Clinical validation of a wearable respiratory rate device: A brief report.

BACKGROUND: Respiratory rate (RR) is used for the diagnosis and management of medical conditions and can predict clinical changes. Heavy workload, understaffing, and errors related to poor recording make it underutilized. Wearable devices may facilitate its use. METHODS: RR measurements using a wearable photoplethysmography-based monitor were compared with medical grade devices in complementary clinical scenarios: Study one included a comparison to a capnograph in 35 healthy volunteers; Study two included a comparison to a ventilator monitor in 18 ventilated patients; and Study three included a comparison to capnograph in 92 COVID-19 patients with active pulmonary disease. Pearson's correlations and Bland-Altman analysis were used to assess the accuracy and agreement between the measurement techniques, including stratification for Body Mass Index (BMI) and skin tone. Statistical significance was set at p ≤ 0.05. RESULTS: High correlation was found in all studies (r = 0.991, 0.884, and 0.888, respectively, p < 0.001 for all). 95% LOA of ±2.3, 1.7-(-1.6), and ±3.9 with a bias of < 0.1 breaths per minute was found in Bland-Altman analysis in studies 1,2, and 3, respectively. In all, high accordance was found in all sub-groups. CONCLUSIONS: RR measurements using the wearable monitor were highly-correlated with medical-grade devices in various clinical settings. TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov/ct2/show/NCT03603860.

Dissociation Between Long-term Weight Loss Intervention and Blood Pressure: an 18-month Randomized Controlled Trial.

BACKGROUND: Obesity is associated with elevated blood pressure (BP). In patients with obesity and hypertension, weight loss lowers BP, but the long-term effect of weight loss on BP is less clear. OBJECTIVE: We aimed to assess the effect of long-term weight loss intervention on BP in normotensive and hypertensive subjects. DESIGN: Randomized controlled trial. PARTICIPANTS: Two hundred seventy-eight subjects (mean age 47.9 ± 9.3 years, 89% male, 56% hypertensive) with abdominal obesity or elevated serum triglycerides and low high-density lipoprotein cholesterol were recruited. INTERVENTION: Eighteen-month weight loss intervention. MAIN MEASURES: Body weight and BP were measured at baseline, after 6 and 18 months. RESULTS: After 6 months of intervention, in the weight loss phase, body mass index (BMI) decreased by an average of -2.2±1.5 kg/m2 (p<0.001) and both diastolic BP (DBP) and systolic BP (SBP) decreased by -2.1±8.8 mmHg and -2.3±12.9 mmHg, respectively (p<0.01 for both). The change in BMI was similar in normotensive and hypertensive subjects (-2.0±1.6 and -2.3±1.5, p = 0.246). However, DBP and SBP decreased significantly (-5.2±7.1 mmHg and -6.2±12.5 mmHg, respectively, p<0.001 for both) in hypertensive subjects, and increased in normotensive subjects (1.8±9.3 mmHg, p = 0.041 and 2.7±11.7 mmHg, p = 0.017, respectively). After 18 months, in the weight maintenance phase, BMI slightly increased (0.9±1.3 kg/m2, p<0.001) but remained significantly lower than at baseline (p<0.0001). Unlike BMI, DBP and SBP increased significantly in hypertensive subjects (p<0.001) and returned almost to baseline levels. CONCLUSION: Weight-loss intervention reduced BP in hypertensive patients, but this was not maintained in the long run. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01530724.

The effects of ambient particulate matter on human adipose tissue.

The effects of particulate matter (PM) air pollution on adipose tissue have mainly been studied in animal models. The aim of this study was to examine the potential associations between PM exposure and 25 cellular markers in human omental (OM) and subcutaneous (SC) adipose tissue. The PM exposure assessments for both PM2.5 (PM <2.5 µm in diameter) and PM10 (<10 µm) were based upon a novel hybrid satellite-based spatio-temporally resolved model. We calculated the PM exposure above the background threshold for 1 week (acute phase), 3 and 6 months (intermediate phase), and 1 year (chronic phase) prior to tissue harvesting and tested the associations with adipose cell metabolic effects using multiple linear regressions and heat maps strategy. Chemokine levels were found to increase after acute and intermediate exposure duration to PM10. The levels of stress signaling biomarkers in the SC and OM tissues rose after acute exposure to PM10 and PM2.5. Macrophage and leucocyte counts were associated with severity of PM exposure in all three duration groups. Adipocyte diameter decreased in all exposure periods. Our results provide evidence for significant contribution of air pollutants exposure to adipose tissue inflammation as well as for pathophysiological mechanisms of metabolic dysregulation that may be involved in the observed responses.

