Impact of the COVID-19 pandemic on services for patients with chronic kidney disease: findings of a national survey of UK kidney centres.

BACKGROUND: Services for patients with kidney disease underwent radical adaptations in response to the COVID-19 pandemic. We undertook an online national survey of UK kidney centres to understand the nature, range, and degree of variation in these changes and to explore factors contributing to differing practice. METHODS: The survey was designed by a multidisciplinary team of kidney professionals, service users and researchers. It enquired about centre services and staffing, including psychosocial provision, and changes to these in response to the COVID-19 pandemic. Links to the survey were sent to all 68 UK kidney centres and remained active from December 2021 to April 2022, and a revised version to nurses in late 2022 for additional data. Quantitative data were analysed descriptively. Content analysis on free-text responses identified common themes. RESULTS: Analysable responses were received from 41 out of the 68 UK centres (60%), with partial data from an additional 7 (11%). Adaptations were system-wide and affected all aspects of service provision. Some changes were almost universal such as virtual consultations for outpatient appointments, with significant variation in others. Outpatient activity varied from fully maintained to suspended. Many centres reduced peritoneal dialysis access provision but in some this was increased. Centres considered that changes to transplant surgical services and for patients with advanced CKD approaching end-stage kidney disease had the greatest impact on patients. Few centres implemented adjustments aimed at vulnerable and underrepresented groups, including the frail elderly, people with language and communication needs, and those with mental health needs. Communication issues were attributed to rapid evolution of the pandemic, changing planning guidance and lack of resources. Staffing shortages, involving all staff groups particularly nurses, mainly due to COVID-19 infection and redeployment, were compounded by deficiencies in staffing establishments and high vacancy levels. Centres cited three main lessons influencing future service delivery, the need for service redesign, improvements in communication, and better support for staff. CONCLUSION: Kidney centre responses to the pandemic involved adaptations across the whole service. Though some changes were almost universal, there was wide variation in other areas. Exploring the role of centre characteristics may help planning for potential future severe service disruptions.

Energy expenditure estimates in chronic kidney disease using a novel physical activity questionnaire.

BACKGROUND: Physical activity (PA) levels are low in patients with advanced chronic kidney disease (CKD), and associate with increased morbidity and mortality. Reliable tools to assess PA in CKD are scarce. We aimed to develop and validate a novel PA questionnaire for use in CKD (CKD-PAQ). METHODS: In Phase 1, a prototype questionnaire was developed based on the validated recent PAQ (RPAQ). Structured feedback on item relevance and clarity was obtained from 40 CKD patients. In Phase 2, the questionnaire was refined in three iterations in a total of 226 CKD patients against 7-day accelerometer and RPAQ measurements. In Phase 3, the definitive CKD-PAQ was compared with RPAQ in 523 CKD patients. RESULTS: In the final iteration of Phase 2, CKD-PAQ data were compared with accelerometer-derived and RPAQ data in 60 patients. Mean daily metabolic equivalent of task (MET) and total energy expenditure (TEE) levels were similar by all methods. Intraclass correlation coefficients showed fair (MET) and good (TEE) agreement between accelerometry and both CKD-PAQ and RPAQ. Agreement between questionnaires was excellent. The mean [standard deviation (SD)] daily MET bias was 0.035 (0.312) for CKD-PAQ and 0.018 (0.326) for RPAQ. The mean (SD) TEE bias was 91 (518) for CKD-PAQ and 44 (548) kcal for RPAQ. Limits of agreement (LOA) were wide for both parameters, with less dispersion of CKD-PAQ values. In Phase 3, agreement between questionnaires was good (MET) and excellent (TEE). Bias of CKD-PAQ-derived mean (SD) daily MET from RPAQ-derived values was 0.031 (0.193), with 95% LOA -0.346 to 0.409. Corresponding mean (SD) values for TEE were 48 (325) and -588 to 685 kcal/day. CKD-PAQ appeared to improve discrimination between low activity groups. CONCLUSIONS: CKD-PAQ performs comparably to the RPAQ though it is shorter, easier to complete, and may better capture low-level activity and improve discrimination between low activity groups.

