An Integrative Literature Review of Heart Rate Variability Measures to Determine Autonomic Nervous System Responsiveness Using Pharmacological Manipulation.

BACKGROUND: Heart rate variability (HRV) is defined as the difference in the timing of intervals between successive heartbeats and is used as a surrogate measure to the responsiveness of the autonomic nervous system. A review and synthesis of HRV as an indicator of autonomic nervous system responsiveness to pharmacologic stimulation/blockade of sympathetic and/or parasympathetic nervous system branches have not been completed. PURPOSE: The aim of this integrative review is to synthesize research examining pharmacological modulation of the autonomic nervous system and the response of time domain, frequency domain, and nonlinear measures of HRV. CONCLUSIONS: Sympathetic nervous system blockade resulted in a consistent decrease in the standard deviation of normal-normal interval metric across studies. Stimulation of the parasympathetic nervous system was associated with an increase in several time, frequency, and nonlinear HRV indices, whereas blockade of the parasympathetic nervous system led to a decrease in similar indices. CLINICAL IMPLICATIONS: Recommendations to improve the reproducibility of future HRV research are provided for standardization of recording, analysis, and metric decisions and more thorough reporting of HRV indices in published studies. Alterations in autonomic nervous system input to the cardiovascular system are associated with an increased risk for adverse patient outcomes and increased mortality; therefore, understanding the influence of pharmacologic autonomic nervous system modulation on HRV indices and important considerations for reproducible HRV research design will inform future translational research on cardiovascular risk reduction.

Cognitive Function and Self-Management Behaviors in Older Adults With Type 2 Diabetes.

BACKGROUND: Type 2 diabetes (T2D) is strongly associated with cognitive impairment. Decreased cognitive function could affect daily self-management behaviors critical for people with T2D. Executive function is significant for daily self-management, and decreased subjective cognitive function could be an early indicator of poor daily self-management. However, little is known about whether executive or subjective cognitive function affects daily self-management behaviors in older adults. OBJECTIVES: We investigated the effect of executive function or subjective cognitive function on daily self-management behaviors (diet, glucose management, physical activity, and physician contact) in older adults with T2D. METHODS: We used a cross-sectional, observational design with convenience sampling of 84 adults aged ≥60 years with T2D. Telephone-administered cognitive function tests measured participants' overall cognitive and executive function levels. Subjective cognitive function, diabetes self-management, and covariates, including demographic information (age, gender, race/ethnicity, and level of education), body mass index, depressive symptoms, and diabetes duration, were assessed using online surveys. Data were analyzed using bivariate correlation and backward stepwise regression. RESULTS: The mean age of the sample was 68.46 ± 5.41 years. Participants were predominantly female and White, and the majority had normal cognitive function. Controlling for demographics, body mass index, depressive symptoms, and diabetes duration, a decrease in executive function indicated by a greater number of errors made during the telephone-administered Oral Trail Making Test Part B relative to the sample was associated with poorer adherence to physician contact behaviors. Subjective cognitive function was not associated with any self-management behaviors. DISCUSSION: A reduction in executive function was associated with poorer adherence to physician contact behaviors in older adults with T2D and normal cognitive function; lack of adherence to physician contact behaviors could be an early indicator of declining cognitive function. Difficulties or changes in routine diabetes self-management behaviors should be closely monitored in older adults. Cognitive assessment should be followed when needed.

Pain Interference in End Stage Kidney Disease is Associated with Changes in Gut Microbiome Features Before and After Kidney Transplantation.

