app dyad for AF monitoring vs. conventional monitoring with an ECG patch (Cardea SoloTM) and monitored participants for up to 45 days. The Perceived Efficacy in Patient-Physician Interactions survey was used to assess patient confidence in physician interaction at baseline with scores ≥45 indicating high perceived efficacy in patient-provider interactions. Generalized Anxiety Disorder-7 Scale, Consumer Health Activation Index, and Short-Form Health Survey were utilized to examine anxiety, patient activation, and physical and mental health status, at baseline, 14, and 44 days, respectively. We used mixed-effects repeated measures linear regression models to assess changes in psychosocial outcomes among smartwatch users in relation to self-reported efficacy in physician interaction over the study period.

RESULTS

A total of 93 participants (average age 64.1 ± 8.9 years; 43.0% female; 88.2% non-Hispanic white) were included in this analysis. At baseline, fifty-six (60%) participants reported high perceived efficacy in patient-physician interaction. In the fully adjusted models, high perceived efficacy (vs. low) at baseline was associated with greater patient activation and perceived mental health (β 12.0, p-value <0.001; β 3.39, p-value <0.05, respectively). High perceived self-efficacy was not associated with anxiety or physical health status (β - 0.61, p-value 0.46; β 0.64, p-value 0.77) among study participants.

CONCLUSIONS

Higher self-efficacy in patient-physician interaction was associated with higher patient activation and mental health status among stroke survivors using smartwatches. Furthermore, we found no association between anxiety and smartwatch prescription for AF in participants with high self-efficacy in patient-physician interaction. Efforts to improve self-efficacy in patient-physician interaction may improve patient activation and self-rated health and subsequently may lead to better clinical outcomes.KEY MESSAGESHigher self-efficacy in patient-physician interaction was associated with higher patient activation and mental health status among stroke survivors using smartwatches.No association between anxiety and smartwatch prescription for AF in participants with high self-efficacy in patient-physician interaction.Efforts to improve self-efficacy in patient-physician interaction may improve patient activation and self-rated health and subsequently may lead to better clinical outcomes.

Accuracy, Usability, and Adherence of Smartwatches for Atrial Fibrillation Detection in Older Adults After Stroke: Randomized Controlled Trial

BACKGROUND

Atrial fibrillation (AF) is a common cause of stroke, and timely diagnosis is critical for secondary prevention. Little is known about smartwatches for AF detection among stroke survivors. We aimed to examine accuracy, usability, and adherence to a smartwatch-based AF monitoring system designed by older stroke survivors and their caregivers.

OBJECTIVE

This study aims to examine the feasibility of smartwatches for AF detection in older stroke survivors.

METHODS

Pulsewatch is a randomized controlled trial (RCT) in which stroke survivors received either a smartwatch-smartphone dyad for AF detection (Pulsewatch system) plus an electrocardiogram patch or the patch alone for 14 days to assess the accuracy and usability of the system (phase 1). Participants were subsequently rerandomized to potentially 30 additional days of system use to examine adherence to watch wear (phase 2). Participants were aged 50 years or older, had survived an ischemic stroke, and had no major contraindications to oral anticoagulants. The accuracy for AF detection was determined by comparing it to cardiologist-overread electrocardiogram patch, and the usability was assessed with the System Usability Scale (SUS). Adherence was operationalized as daily watch wear time over the 30-day monitoring period.

RESULTS

A total of 120 participants were enrolled (mean age 65 years; 50/120, 41% female; 106/120, 88% White). The Pulsewatch system demonstrated 92.9% (95% CI 85.3%-97.4%) accuracy for AF detection. Mean usability score was 65 out of 100, and on average, participants wore the watch for 21.2 (SD 8.3) of the 30 days.

CONCLUSIONS

Our findings demonstrate that a smartwatch system designed by and for stroke survivors is a viable option for long-term arrhythmia detection among older adults at risk for AF, though it may benefit from strategies to enhance adherence to watch wear.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03761394; https://clinicaltrials.gov/study/NCT03761394.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1016/j.cvdhj.2021.07.002.

Differential Viral Dynamics by Sex and Body Mass Index During Acute SARS-CoV-2 Infection: Results from a Longitudinal Cohort Study

BACKGROUND

There is evidence of an association of severe COVID-19 outcomes with increased body mass index (BMI) and male sex. However, few studies have examined the interaction between sex and BMI on SARS-CoV-2 viral dynamics.

METHODS

Participants conducted RT-PCR testing every 24-48 hours over a 15-day period. Sex and BMI were self-reported, and Ct values from E-gene were used to quantify viral load. Three distinct outcomes were examined using mixed effects generalized linear models, linear models, and logistic models, respectively: all Ct values (Model 1); nadir Ct value (model 2); and strongly detectable infection (at least one Ct value ≤28 during their infection) (Model 3). An interaction term between BMI and sex was included, and inverse logit transformations were applied to quantify the differences by BMI and sex using marginal predictions.

RESULTS

In total, 7,988 participants enrolled in this study, and 439 participants (Model 1) and 309 (Model 2 and 3) were eligible for these analyses. Among males, increasing BMI was associated with lower Ct values in a dose-response fashion. For participants with BMIs greater than 29, males had significantly lower Ct values and nadir Ct values than females. In total, 67.8% of males and 55.3% of females recorded a strongly detectable infection; increasing proportions of men had Ct values <28 with BMIs of 35 and 40.

CONCLUSIONS

We observed sex-based dimorphism in relation to BMI and COVID-19 viral load. Further investigation is needed to determine the cause, clinical impact, and transmission implications of this sex-differential effect of BMI on viral load.

Anxiety, patient activation, and quality of life among stroke survivors prescribed smartwatches for atrial fibrillation monitoring

Background

The detection of atrial fibrillation (AF) in stroke survivors is critical to decreasing the risk of recurrent stroke. Smartwatches have emerged as a convenient and accurate means of AF diagnosis; however, the impact on critical patient-reported outcomes, including anxiety, engagement, and quality of life, remains ill defined.

Objectives

To examine the association between smartwatch prescription for AF detection and the patient-reported outcomes of anxiety, patient activation, and self-reported health.

Methods

We used data from the Pulsewatch trial, a 2-phase randomized controlled trial that included participants aged 50 years or older with a history of ischemic stroke. Participants were randomized to use either a proprietary smartphone-smartwatch app for 30 days of AF monitoring or no cardiac rhythm monitoring. Validated surveys were deployed before and after the 30-day study period to assess anxiety, patient activation, and self-rated physical and mental health. Logistic regression and generalized estimation equations were used to examine the association between smartwatch prescription for AF monitoring and changes in the patient-reported outcomes.