Recovery of dialysis patients with COVID-19: health outcomes 3 months after diagnosis in ERACODA.

BACKGROUND: Coronavirus disease 2019 (COVID-19)-related short-term mortality is high in dialysis patients, but longer-term outcomes are largely unknown. We therefore assessed patient recovery in a large cohort of dialysis patients 3 months after their COVID-19 diagnosis. METHODS: We analyzed data on dialysis patients diagnosed with COVID-19 from 1 February 2020 to 31 March 2021 from the European Renal Association COVID-19 Database (ERACODA). The outcomes studied were patient survival, residence and functional and mental health status (estimated by their treating physician) 3 months after COVID-19 diagnosis. Complete follow-up data were available for 854 surviving patients. Patient characteristics associated with recovery were analyzed using logistic regression. RESULTS: In 2449 hemodialysis patients (mean ± SD age 67.5 ± 14.4 years, 62% male), survival probabilities at 3 months after COVID-19 diagnosis were 90% for nonhospitalized patients (n = 1087), 73% for patients admitted to the hospital but not to an intensive care unit (ICU) (n = 1165) and 40% for those admitted to an ICU (n = 197). Patient survival hardly decreased between 28 days and 3 months after COVID-19 diagnosis. At 3 months, 87% functioned at their pre-existent functional and 94% at their pre-existent mental level. Only few of the surviving patients were still admitted to the hospital (0.8-6.3%) or a nursing home (∼5%). A higher age and frailty score at presentation and ICU admission were associated with worse functional outcome. CONCLUSIONS: Mortality between 28 days and 3 months after COVID-19 diagnosis was low and the majority of patients who survived COVID-19 recovered to their pre-existent functional and mental health level at 3 months after diagnosis.

Effect of Chronic Kidney Disease on Metabolic Rate: Studies Using Doubly Labelled Water.

OBJECTIVE: The causes of protein malnutrition and body composition changes in chronic kidney disease (CKD) are poorly understood. Alterations to metabolic rate caused by CKD may be a contributor. Using the doubly labeled water technique and indirect calorimetry, we set out to determine whether reduced glomerular filtration rate is associated with alterations to total energy expenditure (TEE) and resting energy expenditure (REE). We also aimed to determine whether TEE in patients with CKD can be easily predicted from a physical activity questionnaire. METHODS: In a prospective, observational study we evaluated 80 patients (52 men; mean age 56.7 ± 16.2 years) with CKD ranging from stage 1 to stage 5 with estimated glomerular filtration rate (eGFR) calculated by the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI). TEE was measured using doubly labeled water isotope excretion over 14 days (TEEDLW), REE by indirect calorimetry (REEIndirectCal) and physical activity level using the Stanford 7-day recall questionnaire. RESULTS: eGFR did not correlate with TEEDLW and REEIndirectCal. Findings with weight-adjusted energy measures were similar. REEIndirectCal and TEEDLW were significantly lower in patients whose eGFR was <50 mL/min/1.73 m2 and those with higher levels. There were similar findings with respect to weight-adjusted energy measures. In multivariable analysis, age, sex, and weight were independent predictors of TEEDLW and REEIndirectCal. eGFR did not predict TEE or REE in either of these models. CONCLUSION: There was no direct relationship between reduced renal function and metabolic rate. Differences in energy metabolism at lower levels of glomerular filtration rate are more likely to be due to factors such as age, body composition, and physical activity.

COVID-19-related mortality in kidney transplant and dialysis patients: results of the ERACODA collaboration.

