Detection of COVID-19 using multimodal data from a wearable device: results from the first TemPredict Study.

Early detection of diseases such as COVID-19 could be a critical tool in reducing disease transmission by helping individuals recognize when they should self-isolate, seek testing, and obtain early medical intervention. Consumer wearable devices that continuously measure physiological metrics hold promise as tools for early illness detection. We gathered daily questionnaire data and physiological data using a consumer wearable (Oura Ring) from 63,153 participants, of whom 704 self-reported possible COVID-19 disease. We selected 73 of these 704 participants with reliable confirmation of COVID-19 by PCR testing and high-quality physiological data for algorithm training to identify onset of COVID-19 using machine learning classification. The algorithm identified COVID-19 an average of 2.75 days before participants sought diagnostic testing with a sensitivity of 82% and specificity of 63%. The receiving operating characteristic (ROC) area under the curve (AUC) was 0.819 (95% CI [0.809, 0.830]). Including continuous temperature yielded an AUC 4.9% higher than without this feature. For further validation, we obtained SARS CoV-2 antibody in a subset of participants and identified 10 additional participants who self-reported COVID-19 disease with antibody confirmation. The algorithm had an overall ROC AUC of 0.819 (95% CI [0.809, 0.830]), with a sensitivity of 90% and specificity of 80% in these additional participants. Finally, we observed substantial variation in accuracy based on age and biological sex. Findings highlight the importance of including temperature assessment, using continuous physiological features for alignment, and including diverse populations in algorithm development to optimize accuracy in COVID-19 detection from wearables.

Effects of modality change on health-related quality of life.

Patients with end-stage renal disease (ESRD) requiring renal replacement have impaired health-related quality of life (HRQoL), and there is general consensus that HRQoL improves with successful transplant and evidence of improvement with frequent hemodialysis. This study reports changes in HRQoL associated with changes in treatment modality to daily hemodialysis (DHD) and transplant among patients requiring renal replacement. This cohort study had assessments at baseline and 6-month following modality change. Subjects were nondiabetic individuals receiving conventional hemodialysis who (a) remained on conventional hemodialysis (n = 13), (b) changed to daily hemodialysis (DHD) (n = 10), or (c) received a living donor transplant (n = 20). Thirty-four healthy controls were assessed once for comparison. HRQoL was measured using the Kidney Disease Quality of Life Instrument. The Physical Functioning and Physical Composite Scale scores were primary outcomes. Transplantation resulted in significant improvements in six of eight generic scales and the physical composite scale (PCS). Those changing to DHD had significant improvements in Physical Function and PCS scales. Those remaining on dialysis remained lower than controls on all scales except for Vitality; the transplant group remained lower than controls only on the Vitality and General Health scales. Transplant resulted in significant improvements in four of the seven disease-specific scales (symptoms, effects, and burden of kidney disease, work). DHD resulted in improvements in the effects of kidney disease. Modality change to transplant results in significant improvement in HRQoL, achieving levels similar to controls. Change to daily hemodialysis improves only select HRQoL domains and remains low in disease-specific domains.

Effects of modality change and transplant on peak oxygen uptake in patients with kidney failure.