Results

A total of 110 participants (mean age 64 years, 41% female, 91% non-Hispanic White) were studied. Seventy percent of intervention participants were novice smartwatch users, as opposed to 84% of controls, and there was no significant difference in baseline rates of anxiety, activation, or self-rated health between the 2 groups. The incidence of new AF among smartwatch users was 6%. Participants who were prescribed smartwatches did not have a statistically significant change in anxiety, activation, or self-reported health as compared to those who were not prescribed smartwatches. The results held even after removing participants who received an AF alert on the watch.

Conclusion

The prescription of smartwatches to stroke survivors for AF monitoring does not adversely affect key patient-reported outcomes. Further research is needed to better inform the successful deployment of smartwatches in clinical practice.

Performance of Rapid Antigen Tests to Detect Symptomatic and Asymptomatic SARS-CoV-2 Infection : A Prospective Cohort Study

BACKGROUND

The performance of rapid antigen tests (Ag-RDTs) for screening asymptomatic and symptomatic persons for SARS-CoV-2 is not well established.

OBJECTIVE

To evaluate the performance of Ag-RDTs for detection of SARS-CoV-2 among symptomatic and asymptomatic participants.

DESIGN

This prospective cohort study enrolled participants between October 2021 and January 2022. Participants completed Ag-RDTs and reverse transcriptase polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 every 48 hours for 15 days.

SETTING

Participants were enrolled digitally throughout the mainland United States. They self-collected anterior nasal swabs for Ag-RDTs and RT-PCR testing. Nasal swabs for RT-PCR were shipped to a central laboratory, whereas Ag-RDTs were done at home.

PARTICIPANTS

Of 7361 participants in the study, 5353 who were asymptomatic and negative for SARS-CoV-2 on study day 1 were eligible. In total, 154 participants had at least 1 positive RT-PCR result.

MEASUREMENTS

The sensitivity of Ag-RDTs was measured on the basis of testing once (same-day), twice (after 48 hours), and thrice (after a total of 96 hours). The analysis was repeated for different days past index PCR positivity (DPIPPs) to approximate real-world scenarios where testing initiation may not always coincide with DPIPP 0. Results were stratified by symptom status.

RESULTS

Among 154 participants who tested positive for SARS-CoV-2, 97 were asymptomatic and 57 had symptoms at infection onset. Serial testing with Ag-RDTs twice 48 hours apart resulted in an aggregated sensitivity of 93.4% (95% CI, 90.4% to 95.9%) among symptomatic participants on DPIPPs 0 to 6. When singleton positive results were excluded, the aggregated sensitivity on DPIPPs 0 to 6 for 2-time serial testing among asymptomatic participants was lower at 62.7% (CI, 57.0% to 70.5%), but it improved to 79.0% (CI, 70.1% to 87.4%) with testing 3 times at 48-hour intervals.

LIMITATION

Participants tested every 48 hours; therefore, these data cannot support conclusions about serial testing intervals shorter than 48 hours.

CONCLUSION

The performance of Ag-RDTs was optimized when asymptomatic participants tested 3 times at 48-hour intervals and when symptomatic participants tested 2 times separated by 48 hours.

PRIMARY FUNDING SOURCE

National Institutes of Health RADx Tech program.

Bilateral Ovarian Serous Borderline Tumor with Non-Invasive Endometrial Implants

Herein, we are presenting a case of a 33-year-old woman who presented to the emergency department complaining of persistent lower abdominal pain of one-day duration. Physical examination revealed abdominal tenderness with right lower quadrant rebound tenderness. Computed tomography abdomen/pelvis showed a 6 cm possible necrotic mass of the left ovary with moderate amount of complex ascites. A laparoscopic left oophorectomy with bilateral salpingectomy, right ovarian biopsy, and appendectomy were performed without complications. The cut surface of the left ovary showed a 9.7 cm × 8 cm × 4 cm ovarian mass, and the cut surface revealed multiple gray-tan friable papillary excrescence. Microscopic evaluation showed findings consistent with left and right ovarian serous borderline tumor (SBT). Subsequently, a tumor staging was conducted with total laparoscopic hysterectomy, pelvic and periaortic lymph node dissection, and omentectomy. The endometrium sections showed several small foci of SBT within the endometrial stroma, consistent with non-invasive implants of the endometrium. The omentum and lymph nodes were all negative for malignancy. SBTs associated with endometrial implants are very rare with only one case reported in the literature. Their existence can cause diagnostic challenges, and they should be acknowledged for early diagnosis and to plan for patient's treatment and outcome.

Design and implementation of a digital site-less clinical study of serial rapid antigen testing to identify asymptomatic SARS-CoV-2 infection

Background

Rapid antigen detection tests (Ag-RDT) for SARS-CoV-2 with emergency use authorization generally include a condition of authorization to evaluate the test's performance in asymptomatic individuals when used serially. We aim to describe a novel study design that was used to generate regulatory-quality data to evaluate the serial use of Ag-RDT in detecting SARS-CoV-2 virus among asymptomatic individuals.

Methods

This prospective cohort study used a siteless, digital approach to assess longitudinal performance of Ag-RDT. Individuals over 2 years old from across the USA with no reported COVID-19 symptoms in the 14 days prior to study enrollment were eligible to enroll in this study. Participants throughout the mainland USA were enrolled through a digital platform between October 18, 2021 and February 15, 2022. Participants were asked to test using Ag-RDT and molecular comparators every 48 hours for 15 days. Enrollment demographics, geographic distribution, and SARS-CoV-2 infection rates are reported.

Key Results

A total of 7361 participants enrolled in the study, and 492 participants tested positive for SARS-CoV-2, including 154 who were asymptomatic and tested negative to start the study. This exceeded the initial enrollment goals of 60 positive participants. We enrolled participants from 44 US states, and geographic distribution of participants shifted in accordance with the changing COVID-19 prevalence nationwide.

Conclusions

The digital site-less approach employed in the "Test Us At Home" study enabled rapid, efficient, and rigorous evaluation of rapid diagnostics for COVID-19 and can be adapted across research disciplines to optimize study enrollment and accessibility.

False Atrial Fibrillation Alerts from Smartwatches are Associated with Decreased Perceived Physical Well-being and Confidence in Chronic Symptoms Management

Wrist-based wearables have been FDA approved for AF detection. However, the health behavior impact of false AF alerts from wearables on older patients at high risk for AF are not known. In this work, we analyzed data from the Pulsewatch (NCT03761394) study, which randomized patients (≥50 years) with history of stroke or transient ischemic attack to wear a patch monitor and a smartwatch linked to a smartphone running the Pulsewatch application vs to only the cardiac patch monitor over 14 days. At baseline and 14 days, participants completed validated instruments to assess for anxiety, patient activation, perceived mental and physical health, chronic symptom management self-efficacy, and medicine adherence. We employed linear regression to examine associations between false AF alerts with change in patient-reported outcomes. Receipt of false AF alerts was related to a dose-dependent decline in self-perceived physical health and levels of disease self-management. We developed a novel convolutional denoising autoencoder (CDA) to remove motion and noise artifacts in photoplethysmography (PPG) segments to optimize AF detection, which substantially reduced the number of false alerts. A promising approach to avoid negative impact of false alerts is to employ artificial intelligence driven algorithms to improve accuracy.

