Minimum accelerometer wear-time for reliable estimates of physical activity and sedentary behaviour of people receiving haemodialysis

Impact of physical activity on surrogate markers of cardiovascular disease in the haemodialysis population

Background

The haemodialysis (HD) population is sedentary, with substantial cardiovascular disease risk. In the general population, small increases in daily step count associate with significant reductions in cardiovascular mortality. This study explores the relationship between daily step count and surrogate markers of cardiovascular disease, including left ventricular ejection fraction (LVEF) and native T1 (a marker of diffuse myocardial fibrosis), within the HD population.

Methods

This was a post hoc analysis of the association between daily step count and metabolic equivalent of task (MET) and prognostically important cardiac magnetic resonance imaging parameters from the CYCLE-HD study (ISRCTN11299707). Unadjusted linear regression and multiple linear regression adjusted for age, body mass index, dialysis vintage, haemoglobin, hypertension and ultrafiltration volume were performed. Significant relationships were explored with natural cubic spline models with four degrees of freedom (five knots).

Results

A total of 107 participants were included [age 56.3 ± 14.1 years, 79 (73.8%) males]. The median daily step count was 2558 (interquartile range 1054-4352). There were significant associations between steps and LVEF (β = 0.292; P = .009) and steps and native T1 (β = -0.245; P = .035). Further modelling demonstrated most of the increase in LVEF occurred at up to 2000 steps/day and there was an inverse dose-response relationship between steps and native T1, with the most pronounced reduction in native T1 between ≈2500 and 6000 steps/day.

Conclusions

The results suggest an association between daily step count and parameters of cardiovascular health in the HD population. These findings support the recommendations for encouraging physical activity but are not the justification. Further research should evaluate whether a simple physical activity intervention improves cardiovascular outcomes in individuals receiving maintenance HD.

Effects of physical activity planning interventions on reducing sedentary behavior in parent-child dyads: A randomized controlled trial

Effects of parent-child dyad interventions on behavior remain unclear. This randomized controlled trial investigated if, compared with a control condition, three types of physical activity (PA) planning interventions (individual "I-for-me," dyadic "we-for-me," and collaborative "we-for-us") would reduce sedentary behavior (SB) time in parents and their children. The study involved 247 dyads comprising parents (aged 29-66) and their children (aged 9-15), randomized into one of the three types of PA planning-intervention arms or the control condition. Mixed models were applied to analyze data from a preregistered trial (NCT02713438) with the outcome of accelerometer-measured SB time, assessed at 1-week and 36-week follow-ups. Although children's SB remained unaffected by the planning interventions, a small reduction of SB time was found among parents in the collaborative (p = .048) and individual (p = .042) planning conditions. The effects were observed at the 1-week follow-up only. While short-term reductions in parents' SB were achieved, these were not sustained long-term. PA planning interventions delivered to parent-child dyads did not substantially reduce children's SB, which may be due to young people's needs of increased independence from their parents.

Does Wrist-Worn Accelerometer Wear Compliance Wane over a Free-Living Assessment Period? An NHANES Analysis

PURPOSE

Accelerometers are used to objectively measure physical behaviors in free-living environments, typically for seven consecutive days or more. We examined whether participants experience "wear fatigue," a decline in wear time day over day, during typical assessment period acquired in a nationally representative sample of 6- to 80-yr-olds in the United States.

METHODS

Participants were instructed to wear an ActiGraph GT3X+ on their nondominant wrist continuously for seven consecutive days. Participants with seven complete days of recorded data, regardless of wear status, were included in the analyses ( N = 13,649). Wear was scored with the sleep, wake, and nonwear algorithm.

RESULTS

Participants averaged 1248 ± 3.6 min·d -1 (mean ± SE) of wear over the assessment, but wear time linearly decreased from day 1 (1295 ± 3.2 min) to day 7 (1170 ± 5.3 min), resulting in a wear fatigue of -18.1 ± 0.7 min·d -1 ( β ± SE). Wear fatigue did not differ by sex but varied by age-group-highest in adolescents (-26.8 ± 2.4 min·d -1 ) and lowest in older adults (-9.3 ± 0.9 min·d -1 ). Wear was lower in evening (1800-2359 h) and early morning (0000-0559 h) compared with the middle of the day and on weekend days compared with weekdays. We verified similar wear fatigue (-23.5 ± 0.7 min·d -1 ) in a separate sample ( N = 14,631) with hip-worn devices and different wear scoring. Applying minimum wear criteria of ≥10 h·d -1 for ≥4 d reduced wear fatigue to -5.3 and -18.7 min·d -1 for the wrist and hip, respectively.