BACKGROUND: Exercise capacity as measured by peak oxygen uptake (Vo2(peak)) is low in hemodialysis patients. The present study assesses determinants of VO2(peak) in patients with chronic kidney failure who either changed kidney replacement modality to frequent hemodialysis therapy or received a kidney transplant. STUDY DESIGN: Cohort study with assessment at baseline and 6 months after modality change. SETTING & PARTICIPANTS: Participants included nondiabetic individuals receiving conventional hemodialysis who: (1) remained on conventional hemodialysis therapy (n = 13), (2) changed to short daily hemodialysis therapy (n = 10), or (3) received a transplant (n = 5) and (4) individuals who underwent a pre-emptive transplant (n = 15). Additionally, 34 healthy controls were assessed at baseline only. PREDICTOR: Modality change. MEASUREMENT & OUTCOMES: Exercise capacity, assessed using the physiologic components of the Fick equation (Vo2 = cardiac output × a-vo2(dif), where a-vo2(dif) is arterial to venous oxygen difference) was determined using measurement of Vo2(peak) and cardiac output during symptom-limited exercise testing. Analysis of covariance was used to compare differences in changes in Vo2(peak), cardiac output, heart rate, stroke volume, and a-vo2(dif) at peak exercise between participants who remained on hemodialysis therapy and those who underwent transplant. RESULTS: Transplant was the only modality change associated with a significant change in Vo2(peak), occurring as a result of increased peak cardiac output and reflecting increased heart rate without a change in peak a-vo2(dif) despite increased hemoglobin levels. There were no differences in participants who changed to daily hemodialysis therapy compared with those who remained on conventional hemodialysis therapy. LIMITATIONS: Small nonrandomized study. CONCLUSIONS: Vo2(peak) increases significantly after kidney transplant, but not with daily hemodialysis; this improvement reflects increased peak cardiac output through increased peak heart rate. Despite statistical significance, the increase in Vo2(peak) was not clinically significant, suggesting the need for interventions such as exercise training to increase Vo2(peak) in all patients regardless of treatment modality.

Habitual physical activity levels are associated with performance in measures of physical function and mobility in older men.

OBJECTIVES: To determine whether objectively measured physical activity levels are associated with physical function and mobility in older men. DESIGN: Cross-sectional. SETTING: Academic research center. PARTICIPANTS: Eighty-two community-dwelling men aged 65 and older with self-reported mobility limitations were divided into a low-activity and a high-activity group based on the median average daily physical activity counts of the whole sample. MEASUREMENTS: Physical activity according to triaxial accelerometers; physical function and mobility according to the Short Physical Performance Battery (SPPB), gait speed, stair climb time, and a lift-and-lower task; aerobic capacity according to maximum oxygen consumption (VO(2) max); and leg press and chest press maximal strength and peak power. RESULTS: Older men with higher physical activity levels had a 1.4-point higher mean SPPB score and a 0.35-m/s faster walking speed than those with lower physical activity levels. They also climbed a standard flight of stairs 1.85 seconds faster and completed 60% more shelves in a lift-and-lower task (all P<.01); muscle strength and power measures were not significantly different between the low- and high-activity groups. Correlation analyses and multiple linear regression models showed that physical activity is positively associated with all physical function and mobility measures, leg press strength, and VO(2) max. CONCLUSION: Older men with higher physical activity levels demonstrate better physical function and mobility than their less-active peers. Moreover, physical activity levels are predictive of performance in measures of physical function and mobility in older men. Future work is needed to determine whether modifications in physical activity levels can improve or preserve physical performance in later life.

Free testosterone levels are associated with mobility limitation and physical performance in community-dwelling men: the Framingham Offspring Study.

CONTEXT: Mobility limitation is associated with increased morbidity and mortality. The relationship between circulating testosterone and mobility limitation and physical performance is incompletely understood. OBJECTIVE: Our objective was to examine cross-sectional and prospective relations between baseline sex hormones and mobility limitations and physical performance in community-dwelling older men. DESIGN, SETTING, AND PARTICIPANTS: We conducted cross-sectional and longitudinal analyses of 1445 men (mean age 61.0 +/- 9.5 yr) who attended Framingham Offspring Study examinations 7 and 8 (mean 6.6 yr apart). Total testosterone (TT) was measured by liquid chromatography tandem mass spectrometry at examination 7. Cross-sectional and longitudinal analyses of mobility limitation and physical performance were performed with continuous (per SD) and dichotomized [low TT and free testosterone (FT) and high SHBG vs. normal] hormone levels. MAIN OUTCOME MEASURES: Self-reported mobility limitation, subjective health, usual walking speed, and grip strength were assessed at examinations 7 and 8. Short physical performance battery was performed at examination 7. RESULTS: Higher continuous FT was positively associated with short physical performance battery score (beta = 0.13; P = 0.008), usual walking speed (beta = 0.02; P = 0.048), and lower risk of poor subjective health [odds ratio (OR) = 0.72; P = 0.01]. In prospective analysis, 1 SD increase in baseline FT was associated with lower risk of developing mobility limitation (OR = 0.78; 95% confidence interval = 0.62-0.97) and progression of mobility limitation (OR = 0.75; 95% confidence interval = 0.60-0.93). Men with low baseline FT had 57% higher odds of reporting incident mobility limitation (P = 0.03) and 68% higher odds of worsening of mobility limitation (P = 0.007). CONCLUSIONS: Lower levels of baseline FT are associated with a greater risk of incident or worsening mobility limitation in community-dwelling older men. Whether this risk can be reduced with testosterone therapy needs to be determined by randomized trials.