Performance of Rapid Antigen Tests Based on Symptom Onset and Close Contact Exposure: A secondary analysis from the Test Us At Home prospective cohort study

Background

The performance of rapid antigen tests for SARS-CoV-2 (Ag-RDT) in temporal relation to symptom onset or exposure is unknown, as is the impact of vaccination on this relationship.

Objective

To evaluate the performance of Ag-RDT compared with RT-PCR based on day after symptom onset or exposure in order to decide on 'when to test'.

Design Setting and Participants

The Test Us at Home study was a longitudinal cohort study that enrolled participants over 2 years old across the United States between October 18, 2021 and February 4, 2022. All participants were asked to conduct Ag-RDT and RT-PCR testing every 48 hours over a 15-day period. Participants with one or more symptoms during the study period were included in the Day Post Symptom Onset (DPSO) analyses, while those who reported a COVID-19 exposure were included in the Day Post Exposure (DPE) analysis.

Exposure

Participants were asked to self-report any symptoms or known exposures to SARS-CoV-2 every 48-hours, immediately prior to conducting Ag-RDT and RT-PCR testing. The first day a participant reported one or more symptoms was termed DPSO 0, and the day of exposure was DPE 0. Vaccination status was self-reported.

Main Outcome and Measures

Results of Ag-RDT were self-reported (positive, negative, or invalid) and RT-PCR results were analyzed by a central laboratory. Percent positivity of SARS-CoV-2 and sensitivity of Ag-RDT and RT-PCR by DPSO and DPE were stratified by vaccination status and calculated with 95% confidence intervals.

Results

A total of 7,361 participants enrolled in the study. Among them, 2,086 (28.3%) and 546 (7.4%) participants were eligible for the DPSO and DPE analyses, respectively. Unvaccinated participants were nearly twice as likely to test positive for SARS-CoV-2 than vaccinated participants in event of symptoms (PCR+: 27.6% vs 10.1%) or exposure (PCR+: 43.8% vs. 22.2%). The highest proportion of vaccinated and unvaccinated individuals tested positive on DPSO 2 and DPE 5-8. Performance of RT-PCR and Ag-RDT did not differ by vaccination status. Ag-RDT detected 78.0% (95% Confidence Interval: 72.56-82.61) of PCR-confirmed infections by DPSO 4. For exposed participants, Ag-RDT detected 84.9% (95% CI: 75.0-91.4) of PCR-confirmed infections by day five post-exposure (DPE 5).

Conclusions and Relevance

Performance of Ag-RDT and RT-PCR was highest on DPSO 0-2 and DPE 5 and did not differ by vaccination status. These data suggests that serial testing remains integral to enhancing the performance of Ag-RDT.

Performance of Rapid Antigen Tests to Detect Symptomatic and Asymptomatic SARS-CoV-2 Infection

Background

Performance of rapid antigen tests for SARS-CoV-2 (Ag-RDT) varies over the course of an infection, and their performance in screening for SARS-CoV-2 is not well established. We aimed to evaluate performance of Ag-RDT for detection of SARS-CoV-2 for symptomatic and asymptomatic participants.

Methods

Participants >2 years old across the United States enrolled in the study between October 2021 and February 2022. Participants completed Ag-RDT and molecular testing (RT-PCR) for SARS-CoV-2 every 48 hours for 15 days. This analysis was limited to participants who were asymptomatic and tested negative on their first day of study participation. Onset of infection was defined as the day of first positive RT-PCR result. Sensitivity of Ag-RDT was measured based on testing once, twice (after 48-hours), and thrice (after 96 hours). Analysis was repeated for different Days Post Index PCR Positivity (DPIPP) and stratified based on symptom-status.

Results

In total, 5,609 of 7,361 participants were eligible for this analysis. Among 154 participants who tested positive for SARS-CoV-2, 97 were asymptomatic and 57 had symptoms at infection onset. Serial testing with Ag-RDT twice 48-hours apart resulted in an aggregated sensitivity of 93.4% (95% CI: 89.1-96.1%) among symptomatic participants on DPIPP 0-6. Excluding singleton positives, aggregated sensitivity on DPIPP 0-6 for two-time serial-testing among asymptomatic participants was lower at 62.7% (54.7-70.0%) but improved to 79.0% (71.0-85.3%) with testing three times at 48-hour intervals.

Discussion

Performance of Ag-RDT was optimized when asymptomatic participants tested three-times at 48-hour intervals and when symptomatic participants tested two-times separated by 48-hours.

Finding a Needle in a Haystack: Design and Implementation of a Digital Site-less Clinical Study of Serial Rapid Antigen Testing to Identify Asymptomatic SARS-CoV-2 Infection

Background

Rapid antigen tests (Ag-RDT) for SARS-CoV-2 with Emergency Use Authorization generally include a condition of authorization to evaluate the test's performance in asymptomatic individuals when used serially.

Objective

To describe a novel study design to generate regulatory-quality data to evaluate serial use of Ag-RDT in detecting SARS-CoV-2 virus among asymptomatic individuals.

Design

Prospective cohort study using a decentralized approach. Participants were asked to test using Ag-RDT and molecular comparators every 48 hours for 15 days.

Setting

Participants throughout the mainland United States were enrolled through a digital platform between October 18, 2021 and February 15, 2022. Ag-RDTs were completed at home, and molecular comparators were shipped to a central laboratory.

Participants

Individuals over 2 years old from across the U.S. with no reported COVID-19 symptoms in the 14 days prior to study enrollment were eligible to enroll in this study.

Measurements

Enrollment demographics, geographic distribution, and SARS-CoV-2 infection rates are reported.

Key Results

A total of 7,361 participants enrolled in the study, and 492 participants tested positive for SARS-CoV-2, including 154 who were asymptomatic and tested negative to start the study. This exceeded the initial enrollment goals of 60 positive participants. We enrolled participants from 44 U.S. states, and geographic distribution of participants shifted in accordance with the changing COVID-19 prevalence nationwide.

Limitations

New, complex workflows required significant operational and data team support. Conclusions: The digital site-less approach employed in the 'Test Us At Home' study enabled rapid, efficient, and rigorous evaluation of rapid diagnostics for COVID-19, and can be adapted across research disciplines to optimize study enrollment and accessibility.

Emphysematous pancreatitis with pulmonary embolism: A case report

Background

Emphysematous pancreatitis is a severe systemic inflammatory process with reports of pulmonary embolism in the setting of acute pancreatitis rarely described.

Case presentation

A 61-year-old woman presented with severe abdominal pain of 1 day duration. She was found to have acute interstitial pancreatitis. During her hospitalization, the patient developed worsening abdominal pain associated with increasing oxygen demands, requiring supplemental oxygen through nasal cannula. Workup showed pulmonary embolism in the posterior segmental branch of the left lower lobar artery and development of emphysematous pancreatitis was noted on imaging. The patient was started on intravenous antibiotics and therapeutic anticoagulation; her condition improved and was discharged home.

