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

BACKGROUND: Low levels of physical activity are implicated in low life expectancies of people receiving maintenance haemodialysis. Accelerometers are increasingly being used to quantify activity behaviours of this population but guidance to quality-assure such data is lacking. The objective of this study was to provide data processing and reduction recommendations to ensure accelerometer-derived outcomes are sufficiently reliable for interpretative analysis. METHODS: Seventy people receiving maintenance haemodialysis (age 55.9 ± 15.7 years, 34% women, 23% diabetic) from a single outpatient renal unit volunteered for the study. Participants wore Actigraph GT3x and ActivPAL monitors during waking hours over seven days. Reliability of accelerometer output (normalised to wear-time) was assessed via intraclass correlation coefficient (ICC). The Spearman-Brown prophecy formula was subsequently applied to the ICCs to derive the minimum required accelerometer wear-time for each behavioural outcome. RESULTS: Monitor wear compliance was greater on dialysis compared to non-dialysis days (90% v 77%). Participants were significantly more active on non-dialysis days compared to dialysis days but there were no significant differences in estimated behaviours between days within the same condition. Average measure ICCs for all accelerometer outcomes were high (range 0.76-0.96). Computations indicated that habitual physical activity and sedentary behaviour could be estimated with a minimum reliability level of 0.80 from one dialysis day and two non-dialysis days, and at least eight hours monitor wear per day. Applying this rubric allowed 90% of participant data to be retained for further analysis. CONCLUSIONS: Regardless of accelerometer, one dialysis and two non-dialysis days data with a minimum of eight hours wear each day should enable habitual activity of people receiving maintenance haemodialysis to be characterised with acceptable reliability. These recommendations reconcile the tension between wear-time criteria stringency and retention of an adequately representative sample.

The relative importance of frailty, physical and cardiovascular function as exercise-modifiable predictors of falls in haemodialysis patients: a prospective cohort study.

BACKGROUND: Stage 5 chronic kidney disease (CKD-5) patients on haemodialysis (HD) are at high risk of accidental falls. Previous research has shown that frailty is one of the primary contributors to the increased risk of falling in this clinical population. However, HD patients often present with abnormalities of cardiovascular function such as baroreflex impairment and orthostatic dysregulation of blood pressure (BP) which may also be implicated in the aetiology of falling. Therefore, we aimed to explore the relative importance of frailty and cardiovascular function as potential exercise-modifiable predictors of falls in these patients. METHODS: Ninety-three prevalent CKD-5 patients on HD from three Renal Units were recruited for this prospective cohort study, which was conducted between October 2015 and August 2018. At baseline, frailty status was assessed using the Fried's frailty phenotype, while physical function was evaluated through timed up and go (TUG), five repetitions chair sit-to-stand (CSTS-5), objectively measured physical activity, and maximal voluntary isometric strength. Baroreflex and haemodynamic function at rest and in response to a 60° head-up tilt test (HUT-60°) were also assessed by means of the Task Force Monitor. The number of falls experienced was recorded once a month during 12 months of follow-up. RESULTS: In univariate negative binomial regression analysis, frailty (RR: 4.10, 95%CI: 1.60-10.51, p = 0.003) and other physical function determinants were associated with a higher number of falls. In multivariate analysis however, only worse baroreflex function (RR: 0.96, 95%CI: 0.94-0.99, p = 0.004), and orthostatic decrements of BP to HUT-60° (RR: 0.93, 95%CI: 0.87-0.99, p = 0.033) remained significantly associated with a greater number of falls. Eighty falls were recorded during the study period and the majority of them (41.3%) were precipitated by dizziness symptoms, as reported by participants. CONCLUSIONS: This prospective study indicates that cardiovascular mechanisms implicated in the short-term regulation of BP showed a greater relative importance than frailty in predicting falls in CKD-5 patients on HD. A high number of falls appeared to be mediated by a degree of cardiovascular dysregulation, as evidenced by the predominance of self-reported dizziness symptoms. TRIAL REGISTRATION: ClinicalTrials.gov (trial registration ID: NCT02392299; date of registration: March 18, 2015).

Factors influencing withdrawal from dialysis: a national registry study.

