Regional variation of COVID-19 admissions, acute kidney injury and mortality in England - a national observational study using administrative data

BACKGROUND

This study explores regional variations in COVID-19 hospitalization rates, in-hospital mortality, and acute kidney injury (AKI) in England. We investigated the influence of population demographic characteristics, viral strain changes, and therapeutic advances on clinical outcomes.

METHODS

Using hospital episode statistics, we conducted a retrospective cohort study with 749,844 admissions in 337,029 adult patients with laboratory-confirmed COVID-19 infection (March 1, 2020, to March 31, 2021). Multivariable logistic regression identified factors predicting AKI and mortality in COVID-19 hospitalized patients.

RESULTS

London had the highest number of COVID-19 admissions (131,338, 18%), followed by the North-west region (122,683, 16%). The North-west had the highest population incidence of COVID-19 hospital admissions (21,167 per million population, pmp), while the South-west had the lowest (9,292 admissions pmp). Patients in London were relatively younger (67.0 ± 17.7 years) than those in the East of England (72.2 ± 16.8 years). The shortest length of stay was in the North-east (12.2 ± 14.9 days), while the longest was in the North-west (15.2 ± 17.9 days). All eight regions had higher odds of death compared to London, ranging from OR 1.04 (95% CI 1.00, 1.07) in the South-west to OR 1.24 (95% CI 1.21, 1.28) in the North-west. Older age, Asian ethnicity, emergency admission, transfers from other hospitals, AKI presence, ITU admission, social deprivation, and comorbidity were associated with higher odds of death. AKI incidence was 30.3%, and all regions had lower odds of developing AKI compared to London. Increasing age, mixed and black ethnicity, emergency admission, transfers from other providers, ITU care, and different levels of comorbidity were associated with higher odds of developing AKI.

CONCLUSIONS

London exhibited higher hospital admission numbers and AKI incidence, but lower odds of death compared to other regions in England.

TRIAL REGISTRATION

Registered on National Library of Medicine website ( www.

CLINICALTRIALS

gov ) with registration number NCT04579562 on 8/10/2020.

Discontinuation of anti-tumour necrosis factor alpha treatment owing to blood test abnormalities, and cost-effectiveness of alternate blood monitoring strategies

BACKGROUND

There is no evidence base to support the use of 6-monthly monitoring blood tests for the early detection of liver, blood and renal toxicity during established anti-tumour necrosis factor alpha (TNFα) treatment.

OBJECTIVES

To evaluate the incidence and risk factors of anti-TNFα treatment cessation owing to liver, blood and renal side-effects, and to estimate the cost-effectiveness of alternate intervals between monitoring blood tests.

METHODS

A secondary care-based retrospective cohort study was performed. Data from the British Association of Dermatologists Biologic and Immunomodulators Register (BADBIR) were used. Patients with at least moderate psoriasis prescribed their first anti-TNFα treatment were included. Treatment discontinuation due to a monitoring blood test abnormality was the primary outcome. Patients were followed-up from start of treatment to the outcome of interest, drug discontinuation, death, 31 July 2021 or up to 5 years, whichever came first. The incidence rate (IR) and 95% confidence intervals (CIs) of anti-TNFα discontinuation with monitoring blood test abnormality was calculated. Multivariate Cox regression was used to examine the association between risk factors and outcome. A mathematical model evaluated costs and quality-adjusted life years (QALYs) associated with increasing the length of time between monitoring blood tests during anti-TNFα treatment.

RESULTS

The cohort included 8819 participants [3710 (42.1%) female, mean (SD) age 44.76 (13.20) years] that contributed 25 058 person-years (PY) of follow-up and experienced 125 treatment discontinuations owing to a monitoring blood test abnormality at an IR of 5.85 (95% CI 4.91-6.97)/1000 PY. Of these, 64 and 61 discontinuations occurred within the first year and after the first year of treatment start, at IRs of 8.62 (95% CI 6.74-11.01) and 3.44 (95% CI 2.67-4.42)/1000 PY, respectively. Increasing age (in years), diabetes and liver disease were associated with anti-TNFα discontinuation after a monitoring blood test abnormality [adjusted hazard ratios of 1.02 (95% CI 1.01-1.04), 1.68 (95% CI 1.00-2.81) and 2.27 (95% CI 1.26-4.07), respectively]. Assuming a threshold of £20 000 per QALY gained, no monitoring was most cost-effective, but all extended periods were cost-effective vs. 3- or 6-monthly monitoring.

CONCLUSIONS

Anti-TNFα drugs were uncommonly discontinued owing to abnormal monitoring blood tests after the first year of treatment. Extending the duration between monitoring blood tests was cost-effective. Our results produce evidence for specialist society guidance to reduce patient monitoring burden and healthcare costs.

Multivariate canonical correlation analysis identifies additional genetic variants for chronic kidney disease

Chronic kidney diseases (CKD) have genetic associations with kidney function. Univariate genome-wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) associated with estimated glomerular filtration rate (eGFR) and blood urea nitrogen (BUN), two complementary kidney function markers. However, it is unknown whether additional SNPs for kidney function can be identified by multivariate statistical analysis. To address this, we applied canonical correlation analysis (CCA), a multivariate method, to two individual-level CKD genotype datasets, and metaCCA to two published GWAS summary statistics datasets. We identified SNPs previously associated with kidney function by published univariate GWASs with high replication rates, validating the metaCCA method. We then extended discovery and identified previously unreported lead SNPs for both kidney function markers, jointly. These showed expression quantitative trait loci (eQTL) colocalisation with genes having significant differential expression between CKD and healthy individuals. Several of these identified lead missense SNPs were predicted to have a functional impact, including in SLC14A2. We also identified previously unreported lead SNPs that showed significant correlation with both kidney function markers, jointly, in the European ancestry CKDGen, National Unified Renal Translational Research Enterprise (NURTuRE)-CKD and Salford Kidney Study (SKS) datasets. Of these, rs3094060 colocalised with FLOT1 gene expression and was significantly more common in CKD cases in both NURTURE-CKD and SKS, than in the general population. Overall, by using multivariate analysis by CCA, we identified additional SNPs and genes for both kidney function and CKD, that can be prioritised for further CKD analyses.

Risk-stratified monitoring for sulfasalazine toxicity: prognostic model development and validation

BACKGROUND

Sulfasalazine-induced cytopenia, nephrotoxicity and hepatotoxicity is uncommon during long-term treatment. Some guidelines recommend 3 monthly monitoring blood tests indefinitely during long-term treatment while others recommend stopping monitoring after 1 year. To rationalise monitoring, we developed and validated a prognostic model for clinically significant blood, liver or kidney toxicity during established sulfasalazine treatment.

DESIGN

Retrospective cohort study.

SETTING

UK primary care. Data from Clinical Practice Research Datalink Gold and Aurum formed independent development and validation cohorts.

PARTICIPANTS

Age ≥18 years, new diagnosis of an inflammatory condition and sulfasalazine prescription.

STUDY PERIOD

1 January 2007 to 31 December 2019.

OUTCOME

Sulfasalazine discontinuation with abnormal monitoring blood-test result.