Conclusion

Patients with severe acute pancreatitis may be at risk for pulmonary embolism due to immobilization and other inflammatory mechanisms. Mitigating individualized risk factors and anticoagulation use as prophylaxis should be considered in patients with pancreatitis to prevent embolism. Early detection by clinicians is critical to reduce misdiagnosis and mortality rates.

Pharmacotherapy of type 2 diabetes: An update and future directions

Type 2 diabetes (T2D) is a widely prevalent disease with substantial economic and social impact for which multiple conventional and novel pharmacotherapies are currently available; however, the landscape of T2D treatment is constantly changing as new therapies emerge and the understanding of currently available agents deepens. This review aims to provide an updated summary of the pharmacotherapeutic approach to T2D. Each class of agents is presented by mechanism of action, details of administration, side effect profile, cost, and use in certain populations including heart failure, non-alcoholic fatty liver disease, obesity, chronic kidney disease, and older individuals. We also review targets of novel therapeutic T2D agent development. Finally, we outline an up-to-date treatment approach that starts with identification of an individualized goal for glycemic control then selection, initiation, and further intensification of a personalized therapeutic plan for T2D.

Comparison of Rapid Antigen Tests' Performance Between Delta and Omicron Variants of SARS-CoV-2 : A Secondary Analysis From a Serial Home Self-testing Study

BACKGROUND

It is important to document the performance of rapid antigen tests (Ag-RDTs) in detecting SARS-CoV-2 variants.

OBJECTIVE

To compare the performance of Ag-RDTs in detecting the Delta (B.1.617.2) and Omicron (B.1.1.529) variants of SARS-CoV-2.

DESIGN

Secondary analysis of a prospective cohort study that enrolled participants between 18 October 2021 and 24 January 2022. Participants did Ag-RDTs and collected samples for reverse transcriptase polymerase chain reaction (RT-PCR) testing every 48 hours for 15 days.

SETTING

The parent study enrolled participants throughout the mainland United States through a digital platform. All participants self-collected anterior nasal swabs for rapid antigen testing and RT-PCR testing. All Ag-RDTs were completed at home, whereas nasal swabs for RT-PCR were shipped to a central laboratory.

PARTICIPANTS

Of 7349 participants enrolled in the parent study, 5779 asymptomatic persons who tested negative for SARS-CoV-2 on day 1 of the study were eligible for this substudy.

MEASUREMENTS

Sensitivity of Ag-RDTs on the same day as the first positive (index) RT-PCR result and 48 hours after the first positive RT-PCR result.

RESULTS

A total of 207 participants were positive on RT-PCR (58 Delta, 149 Omicron). Differences in sensitivity between variants were not statistically significant (same day: Delta, 15.5% [95% CI, 6.2% to 24.8%] vs. Omicron, 22.1% [CI, 15.5% to 28.8%]; at 48 hours: Delta, 44.8% [CI, 32.0% to 57.6%] vs. Omicron, 49.7% [CI, 41.6% to 57.6%]). Among 109 participants who had RT-PCR-positive results for 48 hours, rapid antigen sensitivity did not differ significantly between Delta- and Omicron-infected participants (48-hour sensitivity: Delta, 81.5% [CI, 66.8% to 96.1%] vs. Omicron, 78.0% [CI, 69.1% to 87.0%]). Only 7.2% of the 69 participants with RT-PCR-positive results for shorter than 48 hours tested positive by Ag-RDT within 1 week; those with Delta infections remained consistently negative on Ag-RDTs.

LIMITATION

A testing frequency of 48 hours does not allow a finer temporal resolution of the analysis of test performance, and the results of Ag-RDTs are based on self-report.

CONCLUSION

The performance of Ag-RDTs in persons infected with the SARS-CoV-2 Omicron variant is not inferior to that in persons with Delta infections. Serial testing improved the sensitivity of Ag-RDTs for both variants. The performance of rapid antigen testing varies on the basis of duration of RT-PCR positivity.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute of the National Institutes of Health.

Patient activation and health-related quality-of-life in association with smartwatch alerts for atrial fibrillation detection

Background

Smartwatches with various alert systems are becoming increasingly popular in the detection of atrial fibrillation (AF) post stroke, however their impact on psychological well-being remains unknown.

Purpose

Assess the association between smartwatch alerts for detected atrial fibrillation in older stroke survivors and patient activation as well as health-related quality-of-life.

Methods

Data were used from the Pulsewatch study, a multiphase, randomized controlled trial, which enrolled older adults (≥50 years of age) from the UMass Memorial Health System with history of a stroke and no contraindications to anticoagulation, who were given a smartwatch for AF detection. In Phase I, participants were randomized 3:1 (intervention:control) to receive a smartwatch/smartphone pair and an FDA-approved cardiac patch monitor or only the patch (control) to monitor for AF for 14 days. In Phase II, participants were re-randomized 1:1, with the intervention group being offered the smartwatch/smartphone pair for an extra 30 days. Participants were grouped into those receiving at least one alert of a possible abnormal rhythm versus those who did not receive any alerts from their smartwatch. At baseline, 14 days, and 44 days the Consumer Health Activation Index was used to assess patient activation and the Physical and Mental Component Summary of Short-Form Health Survey were utilized to evaluate physical and mental health-related quality-of-life, respectively. Mixed-effects repeated measures linear regression models were used to examine changes in patient activation and physical and mental health-related quality-of-life, in relation to alerts, adjusting for confounding variables including age, sex, race, history of arrhythmias, history of congestive heart failure, history of coronary artery disease, baseline depression, and baseline cognitive impairment, over the study period.

Results

94 participants (64.6±9.1 years of age, 87.2% non-Hispanic white, and 43.6% female) were included in the analysis; 16 of whom received at least one alert. Specifically, twelve participants received 1 to 3 alerts, three participants received 11 to 18, and one participant received 226. In fully adjusted models, receiving alerts was not associated with changes in patient activation or mental health-related quality-of-life (β −1.70, p-value 0.60 and β 2.85, p-value 0.09 respectively), but was associated with a significant reduction in physical health-related quality-of-life (β −4.67, p-value 0.04).

Conclusions

In a cohort of older stroke survivors who wore smartwatches for up to 44 days, reception of alerts was not significantly associated with changes in patient activation or mental health-related quality-of-life but was significantly related to a decline in physical health-related quality-of-life. Further studies are necessary to explore the use of smartwatches in AF screening and their impact on psychological health and quality-of-life.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): R01HL137734 from the National Heart, Lung, and Blood Institute

Abstract P300: Patterns Of Adherence To Home Blood Pressure Monitoring Among Men And Women In The Electronic Framingham Heart Study

Blood pressure (BP) measures in women more sharply increase with age compared with men, with a widening disparity in older women. The use of home blood pressure monitoring (HBPM) among women may improve this inequity. However, sex-related differences in adherence to HBPM are not well understood.