BACKGROUND: Pain, a common debilitating symptom among kidney transplant recipients (KTRs), is among the most common and undertreated symptoms after kidney transplantation. AIMS: Characterize associations between gut microbiome features and pain interference before and after kidney transplantation. DESIGN: Longitudinal, repeated measures study, collecting fecal specimens and pain interference data pretransplant and 3 months posttransplant. SETTING: Participants were recruited at the kidney transplant clinic at the University of Illinois Hospital & Health Sciences System. PARTICIPANTS/SUBJECTS: 19 living donor kidney transplant recipients. METHODS: We assessed fecal microbial community structure with shotgun metagenomic sequencing; we used pain interference scores derived from the Patient-Reported Outcomes Measurement Information System-57. RESULTS: We measured a reduction in the Shannon diversity index in both groups after transplantation but observed no significant differences between groups at either time point. We did observe significant differences in fecal microbial Bray-Curtis similarity index among those reporting pain interference pre- transplant versus no pain interference at 3-months posttransplant (R = .306, p = .022), and between pain interference groups at posttransplant (R = .249, p = .041). Pairwise models showed significant differences between groups posttransplant in relative abundances of several taxa, including a 5-fold reduction.ßin Akkermansia among those with pain interference and a higher relative abundance of taxa associated with chronic inflammation in those with pain interference posttransplant. Functional gene analysis identified two features that were significantly enriched in those with pain interference, including a peptide transport system gene. CONCLUSIONS: Gut microbiota community structure differs between groups with and without pain interference at 3 months after kidney transplantation. Several taxa involved in intestinal barrier integrity and chronic inflammation were associated with posttransplant pain.

Accelerometer Use to Measure Physical Activity in Older Adults With Coronary Artery Disease: An Integrative Review.

BACKGROUND: Physical activity is necessary for improved health outcomes among older adults with coronary artery disease (CAD), and device-based assessment of physical activity is preferred for accurate measurement. Many previous studies have applied accelerometry to examine physical activity in this population, but no reviews have systematically examined the application of various accelerometers to measure physical activity in older adults with CAD. OBJECTIVE: This integrative review aimed to examine accelerometry application to measure physical activity in older adults with CAD and provide guidance for accelerometer selection and settings. METHODS: Six databases-CINAHL, PubMed, PsycINFO, Scopus, EMBASE, and Google Scholar-were searched for information sources. Authors of selected studies applied accelerometers to measure physical activity and included adults 60 years or older with CAD. RESULTS: Among 12 studies reviewed, 5 were randomized controlled trials, and most used an age cutoff of 65 years for older adults. The most frequently used accelerometer was the RT3, and the most common device placement was the waist/hip. Data collection duration was typically 3 consecutive days. However, many study authors did not report epoch length, sampling frequency, number of valid hours of data required per day, total number of valid days of data needed, or criteria for nonwear time. CONCLUSIONS: On the basis of data synthesis and previous study results, triaxial research-grade accelerometers, waist/hip placement, and a 5- to 7-day monitoring period are recommended for measuring physical activity in older adults with CAD. However, the study purpose, device and participant characteristics, and physical activity outcomes of interest should be considered during device selection.

The Relationship Between Sleep and Brain Function in Older Adults With Chronic Kidney Disease and Self-Identified Cognitive Impairment.

Older adults with chronic kidney disease (CKD) are at risk for cognitive impairment and sleep disturbances. The purpose of the current study was to investigate the relationship between sleep and brain structure/function in older adults with CKD and self-identified cognitive impairment. The sample (N = 37) had a mean age of 68 years (SD = 4.9 years), estimated glomerular filtration rate of 43.7 mL/min/1.73m2 (SD = 10.98), median sleep time of 7.4 hours, and was 70% female. Sleeping <7.4 hours, compared to ≥7.4 hours, was associated with better attention/information processing (ß = 11.46, 95% confidence interval [CI] [3.85, 19.06]) and better learning/memory (ß = 2.06, 95% CI [0.37, 3.75]). Better sleep efficiency was associated with better global cerebral blood flow (ß = 3.30, 95% CI [0.65, 5.95]). Longer awake length after sleep onset was associated with worse fractional anisotropy of the cingulum (ß = -0.01, 95% CI [-0.02, -0.003]). Sleep duration and continuity may be related to brain function in older adults with CKD and self-identified cognitive impairment. [Journal of Gerontological Nursing, 49(7), 31-39.].

Connecting the past to the present: A historical review of exercise training for peripheral artery disease.