ANALYSIS

Patients were followed up from 6 months after first primary care prescription to the earliest of outcome, drug discontinuation, death, 5 years or 31 December 2019. Penalised Cox regression was performed to develop the risk equation. Multiple imputation handled missing predictor data. Model performance was assessed in terms of calibration and discrimination.

RESULTS

8936 participants were included in the development cohort (473 events, 23 299 person-years) and 5203 participants were included in the validation cohort (280 events, 12 867 person-years). Nine candidate predictors were included. The optimism adjusted R2 D and Royston D statistic in the development data were 0.13 and 0.79, respectively. The calibration slope (95% CI) and Royston D statistic (95% CI) in validation cohort was 1.19 (0.96 to 1.43) and 0.87 (0.67 to 1.07), respectively.

CONCLUSION

This prognostic model for sulfasalazine toxicity uses readily available data and should be used to risk-stratify blood-test monitoring during established sulfasalazine treatment.

Potentially modifiable factors associated with health-related quality of life among people with chronic kidney disease: baseline findings from the National Unified Renal Translational Research Enterprise CKD (NURTuRE-CKD) cohort

Background

Many non-modifiable factors are associated with poorer health-related quality of life (HRQoL) experienced by people with chronic kidney disease (CKD). We hypothesize that potentially modifiable factors for poor HRQoL can be identified among CKD patients, providing potential targets for intervention.

Method

The National Unified Renal Translational Research Enterprise Chronic Kidney Disease (NURTuRE-CKD) cohort study recruited 2996 participants from nephrology centres with all stages of non-dialysis-dependent CKD. Baseline data collection for sociodemographic, anthropometric, biochemical and clinical information, including Integrated Palliative care Outcome Scale renal, Hospital Anxiety and Depression score (HADS) and the 5-level EuroQol-5D (EQ-5D-5L) as HRQoL measure, took place between 2017 and 2019. EQ-5D-5L dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) were mapped to an EQ-5D-3L value set to derive index value. Multivariable mixed effects regression models, adjusted for known factors affecting HRQoL with recruitment region as a random effect, were fit to assess potentially modifiable factors associated with index value (linear) and within each dimension (logistic).

Results

Among the 2958/2996 (98.7%) participants with complete EQ-5D data, 2201 (74.4%) reported problems in at least one EQ-5D-5L dimension. Multivariable linear regression identified independent associations between poorer HRQoL (EQ-5D-3L index value) and obesity (body mass index ≥30.0 kg/m2, β -0.037, 95% CI -0.058 to -0.016, P = .001), HADS depression score ≥8 (β -0.159, -0.182 to -0.137, P < .001), anxiety score ≥8 (β -0.090, -0.110 to -0.069, P < .001), taking ≥10 medications (β -0.065, -0.085 to -0.046, P < .001), sarcopenia (β -0.062, -0.080 to -0.043, P < .001) haemoglobin <100 g/L (β -0.047, -0.085 to -0.010, P = .012) and pain (β -0.134, -0.152 to -0.117, P < .001). Smoking and prescription of prednisolone independently associated with problems in self-care and usual activities respectively. Renin-angiotensin system inhibitor (RASi) prescription associated with fewer problems with mobility and usual activities.

Conclusion

Potentially modifiable factors including obesity, pain, depression, anxiety, anaemia, polypharmacy, smoking, steroid use and sarcopenia associated with poorer HRQoL in this cohort, whilst RASi use was associated with better HRQoL in two dimensions.

Randomized trial comparing standard versus thermocontrolled haemodialysis using intradialytic cardiac, brain and renal magnetic resonance imaging

BACKGROUND

Ischaemic end-organ damage during haemodialysis (HD) is a significant problem that may be ameliorated by intradialytic cooling. A randomised trial was performed to compare standard HD (SHD; dialysate temperature 37°C) and programmed cooling of the dialysate [thermocontrolled HD (TCHD)] using multiparametric magnetic resonance imaging (MRI) to assess structural, functional and blood flow changes in the heart, brain and kidneys.

METHODS

Prevalent HD patients were randomly allocated to receive either SHD or TCHD for 2 weeks before undergoing serial MRI at four time points: pre-, during (30 min and 180 min) and post-dialysis. MRI measures include cardiac index, myocardial strain, longitudinal relaxation time (T1), myocardial perfusion, internal carotid and basilar artery flow, grey matter perfusion and total kidney volume. Participants then crossed to the other modality to repeat the study protocol.

RESULTS

Eleven participants completed the study. Separation in blood temperature between TCHD (-0.1 ± 0.3°C) and SHD (+0.3 ± 0.2°C; P = .022) was observed, although there was no difference in tympanic temperature changes between arms. There were significant intradialytic reductions in cardiac index, cardiac contractility (left ventricular strain), left carotid and basilar artery blood flow velocities, total kidney volume, longitudinal relaxation time (T1) of the renal cortex and transverse relaxation rate (T2*) of the renal cortex and medulla, but no differences between arms. Pre-dialysis T1 of the myocardium and left ventricular wall mass index were lower after 2 weeks of TCHD compared with SHD [1266 ms (interquartile range 1250-1291) versus 1311 ± 58 ms, P = .02; 66 ± 22 g/m2 versus 72 ± 23 g/m2, P = .004].

CONCLUSIONS

HD adversely affects cardiac function, reduces carotid and basilar artery blood flow and total kidney volume, but mild dialysate cooling using a biofeedback module did not result in differences in intradialytic MRI measures compared with SHD.

The development and internal pilot trial of a digital physical activity and emotional well-being intervention (Kidney BEAM) for people with chronic kidney disease

This trial assessed the feasibility and acceptability of Kidney BEAM, a physical activity and emotional well-being self-management digital health intervention (DHI) for people with chronic kidney disease (CKD), which offers live and on-demand physical activity sessions, educational blogs and videos, and peer support. In this mixed-methods, multicentre randomised waitlist-controlled internal pilot, adults with established CKD were recruited from five NHS hospitals and randomised 1:1 to Kidney BEAM or waitlist control. Feasibility outcomes were based upon a priori progression criteria. Acceptability was primarily explored via individual semi-structured interviews (n = 15). Of 763 individuals screened, n = 519 (68%, 95% CI 65 to 71%) were eligible. Of those eligible, n = 303 (58%, 95% CI 54-63%) did not respond to an invitation to participate by the end of the pilot period. Of the 216 responders, 50 (23%, 95% CI 18-29%) consented. Of the 42 randomised, n = 22 (10 (45%) male; 49 ± 16 years; 14 (64%) White British) were allocated to Kidney BEAM and n = 20 (12 (55%) male; 56 ± 11 years; 15 (68%) White British) to the waitlist control group. Overall, n = 15 (30%, 95% CI 18-45%) withdrew during the pilot phase. Participants completed a median of 14 (IQR 5-21) sessions. At baseline, 90-100% of outcome data (patient reported outcome measures and a remotely conducted physical function test) were completed and 62-83% completed at 12 weeks follow-up. Interview data revealed that remote trial procedures were acceptable. Participants' reported that Kidney BEAM increased their opportunity and motivation to be physically active, however, lack of time remained an ongoing barrier to engagement with the DHI. An randomised controlled trial of Kidney BEAM is feasible and acceptable, with adaptations to increase recruitment, retention and engagement.Trial registration NCT04872933. Date of first registration 05/05/2021.