We analyzed data from electronic Framingham Heart Study participants who were given a Withings digital BP cuff and instructed to perform HBPM weekly for 1 year. Adherence was defined as ≥1 BP measurement per week, averaged over 4-week segments. HTN status was self-reported. Group-based trajectory modeling (GBTM) was used to identify trajectory patterns of adherence. We investigated the association of 3 adherence patterns with HTN status stratified by sex using multinomial logistic models adjusting for age group, marital status, education, employment status, income, non-BP cardiac medication use, subjective health, depression and anxiety.

Among 1,048 participants (59% female, mean age 53±9 years, 25% with HTN), we identified 3 trajectory groups corresponding to distinct patterns of HBPM adherence: early discontinuation (N = 458, 58% female, 21% HTN), gradual decrease (N = 360, 60% female, 27% HTN), and high adherence (N = 230, 57% female, 31% HTN, Figure 1 ). Women with HTN compared to women without HTN had 80% higher odds of being in the high adherence group versus early discontinuation group (aOR 1.80; 95% CI 1.02-3.17). This pattern was not observed for men (aOR 1.12; 95% CI 0.68-1.63).

In this middle-aged eCohort, HTN was associated with high adherence to HBPM in women but not men. The targeted prescription of HBPM for woman should be studied to see if it can reduce sex disparities in BP control.

Age and Sex Differences and Temporal Trends in the Use of Invasive and Noninvasive Procedures in Patients Hospitalized With Acute Myocardial Infarction

Background

Few studies have examined age and sex differences in the receipt of cardiac diagnostic and interventional procedures in patients hospitalized with acute myocardial infarction and trends in these possible differences during recent years.

Methods and Results

Data from patients hospitalized with a first acute myocardial infarction at the major medical centers in the Worcester, Massachusetts, metropolitan area were utilized for this study. Logistic regression analysis was used to examine age (<55, 55–64, 65–74, and ≥75 years) and sex differences in the receipt of echocardiography, exercise stress testing, coronary angiography, percutaneous coronary interventions, and coronary artery bypass graft surgery, and trends in the use of those procedures during patients' acute hospitalization, between 2005 and 2018, while adjusting for important confounding factors. The study population consisted of 1681 men and 1154 women with an initial acute myocardial infarction who were hospitalized on an approximate biennial basis between 2005 and 2018. A smaller proportion of women underwent cardiac catheterization, percutaneous coronary intervention, and coronary artery bypass graft surgery, while there were no sex differences in the receipt of echocardiography and exercise stress testing. Patients aged ≥75 years were less likely to undergo cardiac catheterization, percutaneous coronary intervention, and coronary artery bypass graft surgery, but were more likely to receive echocardiography compared with younger patients. Between 2005 and 2018, the use of echocardiography and coronary artery bypass graft surgery nonsignificantly increased among all age groups and both sexes, while the use of cardiac catheterization and percutaneous coronary intervention increased nonsignificantly faster in women and older patients.

Conclusions

We observed a continued lower receipt of invasive cardiac procedures in women and patients aged ≥75 years with acute myocardial infarction, but age and sex gaps associated with these procedures have narrowed during recent years.

Short- and Long-Term Risk of Lead Dislodgement Events: Real-World Experience From Product Surveillance Registry

BACKGROUND

Lead dislodgement (LD) has been one of the most common early complications after cardiovascular implantable electronic device implant. However, limited data are available on the clinical characteristics and long-term outcomes of LD events. The aim of this study was to examine the risk factors, clinical significance, and management strategies of LD events after cardiovascular implantable electronic device implant.

METHODS

This study was a retrospective cohort analysis of 20 683 patients who underwent cardiovascular implantable electronic device implant between January 1, 2010 and January 31, 2020 in Medtronic's Product Surveillance Registry, with a mean follow-up time of 3.3±2.5 SD years. The study population was divided into 2 groups: group A with LD events (N=350) and group B without LD events (N=20 333).

RESULTS

During this period, 350 patients (1.69%) had LD events involving 371 leads (0.95%), among a total of 39 060 leads implanted. Passive fixation type (right atrium pacing lead, P=0.041), lower sensing amplitude (right ventricle defibrillating lead, P=0.020), and lower lead impedance at implant (right atrium pacing lead, P=0.009) were associated with increased LD risk. Multivariate analysis showed female sex (hazard ratio, 1.520, P=0.008) and higher body mass index (hazard ratio, 1.012, P=0.001) were independently associated with increased risk of LD events. LD events were not associated with significant changes in the long-term risks of cardiac and overall mortality. In group A, repositioning the dislodged leads increased the risk of a second LD event compared with implanting new leads (P=0.012).

CONCLUSIONS

Female sex and higher body mass index were associated with higher risk of LD events in the Product Surveillance Registry. Among patients with dislodged leads, implanting new leads was associated with lower risk of future LD events. Further studies on how to reduce LD risk and to improve management of these events are needed.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01524276.

Usability of a smartwatch for atrial fibrillation detection in older adults after stroke

Background

Smartwatches can be used for atrial fibrillation (AF) detection, but little is known about how older adults at risk for AF perceive their usability.

Methods

We employed a mixed-methods study design using data from the ongoing Pulsewatch study, a randomized clinical trial (NCT03761394) examining the accuracy of a smartwatch-smartphone app dyad (Samsung/Android) compared to usual care with a patch monitor (Cardea SOLO™ ECG System) for detection of AF among older stroke survivors. To be eligible to participate in Pulsewatch, participants needed to be at least 50 years of age, have had an ischemic stroke, and have no major contraindications to anticoagulation therapy should AF be detected. After 14 days of use, usability was measured by the System Usability Scale (SUS) and investigator-generated questions. Qualitative interviews were conducted, transcribed, and coded via thematic analysis.

Results

Ninety participants in the Pulsewatch trial were randomized to use a smartwatch-smartphone app dyad for 14 days (average age: 65 years, 41% female, 87% White), and 46% found it to be highly usable (SUS ≥68). In quantitative surveys, participants who used an assistive device (eg, wheelchair) and those with history of anxiety or depression were more likely to report anxiety associated with watch use. In qualitative interviews, study participants reported wanting a streamlined system that was more focused on rhythm monitoring and a smartwatch with a longer battery life. In-person training and support greatly improved their experience, and participants overwhelmingly preferred use of a smartwatch over traditional cardiac monitoring owing to its comfort, appearance, and convenience.

Conclusion

Older adults at high risk for AF who were randomized to use a smartwatch-app dyad for AF monitoring over 14 days found it to be usable for AF detection and preferred their use to the use of a patch monitor. However, participants reported that a simpler device interface and longer smartwatch battery life would increase the system's usability.