CONCLUSIONS

Patterns of wear suggest noncompliance may disproportionately affect estimates of sleep and sedentary behavior, particularly for adolescents. Further study is needed to determine the effect of wear fatigue on longer assessments.

Determining minimum number of valid days for accurate estimation of sedentary behaviour and awake-time movement behaviours using the ActivPAL3 in nursing home residents

INTRODUCTION

Scarce evidence is available about the minimum number of valid days wearing the activPAL3 to obtain a precise estimate of sedentary behaviour (SB) and awake-time movement behaviours (ATMB) in nursing home (NH) residents. The study aimed to determine the minimum number of valid days required for accurately estimate SB and ATMB using the activPAL3 device in NH residents. It also investigated how the starting point of a day (the 24-h period) impacted reliability.

METHODS

Participants wore an activPAL3 for 7 consecutive days. The data was classified in two-time blocks (00:00 Ante Meridiem (AM)-00:00 AM midnight vs 12:00 Post Meridiam (PM) -12:00 PM midday) and the sample was stratified into two groups according to their capacity to stand and walk, to examine if timing of sampling or physical functioning affected minimum wear time. SB, ATMB, sociodemographic, and health-related variables were collected. Sensitivity of the time-blocks were tested through the dispersion frequencies and differences between blocks through Kolmogorov-Smirnov test for normality; parametric variables through two-related means T-test and Wilcoxon test for non-parametric data. Reliability was assessed with the Cronbach's Alpha and the intra-class correlation coefficient (ICC), using a one-factor model estimating the reliability for each measurement day loading in the same latent factor.

RESULTS

Ninety-five NH residents (81.1% women; age = 85.8 ± 7.2 years) were included. The midnight block had higher reliability, sensitivity and no statistically significant differences between days were found. At least three consecutive days of monitoring were necessary to achieve a reliability of ICC ≥ 0.8 for those NH residents able to stand and walk and six days for those unable.

CONCLUSIONS

NH residents who are able to stand and walk require a minimum of three consecutive days wearing the device, while those who are unable require at least six days due to their highly homogenous daily routines and sensitivity to PA events. Regardless of the activPAL3 recording start time, data processing should reference the midnight time block.

Physical activity planning interventions, body fat and energy-dense food intake in dyads: ripple, spillover, or compensatory effects?

OBJECTIVES

It is unclear if planning to change one behavior may prompt changes in other health behaviors or health outcomes. This study tested if physical activity (PA) planning interventions may result in (i) a body fat reduction in target persons and their dyadic partners (a ripple effect), (ii) a decrease in energy-dense food intake (a spillover effect), or an increase in energy-dense food intake (a compensatory effect).

METHOD

N = 320 adult-adult dyads were assigned to an individual ('I-for-me'), dyadic ('we-for-me'), or collaborative ('we-for-us') PA planning intervention or a control condition. Body fat and energy-dense food intake were measured at baseline and at the 36-week follow-up.

RESULTS

No Time x Condition effects were found for target persons' body fat. There was a reduction in body fat among partners participating in any PA planning intervention, compared to the control condition. Across conditions, target persons and partners reduced energy-dense food intake over time. The reduction was smaller among target persons assigned to the individual PA planning condition compared to the control condition.

CONCLUSIONS

PA planning interventions delivered to dyads may result in a ripple effect involving body fat reduction among partners. Among target persons, the individual PA planning may activate compensatory changes in energy-dense food intake.

Factors associated with postural balance in patients with end-stage renal disease on hemodialysis

BACKGROUND

Patients with end-stage renal disease on hemodialysis have postural balance impairments due to uremic syndrome and hemodialysis complications. This study evaluated the factors associated with postural balance in patients on hemodialysis.