Peripheral artery disease (PAD), a prevalent manifestation of atherosclerosis, is associated with increased cardiovascular morbidity and mortality as well as decreased functional ability. Exercise training for PAD is acknowledged to be a highly effective treatment, which improves walking ability and cardiovascular risk. The historical development of this treatment has not been the focus of a report. Therefore, we present a historical review of research on exercise training for PAD. Overall, this body of knowledge has provided strong evidence of the efficacy of supervised exercise training (SET) to improve walking ability for patients with claudication due to PAD. SET, using intermittent bouts of walking exercise to moderate claudication pain on a treadmill, is considered the most efficacious mode of exercise to improve walking ability in patients with claudication. This compelling evidence published over the past 60 years was evaluated by the Centers for Medicare & Medicaid Services in 2017, which culminated in a national coverage determination for SET to improve symptomatic PAD. Future directions include determining optimal delivery strategies for SET and further elucidation of the mechanisms of improvement in walking ability resulting from SET. In addition, alternative forms of exercise should be evaluated and effective home- and community-based exercise interventions should be assessed. There is an enormous need to increase the inclusion of women and racial and ethnic minority groups in studies. It is to be hoped that researchers will continue with new innovative research and persistence in the treatment of claudication due to PAD.

Exercise Training and Cognitive Function in Kidney Disease: Protocol for a Pilot Randomized Controlled Trial.

BACKGROUND: Chronic kidney disease (CKD) is extremely common in older adults and is associated with cognitive impairment. It is hypothesized that accelerated cognitive decline in CKD results from a vascular dysfunction-induced reduction in the integrity of the brain white matter. OBJECTIVE: The aim of this study was to describe the protocol for a study to evaluate whether exercise training provides a cerebroprotective effect by improving cerebrovascular health. METHODS: This is a randomized controlled trial investigating feasibility and effect size. RESULTS: Participants will be randomized to either a 24-week, home-based, walking program or a usual care group. Participants will undergo evaluation of cognitive function, brain structure via magnetic reasoning imaging, physical function, physical activity, and vascular function. The primary outcome is change in cognitive function. DISCUSSION: The findings of this study will help determine whether exercise training influences cognitive function during a therapeutic window in the disease process of cognitive impairment in older adults with CKD. CONCLUSION: This protocol describes a study to evaluate cognition and brain structure following a home-based exercise program to an at-risk population.

Independent associations between sleep duration, gamma gap, and cognitive function among older adults: Results from the NHANES 2013-2014.

This study examined whether gamma gap mediated the association between sleep and cognitive function. Data from NHANES 2013-2014 were used. Three tests were used to measure cognitive function. Sleep was measured by three single questions. Gamma gap was calculated by subtracting albumin from total protein. Participants were 1392 older adults (53.2% females). Approximately 12% reported being told having sleep disorder, 1/3 reported having trouble sleeping, 25.9% had short sleep, and 12.5% had long sleep. Sleep disorders and sleep quality were not associated with cognitive function. Long sleep duration was an independent risk factor of reduced cognitive function on immediate recall, delayed recall, and executive function. Elevated gamma gap was also an independent risk factor of lower cognitive function. In a representative sample of older adults in the US, gamma gap and sleep duration were independent predictors of cognitive function. This study highlights the need for sleep assessment among older adults.

Impact of worries associated with COVID-19 on diabetes-related psychological symptoms in older adults with Type 2 diabetes.

This study examined the associations between worries associated with COVID-19, diabetes-specific distress, and depressive symptoms in older adults with type 2 diabetes (T2D), who are particularly vulnerable to COVID-19 and its psychological impacts. A cross-sectional online survey was conducted with 84 older adults with T2D from June to December 2020. Participants had little to moderate worries associated with COVID-19, with the greatest worries about the economy recession, followed by a family member catching COVID-19, lifestyle disruptions, and overwhelmed local hospitals. Bivariate correlation and tobit regression revealed that increases in worries associated with COVID-19 were associated with increased diabetes distress and depressive symptoms. Specifically, worries associated with COVID-19 increased diabetes-specific emotional burden and physician-related and regimen-related distress. Increased diabetes distress and depressive symptoms worsened by COVID-19 may ultimately lead to poor glucose control. Additional assessment by mental health experts should be considered for older adults with T2D during and after infectious disease pandemic.

Suicide Risk Management Protocol for a Randomized Controlled Trial of Cardiac Patients Reporting Hopelessness.