Comparison of Rapid Antigen Tests' Performance between Delta (B.1.61.7; AY.X) and Omicron (B.1.1.529; BA1) Variants of SARS-CoV-2: Secondary Analysis from a Serial Home Self-Testing Study

Background

There is a need to understand the performance of rapid antigen tests (Ag-RDT) for detection of the Delta (B.1.61.7; AY.X) and Omicron (B.1.1.529; BA1) SARS-CoV-2 variants.

Methods

Participants without any symptoms were enrolled from October 18, 2021 to January 24, 2022 and performed Ag-RDT and RT-PCR tests every 48 hours for 15 days. This study represents a non-pre-specified analysis in which we sought to determine if sensitivity of Ag-RDT differed in participants with Delta compared to Omicron variant. Participants who were positive on RT-PCR on the first day of the testing period were excluded. Delta and Omicron variants were defined based on sequencing and date of first RT-PCR positive result (RT-PCR+). Comparison of Ag-RDT performance between the variants was based on sensitivity, defined as proportion of participants with Ag-RDT+ results in relation to their first RT-PCR+ result, for different duration of testing with rapid Ag-RDT. Subsample analysis was performed based on the result of participants' second RT-PCR test within 48 hours of the first RT-PCR+ test.

Results

From the 7,349 participants enrolled in the parent study, 5,506 met the eligibility criteria for this analysis. A total of 153 participants were RT-PCR+ (61 Delta, 92 Omicron); among this group, 36 (23.5%) tested Ag-RDT+ on the same day, and 84 (54.9%) tested Ag-RDT+ within 48 hours as first RT-PCR+. The differences in sensitivity between variants were not statistically significant (same-day: Delta 16.4% [95% CI: 8.2-28.1] vs Omicron 28.2% [95% CI: 19.4-38.6]; and 48-hours: Delta 45.9% [33.1-59.2] vs. Omicron 60.9% [50.1-70.9]). This trend continued among the 86 participants who had consecutive RT-PCR+ result (48-hour sensitivity: Delta 79.3% [60.3-92.1] vs. Omicron: 89.5% [78.5-96.0]). Conversely, the 38 participants who had an isolated RT-PCR+ remained consistently negative on Ag-RDT, regardless of the variant.

Conclusions

The performance of Ag-RDT is not inferior among individuals infected with the SARS-CoV-2 Omicron variant as compared to the Delta variant. The improvement in sensitivity of Ag-RDT noted with serial testing is consistent between Delta and Omicron variant. Performance of Ag-RDT varies based on duration of RT-PCR+ results and more studies are needed to understand the clinical and public health significance of individuals who are RT-PCR+ for less than 48 hours.

Online Health Information Seeking, Low AF-Related Quality of Life, and High Perceived Efficacy in Patient-Physician Interactions in Older Adults with Atrial Fibrillation

Background

Little is known about online health information–seeking behavior among older adults with atrial fibrillation (AF) and its association with self-reported outcomes.

Objective

To examine patient characteristics associated with online health information seeking and the association between information seeking and low AF-related quality of life and high perceived efficacy in patient-physician interaction.

Methods

We used data from the SAGE-AF (Systematic Assessment of Geriatric Elements in AF) study, which includes older participants aged ≥65 years with AF and a CHA₂DS₂-VASc risk score ≥2. To assess online health information seeking, participants who reported using the Internet were asked at baseline if they used the Internet to search for advice or information about their health in the past 4 weeks (not at all vs at least once). Atrial Fibrillation Effect on Quality of Life and Perceived Efficacy in Patient-Physician Interactions questionnaires were used to examine AF-related quality of life (QOL) and patient-reported confidence in physicians. Logistic regression models were used to examine demographic and clinical factors associated with online health information seeking and associations between information seeking and low AF-related QOL (AFEQT <80) and high perceived efficacy for patient-physician interactions (PEPPI ≥45).

Results

A total of 874 online participants (mean age 74.5 years, 51% male, 91% non-Hispanic White) were studied. Approximately 60% of participants sought health information online. Participants aged 74 years or older and those on anticoagulation were less likely, while those with a college degree were more likely, to seek online health information after adjusting for potential confounders. Participants who sought health information online, compared to those who did not, were significantly more likely to have a low AF-related QOL, but less likely to self-report confidence in patient-physician interaction (aOR = 1.56, 95% CI: 1.15–2.13; aOR = 0.68, 95% CI: 0.49–0.93, respectively).

Conclusion

Clinicians should consider barriers to patient-physician interaction in older adults who seek health information online, encourage shared decision-making, and provide patients with a list of online resources for AF in addition to disease education plans to help patients manage their health.

Severe insulin resistance syndromes

Severe insulin resistance syndromes are a heterogeneous group of rare disorders characterized by profound insulin resistance, substantial metabolic abnormalities, and a variety of clinical manifestations and complications. The etiology of these syndromes may be hereditary or acquired, due to defects in insulin potency and action, cellular responsiveness to insulin, and/or aberrations in adipose tissue function or development. Over the past decades, advances in medical technology, particularly in genomic technologies and genetic analyses, have provided insights into the underlying pathophysiological pathways and facilitated the more precise identification of several of these conditions. However, the exact cellular and molecular mechanisms of insulin resistance have not yet been fully elucidated for all syndromes. Moreover, in clinical practice, many of the syndromes are often misdiagnosed or underdiagnosed. The majority of these disorders associate with an increased risk of severe complications and mortality; thus, early identification and personalized clinical management are of the essence. This Review aims to categorize severe insulin resistance syndromes by disease process, including insulin receptor defects, signaling defects, and lipodystrophies. We also highlight several complex syndromes and emphasize the need to identify patients, investigate underlying disease mechanisms, and develop specific treatment regimens.

Short-term administration of the GLP-1 analog liraglutide decreases circulating leptin and increases GIP levels and these changes are associated with alterations in CNS responses to food cues: A randomized, placebo-controlled, crossover study

BACKGROUND

GLP-1 agonists, including liraglutide, have emerged as effective therapies for type 2 diabetes (DM) and obesity. Here, we attempted to delineate how liraglutide, at doses approved for DM, may impact circulating hormones influencing energy homeostasis in diabetics.

BASIC PROCEDURES

Using a randomized, placebo-controlled, double-blind, cross-over trial of 20 patients with type 2 diabetes, we examined the effects of liraglutide as compared to placebo on fasting levels of circulating hormones important to energy homeostasis, including leptin, ghrelin, PYY, and GIP. After 17days (0.6mg for 7days, 1.2mg for 7days and 1.8mg for 3days) of treatment, we also studied changes in fMRI responses to food cues.