METHODS

This cross-sectional study included patients on hemodialysis [n = 93, 62.0 (16.0) years]. Postural balance was evaluated using a force plate in a static position with eyes opened and eyes closed on a firm surface and with eyes opened on a foam surface to register the center of pressure path length. Physical function was assessed by isometric handgrip force, the 5-repetition sit-to-stand test, and gait speed. The level of physical activity and quality of life were evaluated by accelerometry and the 36-Item Short Form Health Survey, respectively.

FINDINGS

After adjustment for potential confounders, the multiple linear regression analysis showed that the presence of diabetes mellitus and neurological disease and gait speed were significantly associated with the center of pressure path length in the eyes opened test (R² = 0.263; p < 0.001). The center of pressure path length in the eyes closed test was significantly associated with the presence of neurological disease (R² = 0.177; p = 0.002). The center of pressure path length in the eyes opened on a foam surface test was significantly associated with the presence of diabetes mellitus (R² = 0.223; p < 0.001).

INTERPRETATION

Poor postural balance was associated with the presence of diabetes mellitus and neurological disease and a slower gait speed in patients on hemodialysis.

Use of a wearable accelerometer to evaluate physical frailty in people receiving haemodialysis

BACKGROUND

Physical frailty is a major health concern among people receiving haemodialysis (HD) for stage-5 chronic kidney disease (CKD-5). Wearable accelerometers are increasingly being recommended to objectively monitor activity levels in CKD-5 and recent research suggests they may also represent an innovative strategy to evaluate physical frailty in vulnerable populations. However, no study has yet explored whether wearable accelerometers may be utilised to assess frailty in the context of CKD-5-HD. Therefore, we aimed to examine the diagnostic performance of a research-grade wearable accelerometer in evaluating physical frailty in people receiving HD.

METHODS

Fifty-nine people receiving maintenance HD [age = 62.3 years (SD = 14.9), 40.7% female] participated in this cross-sectional study. Participants wore a uniaxial accelerometer (ActivPAL) for seven consecutive days and the following measures were recorded: total number of daily steps and sit-to-stand transitions, number of daily steps walked with cadence < 60 steps/min, 60-79 steps/min, 80-99 steps/min, 100-119 steps/min, and ≥ 120 steps/min. The Fried phenotype was used to evaluate physical frailty. Receiver operating characteristics (ROC) analyses were performed to examine the diagnostic accuracy of the accelerometer-derived measures in detecting physical frailty status.

RESULTS

Participants classified as frail (n = 22, 37.3%) had a lower number of daily steps (2363 ± 1525 vs 3585 ± 1765, p = 0.009), daily sit-to-stand transitions (31.8 ± 10.3 vs 40.6 ± 12.1, p = 0.006), and lower number of steps walked with cadence of 100-119 steps/min (336 ± 486 vs 983 ± 797, p < 0.001) compared to their non-frail counterparts. In ROC analysis, the number of daily steps walked with cadence ≥ 100 steps/min exhibited the highest diagnostic performance (AUC = 0.80, 95% CI: 0.68-0.92, p < 0.001, cut-off ≤ 288 steps, sensitivity = 73%, specificity = 76%, PPV = 0.64, NPV = 0.82, accuracy = 75%) in detecting physical frailty.

CONCLUSIONS

This study provided initial evidence that a wearable accelerometer may be a useful tool in evaluating physical frailty in people receiving HD. While the total number of daily steps and sit-to-stand transitions could significantly discriminate frailty status, the number of daily steps walked with cadences reflecting moderate to vigorous intensity of walking may be more useful in monitoring physical frailty in people receiving HD.

The Dyadic Interplay Between Relationship Satisfaction, Perceived Positive and Negative Social Control, and a Reduction of Sedentary Behavior Time

BACKGROUND

Both the close relationship processes and health model and the dyadic health influence model posit that beliefs about the relationship (e.g., relationship satisfaction) and influence strategies (e.g., social control) serve as mediators of health behavior change. The evidence for such mediation is limited.