Evaluating the effect of a digital health intervention to enhance physical activity in people with chronic kidney disease (Kidney BEAM): a multicentre, randomised controlled trial in the UK

BACKGROUND

Remote digital health interventions to enhance physical activity provide a potential solution to improve the sedentary behaviour, physical inactivity, and poor health-related quality of life that are typical of chronic conditions, particularly for people with chronic kidney disease. However, there is a need for high-quality evidence to support implementation in clinical practice. The Kidney BEAM trial evaluated the clinical effect of a 12-week physical activity digital health intervention on health-related quality of life.

METHODS

In a single-blind, randomised controlled trial conducted at 11 centres in the UK, adult participants (aged ≥18 years) with chronic kidney disease were recruited and randomly assigned (1:1) to the Kidney BEAM physical activity digital health intervention or a waiting list control group. Randomisation was performed with a web-based system, in randomly permuted blocks of six. Outcome assessors were masked to treatment allocation. The primary outcome was the difference in the Kidney Disease Quality of Life Short Form version 1.3 Mental Component Summary (KDQoL-SF1.3 MCS) between baseline and 12 weeks. The trial was powered to detect a clinically meaningful difference of 3 arbitrary units (AU) in KDQoL-SF1.3 MCS. Outcomes were analysed by an intention-to-treat approach using an analysis of covariance model, with baseline measures and age as covariates. The trial was registered with ClinicalTrials.gov, NCT04872933.

FINDINGS

Between May 6, 2021, and Oct 30, 2022, 1102 individuals were assessed for eligibility, of whom 340 participants were enrolled and randomly assigned to the Kidney BEAM intervention group (n=173) or the waiting list control group (n=167). 268 participants completed the trial (112 in the Kidney BEAM group and 156 in the waiting list control group). All 340 randomly assigned participants were included in the intention-to treat population. At 12 weeks, there was a significant improvement in KDQoL-SF.13 MCS score in the Kidney BEAM group (from mean 44·6 AU [SD 10·8] at baseline to 47·0 AU [10·6] at 12 weeks) compared with the waiting list control group (from 46·1 AU [10·5] to 45·0 AU [10·1]; between-group difference of 3·1 AU [95% CI 1·8-4·4]; p<0·0001).

INTERPRETATION

The Kidney BEAM physical activity platform is an efficacious digital health intervention to improve mental health-related quality of life in patients with chronic kidney disease. These findings could facilitate the incorporation of remote digital health interventions into clinical practice and offer a potential intervention worthy of investigation in other chronic conditions.

FUNDING

Kidney Research UK.

Blood pressure targets in chronic kidney disease: still no consensus

PURPOSE OF REVIEW

Despite a strong consensus that treatment of hypertension is fundamental to strategies seeking to slow chronic kidney disease (CKD) progression and reduce the associated risk of cardiovascular events (CVE), controversy persists regarding optimal blood pressure (BP) targets. This article reviews the evidence for different targets, discusses associated controversies and suggests approaches to improve BP control.

RECENT FINDINGS

Landmark clinical trials established the principle that lower BP targets are associated with slower progression of CKD in people with a greater magnitude of proteinuria and previous guidelines recommended a target BP of <130/80 mmHg for those with proteinuria. However, the Systolic Blood Pressure Intervention Trial provided new evidence that a systolic BP target of <120 mmHg was associated with a reduced risk of CVE, though there was no impact on CKD progression and there was concern about an increase in renal adverse events. Nevertheless, 2021 Kidney Disease Improving Global Outcomes guidelines recommended systolic BP <120 mmHg, though other updated guidelines did not follow this trend. All guidelines emphasise the importance of standardised BP measurement and a personalised approach.

SUMMARY

An individualised and shared decision-making approach to BP target setting and management is recommended, guided by standardised BP measurement.

Associations with age and glomerular filtration rate in a referred population with chronic kidney disease: methods and baseline data from a UK multicentre cohort study (NURTuRE-CKD)

BACKGROUND

Chronic kidney disease (CKD) is common but heterogenous and is associated with multiple adverse outcomes. The National Unified Renal Translational Research Enterprise (NURTuRE)-CKD cohort was established to investigate risk factors for clinically important outcomes in persons with CKD referred to secondary care.

METHODS

Eligible participants with CKD stages G3-4 or stages G1-2 plus albuminuria >30 mg/mmol were enrolled from 16 nephrology centres in England, Scotland and Wales from 2017 to 2019. Baseline assessment included demographic data, routine laboratory data and research samples. Clinical outcomes are being collected over 15 years by the UK Renal Registry using established data linkage. Baseline data are presented with subgroup analysis by age, sex and estimated glomerular filtration rate (eGFR).

RESULTS

A total of 2996 participants was enrolled. Median (interquartile range) age was 66 (54-74) years, eGFR 33.8 (24.0-46.6) mL/min/1.73 m2 and urine albumin to creatinine ratio 209 (33-926) mg/g; 58.5% were male. Of these participants, 1883 (69.1%) were in high-risk CKD categories. Primary renal diagnosis was CKD of unknown cause in 32.3%, glomerular disease in 23.4% and diabetic kidney disease in 11.5%. Older participants and those with lower eGFR had higher systolic blood pressure and were less likely to be treated with renin-angiotensin system inhibitors (RASi) but were more likely to receive a statin. Female participants were less likely to receive a RASi or statin.

CONCLUSIONS

NURTuRE-CKD is a prospective cohort of persons who are at relatively high risk of adverse outcomes. Long-term follow-up and a large biorepository create opportunities for research to improve risk prediction and to investigate underlying mechanisms to inform new treatment development.

Risk-stratified monitoring for thiopurine toxicity in immune-mediated inflammatory diseases: prognostic model development, validation, and, health economic evaluation

Background

Patients established on thiopurines (e.g., azathioprine) are recommended to undergo three-monthly blood tests for the early detection of blood, liver, or kidney toxicity. These side-effects are uncommon during long-term treatment. We developed a prognostic model that could be used to inform risk-stratified decisions on frequency of monitoring blood-tests during long-term thiopurine treatment, and, performed health-economic evaluation of alternate monitoring intervals.

Methods

This was a retrospective cohort study set in the UK primary-care. Data from the Clinical Practice Research Datalink Aurum and Gold formed development and validation cohorts, respectively. People age ≥18 years, diagnosed with an immune mediated inflammatory disease, prescribed thiopurine by their general practitioner for at-least six-months between January 1, 2007 and December 31, 2019 were eligible. The outcome was thiopurine discontinuation with abnormal blood-test results. Patients were followed up from six-months after first primary-care thiopurine prescription to up to five-years. Penalised Cox regression developed the risk equation. Multiple imputation handled missing predictor data. Calibration and discrimination assessed model performance. A mathematical model evaluated costs and quality-adjusted life years associated with lengthening the interval between blood-tests.