Transcriptional Dysregulation of Adipose Tissue Autophagy in Obesity.

There is growing interest in understanding how dysregulated autophagy may contribute to pathogenesis of disease. Most frequently, disease states are associated with diminished autophagy, mostly attributed to genetic variation in autophagy genes and/or to dysfunctional posttranscriptional mechanisms. In human adipose tissue (AT), in obesity, expression of autophagy genes is upregulated and autophagy is likely activated, associating with adipose dysfunction. This review explores the emerging role of transcriptional mechanisms regulating AT autophagy in obesity.

Continuous Monitoring of Advanced Hemodynamic Parameters during Hemodialysis Demonstrated Early Variations in Patients Experiencing Intradialytic Hypotension.

Intradialytic hypotension (IDH) is a severe complication of hemodialysis (HD) with a significant impact on morbidity and mortality. In this study, we used a wearable device for the continuous monitoring of hemodynamic vitals to detect hemodynamic changes during HD and attempted to identify IDH. End-stage kidney disease patients were continuously monitored 15 min before starting the session and until 15 min after completion of the session, measuring heart rate (HR), noninvasive cuffless systolic and diastolic blood pressure (SBP and DBP), stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR). Data were analyzed retrospectively and included comparing BP measured by the wearable devices (recorded continuously every 5 s) and the cuff-based devices. A total of 98 dialysis sessions were included in the final analysis, and IDH was identified in 22 sessions (22.5%). Both SBP and DBP were highly correlated (r > 0.62, p < 0.001 for all) between the wearable device and the cuff-based measurements. Based on the continuous monitoring, patients with IDH had earlier and more profound reductions in SBP and DBP during the HD treatment. In addition, nearly all of the advanced vitals differed between groups. Further studies should be conducted in order to fully understand the potential of noninvasive advanced continuous monitoring in the prediction and prevention of IDH events.

Developing a real-time detection tool and an early warning score using a continuous wearable multi-parameter monitor.

Background: Currently-used tools for early recognition of clinical deterioration have high sensitivity, but with low specificity and are based on infrequent measurements. We aimed to develop a pre-symptomatic and real-time detection and warning tool for potential patients' deterioration based on multi-parameter real-time warning score (MPRT-WS). Methods: A total of more than 2 million measurements were collected, pooled, and analyzed from 521 participants, of which 361 were patients in general wards defined at high-risk for deterioration and 160 were healthy participants allocation as controls. The risk score stratification was based on cutoffs of multiple physiological parameters predefined by a panel of specialists, and included heart rate, blood oxygen saturation (SpO2), respiratory rate, cuffless systolic and diastolic blood pressure (SBP and DBP), body temperature, stroke volume (SV), cardiac output, and systemic vascular resistance (SVR), recorded every 5 min for a period of up to 72 h. The data was used to define the various risk levels of a real-time detection and warning tool, comparing it with the clinically-used National Early Warning Score (NEWS). Results: When comparing risk levels among patients using both tools, 92.6%, 6.1%, and 1.3% of the readings were defined as "Low", "Medium", and "High" risk with NEWS, and 92.9%, 6.4%, and 0.7%, respectively, with MPRT-WS (p = 0.863 between tools). Among the 39 patients that deteriorated, 30 patients received 'High' or 'Urgent' using the MPRT-WS (42.7 ± 49.1 h before they deteriorated), and only 6 received 'High' score using the NEWS. The main abnormal vitals for the MPRT-WS were SpO2, SBP, and SV for the "Urgent" risk level, DBP, SVR, and SBP for the "High" risk level, and DBP, SpO2, and SVR for the "Medium" risk level. Conclusion: As the new detection and warning tool is based on highly-frequent monitoring capabilities, it provides medical teams with timely alerts of pre-symptomatic and real-time deterioration.

Comparing body temperature measurements using the double sensor method within a wearable device with oral and core body temperature measurements using medical grade thermometers-a short report.