BACKGROUND: Patients on kidney replacement therapy comprise a vulnerable population and may be at increased risk of death from coronavirus disease 2019 (COVID-19). Currently, only limited data are available on outcomes in this patient population. METHODS: We set up the ERACODA (European Renal Association COVID-19 Database) database, which is specifically designed to prospectively collect detailed data on kidney transplant and dialysis patients with COVID-19. For this analysis, patients were included who presented between 1 February and 1 May 2020 and had complete information available on the primary outcome parameter, 28-day mortality. RESULTS: Of the 1073 patients enrolled, 305 (28%) were kidney transplant and 768 (72%) dialysis patients with a mean age of 60 ± 13 and 67 ± 14 years, respectively. The 28-day probability of death was 21.3% [95% confidence interval (95% CI) 14.3-30.2%] in kidney transplant and 25.0% (95% CI 20.2-30.0%) in dialysis patients. Mortality was primarily associated with advanced age in kidney transplant patients, and with age and frailty in dialysis patients. After adjusting for sex, age and frailty, in-hospital mortality did not significantly differ between transplant and dialysis patients [hazard ratio (HR) 0.81, 95% CI 0.59-1.10, P = 0.18]. In the subset of dialysis patients who were a candidate for transplantation (n = 148), 8 patients died within 28 days, as compared with 7 deaths in 23 patients who underwent a kidney transplantation <1 year before presentation (HR adjusted for sex, age and frailty 0.20, 95% CI 0.07-0.56, P < 0.01). CONCLUSIONS: The 28-day case-fatality rate is high in patients on kidney replacement therapy with COVID-19 and is primarily driven by the risk factors age and frailty. Furthermore, in the first year after kidney transplantation, patients may be at increased risk of COVID-19-related mortality as compared with dialysis patients on the waiting list for transplantation. This information is important in guiding clinical decision-making, and for informing the public and healthcare authorities on the COVID-19-related mortality risk in kidney transplant and dialysis patients.

Initiating haemodialysis twice-weekly as part of an incremental programme may protect residual kidney function.

BACKGROUND: Initiating twice-weekly haemodialysis (2×HD) in patients who retain significant residual kidney function (RKF) may have benefits. We aimed to determine differences between patients initiated on twice- and thrice-weekly regimes, with respect to loss of kidney function, survival and other safety parameters. METHODS: We conducted a single-centre retrospective study of patients initiating dialysis with a residual urea clearance (KRU) of ≥3 mL/min, over a 20-year period. Patients who had 2×HD for ≥3 months during the 12 months following initiation of 2×HD were identified for comparison with those dialysed thrice-weekly (3×HD). RESULTS: The 2×HD group consisted of 154 patients, and the 3×HD group 411 patients. The 2×HD patients were younger (59 ± 15 versus 62 ± 15 years: P = 0.014) and weighed less (70 ± 16 versus 80 ± 18 kg: P < 0.001). More were females (34% versus 27%: P = 0.004). Fewer had diabetes (25% versus 34%: P = 0.04) and peripheral vascular disease (PVD) (13% versus 23%: P = 0.008). Baseline KRU was similar in both groups (5.3 ± 2.4 for 2 × HD versus 5.1 ± 2.8 mL/min for 3 × HD: P = 0.507). In a mixed effects model correcting for between-group differences in comorbidities and demographics, 3×HD was associated with increased rate of loss of KRU and separation of KRU. In separate mixed effects models, group (2×HD versus 3×HD) was not associated with differences in serum potassium or phosphate, and the groups did not differ with respect to total standard Kt/V. Survival, adjusted for age, gender, weight, baseline KRU and comorbidity (prevalence of diabetes, cardiac disease, PVD and malignancy) was greater in the 2×HD group (hazard ratio 0.755: P = 0.044). In sub-analyses, the survival benefit was confined to women, and those of less than median bodyweight. CONCLUSION: 2×HD initiation as part of an incremental programme with regular monthly monitoring of KRU was safe and associated with a reduced rate of loss of RKF early after dialysis initiation and improved survival. Randomized controlled trials of this approach are indicated.

Comparison of resting energy equations and total energy expenditure in haemodialysis patients and body composition measured by multi-frequency bioimpedance.