PURPOSE

This study investigated two competing hypotheses that arise from these models: (1) perceived use of positive and negative social control (attempts to influence the partner's behaviors) predict sedentary behavior (SB) indirectly, via relationship satisfaction; or (2) relationship satisfaction predicts SB indirectly, via positive and negative social control.

METHODS

Data from 320 dyads (target persons and their partners, aged 18-90 years), were analyzed using mediation models. SB time was measured with GT3X-BT accelerometers at Time 1 (T1; baseline) and Time 3 (T3; 8 months following baseline). Relationship satisfaction and social control were assessed at T1 and Time 2 (T2; 2 months following baseline).

RESULTS

Higher T1 relationship satisfaction among target persons predicted target persons' reporting of higher T2 negative control from partners, which in turn predicted lower T3 SB time among target persons. Lower T1 relationship satisfaction among partners predicted target persons' reporting of higher T2 perceived negative control from partners, which predicted lower T3 SB time among target persons. On average, both members of the dyad reported moderate-to-high relationship satisfaction and low-to-moderate negative control.

CONCLUSIONS

In contrast to very low levels of negative control, its low-to-moderate levels may be related to beneficial behavioral effects (lower SB time) among target persons reporting moderate-to-high relationship satisfaction.

Pilot Study of a Wearable Hydration Monitor in Haemodialysis Patients: Haemodialysis Outcomes & Patient Empowerment Study 02

Introduction

We aimed to assess the validity and reproducibility of a wearable hydration device in a cohort of maintenance dialysis patients.

Methods

We conducted a prospective, single-arm observational study on 20 haemodialysis patients between January and June 2021 in a single centre. A prototype wearable infrared spectroscopy device, termed the Sixty device, was worn on the forearm during dialysis sessions and nocturnally. Bioimpedance measurements were performed 4 times using the body composition monitor (BCM) over 3 weeks. Measurements from the Sixty device were compared with the BCM overhydration index (litres) pre- and post-dialysis and with standard haemodialysis parameters.

Results

12 out of 20 patients had useable data. Mean age was 52 ± 12.4 years. The overall accuracy for predicting pre-dialysis categories of fluid status using Sixty device was 0.55 [K = 0.00; 95% CI: -0.39-0.42]. The accuracy for the prediction of post-dialysis categories of volume status was low [accuracy = 0.34, K = 0.08; 95% CI: -0.13-0.3]. Sixty outputs at the start and end of dialysis were weakly correlated with pre- and post-dialysis weights (r = 0.27 and r = 0.27, respectively), as well as weight loss during dialysis (r = 0.31), but not ultrafiltration volume (r = 0.12). There was no difference between the change in Sixty readings overnight and the change in Sixty readings during dialysis (mean difference 0.09 ± 1.5 kg), [t(39) = 0.38, p = 0.71].

Conclusion

A prototype wearable infrared spectroscopy device was unable to accurately assess changes in fluid status during or between dialysis sessions. In the future, hardware development and advances in photonics may enable the tracking of interdialytic fluid status.

Insights into effects of individual, dyadic, and collaborative planning interventions on automatic, conscious, and social process variables

OBJECTIVE

Going beyond the effects of individual planning ("I-for-me"), we investigate the associations of dyadic ("we-for-me") and collaborative ("we-for-us") planning with automatic, conscious, and social process variables that may elucidate the differences through which these three types of planning operate. We tested the effects of three planning interventions on: (1) habit strength, representing an automatic process, (2) the use of individual planning, representing a conscious process, (3) the use of collaborative planning, representing conscious and social processes, and (4) collaborative social control, representing a social process.

METHODS

N = 320 adults were randomly assigned to one of four conditions: (1) the active control condition, (2) the individual planning condition, (3) the dyadic planning condition, or (4) the collaborative planning condition. Self-reported data on habit strength, the use of individual planning, the use of collaborative planning, and collaborative social control were assessed at baseline and at the 9-week follow-up. Analyses used linear mixed modelling.

RESULTS

Compared to the control group, participants in the individual planning condition had stronger habits at the 9-week follow-up. Those in the dyadic planning condition reported higher levels of the use of collaborative planning and higher levels of collaborative social control at the follow-up. Finally, compared to those assigned to the control group, participants in the collaborative planning condition reported stronger habits, higher levels of the use of both individual and collaborative planning, and higher levels of collaborative social control at the follow-up.