Introduction: Body temperature is essential for diagnosing, managing, and following multiple medical conditions. There are several methods and devices to measure body temperature, but most do not allow continuous and prolonged measurement of body temperature. Noninvasive skin temperature sensor combined with a heat flux sensor, also known as the "double sensor" technique, is becoming a valuable and simple method for frequently monitoring body temperature. Methods: Body temperature measurements using the "double sensor" method in a wearable monitoring device were compared with oral and core body temperature measurements using medical grade thermometers, analyzing data from two prospective clinical trials of different clinical scenarios. One study included 45 hospitalized COVID-19 patients in which oral measurements were taken using a hand-held device, and the second included 18 post-cardiac surgery patients in which rectal measurements were taken using a rectal probe. Results: In study 1, Bland-Altman analysis showed a bias of -0.04°C [0.34-(-0.43)°C, 95% LOA] with a correlation of 99.4% (p < 0.001). In study 2, Bland-Altman analysis showed a bias of 0.0°C [0.27-(-0.28)°C, 95% LOA], and the correlation was 99.3% (p < 0.001). In both studies, stratifying patients based on BMI and skin tone showed high accordance in all sub-groups. Discussion: The wearable monitor showed high correlation with oral and core body temperature measurements in different clinical scenarios.

Diurnal cardio-respiratory changes in ambulatory individuals deciphered using a multi-parameter wearable device.

Background: Recent technological developments enable big data-driven insights on diurnal changes. This study aimed to describe the trajectory of multiple and advanced parameters using a medical-grade wearable remote patient monitor. Methods: Parameters were monitored for 24 h in 256 ambulatory participants who kept living their normal life. Parameters included heart rate, blood pressure, stroke volume, cardiac index, systemic vascular resistance, blood oxygen saturation, and respiratory rate. Diurnal variations were evaluated, and analyses were stratified based on sex, age, and body mass index. Results: All parameters showed diurnal changes (p < 0.001). Females demonstrated higher heart rate and cardiac index with lower systemic vascular resistance. Obese participants had a higher blood pressure, and lower stroke volume and cardiac index. Systemic vascular resistance was higher among the elderly. Diurnal changes corresponded with awake-sleep hours and differed between sex, age, and body mass index groups. Conclusion: Wearable monitoring platforms could decipher hemodynamic changes in subgroups of individuals, and might help with efforts to provide personalized medicine, pre-symptomatic diagnosis and prevention, and drug development.

Influence of Sex, BMI, and Skin Color on the Accuracy of Non-Invasive Cuffless Photoplethysmography-Based Blood Pressure Measurements.

Vital signs obtained by photoplethysmography-based devices might be influenced by subcutaneous fat and skin color. This observational comparison study aimed to test the accuracy of blood pressure (BP) measurements between a photoplethysmography-based device and cuff-based BP device in ambulatory individuals, coming for a routine BP checkup. Systolic BP (SBP) and diastolic BP (DBP) measurements were stratified based on sex, BMI (<25; 25 ≤BMI<30; 30 ≤kg/m2), and skin color (types 1-3 and 4-6 by the Fitzpatrick scale). A total of 1548 measurements were analyzed. Correlations of SBP and DBP between the devices among males/females were between 0.914-0.987 (p < 0.001), and Bland-Altman analysis showed a bias of less than 0.5 mmHg for both sexes. Correlations of SBP and DBP between the devices among BMI groups were between 0.931-0.991 (p < 0.001), and Bland-Altman analysis showed a bias of less than 1 mmHg for all. Correlations of SBP and DBP between the devices among the skin color groups were between 0.936-0.983 (p < 0.001), and Bland-Altman analysis showed a bias of less than 1 mmHg for all. This study shows similar and high agreements between BP measurements obtained using a PPG-based non-invasive cuffless BP device and a cuff-based BP device across sex, BMI, and skin color groups.

Utilizing wearable sensors for continuous and highly-sensitive monitoring of reactions to the BNT162b2 mRNA COVID-19 vaccine.

Background: Clinical trial guidelines for assessing the safety of vaccines, are primarily based on self-reported questionnaires. Despite the tremendous technological advances in recent years, objective, continuous assessment of physiological measures post-vaccination is rarely performed. Methods: We conducted a prospective observational study during the mass vaccination campaign in Israel. 160 participants >18 years who were not previously found to be COVID-19 positive and who received the BNT162b2 COVID-19 (Pfizer BioNTech) vaccine were equipped with an FDA-approved chest-patch sensor and a dedicated mobile application. The chest-patch sensor continuously monitored 13 different cardiovascular, and hemodynamic vitals: heart rate, blood oxygen saturation, respiratory rate, systolic and diastolic blood pressure, pulse pressure, mean arterial pressure, heart rate variability, stroke volume, cardiac output, cardiac index, systemic vascular resistance and skin temperature. The mobile application collected daily self-reported questionnaires on local and systemic reactions. Results: We identify continuous and significant changes following vaccine administration in nearly all vitals. Markedly, these changes are observed even in presumably asymptomatic participants who did not report any local or systemic reaction. Changes in vitals are more apparent at night, in younger participants, and in participants following the second vaccine dose. Conclusion: the considerably higher sensitivity of wearable sensors can revolutionize clinical trials by enabling earlier identification of abnormal reactions with fewer subjects.