BACKGROUND: Investigators conducting studies that include potentially suicidal individuals are obligated to develop a suicide risk management (SRM) protocol. There is little available in the literature to guide researchers in SRM protocol development. OBJECTIVES: The aim of the study was to describe an SRM protocol developed for a randomized controlled trial (RCT) currently enrolling cardiac patients who report moderate to severe levels of hopelessness. METHODS: The SRM protocol identifies suicidal ideation and measures ideation severity through use of the Columbia-Suicide Severity Rating Scale risk factor questions. Based on responses, study participants are deemed safe or at low, moderate, or high risk for suicide. The SRM protocol guides research staff through a plan of action based on risk level. The protocol further guides staff through a plan over the course of this prospective study-from hospital enrollment to home-based visits. RESULTS: Research staff are well trained to identify suicidal ideation risk factors, initiate specific questioning about suicidal intent, determine level of risk, identify protective factors and a safe environment, and make referrals if needed. Of the 51 patients hospitalized with cardiac disease who reported moderate to severe hopelessness, 43 scored at a safe suicide risk level and 8 scored at low risk. Thirty-five of the 51 patients enrolled in the RCT. Of the 35 participants who received home visits to date, there have been three instances of low and one instance of moderate suicide risk. The SRM protocol has been consistently and accurately used by research personnel in both hospital and home settings. One modification has been made to the protocol since study activation, namely, the addition of an assessment of counseling history and encouragement of continued counseling. Booster training sessions of research staff will continue throughout the course of the RCT. DISCUSSION: Use of the SRM protocol identifies study participants who are safe or at risk for suicide in both hospital and home settings, and research staff can refer participants accordingly. CONCLUSION: The SRM protocol developed for this RCT can serve as a model in the development of SRM protocols for future research in acute care, community, or home-based settings.

Cognitive and vascular function in older adults with and without CKD.

BACKGROUND: Cognitive impairment is a common complication of aging that is also associated with chronic kidney disease (CKD). Vascular dysfunction has been implicated as a potential cause of cognitive impairment in older adults, with particular deficits noted in those with CKD. AIMS: To determine the differences in cognitive function and vascular compliance in older adults with and without CKD with preclinical cognitive impairment and the relationship between these factors. METHODS: Utilizing a cross-sectional approach, 48 older adults with preclinical cognitive impairment (24 with and 24 without CKD) were evaluated for performance on a test of global cognition and executive function, and vascular compliance via tonometry and ultrasound. RESULTS: Cognitive function and some indicators of vascular function were significantly different in older adults with and without CKD. Global cognition was correlated with carotid-femoral pulse wave velocity (r = - 0.36, p = 0.02) in the entire sample. Vascular function was not correlated with executive function. DISCUSSION: Older adults with preclinical cognitive impairment and CKD had different cognitive and vascular function than those without CKD, and an indicator of vascular function may have a relationship with cognitive function in older adults. CONCLUSIONS: The findings of this study support the assessment of cognitive and vascular function in older adults with and without CKD with preclinical cognitive impairment.

Heart up! RCT protocol to increase physical activity in cardiac patients who report hopelessness: Amended for the COVID-19 pandemic.

Hopelessness is associated with decreased physical activity (PA) and increased adverse events and death in patients with ischemic heart disease (IHD). Rates of PA in patients with IHD continue to be low in both hospital-based cardiac rehabilitation and home settings. While researchers have investigated strategies to increase PA among patients with IHD, interventions to promote PA specifically in IHD patients who report hopelessness are lacking. We describe the protocol for a NIH-funded randomized controlled trial designed to establish the effectiveness of a 6-week intervention (Heart Up!) to promote increased PA in IHD patients who report hopelessness. Participants (n = 225) are randomized to one of three groups: (1) motivational social support (MSS) from a nurse, (2) MSS from a nurse plus significant other support (SOS), or (3) attention control. Aims are to: (1) test the effectiveness of 6 weeks of MSS and MSS with SOS on increasing mean minutes per day of moderate to vigorous PA; (2) determine the effects of change in moderate to vigorous PA on hopelessness; and (3) determine if perceived social support and motivation (exercise self-regulation) mediate the effects of the intervention on PA. A total of 69 participants have been enrolled to date. The protocol has been consistently and accurately used by research personnel. We address the protocol challenges presented by the COVID-19 pandemic and steps taken to maintain fidelity to the intervention. Findings from this study could transform care for IHD patients who report hopelessness by promoting self-management of important PA goals that can contribute to better health outcomes.

Sedentary Behavior in Older Adults With Preclinical Cognitive Impairment With and Without Chronic Kidney Disease.