Findings

Data from 5982 (405 events over 16,117 person-years) and 3573 (269 events over 9075 person-years) participants were included in the development and validation cohorts, respectively. Fourteen candidate predictors (21 parameters) were included. The optimism adjusted R2 and Royston D statistic in development data were 0.11 and 0.76, respectively. The calibration slope and Royston D statistic (95% Confidence Interval) in the validation data were 1.10 (0.84-1.36) and 0.72 (0.52-0.92), respectively. A 2-year period between monitoring blood-test was most cost-effective in all deciles of predicted risk but the gain between monitoring annually or biennially reduced in higher risk deciles.

Interpretation

This prognostic model requires information that is readily available during routine clinical care and may be used to risk-stratify blood-test monitoring for thiopurine toxicity. These findings should be considered by specialist societies when recommending blood monitoring during thiopurine prescription to bring about sustainable and equitable change in clinical practice.

Funding

National Institute for Health and Care Research.

Magnetic Resonance Imaging to Evaluate Kidney Structure, Function, and Pathology: Moving Toward Clinical Application

Recent advances in multiparametric magnetic resonance imaging (MRI) allow multiple quantitative measures to assess kidney morphology, tissue microstructure, oxygenation, kidney blood flow, and perfusion to be collected in a single scan session. Animal and clinical studies have investigated the relationship between the different MRI measures and biological processes, although their interpretation can be complex due to variations in study design and generally small participant numbers. However, emerging themes include the apparent diffusion coefficient derived from diffusion-weighted imaging, T1 and T2 mapping parameters, and cortical perfusion being consistently associated with kidney damage and predicting kidney function decline. Blood oxygen level-dependent (BOLD) MRI has shown inconsistent associations with kidney damage markers but has been predictive of kidney function decline in several studies. Therefore, multiparametric MRI of the kidneys has the potential to address the limitations of existing diagnostic methods to provide a noninvasive, noncontrast, and radiation-free method to assess whole kidney structure and function. Barriers to be overcome to facilitate widespread clinical application include improved understanding of biological factors that impact MRI measures, development of a larger evidence base for clinical utility, standardization of MRI protocols, automation of data analysis, determining optimal combination of MRI measures, and health economic evaluation.

Regional Variation in Hemoglobin Distribution Among Individuals With CKD: the ISN International Network of CKD Cohorts

Introduction

Despite recognized geographic and sex-based differences in hemoglobin in the general population, these factors are typically ignored in patients with chronic kidney disease (CKD) in whom a single therapeutic range for hemoglobin is recommended. We sought to compare the distribution of hemoglobin across international nondialysis CKD populations and evaluate predictors of hemoglobin.

Methods

In this cross-sectional study, hemoglobin distribution was evaluated in each cohort overall and stratified by sex and estimated glomerular filtration rate (eGFR). Relationships between candidate predictors and hemoglobin were assessed from linear regression models in each cohort. Estimates were subsequently pooled in a random effects model.

Results

A total of 58,613 participants from 21 adult cohorts (median eGFR range of 17-49 ml/min) and 3 pediatric cohorts (median eGFR range of 26-45 ml/min) were included with broad geographic representation. Hemoglobin values varied substantially among the cohorts, overall and within eGFR categories, with particularly low mean hemoglobin observed in women from Asian and African cohorts. Across the eGFR range, women had a lower hemoglobin compared to men, even at an eGFR of 15 ml/min (mean difference 5.3 g/l, 95% confidence interval [CI] 3.7-6.9). Lower eGFR, female sex, older age, lower body mass index, and diabetic kidney disease were all independent predictors of a lower hemoglobin value; however, this only explained a minority of variance (R2 7%-44% across cohorts).

Conclusion

There are substantial regional differences in hemoglobin distribution among individuals with CKD, and the majority of variance is unexplained by demographics, eGFR, or comorbidities. These findings call for a renewed interest in improving our understanding of hemoglobin determinants in specific CKD populations.

An exploration of successful psychosocial adjustment to long-term in-centre haemodialysis

OBJECTIVES

Haemodialysis extends life for people with end-stage kidney disease (ESKD) worldwide, but it imposes significant psychosocial burdens and there is little evidence about successful adjustment. This study aimed to improve understanding of successful psychosocial adjustment to in-centre haemodialysis (ICHD; dialysis in a hospital or satellite unit).

METHODS

Individual semi-structured interviews were conducted with a purposive sample of 18 people with ESKD who had all received in-centre haemodialysis in the UK for at least 90 days in the last two years. An inductive thematic analysis was employed to identify themes from the verbatim interview transcripts.

RESULTS

There were four themes: 1) reaching a state of acceptance, which described the importance of accepting the necessity of dialysis; 2) taking an active role in treatment, which described how being actively involved in treatment gave participants greater feelings of autonomy and control; 3) utilising social support networks, which described the benefits of instrumental and emotional support; and 4) building emotional resilience, which described the importance of optimism and positivity.

CONCLUSIONS

The themes demonstrated elements of successful adjustment that could be targeted by interventions to promote psychological flexibility and positive adjustment among people receiving in-centre haemodialysis worldwide.

Risk stratified monitoring for methotrexate toxicity in immune mediated inflammatory diseases: prognostic model development and validation using primary care data from the UK

OBJECTIVE

To develop and validate a prognostic model to inform risk stratified decisions on frequency of monitoring blood tests during long term methotrexate treatment.

DESIGN

Retrospective cohort study.

SETTING

Electronic health records within the UK's Clinical Practice Research Datalink (CPRD) Gold and CPRD Aurum.

PARTICIPANTS

Adults (≥18 years) with a diagnosis of an immune mediated inflammatory disease who were prescribed methotrexate by their general practitioner for six months or more during 2007-19.

MAIN OUTCOME MEASURE

Discontinuation of methotrexate owing to abnormal monitoring blood test result. Patients were followed-up from six months after their first prescription for methotrexate in primary care to the earliest of outcome, drug discontinuation for any other reason, leaving the practice, last data collection from the practice, death, five years, or 31 December 2019. Cox regression was performed to develop the risk equation, with bootstrapping used to shrink predictor effects for optimism. Multiple imputation handled missing predictor data. Model performance was assessed in terms of calibration and discrimination.

RESULTS

Data from 13 110 (854 events) and 23 999 (1486 events) participants were included in the development and validation cohorts, respectively. 11 candidate predictors (17 parameters) were included. In the development dataset, the optimism adjusted R² was 0.13 and the optimism adjusted Royston D statistic was 0.79. The calibration slope and Royston D statistic in the validation dataset for the entire follow-up period was 0.94 (95% confidence interval 0.85 to 1.02) and 0.75 (95% confidence interval 0.67 to 0.83), respectively. The prognostic model performed well in predicting outcomes in clinically relevant subgroups defined by age group, type of immune mediated inflammatory disease, and methotrexate dose.

CONCLUSION

A prognostic model was developed and validated that uses information collected during routine clinical care and may be used to risk stratify the frequency of monitoring blood test during long term methotrexate treatment.

Potential clinical value of catheters impregnated with antimicrobials for the prevention of infections associated with peritoneal dialysis

INTRODUCTION

Peritoneal dialysis (PD) is a widely used dialysis modality, which offers the advantage of being a home therapy but is associated with a risk of potentially serious infections, including exit site infection, catheter tunnel infection, and peritonitis that may result in morbidity, technique failure, and increased mortality. Catheters impregnated with antimicrobials hold promise as a novel technique to reduce PD associated infections.