Interunit and intraunit reliability of the RT3 triaxial accelerometer.

BACKGROUND: Interest in the quantification of physical activity is on the rise. Triaxial accelerometry has frequently been used; however, research on the reliability of these devices is limited. We examine the interunit and intraunit reliability of 22 RT3 triaxial accelerometers using a performance-documented laboratory agitator. METHODS: The RT3 units were tested while moving in 2 directions (antero-posterior, medio-lateral) and speeds (150 and 275 RPM) on a shaker with simultaneous documented performance output for three 24-hour periods. RESULTS: Minimal shaker variance was recorded for all trials (coefficients of variation [CVs] < 0.52%). Our data demonstrate good reliability within RT3s (CVs < 1.81%) but poor reliability among the 22 units (CVs range = 9.5% to 34.7%). CONCLUSIONS: In longitudinal studies, each subject should use the same RT3 unit at each assessment. The use of multiple RT3 units in cross-sectional studies is not recommended because data interpretation would be compromised by the high between-unit variability.

Health-related fitness and physical activity in patients with nonalcoholic fatty liver disease.

UNLABELLED: Nonalcoholic fatty liver disease (NAFLD) has been referred to as the hepatic manifestation of the metabolic syndrome. There is a lower prevalence of metabolic syndrome in individuals with higher health-related fitness (HRF) and physical activity (PA) participation. The relationship between NAFLD severity and HRF or PA is unknown. Our aim was to compare measures of HRF and PA in patients with a histological spectrum of NAFLD severity. Thirty-seven patients with liver biopsy-confirmed NAFLD (18 women/19 men; age = 45.9 +/- 12.7 years) completed assessment of cardiorespiratory fitness (CRF, VO(2peak)), muscle strength (quadriceps peak torque), body composition (%fat), and PA (current and historical questionnaire). Liver histology was used to classify severity by steatosis (mild, moderate, severe), fibrosis stage (stage 1 versus stage 2/3), necroinflammatory activity (NAFLD Activity Score; or=5 NAS2) and diagnosis of NASH by Brunt criteria (NASH versus NotNASH). Analysis of variance and independent t tests were used to determine the differences among groups. Fewer than 20% of patients met recommended guidelines for PA, and 97.3% were classified at increased risk of morbidity and mortality by %fat. No differences were detected in VO(2peak) (x = 26.8 +/- 7.4 mL/g/min) or %fat (x = 38.6 +/- 8.2%) among the steatosis or fibrosis groups. Peak VO(2) was significantly higher in NAS1 versus NAS2 (30.4 +/- 8.2 versus 24.4 +/- 5.7 mL/kg/min, P = 0.013) and NotNASH versus NASH (34.0 +/- 9.5 versus 25.1 +/- 5.7 mL/kg/min, P = 0.048). CONCLUSION: Patients with NAFLD of differing histological severity have suboptimal HRF. Lifestyle interventions to improve HRF and PA may be beneficial in reducing the associated risk factors and preventing progression of NAFLD.

The comprehensive assessment of physical fitness in children following kidney and liver transplantation.