MAIN FINDINGS

By design, to avoid any confounding by weight changes, subjects were studied for 17days, i.e. before body weight changed. Participants on liraglutide had significantly increased GLP-1 levels (p<0.001), decreased percent change in leptin levels (p<0.01) and increased GIP levels (p<0.03) in comparison to placebo treated subjects. Whole brain regressions of functional activity in response to food cues reveal that increased GIP levels were associated with deactivation of the attention- and reward-related insula. Decreases in leptin levels were associated with activations in the reward-related midbrain, precuneus, and dorsolateral prefrontal cortex (DLPFC), and sensorimotor-related motor cortex and with deactivations in the attention-related parietal cortex and the cognitive control-related thalamus and pre-SMA.

PRINCIPAL CONCLUSIONS

We demonstrate herein short-term changes to circulating levels of GIP and leptin in response to GLP-1 agonist liraglutide therapy. These findings suggest that liraglutide may alter the circulating levels of hormones important in energy homeostasis that, in turn, influence CNS perception of food cues. This could possibly lead to compensatory changes in energy homeostasis that could over time limit the efficacy of liraglutide to decrease body weight. These novel findings, which, pointing to the potential advantages of combination therapies, may have therapeutic implications, will need to be confirmed by larger and longer-term trials.

GLP-1 receptors exist in the parietal cortex, hypothalamus and medulla of human brains and the GLP-1 analogue liraglutide alters brain activity related to highly desirable food cues in individuals with diabetes: a crossover, randomised, placebo-controlled trial

AIMS/HYPOTHESIS

Liraglutide is a glucagon-like peptide-1 (GLP-1) analogue that has been demonstrated to successfully treat diabetes and promote weight loss. The mechanisms by which liraglutide confers weight loss remain to be fully clarified. Thus, we investigated whether GLP-1 receptors are expressed in human brains and whether liraglutide administration affects neural responses to food cues in diabetic individuals (primary outcome).

METHODS

In 22 consecutively studied human brains, expression of GLP-1 receptors in the hypothalamus, medulla oblongata and parietal cortex was examined using immunohistochemistry. In a randomised (assigned by the pharmacy using a randomisation enrolment table), placebo-controlled, double-blind, crossover trial, 21 individuals with type 2 diabetes (18 included in analysis due to lack or poor quality of data) were treated with placebo and liraglutide for a total of 17 days each (0.6 mg for 7 days, 1.2 mg for 7 days, and 1.8 mg for 3 days). Participants were eligible if they had type 2 diabetes and were currently being treated with lifestyle changes or metformin. Participants, caregivers, people doing measurements and/or examinations, and people assessing the outcomes were blinded to the medication assignment. We studied metabolic changes as well as neurocognitive and neuroimaging (functional MRI) of responses to food cues at the clinical research centre of Beth Israel Deaconess Medical Center.

RESULTS

Immunohistochemical analysis revealed the presence of GLP-1 receptors on neurons in the human hypothalamus, medulla and parietal cortex. Liraglutide decreased activation of the parietal cortex in response to highly desirable (vs less desirable) food images (p < 0.001; effect size: placebo 0.53 ± 0.24, liraglutide -0.47 ± 0.18). No significant adverse effects were noted. In a secondary analysis, we observed decreased activation in the insula and putamen, areas involved in the reward system. Furthermore, we showed that increased ratings of hunger and appetite correlated with increased brain activation in response to highly desirable food cues while on liraglutide, while ratings of nausea correlated with decreased brain activation.

CONCLUSIONS/INTERPRETATION

For the first time, we demonstrate the presence of GLP-1 receptors in human brains. We also observe that liraglutide alters brain activity related to highly desirable food cues. Our data point to a central mechanism contributing to, or underlying, the effects of liraglutide on metabolism and weight loss. Future studies will be needed to confirm and extend these findings in larger samples of diabetic individuals and/or with the higher doses of liraglutide (3 mg) recently approved for obesity.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01562678 FUNDING : The study was funded by Novo Nordisk, NIH UL1 RR025758 and 5T32HD052961.

Cord blood irisin levels are positively correlated with birth weight in newborn infants

BACKGROUND

Irisin is a novel myokine, secreted from skeletal muscle after exercise. Irisin mediates exercise-related energy expenditure by turning white adipose tissue (WAT) into brown adipose tissue (BAT). Thus, irisin is considered as a potential biomarker for obesity and metabolic syndrome. Infants born small for gestational age (SGA) have increased risk for metabolic syndrome. However, the physiologic role of irisin in neonates remains to be studied.

OBJECTIVE

To evaluate the association of umbilical cord blood irisin levels with gestational age and birth weight categories in neonates.

METHODS

A cross-sectional study of 341 newborns, from 26 to 41weeks' gestation. We collected umbilical cord blood and analyzed plasma for irisin by ELISA.

RESULTS

Plasma irisin levels were positively correlated with gestational age (r=0.21, p<0.001), and birth weight Z-score (r=0.18, p<0.001). SGA infants had significantly lower irisin (median [interquartile range] 55.38 [46.56-65.72]ng/mL) compared to appropriate for gestational age infants (64.41 [53.87-76.76]ng/mL) and large for gestational age infants (68.70 [54.78-79.09]ng/mL, p<0.01). The association between SGA and lower irisin remained significant in multivariate analysis independent of gestational age, maternal age, maternal BMI, and gestational diabetes (p=0.03). In singleton infants, irisin was also significantly negatively associated with maternal preeclampsia (p=0.01).

CONCLUSIONS

Our results support the notion that irisin may have a physiologic role in neonates. We speculate that decreased levels of irisin in SGA infants may contribute to the development of catch-up growth and metabolic syndrome later in life.

Exercise-induced irisin secretion is independent of age or fitness level and increased irisin may directly modulate muscle metabolism through AMPK activation

CONTEXT

Irisin has been proposed to be a myokine mediating the effect of exercise on adipocyte browning. The physiology of irisin in humans is not completely understood.

OBJECTIVE

To study the physiology of irisin in healthy individuals with different age and fitness levels and to explore the direct effects of irisin on muscle metabolism.

DESIGN, SETTING, AND SUBJECTS

Treadmill exercise studies were conducted to measure circulating irisin at baseline and in response to exercise among old and young, physically active and sedentary individuals. Also, high- and moderate-intensity swimming was performed in adolescent men and women to study the effect of exercise intensity and the time course of irisin induction by acute bouts of exercise. Human myotubes were treated with recombinant irisin, and the effect on gene expression, cell signaling, and metabolism was examined.

RESULTS

Baseline circulating irisin was lower in old (vs young) and physically active (vs sedentary) subjects. Despite differences in basal levels, the percentage increase of irisin by acute bouts of exercise was not related to age or fitness level. The time course study revealed that circulating irisin increased immediately after high-intensity interval exercise and declined 1 hour thereafter. In vitro experiments showed that irisin facilitates glucose and lipid metabolism in human muscle through AMP kinase phosphorylation.

CONCLUSIONS

Despite the differences in basal irisin levels, exercise-induced irisin secretion is independent of age or fitness level. Increased irisin can directly modulate muscle metabolism through AMP kinase activation.