Comparing Cardiac Output Measurements Using a Wearable, Wireless, Noninvasive Photoplethysmography-Based Device to Pulse Contour Cardiac Output in the General ICU: A Brief Report.

OBJECTIVES: Cardiac output (CO) measurements in the ICU are usually based on invasive techniques, which are technically complex and associated with clinical complications. This study aimed to compare CO measurements obtained from a noninvasive photoplethysmography-based device to a pulse contour cardiac output device in ICU patients. DESIGN: Observational, prospective, comparative clinical trial. SETTING: Single-center general ICU. PATIENTS: Patients admitted to the general ICU monitored using a pulse contour cardiac output device as per the decision of the attending physician. INTERVENTIONS: Parallel monitoring of CO using a photoplethysmography-based chest patch device and pulse contour cardiac output while the medical team was blinded to the values obtained by the noninvasive device. MEASUREMENTS AND MAIN RESULTS: Seven patients (69 measurements) were included in the final analysis. Mean CO were 7.3 ± 2.0 L/m and 7.0 ± 1.5 L/m for thermodilution and photoplethysmography, respectively. Bland-Altman showed that the photoplethysmography has a bias of 0.3 L/m with -1.6 and 2.2 L/m 95% limit of agreement (LOA) and a bias of 2.4% with 95% LOA between -25.7% and 30.5% when calculating the percentage of difference from thermodilution. The values obtained by thermodilution and photoplethysmography were highly correlated (r = 0.906). CONCLUSIONS: The tested chest patch device offers a high accuracy for CO compared to data obtained by the pulse contour cardiac output and the thermodilution method in ICU patients. Such devices could offer advanced monitoring capabilities in a variety of clinical settings, without the complications of invasive devices.

Advanced Hemodynamic Monitoring Allows Recognition of Early Response Patterns to Diuresis in Congestive Heart Failure Patients.

There are no clear guidelines for diuretic administration in heart failure (HF), and reliable markers are needed to tailor treatment. Continuous monitoring of multiple advanced physiological parameters during diuresis may allow better differentiation of patients into subgroups according to their responses. In this study, 29 HF patients were monitored during outpatient intravenous diuresis, using a noninvasive wearable multi-parameter monitor. Analysis of changes in these parameters during the course of diuresis aimed to recognize subgroups with different response patterns. Parameters did not change significantly, however, subgroup analysis of the last quartile of treatment showed significant differences in cardiac output, cardiac index, stroke volume, pulse rate, and systemic vascular resistance according to gender, and in systolic blood pressure according to habitus. Changes in the last quartile could be differentiated using k-means, a technique of unsupervised machine learning. Moreover, patients' responses could be best clustered into four groups. Analysis of baseline parameters showed that two of the clusters differed by baseline parameters, body mass index, and diabetes status. To conclude, we show that physiological changes during diuresis in HF patients can be categorized into subgroups sharing similar response trends, making noninvasive monitoring a potential key to personalized treatment in HF.

Characteristics and outcomes of ambulatory patients with suspected COVID-19 at a respiratory referral center.

RATIONALE: SARS-CoV-2 continues to cause a global pandemic and management of COVID-19 in outpatient settings remains challenging. OBJECTIVE: We sought to describe characteristics of patients with chronic respiratory disease (CRD) experiencing symptoms consistent with COVID-19, who were seen in a novel Acute Respiratory Clinic, prior to widely available testing, emergence of variants, COVID-19 vaccination, and post-vaccination (breakthrough) SARS-CoV-2 infections. METHODS: Retrospective electronic medical record data were analyzed from 907 adults with presumed COVID-19 seen between March 16, 2020 and January 7, 2021. Data included demographics, comorbidities, medications, vital signs, laboratory tests, pulmonary function tests, patient disposition, and co-infections. The overdispersed data (aod) R package was used to create a logit model using COVID-19 diagnosis by PCR as the dichotomous outcome variable. Univariate, conventional multivariate and elastic net machine learning were used to analyze data. RESULTS: Male gender, elevated baseline temperature, and respiratory rate predicted COVID-19 diagnosis. Eosinopenia, neutrophilia, and lymphocytosis were also associated with COVID-19 diagnosis. However, asthma and COPD diagnoses were not associated with SARS-CoV-2 PCR positive test. Male gender, low oxygen saturation, and lower forced expiratory volume in 1 s (FEV1) were associated with higher hospital referral. CONCLUSIONS: CRD patients with acute respiratory symptoms in the ambulatory setting were more likely to have COVID-19 if male, febrile and tachypneic. Patients with lower pre-morbid FEV1 and lower SPO2 are more likely to be referred to the hospital. A composite of vitals sigs and WBC differential help risk stratify CRD patients seeking care for presumed COVID-19.