BACKGROUND: Pediatric organ transplant recipients may have elevated cardiovascular (CV) risk. Low cardiorespiratory fitness (CRF) may contribute to CV risk; however, studies of CRF in children following kidney transplantation (KTx) and liver transplantation (LTx) are limited. METHODS: Laboratory testing included assessment of CRF (VO2peak), muscle strength, and body composition (%fat). Field testing (FITNESSGRAM) included the PACER, curl-up, and sit-and-reach tests. Values obtained were compared to sex- and age-based criterion-referenced standards (Healthy Fitness Zone, HFZ). The Previous Day Physical Activity Recall was used to assess after-school physical activity (PA) participation. Independent t tests were used to compare groups. RESULTS: Twenty-five KTx and 11 LTx recipients were tested. The groups were similar in all measures. Both groups demonstrated below normative values for VO2peak and muscle strength. Only 4% of the KTx and 9% of the LTx recipients achieved the HFZ for the PACER and 24% of the KTx and 45% of the LTx attained the HFZ for the curl-up test. Approximately 44% of both groups had percent fat greater than the upper criterion value of the HFZ. Both groups reported spending only 8% of their after-school time participating in physical activity. CONCLUSIONS: Pediatric KTx and LTx recipients have significantly reduced CRF, muscle strength, and physical activity. Routine counseling and encouragement for increased physical activity is recommended as a part of routine care. A randomized clinical exercise intervention trial after pediatric solid organ transplantation is warranted to determine the impact of such lifestyle intervention on improving physical fitness and cardiovascular health.

Objective measures of health-related quality of life over 24 months post-liver transplantation.

Many studies have reported improved health-related quality of life (HRQoL) from pre- to immediate post-orthotopic liver transplantation (OLT). However, few studies have evaluated longitudinal changes over the first 2 yr post-OLT and none have simultaneously examined objective measures of health-related fitness. A total of 50 OLT recipients (32 males,18 females; 51.4 +/- 11.8 yr) completed testing at 2, 6, 12, and 24 months post-OLT. Testing included assessment of exercise capacity (peak VO2), quadriceps muscle strength, body composition, physical activity participation, and self-reported functioning (SF-36). Repeated measures of analysis of variance (ANOVA) with post hoc contrasts was performed to determine differences over time and a second ANOVA assessed differences over time between genders. All patients increased peak VO2, quadriceps muscle strength, and percent body fat (p < 0.0001) from 2 to 24 months. Men and women differed in their changes of peak VO2 and percent body fat (p < 0.05). At 24 months, only 50% of the patients reported participating in regular physical activity. All SF-36 physical measures except general health, improved from 2 to 24 months (p < 0.0001). Measures of health-related fitness and QoL improve over the first 2 yr post-OLT with the greatest gains occurring in the first 6 months and all measures remain lower than recommended for cardiovascular and overall health. A randomized clinical trial of lifestyle modifications such as diet and exercise intervention is warranted to determine the impact of such modifications on HRQoL and fitness post-OLT.

Roles of nutrition and physical activity in musculoskeletal complications before and after liver transplantation.

End-stage liver disease (ESLD) affects thousands of people in the United States annually. Improvements in survival after liver transplantation have broadened the indications for its use as a proven therapy for ESLD, rapidly increasing the number of transplant candidates. However, the number of patients awaiting transplantation far surpasses the donor supply, resulting in lengthy waiting times. During this wait, these patients experience progressive disease-related decompensation that is often accompanied by malnutrition and reduced physical activity. This chronic disease triad can have profound effects on musculoskeletal complications, such as cachexia and osteoporosis. In the absence of proper interventional strategies before transplantation, these complications can intensify after the transplantation, as a result of continued poor nutrition intake, bed rest, and pharmacotherapies. This article discusses levels of physical functioning and nutrition status in both the pre-and post-transplant populations, the risks associated with current levels, and the roles that diet and activity therapies can have to improve outcomes.