BACKGROUND: Dialysis withdrawal is the third most common cause of death in patients receiving dialysis for established renal failure (ERF) in Scotland. We describe incidence, risk factors and themes influencing decision-making in a national renal registry. METHODS: Details of deaths in those receiving renal replacement therapy (RRT) for ERF in Scotland are reported to the Scottish Renal Registry via a unique mortality report. We extracted patient demographics and comorbidity, cause and location of death, duration of RRT and pertinent free text comments from 1 January 2008 to 31 December 2014. Withdrawal incidence was calculated and logistic regression used to identify significantly influential variables. Themes emerging from clinician comments were tabulated for descriptive purposes. RESULTS: There were 2596 deaths; median age at death was 68 [interquartile range (IQR) 58, 76] years, 41.5% were female. Median duration on RRT was 1110 (IQR 417, 2151) days. Dialysis withdrawal was the primary cause of death in 497 (19.1%) patients and withdrawal contributed to death in a further 442 cases (17.0%). The incidence was 41 episodes per 1000 patient-years. Regression analysis revealed increasing age, female sex and prior cerebrovascular disease were associated with dialysis withdrawal as a primary cause of death. Conversely, interstitial renal disease, angiographically proven ischaemic heart disease, valvular heart disease and malignancy were negatively associated. Analysis of free text comments revealed common themes, portraying an image of physical and psychological decline accelerated by acute illnesses. CONCLUSIONS: Death following dialysis withdrawal is common. Factors important to physical independence-prior cerebrovascular disease and increasing age-are associated with withdrawal. When combined with clinician comments this study provides an insight into the clinical decline affecting patients and the complexity of this decision. Early recognition of those likely to withdraw may improve end of life care.

How safe is renal replacement therapy? A national study of mortality and adverse events contributing to the death of renal replacement therapy recipients.

BACKGROUND: Patients receiving treatment with renal replacement therapy (RRT) have high mortality, and ensuring patient safety in this population is difficult. We aimed to estimate the incidence and nature of medical adverse events contributing to the death of patients being treated with RRT. METHODS: This population registry-based retrospective case review study included all patients being treated with RRT for established renal failure in Scotland and who died between 1 January 2008 and 30 June 2011. Deaths were reviewed by consultant nephrologists using a structured questionnaire to identify factors contributing to death occurring in both the inpatient and outpatient setting. Reviewers were able to use any information source deemed relevant, including paper and electronic clinical records, mortality and morbidity meetings and procurator fiscal (Scottish coroner) investigations. Deaths occurring in 2008 and 2009 where avoidable factors were identified that may have or did lead to death of a patient were subject to further review and root cause analysis, in order to identify recurrent themes. RESULTS: Of 1551 deaths in the study period, 1357 were reviewed (87.5%). Cumulative RRT exposure in the cohort was 2.78 million person-days. RRT complications were the primary cause of death in 28 (2.1%). Health-care-associated infection had contributed to 9.6% of all deaths. In 3.5% of deaths, factors were identified which may have or did contribute to death. These were both organizational and human error related and were largely due to five main causes: management of hyperkalaemia, prescribing, out of hours care, infection and haemodialysis vascular access. CONCLUSIONS: Adverse events contributing to death in RRT recipients mainly relate to the everyday management of common medical problems and not the technical aspects of RRT. Efforts to avoid harm in this population should address these ubiquitous causes of harm.

Association of postural balance and falls in adult patients receiving haemodialysis: A prospective cohort study.