AREAS COVERED

We describe PD modalities, catheters, technique, complications, and the microbiology of associated infections, as well as standard measures to reduce the risk of infection. A novel technique for the impregnation of silicone devices with antimicrobial agents has been used to produce antimicrobial impregnated ventricular shunt catheters with proven clinical efficacy that have now been adopted as the standard of care to reduce neurosurgical infections. Using the same technology, we have developed PD and urinary catheters impregnated with sparfloxacin, triclosan, and rifampicin. Safety and tolerability have been demonstrated in urinary catheters, and a similar study is planned in PD catheters.

EXPERT OPINION

Catheters impregnated with antimicrobials offer a simple technique to reduce PD associated infections and thereby enable more people to enjoy the advantages of PD. Clinical trials are needed to establish efficacy.

The effect of a novel, digital physical activity and emotional well-being intervention on health-related quality of life in people with chronic kidney disease: trial design and baseline data from a multicentre prospective, wait-list randomised controlled trial (kidney BEAM)

BACKGROUND

Physical activity and emotional self-management has the potential to enhance health-related quality of life (HRQoL), but few people with chronic kidney disease (CKD) have access to resources and support. The Kidney BEAM trial aims to evaluate whether an evidence-based physical activity and emotional wellbeing self-management programme (Kidney BEAM) leads to improvements in HRQoL in people with CKD.

METHODS

This was a prospective, multicentre, randomised waitlist-controlled trial, with health economic analysis and nested qualitative studies. In total, three hundred and four adults with established CKD were recruited from 11 UK kidney units. Participants were randomly assigned to the intervention (Kidney BEAM) or a wait list control group (1:1). The primary outcome was the between-group difference in Kidney Disease Quality of Life (KDQoL) mental component summary score (MCS) at 12 weeks. Secondary outcomes included the KDQoL physical component summary score, kidney-specific scores, fatigue, life participation, depression and anxiety, physical function, clinical chemistry, healthcare utilisation and harms. All outcomes were measured at baseline and 12 weeks, with long-term HRQoL and adherence also collected at six months follow-up. A nested qualitative study explored experience and impact of using Kidney BEAM.

RESULTS

340 participants were randomised to Kidney BEAM (n = 173) and waiting list (n = 167) groups. There were 96 (55%) and 89 (53%) males in the intervention and waiting list groups respectively, and the mean (SD) age was 53 (14) years in both groups. Ethnicity, body mass, CKD stage, and history of diabetes and hypertension were comparable across groups. The mean (SD) of the MCS was similar in both groups, 44.7 (10.8) and 45.9 (10.6) in the intervention and waiting list groups respectively.

CONCLUSION

Results from this trial will establish whether the Kidney BEAM self management programme is a cost-effective method of enhancing mental and physical wellbeing of people with CKD.

TRIAL REGISTRATION

NCT04872933. Registered 5th May 2021.

Quality of life in older adults with chronic kidney disease and transient changes in renal function: Findings from the Oxford Renal cohort

Background

Quality of life (QoL) is an important measure of disease burden and general health perception. The relationship between early chronic kidney disease (CKD) and QoL remains poorly understood. The Oxford Renal Study (OxRen) cohort comprises 1063 adults aged ≥60 years from UK primary care practices screened for early CKD, grouped according to existing or screen-detected CKD diagnoses, or biochemistry results indicative of reduced renal function (referred to as transient estimated glomerular filtration rate (eGFR) reduction).

Objectives

This study aimed to compare QoL in participants known to have CKD at recruitment to those identified as having CKD through a screening programme.

Methods

Health profile data and multi-attribute utility scores were reported for two generic questionnaires: 5-level EuroQol-5 Dimension (EQ-5D-5L) and ICEpop CAPability measure for Adults (ICECAP-A). QoL was compared between patients with existing and screen-detected CKD; those with transient eGFR reduction served as the reference group in univariable and multivariable linear regression.

Results

Mean and standard deviation utility scores were not significantly different between the subgroups for EQ-5D-5L (screen-detected:0.785±0.156, n = 480, transient:0.779±0.157, n = 261, existing CKD:0.763±0.171, n = 322, p = 0.216) or ICECAP-A (screen-detected:0.909±0.094, transient:0.904±0.110, existing CKD:0.894±0.115, p = 0.200). Age, smoking status, and number of comorbidities were identified as independent predictors of QoL in this cohort.

Conclusion

QoL of participants with existing CKD diagnoses was not significantly different from those with screen-detected CKD or transient eGFR reduction and was similar to UK mean scores for the same age, suggesting that patient burden of early CKD is minor. Moreover, CKD-related comorbidities contribute more significantly to disease burden in earlier stages of CKD than renal function per se. Larger prospective studies are required to define the relationship between QoL and CKD progression more precisely. These data also confirm the essentially asymptomatic nature of CKD, implying that routine screening or case finding are required to diagnose it.

Simple, high-throughput measurement of gut-derived short-chain fatty acids in clinically relevant biofluids using gas chromatography-mass spectrometry

•

A high-throughput assay for measurement of short-chain fatty acids in biofluids.

•

A simple, time efficient liquid–liquid extraction protocol with no derivatization.

•

Recommend use of lithium heparin plasma or clotting activator serum collection.

•

Clinical applicability demonstrated by measurement of kidney disease patient samples.

Introduction

The quantitative measurement of circulating gut bacteria-derived metabolites has increased in recent years due to their associations with health and disease. While much of the previous attention has been placed on metabolites considered as deleterious to health, a shift to the investigation of short-chain fatty acids (SCFAs) as potential health promotors has been observed.

Objectives

To develop a simple, high-throughput and quantitative assay to measure gut-derived SCFAs in clinically relevant biofluids using gas chromatography-mass spectrometry (GC–MS).

Methods

A short (7.5 min) GC–MS assay was optimized for measurement of seven straight- and branched-chain SCFAs and their deuterated isotopes using a wax-based column for analysis without prior derivatization. The assay was validated using routine criteria to assess precision, accuracy, matrix effects, recovery, and extraction reproducibility. Assay applicability was tested in cohorts of healthy individuals and kidney disease patients.

Results

The assay was demonstrated to be precise, accurate and reproducible with acceptable levels of matrix effect and analyte recovery. Lower limits of detection and quantitation were in the low ng/mL range. An investigation into different blood collection tube chemistries demonstrated that lithium heparin plasma and serum clotting activator tubes are recommended for use in future cross-study comparisons. Kidney disease patient analyses demonstrated variable differences across SCFAs when comparing hemodialysis to earlier stages of chronic kidney disease, demonstrating the suitability of the assay for translation to clinical analyses.

Conclusion

The assay has been validated and identified as reliable for use in larger-scale studies for the analysis of SCFAs in human plasma and serum.

Incidence and pattern of mycophenolate discontinuation associated with abnormal monitoring blood-test results: cohort study using data from the Clinical Practice Research Datalink Aurum

Objective

To examine the incidence and pattern of mycophenolate discontinuation associated with abnormal monitoring blood-tests.