CONCLUSIONS

Individual, dyadic, and collaborative planning interventions may result in distinct patterns of changes in the variables representing automatic, conscious, and social processes. In particular, changes in automatic, conscious and social process variables, evoked by the collaborative "we-for-us" planning intervention may reflect the major regulatory effort of forming joint plans and subsequently integrating regular joint exercise into the weekly schedule.

Detection and Monitoring of Viral Infections via Wearable Devices and Biometric Data

Mounting clinical evidence suggests that viral infections can lead to detectable changes in an individual's normal physiologic and behavioral metrics, including heart and respiration rates, heart rate variability, temperature, activity, and sleep prior to symptom onset, potentially even in asymptomatic individuals. While the ability of wearable devices to detect viral infections in a real-world setting has yet to be proven, multiple recent studies have established that individual, continuous data from a range of biometric monitoring technologies can be easily acquired and that through the use of machine learning techniques, physiological signals and warning signs can be identified. In this review, we highlight the existing knowledge base supporting the potential for widespread implementation of biometric data to address existing gaps in the diagnosis and treatment of viral illnesses, with a particular focus on the many important lessons learned from the coronavirus disease 2019 pandemic.

Physical activity moderates the association between executive function and functional connectivity in older adults

Recent evidence suggests that physical activity may influence the functional connectivity of the aging brain. The purpose of this study was to examine the influence of physical activity on the association between executive function and functional connectivity of key brain networks and graph theory metrics in community-dwelling older adults. Participants were 47 older adults (M = 73 years; SD = 5.92) who participated in neuropsychological testing, physical activity measurements, and magnetic resonance imaging (MRI). Seed-to-voxel moderation analyses and graph theory analyses were conducted. Physical activity was significantly positively associated with default mode network functional connectivity (DMN FC; Posterior Cingulate Gyrus, p-FDR = 0.005; Frontal Pole (L), p-FDR = 0.005; Posterior Cingulate Gyrus, p-FDR = 0.006; Superior Frontal Gyrus (L), p-FDR = 0.016) and dorsal attention network functional connectivity (DAN FC; Inferior Frontal Gyrus Pars Opercularis (R), p-FDR = 0.044). The interaction between physical activity and executive function on the DMN FC and DAN FC was analyzed. The interaction between executive function and physical activity was significantly associated with DMN FC. When this significant interaction was probed, the association between physical activity and DMN FC differed between levels of high and low executive function such that the association was only significant at levels of high executive function. These results suggest that greater physical activity in later life is associated with greater DMN and DAN FC and provides evidence for the importance of physical activity in cognitively healthy older adults.

Patterns and correlates of sedentary behaviour among people with multiple sclerosis: a cross-sectional study

High levels of sedentary behaviour are associated with poor health outcomes in people with multiple sclerosis (MS). Identifying modifiable correlates of sedentary behaviour for people with MS is essential to design effective intervention strategies to minimise sedentary time. This study aimed to quantify patterns and identify correlates of sedentary behaviour among adults with MS. Fatigue, self-efficacy, walking capability, the physical and psychological impact of MS, health-related quality of life, and participation and autonomy were assessed by questionnaire. Participants wore an activPAL monitor. Total (min/day), prolonged bouts (≥ 30 min) and breaks in sedentary time were calculated. Associations were examined using regression analysis adjusted for demographic and clinical confounders. Fifty-six adults with MS participated (mean ± SD age: 57.0 ± 9.25 years; 66% female). Self-efficacy for control over MS was associated with sedentary time (β = 0.16, 95% CI 0.01, 0.30). Self-efficacy in function maintenance (β = 0.02, 95% CI 0.00, 0.04), health-related quality of life (EuroQol-5D) (β = 31.60, 95% CI 7.25, 55.96), and the autonomy indoors subscale of the Impact on Participation and Autonomy Questionnaire (β = − 5.11, 95% CI − 9.74, − 0.485) were associated with breaks in sedentary time. Future studies should consider self-efficacy, health-related quality of life and participation and autonomy as potential components of interventions to reduce sedentary behaviour.