AIM: Waste products of metabolism are retained in haemodialysis (HD) patients. Cellular metabolism generates energy, and patients with greater energy expenditure may therefore require more dialysis. The aim of the present study was to determine the amount of dialysis required, to determine equations estimating the required resting and total energy expenditure (REE, TEE). METHODS: Estimates of REE in HD patients were compared using established equations with a novel equation recently validated in HD patients (HD equation). TEE was derived from REE (HD equation) and estimates of physical activity obtained by questionnaire. REE and TEE relationships with bioimpedance measured body composition were then determined. RESULTS: A total of 317 HD patients were studied: 195 males (61.5%), 123 diabetic (38.9%), mean age 65.0 ± 15.3 and weight 73.1 ± 16.8 kg. REE from HD Equation was 1509 ± 241 kcal/day, which was greater than for Mifflin St Joer 1384 ± 259, Harris-Benedict 1437 ± 244, Katch-McArdle 1345 ± 232 (all P < 0.05 vs. HD Equation), but less than Cunningham 1557 ± 236 kcal/day. Bland-Altman mean bias ranged from -263 to 55 kcal/day. TEE was 1727 (1558-1976) kcal/day, and on multi-variable analysis was positively associated with skeletal muscle mass (ß 23.3, P < 0.001), employment (ß 406.5, P < 0.001), low co-morbidity (ß 105.1, P = 0.006), and protein nitrogen appearance (ß 2.7, P = 0.015), and negatively with age (ß -7.9, P < 0.001), and dialysis vintage (ß -121.2, P = 0.002). CONCLUSIONS: Most standard equations underestimate REE in HD patients compared to the HD Equation. TEE was greater in those with higher skeletal muscle mass and protein nitrogen appearance, lower co-morbidity, age, and dialysis vintage, and the employed. More metabolically active patients may require greater dialytic clearances.

Scaling Hemodialysis Target Dose to Reflect Body Surface Area, Metabolic Activity, and Protein Catabolic Rate: A Prospective, Cross-sectional Study.

BACKGROUND: Women and small men treated by hemodialysis (HD) have reduced survival. This may be due to use of total-body water (V) as the normalizing factor for dialysis dosing. In this study, we explored the equivalent dialysis dose that would be delivered using alternative scaling parameters matching the current recommended minimum Kt/V target of 1.2. STUDY DESIGN: Prospective cross-sectional study. SETTING & PARTICIPANTS: 1,500 HD patients on a thrice-weekly schedule, recruited across 5 different centers. PREDICTORS: Age, sex, weight, race/ethnicity, comorbid condition level, and employment status. OUTCOMES: Kt was estimated by multiplying V by 1.2. Kt/body surface area (BSA), Kt/resting energy expenditure (REE), Kt/total energy expenditure (TEE) and Kt/normalized protein catabolic rate (nPCR) equivalent to a target Kt/V of 1.2 were then estimated by dividing Kt by the respective parameters. MEASUREMENTS: Anthropometry, HD adequacy details, and BSA were obtained by standard procedures. REE was estimated using a novel validated equation. TEE was calculated from physical activity data obtained using the Recent Physical Activity Questionnaire. nPCR was estimated using a standard formula. RESULTS: Mean BSA was 1.87m2; mean REE, 1,545kcal/d; mean TEE, 1,841kcal/d; and mean nPCR, 1.03g/kg/d. For Kt/V of 1.2, there was a wide range of equivalent doses expressed as Kt/BSA, Kt/REE, Kt/TEE, and Kt/nPCR. The mean equivalent dose was lower in women for all 4 parameters (P<0.001). Small men would also receive lower doses compared with larger men. Younger patients, those with low comorbidity, those employed, and those of South Asian race/ethnicity would receive significantly lower dialysis doses with current practice. LIMITATIONS: Cross-sectional study; physical activity data collected by an activity questionnaire. CONCLUSIONS: Current dosing practices may risk underdialysis in women, men of smaller body size, and specific subgroups of patients. Using BSA-, REE-, or TEE-based dialysis prescription would result in higher dose delivery in these patients.

A single weekly Kt/Vurea target for peritoneal dialysis patients does not provide an equal dialysis dose for all.