Methods

Data from people prescribed mycophenolate for common inflammatory conditions in the Clinical Practice Research Datalink was used. Participants were followed from first mycophenolate prescription. Primary outcome was drug discontinuation with an associated abnormal blood-test result within 60 days. Secondary outcomes were drug discontinuation for any reason, and discontinuations associated with severely abnormal blood-test results within 60 days. Multivariable cox-regression was used to examine factors associated with primary outcome.

Results

The cohort included 992 participants (68.9% female, mean age 51.95 years, 47.1% with SLE) contributing 1,885 person-years of follow-up. The incidence of mycophenolate discontinuation associated with any (severely) abnormal blood-test results was 153.46 (21.07) per 1000 person-years in the first, and 32.39 (7.91) per 1000 person-years in later years of prescription, respectively. 11.5% (1.7%) patients prescribed mycophenolate discontinued treatment with any (severely) abnormal blood-test results in the first year of prescription. After this period mean 2.6% (0.7%) patients discontinued treatment with any (severely) abnormal blood-test results per year. Increased serum creatinine and cytopenia were more commonly associated with mycophenolate discontinuation than elevated liver enzymes. CKD-stage ≥3 was significantly associated with mycophenolate discontinuation with any blood-test abnormalities (aHR (95%CI) 2.22 (1.47–3.37)).

Conclusion

Mycophenolate is uncommonly discontinued for blood-test abnormalities, and, even less often discontinued for severe blood-test abnormalities after the first year of prescription. Consideration may be given for less frequent monitoring after one-year of treatment, especially in those without CKD-stage ≥3.

Repeatability of Contrast-Enhanced Ultrasound to Determine Renal Cortical Perfusion

Alterations in renal perfusion play a major role in the pathogenesis of renal diseases. Renal contrast-enhanced ultrasound (CEUS) is increasingly applied to quantify renal cortical perfusion and to assess its change over time, but comprehensive assessment of the technique’s repeatability is lacking. Ten adults attended two renal CEUS scans within 14 days. In each session, five destruction/reperfusion sequences were captured. One-phase association was performed to derive the following parameters: acoustic index (AI), mean transit time (mTT), perfusion index (PI), and wash-in rate (WiR). Intra-individual and inter-operator (image analysis) repeatability for the perfusion variables were assessed using intra-class correlation (ICC), with the agreement assessed using a Bland–Altman analysis. The 10 adults had a median (IQR) age of 39 years (30–46). Good intra-individual repeatability was found for mTT (ICC: 0.71) and PI (ICC: 0.65). Lower repeatability was found for AI (ICC: 0.50) and WiR (ICC: 0.56). The correlation between the two operators was excellent for all variables: the ICCs were 0.99 for PI, 0.98 for AI, 0.87 for mTT, and 0.83 for WiR. The Bland–Altman analysis showed that the mean biases (± SD) between the two operators were 0.03 ± 0.16 for mTT, 0.005 ± 0.09 for PI, 0.04 ± 0.19 for AI, and −0.02 ± 0.11 for WiR.

Aspirin to target arterial events in chronic kidney disease (ATTACK): study protocol for a multicentre, prospective, randomised, open-label, blinded endpoint, parallel group trial of low-dose aspirin vs. standard care for the primary prevention of cardiovascular disease in people with chronic kidney disease

Background

Chronic kidney disease (CKD) is a very common long-term condition and powerful risk factor for cardiovascular disease (CVD).

Low-dose aspirin is of proven benefit in the secondary prevention of myocardial infarction (MI) and stroke in people with pre-existing CVD. However, in people without CVD, the rates of MI and stroke are much lower, and the benefits of aspirin in the primary prevention of CVD are largely balanced by an increased risk of bleeding.

People with CKD are at greatly increased risk of CVD and so the absolute benefits of aspirin are likely to be greater than in lower-risk groups, even if the relative benefits are the same. Post hoc evidence suggests the relative benefits may be greater in the CKD population but the risk of bleeding may also be higher. A definitive study of aspirin for primary prevention in this high-risk group, recommended by the National Institute for Health and Care Excellence (NICE) in 2014, has never been conducted. The question has global significance given the rising burden of CKD worldwide and the low cost of aspirin.

Methods

ATTACK is a pragmatic multicentre, prospective, randomised, open-label, blinded endpoint adjudication superiority trial of aspirin 75 mg daily vs. standard care for the primary prevention of CVD in 25,210 people aged 18 years and over with CKD recruited from UK Primary Care.

Participants aged 18 years and over with CKD (GFR category G1-G4) will be identified in Primary Care and followed up using routinely collected data and annual questionnaires for an average of 5 years. The primary outcome is the time to first major vascular event (composite of non-fatal MI, non-fatal stroke and cardiovascular death [excluding confirmed intracranial haemorrhage and other fatal cardiovascular haemorrhage]). Deaths from other causes (including fatal bleeding) will be treated as competing events. The study will continue until 1827 major vascular events have occurred. The principal safety outcome is major intracranial and extracranial bleeding; this is hypothesised to be increased in those randomised to take aspirin. The key consideration is then whether and to what extent the benefits of aspirin from the expected reduction in CVD events exceed the risks of major bleeding.

Discussion

This will be the first definitive trial of aspirin for primary CVD prevention in CKD patients. The research will be of great interest to clinicians, guideline groups and policy-makers, in the UK and globally, particularly given the high and rising prevalence of CKD that is driven by population ageing and epidemics of obesity and diabetes. The low cost of aspirin means that a positive result would be of relevance to low- and middle-income countries and the impact in the developed world less diluted by any inequalities in health care access.

Trial registration

ISRCTN: ISRCTN40920200. EudraCT: 2018-000644-26. ClinicalTrials.gov: NCT03796156

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06132-z.

Using patient feedback to adapt intervention materials based on acceptance and commitment therapy for people receiving renal dialysis

Background

Theory-based intervention materials must be carefully adapted to meet the needs of users with specific physical conditions. Acceptance and Commitment Therapy (ACT) has been adapted successfully for cancer, chronic pain, diabetes, irritable bowel syndrome, multiple sclerosis, and a range of other conditions, but not so far for people receiving renal haemodialysis. This paper presents findings from a study to adapt ACT-based intervention materials specifically for renal dialysis.

Methods

Draft written materials consisting of four stories depicting fictitious individuals who used ACT-related techniques to help overcome different challenges and difficulties related to dialysis were adapted using a systematic patient consultation process. The participants were 18 people aged 19–80 years, with chronic kidney disease and receiving renal dialysis. Individual, semi-structured interviews were conducted to elicit participants’ views about how the content of the draft materials should be adapted to make them more realistic and relevant for people receiving renal dialysis and about how the materials should be presented and delivered to people receiving renal dialysis. The interview transcripts were analysed using a qualitative adaptation of the Delphi method in which themes are used as a framework for translating feedback into proposals for modifications.