Age Differences in Recovery Rate Following an Aerobic-Based Exercise Protocol Inducing Muscle Damage Among Amateur, Male Athletes.

Purpose: Compare recovery rates between active young (Y) and middle-aged (MA) males up to 48H post aerobically based, exercise-induced muscle damage (EIMD) protocol. A secondary aim was to explore the relationships between changes in indices associated with EIMD and recovery throughout this timeframe. Methods: Twenty-eight Y (n = 14, 26.1 ± 2.9y, 74.5 ± 9.3 kg) and MA (n = 14, 43.6 ± 4.1y, 77.3 ± 12.9 kg) physically active males, completed a 60-min downhill running (DHR) on a treadmill at -10% incline and at 65% of maximal heart rate (HR). Biochemical, biomechanical, psychological, force production and muscle integrity (using MRI diffusion tensor imaging) markers were measured at baseline, immediately-post, and up to 48H post DHR. Results: During the DHR, HR was lower (p < 0.05) in MA compared to Y, but running pace and distance covered were comparable between groups. No statistical or meaningful differences were observed between groups for any of the outcomes. Yet, Significant (p < 0.05) time-effects within each group were observed: markers of muscle damage, cadence and perception of pain increased, while TNF-a, isometric and dynamic force production and stride-length decreased. Creatine-kinase at 24H-post and 48H-post were correlated (p < 0.05, r range = -0.57 to 0.55) with pain perception, stride-length, and cadence at 24H-post and 48H-post. Significant (p < 0.05) correlations were observed between isometric force production at all time-points and IL-6 at 48H-post DHR (r range = -0.62 to (-0.74). Conclusion: Y and MA active male amateur athletes recover in a comparable manner following an EIMD downhill protocol. These results indicate that similar recovery strategies can be used by trainees from both age groups following an aerobic-based EIMD protocol.

An Exercise-Induced Metabolic Shield in Distant Organs Blocks Cancer Progression and Metastatic Dissemination.

Exercise prevents cancer incidence and recurrence, yet the underlying mechanism behind this relationship remains mostly unknown. Here we report that exercise induces the metabolic reprogramming of internal organs that increases nutrient demand and protects against metastatic colonization by limiting nutrient availability to the tumor, generating an exercise-induced metabolic shield. Proteomic and ex vivo metabolic capacity analyses of murine internal organs revealed that exercise induces catabolic processes, glucose uptake, mitochondrial activity, and GLUT expression. Proteomic analysis of routinely active human subject plasma demonstrated increased carbohydrate utilization following exercise. Epidemiologic data from a 20-year prospective study of a large human cohort of initially cancer-free participants revealed that exercise prior to cancer initiation had a modest impact on cancer incidence in low metastatic stages but significantly reduced the likelihood of highly metastatic cancer. In three models of melanoma in mice, exercise prior to cancer injection significantly protected against metastases in distant organs. The protective effects of exercise were dependent on mTOR activity, and inhibition of the mTOR pathway with rapamycin treatment ex vivo reversed the exercise-induced metabolic shield. Under limited glucose conditions, active stroma consumed significantly more glucose at the expense of the tumor. Collectively, these data suggest a clash between the metabolic plasticity of cancer and exercise-induced metabolic reprogramming of the stroma, raising an opportunity to block metastasis by challenging the metabolic needs of the tumor. SIGNIFICANCE: Exercise protects against cancer progression and metastasis by inducing a high nutrient demand in internal organs, indicating that reducing nutrient availability to tumor cells represents a potential strategy to prevent metastasis. See related commentary by Zerhouni and Piskounova, p. 4124.

Food-seeking behavior is triggered by skin ultraviolet exposure in males.