Dialysis adequacy is traditionally based on urea clearance, adjusted for total body volume (Kt/Vurea), and clinical guidelines recommend a Kt/Vurea target for peritoneal dialysis. We wished to determine whether adjusting dialysis dose by resting and total energy expenditure would alter the delivered dialysis dose. The resting and total energy expenditures were determined by equations based on doubly labeled isotopic water studies and adjusted Kturea for resting energy expenditure and total energy expenditure in 148 peritoneal dialysis patients (mean age, 60.6 years; 97 male [65.5%]; 54 diabetic [36.5%]). The mean resting energy expenditure was 1534 kcal/d, and the total energy expenditure was 1974 kcal/day. Using a weekly target Kt/V of 1.7, Kt was calculated using V measured by bioimpedance and the significantly associated (r = 0.67) Watson equation for total body water. Adjusting Kt for resting energy expenditure showed a reduced delivered dialysis dose (ml/kcal per day) for women versus men (5.5 vs. 6.2), age under versus over 65 years (5.6 vs. 6.4), weight <65 versus >80 kg (5.8 vs. 6.1), low versus high comorbidity (5.9 vs. 6.2), all of which were significant. Adjusting for the total energy expenditure showed significantly reduced dosing for those employed versus not employed (4.3 vs. 4.8), a low versus high frailty score (4.5 vs. 5.0) and nondiabetic versus diabetic (4.6 vs. 4.9). Thus, the current paradigm for a single target Kt/Vurea for all peritoneal dialysis patients does not take into account energy expenditure and metabolic rate and may lead to lowered dialysis delivery for the younger, more active female patient.

Predicting residual kidney function in hemodialysis patients using serum ß-trace protein and ß2-microglobulin.

Residual kidney function (RKF) contributes significant solute clearance in hemodialysis patients. Kidney Diseases Outcomes Quality Initiative (KDOQI) guidelines suggest that hemodialysis dose can be safely reduced in those with residual urea clearance (KRU) of 2 ml/min/1.73 m(2) or more. However, serial measurement of RKF is cumbersome and requires regular interdialytic urine collections. Simpler methods for assessing RKF are needed. ß-trace protein (ßTP) and ß2-microglobulin (ß2M) have been proposed as alternative markers of RKF. We derived predictive equations to estimate glomerular filtration rate (GFR) and KRU based on serum ßTP and ß2M from 191 hemodialysis patients based on standard measurements of KRU and GFR (mean of urea and creatinine clearances) using interdialytic urine collections. These modeled equations were tested in a separate validation cohort of 40 patients. A prediction equation for GFR that includes both ßTP and ß2M provided a better estimate than either alone and contained the terms 1/ßTP, 1/ß2M, 1/serum creatinine, and a factor for gender. The equation for KRU contained the terms 1/ßTP, 1/ß2M, and a factor for ethnicity. Mean bias between predicted and measured GFR was 0.63 ml/min and 0.50 ml/min for KRU. There was substantial agreement between predicted and measured KRU at a cut-off level of 2 ml/min/1.73 m(2). Thus, equations involving ßTP and ß2M provide reasonable estimates of RKF and could potentially be used to identify those with KRU of 2 ml/min/1.73 m(2) or more to follow the KDOQI incremental hemodialysis algorithm.

A self-report comorbidity questionnaire for haemodialysis patients.

BACKGROUND: Patients with end-stage renal disease (ESRD) have multiple comorbid conditions. Obtaining comorbidity data from medical records is cumbersome. A self-report comorbidity questionnaire is a useful alternative. Our aim in this study was to examine the predictive value of a self-report comorbidity questionnaire in terms of survival in ESRD patients. METHODS: We studied a prospective cross-sectional cohort of 282 haemodialysis (HD) patients in a single centre. Participants were administered the self-report questionnaire during an HD session. Information on their comorbidities was subsequently obtained from an examination of the patient's medical records. Levels of agreement between parameters derived from the questionnaire, and from the medical records, were examined. Participants were followed-up for 18 months to collect survival data. The influence on survival of comorbidity scores derived from the self-report data (the Composite Self-report Comorbidity Score [CSCS]) and from medical records data--the Charlson Comorbidity Index [CCI] were compared. RESULTS: The level of agreement between the self-report items and those obtained from medical records was almost perfect with respect the presence of diabetes (Kappa score κ 0.97), substantial for heart disease and cancer (κ 0.62 and κ 0.72 respectively), moderate for liver disease (κ 0.51), only fair for lung disease, arthritis, cerebrovascular disease, and depression (κ 0.34, 0.35, 0.34 and 0.29 respectively). The CSCS was strongly predictive of survival in regression models (Nagelkerke R(2) value 0.202), with a predictive power similar to that of the CCI (Nagelkerke R(2) value 0.211). The influences of these two parameters were additive in the models--suggesting that these parameters make different contributions to the assessment of comorbidity. CONCLUSION: This self-report comorbidity questionnaire is a viable tool to collect comorbidity data and may have a role in the prediction of short-term survival in patients with end-stage renal disease on haemodialysis. Further work is required in this setting to refine the tool and define its role.