Results

The analysis of patient feedback supported the use of patient stories but suggested they should be presented by video and narrated by real dialysis patients. They also indicated specific adaptations to make the stories more credible and realistic. Participant feedback was translated into proposals for change that were considered along with clinical, ethical and theoretical factors. The outcome was a design for a video-based intervention that separated the stories about individuals from the explanations of the specific ACT techniques and provided greater structure, with material organised into smaller chunks. This intervention is adapted specifically for people receiving renal dialysis while retaining the distinctive theoretical principles of ACT.

Conclusions

The study shows the value of consulting patients in the development of intervention materials and illustrates a process for integrating patient feedback with theoretical, clinical and practical considerations in intervention design.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-021-00921-5.

Development and validation of a prognostic model for leflunomide discontinuation with abnormal blood-tests during long-term treatment: cohort study using data from Clinical Practice Research Datalink Gold and Aurum

OBJECTIVE

To develop and validate a prognostic model for leflunomide discontinuation with abnormal blood-test results.

METHODS

Data from CPRD Gold and Aurum were used for model development and external validation respectively. Participants prescribed leflunomide between 01/01/2007 and 31/12/2019 were followed-up from six-months after first GP-prescription to the earliest of date of outcome, death, 5-year follow-up or 31/12/2019. Candidate prognostic factors were ascertained using theory and data driven approaches. Penalised Cox regression was performed to develop the risk equation, followed by internal validation using 500-bootstraps to correct for optimism. Multiple imputation was applied to handle missing data. Model performance was assessed in terms of calibration and discrimination.

RESULTS

Data for 1,487 and 2,329 participants contributing 3,140 and 5,246 person-years follow-up were included in the development and validation cohorts, respectively. Thirteen candidate predictors were included in the model. Epilepsy, and either cytopenia or elevated liver enzymes during first six months of shared-care leflunomide prescription were strong predictors of drug discontinuation with hazard ratio (95%CI) 4.39 (1.74 -11.06) and 3.06 (2.15 - 4.35), respectively. The unadjusted and optimism adjusted calibration slope in development data was 1.00 (95% CI 0.75-1.25) and 0.72 (95% CI 0.47-0.97), respectively. The calibration slope in validation data was 0.91 (95% CI 0.74-1.07). The model showed prognostic separation with optimism adjusted Royston D statistic of 0.73 (95% CI 0.44-1.02).

CONCLUSION

We have developed and externally validated an easy-to-use prognostic model that may be used to risk-stratify monitoring for leflunomide toxicity and to make informed choices about risks when choosing treatments.

An Analysis of Frequency of Continuous Blood Pressure Variation and Haemodynamic Responses during Haemodialysis

BACKGROUND

Higher beat-to-beat blood pressure (BP) variation during haemodialysis (HD) has been shown to be associated with elevated cardiac damage markers and white matter ischaemic changes in the brain suggesting relevance to end-organ perfusion. We aimed to characterize individual patterns of BP variation and associated haemodynamic responses to HD.

METHODS

Fifty participants underwent continuous non-invasive haemodynamic monitoring during HD and BP variation were assessed using extrema point (EP) frequency analysis. Participants were divided into those with a greater proportion of low frequency (LF, n = 21) and high frequency (HF, n = 22) of BP variation. Clinical and haemodynamic data were compared between groups.

RESULTS

Median EP frequencies for mean arterial pressure (MAP) of mid-week HD sessions were 0.54 Hz (interquartile range 0.18) and correlated with dialysis vintage (r = 0.32, p = 0.039), NT pro-BNP levels (r = 0.32, p = 0.038), and average real variability (ARV) of systolic BP (r = 0.33, p = 0.029), ARV of diastolic BP (r = 0.46, p = 0.002), and ARV of MAP (r = 0.57, p < 0.001). In the LF group, MAP positively correlated with cardiac power index (CPI) in each hour of dialysis, but not with total peripheral resistance index (TPRI). In contrast, in the HF group, MAP correlated with TPRI in each hour of dialysis but only with CPI in the first hour.

CONCLUSIONS

EP frequency analysis of continuous BP monitoring during dialysis allows assessment of BP variation and categorization of individuals into low- or high-frequency groups, which were characterized by different haemodynamic responses to dialysis. This may assist in improved individualization of dialysis therapy.

Exercise programme to improve quality of life for patients with end-stage kidney disease receiving haemodialysis: the PEDAL RCT

BACKGROUND

Whether or not clinically implementable exercise interventions in haemodialysis patients improve quality of life remains unknown.

OBJECTIVES

The PEDAL (PrEscription of intraDialytic exercise to improve quAlity of Life in patients with chronic kidney disease) trial evaluated the clinical effectiveness and cost-effectiveness of a 6-month intradialytic exercise programme on quality of life compared with usual care for haemodialysis patients.

DESIGN

We conducted a prospective, multicentre randomised controlled trial of haemodialysis patients from five haemodialysis centres in the UK and randomly assigned them (1 : 1) using a web-based system to (1) intradialytic exercise training plus usual-care maintenance haemodialysis or (2) usual-care maintenance haemodialysis.

SETTING

The setting was five dialysis units across the UK from 2015 to 2019.

PARTICIPANTS

The participants were adult patients with end-stage kidney disease who had been receiving haemodialysis therapy for > 1 year.

INTERVENTIONS

Participants were randomised to receive usual-care maintenance haemodialysis or usual-care maintenance haemodialysis plus intradialytic exercise training.

MAIN OUTCOME MEASURES

The primary outcome of the study was change in Kidney Disease Quality of Life Short Form, version 1.3, physical component summary score (from baseline to 6 months). Cost-effectiveness was determined using health economic analysis and the EuroQol-5 Dimensions, five-level version. Additional secondary outcomes included quality of life (Kidney Disease Quality of Life Short Form, version 1.3, generic multi-item and burden of kidney disease scales), functional capacity (sit-to-stand 60 and 10-metre Timed Up and Go tests), physiological measures (peak oxygen uptake and arterial stiffness), habitual physical activity levels (measured by the International Physical Activity Questionnaire and Duke Activity Status Index), fear of falling (measured by the Tinetti Falls Efficacy Scale), anthropometric measures (body mass index and waist circumference), clinical measures (including medication use, resting blood pressure, routine biochemistry, hospitalisations) and harms associated with intervention. A nested qualitative study was conducted.

RESULTS

We randomised 379 participants; 335 patients completed baseline assessments and 243 patients (intervention, n = 127; control, n = 116) completed 6-month assessments. The mean difference in change in physical component summary score from baseline to 6 months between the intervention group and control group was 2.4 arbitrary units (95% confidence interval -0.1 to 4.8 arbitrary units; p = 0.055). Participants in the intervention group had poor compliance (49%) and very poor adherence (18%) to the exercise prescription. The cost of delivering the intervention ranged from £463 to £848 per participant per year. The number of participants with harms was similar in the intervention (n = 69) and control (n = 56) groups.

LIMITATIONS

Participants could not be blinded to the intervention; however, outcome assessors were blinded to group allocation.

CONCLUSIONS

On trial completion the primary outcome (Kidney Disease Quality of Life Short Form, version 1.3, physical component summary score) was not statistically improved compared with usual care. The findings suggest that implementation of an intradialytic cycling programme is not an effective intervention to enhance health-related quality of life, as delivered to this cohort of deconditioned patients receiving haemodialysis.