Can individual, dyadic, or collaborative planning reduce sedentary behavior? A randomized controlled trial

RATIONALE

Although effects of individual planning interventions on physical activity (PA) are well established, less is known about the relationships between planning and sedentary behavior (SB).

OBJECTIVE

This study evaluated the efficacy of individual planning, dyadic planning (i.e., joint planning, targeting the behavior of one person only: the target person), and collaborative planning (i.e., joint planning and joint behavioral performance) on sedentary behavior among dyads.

METHODS

Dyads (N = 320 target persons and their partners, aged 18-90 years) were randomized into three PA planning conditions (individual, dyadic, or collaborative) or an active (education) control condition. Main outcomes, i.e., sedentary time, proportion of time spent in SB and light-intensity PA, proportion of time spent in SB and total PA were measured with GT3X-BT accelerometers at baseline, 1-week follow-up, and 36-week follow-up. Two-level models with measurement points nested in participants were fit, separately for target persons and partners.

RESULTS

Findings for target persons obtained at 1-week follow-up indicated that in the collaborative planning condition SB time significantly decreased, compared to the control condition (p = .013). There was an improvement in the proportion of time spent in SB and light-intensity PA (p = .019), and the proportion of time spent in SB and total PA (p = .018), indicating that SB time was displaced by PA. Effects of individual and dyadic planning were not significant, compared to the control condition. None of interventions had a significant effect on SB indices at 36-week follow-up. Regarding dyadic partners, there were no effects of planning interventions at 1-week follow-up or 36-week follow-up, compared to the control condition.

CONCLUSIONS

Collaborative planning may prompt a short-term reduction of SB time and result in a shift towards a healthier balance between SB time and PA time among target persons, who did not adhere to PA guidelines at baseline.

The Relations Between Physical Activity Level, Executive Function, and White Matter Microstructure in Older Adults

The population of older adults is increasing, indicating a need to examine factors that may prevent or mitigate age-related cognitive decline. The current study examined whether microstructural white matter characteristics mediated the relation between physical activity and executive function in older adults without any self-reported psychiatric and neurological disorders or cognitive impairment (N = 43, mean age = 73 y). Physical activity was measured by average intensity and number of steps via accelerometry. Diffusion tensor imaging was used to examine microstructural white matter characteristics, and neuropsychological testing was used to examine executive functioning. Parallel mediation models were analyzed using microstructural white matter regions of interest as mediators of the association between physical activity and executive function. Results indicated that average steps was significantly related to executive function (β = 0.0003, t = 2.829, P = .007), while moderate to vigorous physical activity was not (β = 0.0007, t = 1.772, P = .08). White matter metrics did not mediate any associations. This suggests that microstructural white matter characteristics alone may not be the mechanism by which physical activity impacts executive function in aging.

Circulating endotoxin and inflammation: associations with fitness, physical activity and the effect of a six-month programme of cycling exercise during haemodialysis

BACKGROUND

Intradialytic cycling (IDC) may provide cardiovascular benefit to individuals receiving haemodialysis, but the exact mechanism behind these improvements remains unclear. The primary aim of this study was to investigate the effect of a six-month programme of IDC on circulating endotoxin (secondary analysis from the CYCLE-HD trial). Secondary aims were to investigate changes in circulating cytokines (IL-6, IL-10, TNF-α, CRP and IL6/IL-10), and their associations with physical activity, fitness and cardiovascular outcomes.

METHODS

Participants were randomised to either a six-month programme of IDC (thrice weekly, moderate intensity cycling at RPE 12-14) in addition to usual care (n = 46), or usual care only (control group; n = 46). Outcome measures were obtained at baseline and then again at six months.

RESULTS

There was no significant (P=0.137) difference in circulating endotoxin between groups at 6-months (IDC group: 0.34±0.08 EU/mL; control group: 0.37±0.07 EU/mL). There were no significant between group difference in any circulating cytokine following the 6-month programme of IDC. Higher levels of physical activity and fitness were associated with lower levels of endotoxin, IL-6, CRP, and IL-6/IL-10.