Impact of COVID-19 on patient experience of kidney care: a rapid review.

INTRODUCTION: In March 2020, a pandemic state was declared due to SARS-COV-2 (COVID-19). Patients with kidney disease, especially those on replacement therapies, proved more susceptible to severe infection. This rapid literature review aims to help understand how the pandemic impacted patient experience of kidney care. METHODS: It was conducted in accordance with Cochrane Rapid Review interim guidance. Search terms, 'coronavirus', 'kidney care', and 'patient-reported experience' and terms with similar semantic meaning, identified 1,117 articles in Medline, Scopus, and Worldwide Science. Seventeen were included in the narrative synthesis. RESULTS: The findings were summarised into three themes: remote consultation and telemedicine (n = 9); psychosocial impact (n = 2); and patient satisfaction and patient-reported experience (n = 6). Patients were mostly satisfied with remote consultations, describing them as convenient and allowing avoidance of hospital visits. Anxieties included missing potentially important clinical findings due to lack of physical examination, poor digital literacy, and technical difficulties. Psychosocial impact differed between treatment modalities-transplant recipients expressing feelings of instability and dread of having to return to dialysis, and generally, were less satisfied, citing reduced ability to work and difficulty accessing medications. Those on home dialysis treatments tended to feel safer. Findings focused on aspects of patient experience of kidney care during the pandemic rather than a holistic view. CONCLUSIONS: There was little direct evaluation of modality differences and limited consideration of health inequalities in care experiences. A fuller understanding of these issues would guide policy agendas to support patient experience during future public health crises.

Dalteparin dosing in high-flux haemodialysis and haemodiafiltration.

BACKGROUND: Low-molecular-weight heparins are being increasingly used as an alternative to unfractionated heparin for anticoagulation of the haemodialysis (HD) circuit. Data on dalteparin use in high-flux HD and haemodiafiltration (HDF) are limited. We examined the safety and efficacy of dalteparin in this setting to enable recommendations on the optimal dose range. METHODS: This prospective study was conducted in a single dialysis unit. Subjects who had been receiving dalteparin for at least 10 HD sessions were studied. Anti-Xa activity was measured for all subjects at the start of the HD session, at 60 min into HD and at the end of dialysis. RESULTS: 55 subjects were studied. None had detectable anti-Xa activity at the start of the session. Using adequacy criteria based on target anti-Xa activity >0.4 IU/ml at 1 h and <0.4 IU/ml at the end of dialysis, 39 (71%) patients had adequate anticoagulation, 12 (22%) patients were under-anticoagulated and 4 (7%) were over-anticoagulated. The mean dose in the adequately anticoagulated group was 60.7 ± 11.7 IU/kg, in the under-anticoagulated group 39.3 ± 9.6 IU/kg and in the over-anticoagulated group 70.1 ± 14.6 IU/kg. The optimal dose of dalteparin appears to be 60 ± 10 IU/kg, which facilitates the achievement of the target anti-Xa activity in the range of 0.4-0.75 IU/ml at 1 h and <0.4 IU/ml at the session end. CONCLUSION: Dalteparin is a safe and effective anticoagulant for patients on high-flux HD and HDF. The optimal dose appears to be 60 ± 10 IU/kg. The desirable target range of anti-Xa activity is 0.4-0.75 at 1 h and <0.4 IU/ml at the session end.

Characteristics of Frailty in Haemodialysis Patients.