Older adults with preclinical cognitive impairment can have chronic conditions and lifestyle factors that influence health. Sedentary behavior is common in older adults with and without chronic kidney disease (CKD). The objective of the current study was to determine the differences in sedentary behavior for older adults with preclinical cognitive impairment with and without CKD. Our study evaluated 48 older adults with preclinical cognitive impairment with and without CKD who underwent assessment of sedentary behavior via accelerometry. We found that older adults with preclinical cognitive impairment with and without CKD were sedentary, but there were no significant differences between groups. Fragmentation index was different (p < 0.05), with a lower fragmentation index found in those with CKD. Sedentary behavior should be assessed and evaluated as a potential target for interventions to improve health in these at-risk older adults; however, further investigation is needed. [Journal of Gerontological Nursing, 47(6), 35-42.].

The Influence of Sedentary Behavior on the Relationship Between Cognitive Function and Vascular Function in Older Adults with and without Chronic Kidney Disease.

Cognitive impairment and vascular dysfunction are common in older adults with and without chronic kidney disease (CKD). Older adults with and without CKD are also sedentary - a behavior associated with cognitive and vascular function. The objective of this study was to explore whether sedentary behavior influenced the relationship between cognitive and vascular function in older adults with preclinical cognitive impairment with and without CKD. In our study, 48 older adults underwent assessment of cognition, vascular compliance, and sedentary behavior, and relationships were explored with regression moderation analysis. Sedentary time and breaks did not moderate the relationship between vascular and cognitive function. Although significant moderation was not found, cognition, vascular function, and sedentary behavior are important to assess when evaluating older adults with and without CKD.

Influence of Changes in Sedentary Time on Outcomes of Supervised Exercise Therapy in Individuals with Comorbid Peripheral Artery Disease and Type 2 Diabetes.

BACKGROUND: Although supervised exercise therapy (SET) is effective in improving walking distance among adults with symptomatic peripheral artery disease (PAD), some research suggests that individuals with comorbid PAD and type 2 diabetes mellitus (T2DM) may experience a blunted response to SET. It is unknown whether free-living sedentary time changes during SET, and if increases in sedentary time could, in part, explain poor response to SET. The purposes of this pilot study were to (1) determine if older adults with PAD (with and without T2DM) engaging in SET change their sedentary behavior and (2) examine the relationship between changes in sedentary behavior and SET outcomes. We hypothesized that decreased sedentary time during SET would be associated with greater improvements in six-minute walk test (6MWT) total distance and other key SET outcomes. METHODS: Participants (n = 44) initiating a 12-week SET program completed the 6MWT, Short Physical Performance Battery, Walking Impairment Questionnaire, and accelerometer-assessed sedentary behavior at SET initiation, 6 weeks, and 12 weeks. RESULTS: Participants' mean age was 72.3 (7.1) years, mean ankle-brachial index was 0.71 (0.25), and 47.7% were female. On average, sedentary time did not change after SET, although there was substantial variability (-40% to +38% change in minutes of sedentary time/day). Participants with T2DM experienced greater improvements in claudication onset distance than participants without T2DM (mean = 35 m, P = 0.044, 95% confidence interval = 1.6 to 115.4 m). Neither changes in sedentary time from baseline to 6 weeks (P = 0.419) nor T2DM (P = 0.154) predicted changes in 6MWT total distance from baseline to 12 weeks. CONCLUSIONS: As SET availability increases, further examination of factors that may influence SET outcomes will help maximize benefits of this proven therapy.

Physical Symptom Cluster Subgroups in Chronic Kidney Disease.