Circulating irisin in healthy, young individuals: day-night rhythm, effects of food intake and exercise, and associations with gender, physical activity, diet, and body composition

CONTEXT

The myokine irisin may increase energy expenditure and affect metabolism.

OBJECTIVE

The objective of the study was to elucidate predictors of irisin and study whether circulating irisin may have day-night rhythm in humans.

DESIGN

This was an observational, cross-sectional study with an additional 24-hour prospective observational arm (day-night rhythm substudy) and two prospective interventional arms (mixed meal substudy and exercise substudy).

SETTING

The study was conducted at the Hellenic Military School of Medicine (Thessaloniki, Greece).

PATIENTS AND INTERVENTIONS

One hundred twenty-two healthy, young individuals were subjected to anthropometric and body composition measurements, and their eating and exercise behavior profiles were assessed with validated questionnaires. Subgroups were subjected to day-night rhythm, standardized meal ingestion, and 30-minute aerobic exercise studies.

MAIN OUTCOME MEASURES

Circulating irisin levels were measured.

RESULTS

Ιrisin levels were lower in males than females (P = .02) after adjustment for lean body mass, which was its major determinant. Irisin levels followed a day-night rhythm (P < .001) with peak at 9:00 pm. Irisin levels were increased at the end of exercise (84.1 ± 10.0 vs 105.8 ± 14.3 ng/mL; P < .001). Irisin levels were not affected by intake of a standardized meal and were not associated with caloric intake or diet quality.

CONCLUSIONS

In healthy, young individuals, circulating irisin displays a day-night rhythm, is correlated with lean body mass, and increases acutely after exercise.

Plasma irisin levels progressively increase in response to increasing exercise workloads in young, healthy, active subjects

BACKGROUND

Irisin, a recently discovered myokine, has been shown to induce browning of white adipose tissue, enhancing energy expenditure and mediating some of the beneficial effects of exercise. We aimed to estimate the time frame of changes in irisin levels after acute exercise and the effect of different exercise workloads and intensities on circulating irisin levels immediately post-exercise.

METHODS

In a pilot study, four healthy subjects (22.5±1.7 years) underwent maximal workload exercise (maximal oxygen consumption, VO2 max) and blood was drawn at prespecified intervals to define the time frame of pre- and post-exercise irisin changes over a 24-h period. In the main study, 35 healthy, non-smoking (23.0±3.3 years) men and women (n=20/15) underwent three exercise protocols ≥48-h apart, in random order: i) maximal workload (VO2 max); ii) relative workload (70% of VO2 max/10 min); and iii) absolute workload (75 W/10 min). Blood was drawn immediately pre-exercise and 3 min post-exercise.

RESULTS

In the pilot study, irisin levels increased by 35% 3 min post-exercise, then dropped and remained relatively constant. In the main study, irisin levels post-exercise were significantly higher than those of pre-exercise after all workloads (all, P<0.001). Post-to-pre-exercise differences in irisin levels were significantly different between workloads (P=0.001), with the greatest increase by 34% following maximal workload (P=0.004 vs relative and absolute).

CONCLUSIONS

Circulating irisin levels were acutely elevated in response to exercise, with a greater increase after maximal workload. These findings suggest that irisin release could be a function of muscle energy demand. Future studies need to determine the underlying mechanisms of irisin release and explore irisin's therapeutic potential.

Effects of a 1-year exercise and lifestyle intervention on irisin, adipokines, and inflammatory markers in obese children

OBJECTIVE

Exercise improves weight status and metabolism. Irisin, a novel myokine, may be involved in the regulation of metabolic function. The effect of an exercise and dietary lifestyle intervention for 1-year on irisin, adipokines (leptin, adiponectin, resistin) and inflammatory markers (C-reactive protein (CRP), soluble tumor necrosis factor receptor II (sTNFR-II) was evaluated, and predictors of irisin levels were characterized in obese children.

METHODS

Parameters were assessed at baseline and at follow-up for 65 obese children who completed the program (7-18 years, 54%boys). Their relation to weight status and metabolic risk was analyzed.

RESULTS

Anthropometric and metabolic parameters improved after completion of the program. Circulating irisin levels at baseline were 111.0 ± 8.0 ng ml(-1) and increased after the intervention by 12% [6%, 17%], P = 0.00003. There was no evidence for differences in irisin levels between genders and across age. Moreover, changes in irisin did not correlate with those in BMI-SDS, adipokines or inflammatory markers. Leptin decreased after the intervention (Δ5.3 ng ml(-1) , [3.2, 6.3], P = 10(-7) ). Anthropometric measures were significantly associated with leptin and inflammatory markers.

CONCLUSIONS

A 1-year long lifestyle intervention program is associated with improvement in anthropometric and metabolic parameters and leads to an elevation in irisin levels in obese children.

Circulating irisin is associated with osteoporotic fractures in postmenopausal women with low bone mass but is not affected by either teriparatide or denosumab treatment for 3 months

In vitro data suggest that myokine irisin may affect bone metabolism by promoting osteoblast differentiation while inhibiting osteoclast differentiation. In this study, circulating irisin levels were associated with previous osteoporotic fractures but not with bone mass and were not affected by denosumab or teriparatide treatment for 3 months.

INTRODUCTION

This study aimed to evaluate predictors of circulating irisin in postmenopausal women with low bone mass and to assess a potential effect of denosumab or teriparatide treatment for 3 months.

METHODS

Serum samples for irisin measurement were obtained from (a) postmenopausal women with low bone mass (lumbar spinal [LS] or femoral neck [FN] bone mineral density [BMD] T-score ≤-2.0) and their age-matched controls at baseline and 3 months after denosumab (Dmab) injection (Dmab group, n = 50; Dmab control group, n = 25) and (b) women with more severe disease (LS or FN BMD T-score ≤-2.8) and their age-matched controls at the above-mentioned time points after teriparatide (TPTD) initiation (TPTD group, n = 25; TPTD control group, n = 25).

RESULTS

At baseline, irisin levels were inversely correlated with age (partial coefficient (r p ) = -0.24; p = 0.009), parathyroid hormone (PTH) (r p  = -0.30; p = 0.001), and creatinine (r p  = -0.23; p = 0.016) in univariate analysis, and were lower in women with (n = 26; 41.6 ± 2.7 ng/dL) than without previous osteoporotic fracture(s) (n = 99; 51.0 ± 1.6 ng/dL; p = 0.007). In multiple linear regression, previous osteoporotic fracture(s) and PTH were independently negatively associated with irisin [p = 0.04, CI -16.1 to -0.4 and p = 0.002, CI -0.3 to -0.07, respectively], but only the association with PTH remained after controlling for creatinine levels. Serum irisin levels were not different between women with or without low bone mass and were not affected by either Dmab or TPTD treatment for 3 months.

CONCLUSIONS

Circulating irisin levels were associated with previous osteoporotic fracture(s); whether this association is independent or is due to confounding by lower muscle mass, potentially reflected by lower creatinine levels, remains to be fully clarified.