Background: Both frailty and cachexia increase mortality in haemodialysis (HD) patients. The clinical frailty score (CFS) is a seven-point scale and less complex than other cachexia and frailty assessments. We wished to determine the characteristics of frail HD patients using the CFS. Methods: Single centre cross-sectional study of HD patients completing physical activity questionnaires with bioimpedance measurements of body composition and hand grip strength (HGS). Results: We studied 172 HD patients. The CFS classified 54 (31.4%) as frail, who were older (70.4±12.2 vs 56.2 ± 16.1 years, p < 0.001), greater modified Charlson co-morbidity (3 (2-3) versus 1.5 (0-3), p < 0.001), and body fat (33 (25.4-40.2) versus 26.2 (15.8-34) %, p < 0.01), but lower total energy expenditure (1720 (1574-1818) versus 1870 (1670-2194) kcal/day, p < 0.01), lean muscle mass index (9.1 (7.7-10.1) versus 9.9 (8.9-10.8) kg/m2), and HGS (15.3 (10.3-21.9) versus 23.6 (16.7-34.4) kg), both p < 0.001. On multivariable logistic analysis, frailty was independently associated with lower active energy expenditure (odds ratio (OR) 0.98, 95% confidence limits (CL) 0.98-0.99, p = 0.001), diabetes (OR 5.09, CL 1.06-16.66) and HGS (OR 0.92, CL 0.86-0.98). Discussion: Frail HD patients reported less active energy expenditure, associated with reduced muscle mass and strength. Frail patients were more likely to have greater co-morbidity, particularly diabetes. Whether physical activity programmes can improve frailty remains to be determined.

Determinants of active energy expenditure in haemodialysis patients.

BACKGROUND: Less active haemodialysis patients have an increased risk of mortality. We wished to determine which factors were associated with active energy expenditure (AEE). METHODS: We used the validated recent physical activity questionnaire to determine AEE and estimated dietary protein intake and creatinine generation rates. We measured extracellular and total body water ratio (ECW/TBW) and appendicular lean muscle with bioimpedance and arm strength by hand grip strength (HGS). Patients were graded using the Charlson co-morbidity and the Clinical Frailty Score (CFS). RESULTS: AEE was calculated in 98 patients (64 male), mean age 62.1 ± 15.5 years, and AEE was negatively associated with CFS (r = -0.48), ECW/TBW (r = -0.47) and age (r = -0.4), all p < 0.001, Charlson co-morbidity score (-0.27, p = 0.007), and positively with serum creatinine (r = 0.38, p < 0.010), and HGS (r = 0.25, p = 0.016). Although protein nitrogen accumulation and creatinine generation were associated with resting energy expenditure (r = 0.70 and r = 0.44 respectively, both p < 0.0001), neither were associated with AEE. On multivariable analysis only CFS remained independently associated with AEE (ß = -0.031, 95% limits: -0.057 to -0.004, p = 0.024), although both age (negative p = 0.07), and ALM (positive p = 0.081) were retained in the model. CONCLUSIONS: We found that AEE was lower with increasing frailty, age, loss of cell mass, co-morbidity and inflammation, and greater AEE in patients with higher serum creatinine and albumin, and greater muscle strength on univariate analysis, but only frailty remained independently associated on multivariable analysis. Whether exercise programmes designed to increase AEE in haemodialysis patients can improve frailty scores, and so reduce mortality risk reman to be determined.

Ultra-Endurance Participation and Acute Kidney Injury: A Narrative Review.

Increasingly popular, ultra-endurance participation exposes athletes to extremely high levels of functional and structural damage. Ultra-endurance athletes commonly develop acute kidney injury (AKI) and other pathologies harmful to kidney health. There is strong evidence that non-steroidal anti-inflammatory drugs, common amongst ultra-athletes, is linked to increased risk and severity of AKI and potentially ischaemic renal injury, i.e., acute tubular necrosis. Ultra-endurance participation also increases the risk of exertional rhabdomyolysis, exercise-associated hyponatremia, and gastrointestinal symptoms, interlinked pathologies all with potential to increase the risk of AKI. Hydration and fuelling both also play a role with the development of multiple pathologies and ultimately AKI, highlighting the need for individualised nutritional and hydration plans to promote athlete health. Faster athletes, supplementing nitrates, and being female also increase the risk of developing AKI in this setting. Serum creatinine criteria do not provide the best indicator for AKI for ultra-athletes therefore further investigations are needed to assess the practicality and accuracy of new renal biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL). The potential of recurring episodes of AKI provide need for further research to assess the longitudinal renal health impact of ultra-participation to provide appropriate advice to athletes, coaches, medical staff, and event organisers.