Sexual dimorphisms are responsible for profound metabolic differences in health and behavior. Whether males and females react differently to environmental cues, such as solar ultraviolet (UV) exposure, is unknown. Here we show that solar exposure induces food-seeking behavior, food intake, and food-seeking behavior and food intake in men, but not in women, through epidemiological evidence of approximately 3,000 individuals throughout the year. In mice, UVB exposure leads to increased food-seeking behavior, food intake and weight gain, with a sexual dimorphism towards males. In both mice and human males, increased appetite is correlated with elevated levels of circulating ghrelin. Specifically, UVB irradiation leads to p53 transcriptional activation of ghrelin in skin adipocytes, while a conditional p53-knockout in mice abolishes UVB-induced ghrelin expression and food-seeking behavior. In females, estrogen interferes with the p53-chromatin interaction on the ghrelin promoter, thus blocking ghrelin and food-seeking behavior in response to UVB exposure. These results identify the skin as a major mediator of energy homeostasis and may lead to therapeutic opportunities for sex-based treatments of endocrine-related diseases.

Characteristics of Post-ICU and Post-COVID Recovery Clinics in 29 U.S. Health Systems.

The multifaceted long-term impairments resulting from critical illness and COVID-19 require interdisciplinary management approaches in the recovery phase of illness. Operational insights into the structure and process of recovery clinics (RCs) from heterogeneous health systems are needed. This study describes the structure and process characteristics of existing and newly implemented ICU-RCs and COVID-RCs in a subset of large health systems in the United States. DESIGN: Cross-sectional survey. SETTING: Thirty-nine RCs, representing a combined 156 hospitals within 29 health systems participated. PATIENTS: None. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: RC demographics, referral criteria, and operating characteristics were collected, including measures used to assess physical, psychologic, and cognitive recoveries. Thirty-nine RC surveys were completed (94% response rate). ICU-RC teams included physicians, pharmacists, social workers, physical therapists, and advanced practice providers. Funding sources for ICU-RCs included clinical billing (n = 20, 77%), volunteer staff support (n = 15, 58%), institutional staff/space support (n = 13, 46%), and grant or foundation funding (n = 3, 12%). Forty-six percent of RCs report patient visit durations of 1 hour or longer. ICU-RC teams reported use of validated scales to assess psychologic recovery (93%), physical recovery (89%), and cognitive recovery (86%) more often in standard visits compared with COVID-RC teams (psychologic, 54%; physical, 69%; and cognitive, 46%). CONCLUSIONS: Operating structures of RCs vary, though almost all describe modest capacity and reliance on volunteerism and discretionary institutional support. ICU- and COVID-RCs in the United States employ varied funding sources and endorse different assessment measures during visits to guide care coordination. Common features include integration of ICU clinicians, interdisciplinary approach, and focus on severe critical illness. The heterogeneity in RC structures and processes contributes to future research on the optimal structure and process to achieve the best postintensive care syndrome and postacute sequelae of COVID outcomes.

Comparison of body composition assessment across body mass index categories by two multifrequency bioelectrical impedance analysis devices and dual-energy X-ray absorptiometry in clinical settings.

BACKGROUND: InBody-770 and SECA mBCA 515 are multifrequency bioelectrical impedance analysis (BIA) devices, which are commonly used in the clinic to assess fat-free mass (FFM) and body fat (BF). However, the accuracy between devices in clinical settings, across different body mass index (BMI) groups remains unclear. METHODS: Body composition for 226 participants (51% men, aged 18-80 years, BMI 18-56 kg/m²) was assessed by two commercial multifrequency BIA devices requiring standing position and using eight-contact electrodes, InBody 770 and SECA mBCA 515, and compared to results from dual-energy X-ray absorptiometry (DXA). Measurements were performed in a random order, after a 3 h fast and no prior exercise. Lin's-concordance correlation and Bland-Altman analyses were used to compare between devices, and linear regression to assess accuracy in BF% across BMI groups. RESULTS: We found strong correlation between DXA results for study population BF% and those obtained by InBody (ρc = 0.922, 95% confidence interval (CI) 0.902, 0.938) and DXA and SECA (ρc = 0.940, CI 0.923, 0.935), with 95% limits of agreements between 2.6 and -8.9, and 7.1 and -7.6, respectively. BF% assessment by SECA was similar to DXA (-0.3%, p = 0.267), and underestimated by InBody (-3.1%, p < 0.0001). InBody deviations were largest among normal weight people and decreased with increasing BMI group, while SECA measurements remained unaffected. CONCLUSIONS: Both BIA devices agreed well with BF% assessment obtained by DXA. Unlike SECA, InBody underestimated BF% in both genders and was influenced by BMI categories. Therefore, in clinical settings, individual assessment of BF% should be taken with caution.