BACKGROUND: Symptom burden associated with chronic kidney disease can be debilitating, with a negative effect on patient health-related quality of life. Latent class clustering analysis is an innovative tool for classifying patient symptom experience. OBJECTIVES: The aim of the study was to identify subgroups of patients at greatest risk for high symptom burden, which may facilitate development of patient-centered symptom management interventions. METHODS: In this cross-sectional analysis, baseline data were analyzed from 3,921 adults enrolled in the Chronic Renal Insufficiency Cohort Study from 2003 to 2008. Latent class cluster modeling using 11 items on the Kidney Disease Quality of Life symptom profile was employed to identify patient subgroups based on similar observed physical symptom response patterns. Multinomial logistic regression models were estimated with demographic variables, lifestyle and clinical variables, and self-reported measures (Kidney Disease Quality of Life physical and mental component summaries and the Beck Depression Inventory). RESULTS: Three symptom-based subgroups were identified, differing in severity (low symptom, moderate symptom, and high symptom). After adjusting for other variables in multinomial logistic regression, membership in the high-symptom subgroup was less likely for non-Hispanic Blacks and men. Other factors associated with membership in the high-symptom subgroup included lower estimated glomerular filtration rate, history of cardiac/cardiovascular disease, higher Beck Depression Inventory scores, and lower Kidney Disease Quality of Life physical and mental component summaries. DISCUSSION: Three symptom subgroups of patients were identified among patients with mild-to-moderate chronic kidney disease. Several demographic and clinical variables predicted membership in subgroups. Further research is needed to determine if symptom subgroups are stable over time and can be used to predict healthcare utilization and clinical outcomes.

Sleep disturbance and next-day physical activity in COPD patients.

Physical inactivity and sleep disturbance are more problematic in patients with chronic obstructive pulmonary disease (COPD) than in healthy individuals. The purpose of the study was to identify impacts of nighttime sleep on next-day physical activity in COPD patients. The study included 52 COPD patients reporting disturbed sleep. Sleep and physical activity were measured using an accelerometer for 5 days. Increased sleep latency was associated with less next-day physical activity during the afternoon (4-6 p.m.). Greater waking duration/times were associated with less next-morning (6-8 a.m.) physical activity. Greater total sleep time was associated with less next-morning (12-9 a.m.) physical activity, and greater sleep efficiency was associated with less next-morning (1-3 a.m.) and more next-evening (6-7 p.m.) physical activity. Results suggest that sleep disturbance had varying influences on next-day hourly physical activity. These results support the potential value of sleep management in promoting physical activity in COPD patients.

Measurement of peripheral blood flow in patients with peripheral artery disease: Methods and considerations.

Peripheral artery disease (PAD) is a manifestation of generalized atherosclerosis which results in hemodynamic compromise of oxygen and substrate delivery to the lower extremity skeletal muscles. Hemodynamic assessments are vital in PAD diagnosis and in the evaluation of strategies aimed at treating claudication (i.e. exercise training, revascularization, and pharmacological agents). Venous occlusion plethysmography (VOP) is a century-old, non-invasive technique used to quantify limb blood flow and has been used to evaluate hemodynamic compromise in patients with PAD. However, the literature suggests a wide array of methodological variability in the measurement and analysis of limb blood flow using VOP. In this manuscript, we overview the clinical application of VOP measurement, and secondly we review the methodological variation that occurs during the measurement and analysis of VOP in healthy individuals and in patients with claudication.

Autonomic regulation during sleep and wakefulness: a review with implications for defining the pathophysiology of neurological disorders.

Cardiovascular and respiratory parameters change during sleep and wakefulness. This observation underscores an important, albeit incompletely understood, role for the central nervous system in the differential regulation of autonomic functions. Understanding sleep/wake-dependent sympathetic modulations provides insights into diseases involving autonomic dysfunction. The purpose of this review was to define the central nervous system nuclei regulating sleep and cardiovascular function and to identify reciprocal networks that may underlie autonomic symptoms of disorders such as insomnia, sleep apnea, restless leg syndrome, rapid eye movement sleep behavior disorder, and narcolepsy/cataplexy. In this review, we examine the functional and anatomical significance of hypothalamic, pontine, and medullary networks on sleep, cardiovascular function, and breathing.

Variability in Individual Response to Aerobic Exercise Interventions Among Older Adults.

Although a plethora of evidence supports the benefits of exercise among older adults, a majority of studies have emphasized group differences, while giving little, if any, attention to individual differences. Given the lack of data on variability in response, the present review examined how nonresponse to aerobic exercise has been defined in older adult populations and characteristics associated with nonresponse among older adults. The results of this review suggest that interindividual variability in response of maximal oxygen consumption to aerobic exercise interventions is prevalent among older adults (1.4-63.4%); age, sex, race, and body mass index may not be critical determinants of nonresponse; whereas health status, baseline fitness, and exercise dose appear important. Future intervention studies should evaluate and report the variability in individual response of older adults to exercise; investigators should develop programs that allow for modification of components to assist older adults in achieving optimal benefit from exercise programs.