Impact of incremental versus conventional initiation of haemodialysis on residual kidney function: study protocol for a multicentre feasibility randomised controlled trial.

INTRODUCTION: Preserving residual kidney function (RKF) may be beneficial to patients on haemodialysis (HD) and it has been proposed that commencing dialysis incrementally rather than three times a week may preserve RKF. In Incremental HD, target dose includes a contribution from RKF, which is added to HD dose, allowing individualisation of the HD prescription. We will conduct a feasibility randomised controlled trial (RCT) comparing incremental HD and conventional three times weekly treatments in incident HD patients. The study is designed also to provide pilot data to allow determination of effect size to power a definitive study. METHODS AND ANALYSIS: After screening to ensure native renal urea clearance >3 mL/min/1.73 m2, the study will randomise 54 patients within 3 months of HD initiation to conventional in-centre thrice weekly dialysis or incremental in-centre HD commencing 2 days a week. Subjects will be followed up for 12 months. The study will be carried out across four UK renal centres.The primary outcome is to evaluate the feasibility of conducting a definitive RCT and to estimate the difference in rate of decline of RKF between the two groups at 6 and 12 months time points. Secondary outcomes will include the impact of dialysis intensity on vascular access events, major adverse cardiac events and survival. Impact of dialysis intensity on patient-reported outcomes measures, cognition and frailty will be assessed using EQ-5D-5L, PHQ-9, Illness Intrusiveness Rating Score, Montreal Cognitive assessment and Clinical Frailty Score. Safety outcomes include hospitalisation, fluid overload episodes, hyperkalaemia events and vascular access events.This study will inform the design of a definitive study, adequately powered to determine whether RKF is better preserved after incremental HD initiation compared with conventional initiation. ETHICS AND DISSEMINATION: Ethics approval has been granted by Cambridge South Research Ethics Committee, United Kingdom(REC17/EE/0311). Results will be disseminated via peer-reviewed publication. TRIAL REGISTRATION NUMBER: NCT03418181.

Comparison of equations of resting and total energy expenditure in peritoneal dialysis patients using body composition measurements determined by multi-frequency bioimpedance.

BACKGROUND & AIMS: Waste products of metabolism accumulate in patients with kidney failure and it has been proposed that the amount of dialysis treatment patients require be adjusted for energy expenditure. This requires validation of methods to estimate energy expenditure in dialysis patients. METHODS: We compared values of resting energy expenditure (REE) estimated in peritoneal dialysis (PD) patients using a selection of available equations with estimates derived using a novel equation recently validated in chronic kidney disease patients (CKD equation). We also determined the relationship of these estimates of REE and of total energy expenditure (TEE - which is REE plus physical activity associated energy expenditure (PAEE) estimated using the Recent Physical Activity Questionnaire) - to bioimpedance-derived parameters of body composition. RESULTS: We studied 118 adult PD patients; 75 male (63.6%), 33 diabetic (28.5%), Caucasoid (42.4%), mean age 59.3 ± 18.2 years and weight 73.1 ± 16.6 kg. REE with the CKD equation was 1532 ± 237 kcal/day, which was more than that for Mifflin-St. Joer 1425 ± 254, Harris-Benedict 1489 ± 267, Katch-McArdle 1492 ± 243, but less than Cunningham 1648 ± 248 kcal/day. Bland Altman mean bias ranged from -107 to 111 kcal/day. TEE was 1924 (1700-2262) kcal/day, and on multi-variate analysis was associated with appendicular muscle mass and nitrogen appearance rate (ß 34.3, p < 0.001 and ß 5.6, p = 0.002, respectively). CONCLUSION: With reference to the CKD equation, the majority of standard equations underestimate REE in PD patients. Whereas the Cunningham equation overestimates REE. TEE was associated with appendicular muscle mass and estimated dietary protein intake.