CONCLUSIONS

Our data show no change in circulating endotoxin or cytokines following a 6-month programme of IDC. However, higher levels of physical activity outside of haemodialysis were associated with lower levels of inflammation.

Feasibility and acceptability of a technology-based, rural weight management intervention in older adults with obesity

BACKGROUND

Older adults with obesity residing in rural areas have reduced access to weight management programs. We determined the feasibility, acceptability and preliminary outcomes of an integrated technology-based health promotion intervention in rural-living, older adults using remote monitoring and synchronous video-based technology.

METHODS

A 6-month, non-randomized, non-blinded, single-arm study was conducted from October 2018 to May 2020 at a community-based aging center of adults aged ≥65 years with a body mass index (BMI) ≥30 kg/m2. Weekly dietitian visits focusing on behavior therapy and caloric restriction and twice-weekly physical therapist-led group strength, flexibility and balance training classes were delivered using video-conferencing to participants in their homes. Participants used a Fitbit Alta HR for remote monitoring with data feedback provided by the interventionists. An aerobic activity prescription was provided and monitored.

RESULTS

Mean age was 72.9±3.9 years (82% female). Baseline anthropometric measures of weight, BMI, and waist circumference were 97.8±16.3 kg, 36.5±5.2 kg/m2, and 115.5±13.0 cm, respectively. A total of 142 participants were screened (n=27 ineligible), and 53 consented. There were nine dropouts (17%). Overall satisfaction with the trial (4.7+ 0.6, scale: 1 (low) to 5 (high)) and with Fitbit (4.2+ 0.9) were high. Fitbit was worn an average of 81.7±19.3% of intervention days. In completers, mean weight loss was 4.6±3.5 kg or 4.7±3.5% (p< 0.001). Physical function measures of 30-s sit-to-stand repetitions increased from 13.5±5.7 to 16.7±5.9 (p< 0.001), 6-min walk improved by 42.0±77.3 m (p=0.005) but no differences were observed in gait speed or grip strength. Subjective measures of late-life function improved (3.4±4.7 points, p< 0.001).

CONCLUSIONS

A technology-based obesity intervention is feasible and acceptable to older adults with obesity and may lead to weight loss and improved physical function.

CLINICAL TRIAL REGISTRATION

Registered on Clinicaltrials.gov # NCT03104205 . Registered on April 7, 2017. First participant enrolled on October 1st, 2018.

Validation of the Chinese version of the low physical activity questionnaire (LoPAQ) with ActiGraph accelerometer in hemodialysis patients

Background

Valid instruments for measuring physical activity at the low end of the physical activity range and producing quantitative results are required among dialysis patients who are extremely inactive. This study aimed to translate and adapt a Chinese version of the low physical activity questionnaire (LoPAQ) and to examine its reliability and validity among hemodialysis patients.

Methods

This was a cross-sectional study. The LoPAQ was translated into Chinese and culturally adapted following the standardized questionnaire adaptation process. Participants wore an ActiGraph for seven consecutive days and were asked to complete the Chinese version of the LoPAQ (C-LoPAQ) following the ActiGraph monitoring period. The criterion validity of the C-LoPAQ was examined with accelerometers using Spearman’s correlation coefficients. Bland-Altman plots were adopted to determine the absolute agreement between methods. The test-retest reliability was analyzed using the intraclass correlation coefficient (ICC).

Results

Eighty-five hemodialysis patients had valid accelerometers and C-LoPAQ data. The total walking time reported on LoPAQ was correlated with step counts by ActiGraph (rho = 0.47, p < 0.01). A moderate correlation was also observed between the C-LoPAQ and the ActiGraph-measured physical activity for total calories (rho = 0.44, p < 0.01). There was a fair correlation between ActiGraph-measured sedentary time and C-LoPAQ-measured inactive time (rho = 0.22, p < 0.05). The test-retest reliability coefficients of C-LoPAQ ranged from 0.30 to 0.66.

Conclusions

The C-LoPAQ demonstrated moderate validity for measuring low levels of physical activity, especially walking, and total kilocalories of physical activity among hemodialysis patients in China.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02230-3.