BACKGROUND: Static postural balance performance is often impaired in people receiving haemodialysis (HD) for the treatment of stage-5 chronic kidney disease (CKD-5). However, the question as to whether lower postural balance is associated with adverse clinical outcomes such as falls has not been addressed yet. RESEARCH QUESTION: We conducted a prospective cohort study to explore the association between static postural balance and falls in people receiving HD. We hypothesised that higher postural sway would be associated with increased odds of falling. METHODS: Seventy-five prevalent CKD-5 patients receiving HD (age: 61.8 ± 13.4 years) from three Renal Units were enrolled in this prospective cohort study. At baseline, postural balance was assessed with a force platform in eyes open (EO) and eyes closed (EC) conditions. Centre of pressure (CoP) measures of range, velocity and area were taken for the analysis. Falls experienced by study participants were prospectively recorded during 12 months of follow-up. Secondary outcomes included timed-up and go, five-repetition sit-to-stand test and the Tinetti falls efficacy scale (FES). RESULTS: In multivariable logistic regression analysis, higher CoP range in medial-lateral direction during EC was associated with increased odds of falling (OR: 1.04, 95 %CI: 1.00-1.07, p = 0.036). In ROC curve analysis, CoP velocity in EO exhibited the greatest prognostic accuracy (AUC: 0.69, 95 %CI: 0.55-0.82), however this was not statistically different from CoP measures of area and range. None of the postural balance measures exceeded the prognostic accuracy of the FES (AUC: 0.70, 95 %CI: 0.58-0.83, p = 0.005). SIGNIFICANCE: This prospective cohort study showed that higher postural sway in medial-lateral direction was associated with increased odds of falling in people receiving HD. CoP measures of range, velocity and area displayed similar prognostic value in discriminating fallers from non-fallers. The overall utility of static posturography to detect future fall-risk may be limited in a clinical setting.

Baroreflex function, haemodynamic responses to an orthostatic challenge, and falls in haemodialysis patients.

BACKGROUND: Stage 5 chronic kidney disease patients on haemodialysis (HD) often present with dizziness and pre-syncopal events as a result of the combined effect of HD therapy and cardiovascular disease. The dysregulation of blood pressure (BP) during orthostasis may be implicated in the aetiology of falls in these patients. Therefore, we explored the relationship between baroreflex function, the haemodynamic responses to a passive orthostatic challenge, and falls in HD patients. METHODS: Seventy-six HD patients were enrolled in this cross-sectional study. Participants were classified as "fallers" and "non-fallers" and completed a passive head up tilting to 60o (HUT-60°) test on an automated tilt table. ECG signals, continuous and oscillometric BP measurements and impedance cardiography were recorded. The following variables were derived from these measurements: heart rate (HR) stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), number of baroreceptor events, and baroreceptor effectiveness index (BEI). RESULTS: The forty-four participants who were classified as fallers (57.9%) had a lower number of baroreceptor events (6.5±8.5 vs 14±16.7, p = .027) and BEI (20.8±24.2% vs 33.4±23.3%, p = .025). In addition, fallers experienced a significantly larger drop in systolic (-6.4±10.9 vs -0.4±7.7 mmHg, p = .011) and diastolic (-2.7±7.3 vs 1.8±6 mmHg, p = .027) oscillometric BP from supine to HUT-60° compared with non-fallers. None of the variables taken for the analysis were significantly associated with falls in multivariate logistic regression analysis. CONCLUSIONS: This cross-sectional comparison indicates that, at rest, HD patients with a positive history of falls present with a lower count of baroreceptor sequences and BEI. Short-term BP regulation warrants further investigation as BP drops during a passive orthostatic challenge may be implicated in the aetiology of falls in HD.

A combined diabetes renal clinic improves risk factor management and progression of renal disease in a district general hospital.

AIMS: Aggressive management of vascular risk factors reduces the rate of progression to end-stage renal failure in patients with diabetic nephropathy. The aim of our audit was to clarify whether improvements in patient care could be demonstrated within a short time period after establishing a combined diabetes renal clinic in a district general hospital. METHODS: A retrospective analysis of weight, glycaemic control, blood pressure control, rate of decline in renal function and appropriate use of medications for vascular risk management for patients in a district general hospital was performed before and after attendance at a combined diabetes renal clinic. RESULTS: Data were complete for 45 patients. There was no significant change in weight from 14 months before attending the combined clinic, referral to the clinic and after 14 months of mean follow-up. An improvement in mean systolic blood pressure was achieved at the combined diabetes renal clinic (from 147 to 134 mmHg with an average fall of 16.5 mmHg, P < 0.01). The mean glycated haemoglobin (HbA1c) improved from 8.6% to 8% (P = 0.002). The rate of decline in estimated glomerular filtration rate of 1.16 mL min(-1) per month prior to referral improved to 0.21 mL min(-1) per month on attending the combined clinic (P = 0.002). CONCLUSIONS: Vascular risk factor management was improved and decline in renal function slowed in patients with diabetic nephropathy within a short period of establishing a combined diabetes renal clinic in a district general hospital.