FUTURE WORK

The benefits of longer interventions, including progressive resistance training, should be confirmed even if extradialytic delivery is required. Future studies also need to evaluate whether or not there are subgroups of patients who may benefit from this type of intervention, and whether or not there is scope to optimise the exercise intervention to improve compliance and clinical effectiveness.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN83508514.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 40. See the NIHR Journals Library website for further project information.

Randomized Trial-PrEscription of intraDialytic exercise to improve quAlity of Life in Patients Receiving Hemodialysis

Introduction

Whether clinically implementable exercise interventions in people receiving hemodialysis (HD) therapy improve health-related quality of life (HRQoL) remains unknown. The PrEscription of intraDialytic exercise to improve quAlity of Life (PEDAL) study evaluated the clinical benefit and cost-effectiveness of a 6-month intradialytic exercise program.

Methods

In a multicenter, single-blinded, randomized, controlled trial, people receiving HD were randomly assigned to (i) intradialytic exercise training (exercise intervention group [EX]) and (ii) usual care (control group [CON]). Primary outcome was change in Kidney Disease Quality of Life Short-Form Physical Component Summary (KDQOL-SF 1.3 PCS) from baseline to 6 months. Cost-effectiveness was determined using health economic analysis; physiological impairment was evaluated by peak oxygen uptake; and harms were recorded.

Results

We randomized 379 participants; 335 and 243 patients (EX n = 127; CON n = 116) completed baseline and 6-month assessments, respectively. Mean difference in change PCS from baseline to 6 months between EX and CON was 2.4 (95% confidence interval [CI]: -0.1 to 4.8) arbitrary units (P = 0.055); no improvements were observed in peak oxygen uptake or secondary outcome measures. Participants in the intervention group had poor compliance (47%) and poor adherence (18%) to the exercise prescription. Cost of delivering intervention ranged from US$598 to US$1092 per participant per year. The number of participants with harms was similar between EX (n = 69) and CON (n = 56). A primary limitation was the lack of an attention CON. Many patients also withdrew from the study or were too unwell to complete all physiological outcome assessments.

Conclusions

A 6-month intradialytic aerobic exercise program was not clinically beneficial in improving HRQoL as delivered to this cohort of deconditioned patients on HD.

What is the incidence of methotrexate or leflunomide discontinuation related to cytopenia, liver enzyme elevation or kidney function decline?

Objectives

To examine incidence of treatment changes due to abnormal blood-test results and, to explore rates of treatment changes due to liver, kidney and haematological blood-test abnormalities in autoimmune rheumatic diseases (AIRD) treated with low-dose MTX or LEF.

Methods

Data for people with AIRDs prescribed MTX or LEF were extracted from the Clinical Practice Research Datalink. Participants were followed-up from first prescription of MTX or LEF in primary care. Primary outcome of interest was drug discontinuation, defined as a prescription gap of ≥90 days following an abnormal (or severely abnormal) blood-test result. Dose reduction was examined between consecutive prescriptions. Incidence rates per 1000 person-years were calculated.

Results

15, 670 and 2,689 participants contributing 46, 571 and 4,558 person-years follow-up were included in MTX and LEF cohorts, respectively. The incidence of MTX and LEF discontinuation with abnormal (severely abnormal) blood-test was 42.24 (6.16) and 106.53 (9.42)/1000 person-years in year 1, and 22.44 (2.84) and 31.69 (4.40)/1000 person years, respectively, thereafter. The cumulative incidence of MTX and LEF discontinuation with abnormal (severely abnormal) blood tests was 1 in 24 (1 in 169), 1 in 9 (1 in 106) at 1 year; and 1 in 45 (1 in 352), 1 in 32 (1 in 227) per-year, respectively, thereafter. Raised liver enzymes were the commonest abnormality associated with drug discontinuation. MTX and LEF dose reduction incidence were comparable in year 1, however, thereafter MTX dose was reduced more often than LEF [16.60 (95% CI 13.05, 21.13) vs 8.10 (95% CI 4.97, 13.20)/1000 person-years].

Conclusion

MTX and LEF were discontinued for blood-test abnormalities after year 1 of treatment, however, discontinuations for severely abnormal results were uncommon.

Multiparametric MRI assessment of renal structure and function in acute kidney injury and renal recovery

Background

Acute kidney injury (AKI) is associated with a marked increase in mortality as well as subsequent chronic kidney disease (CKD) and end-stage kidney disease. We performed multiparametric magnetic resonance imaging (MRI) with the aim of identifying potential non-invasive MRI markers of renal pathophysiology in AKI and during recovery.

Methods

Nine participants underwent inpatient MRI scans at time of AKI; seven had follow-up scans at 3 months and 1 year following AKI. Multiparametric renal MRI assessed total kidney volume (TKV), renal perfusion using arterial spin labelling, T₁ mapping and blood oxygen level-dependent (BOLD) R₂* mapping.

Results

Serum creatinine concentration had recovered to baseline levels at 1-year post-AKI in all participants. At the time of AKI, participants had increased TKV, increased cortex/medulla T₁ and reduced cortical perfusion compared with the expected ranges in healthy volunteers and people with CKD. TKV and T₁ values decreased over time after AKI and returned to expected values in most but not all patients by 1 year. Cortical perfusion improved to a lesser extent and remained below the expected range in the majority of patients by 1-year post-AKI. BOLD R₂* data showed a non-significant trend to increase over time post-AKI.

Conclusions

We observed a substantial increase in TKV and T₁ during AKI and a marked decrease in cortical perfusion. Despite biochemical recovery at 1-year post-AKI, MRI measures indicated persisting abnormalities in some patients. We propose that such patients may be more likely to have further AKI episodes or progress to CKD and further longitudinal studies are required to investigate this. .

Determinants of change in arterial stiffness over 5 years in early chronic kidney disease

BACKGROUND

Arterial stiffness (AS) is an established and potentially modifiable risk factor for cardiovascular disease associated with chronic kidney disease (CKD). There have been few studies to evaluate the progression of AS over time or factors that contribute to this, particularly in early CKD. We therefore investigated AS over 5 years in an elderly population with CKD Stage 3 cared for in primary care.

METHODS

A total of 1741 persons with an estimated glomerular filtration rate of 30-59 mL/min/1.73 m2 underwent detailed clinical and biochemical assessment at baseline and Years 1 and 5. Carotid to femoral pulse wave velocity (PWV) was measured to assess AS using a Vicorder device.

RESULTS

970 participants had PWV assessments at baseline and 5 years. PWV increased significantly by a mean of 1.1 m/s (from 9.7 ± 1.9 to 10.8 ± 2.1 m/s). Multivariable linear regression analysis identified the following independent determinants of ΔPWV at Year 5: baseline age, diabetes status, baseline systolic blood pressure (SBP) and diastolic blood pressure, baseline PWV, ΔPWV at 1 year, ΔSBP over 5 years and Δserum bicarbonate over 5 years (R2 = 0.38 for the equation).

CONCLUSIONS

We observed a clinically significant increase in PWV over 5 years in a cohort with early CKD despite reasonably well-controlled hypertension. Measures of BP were identified as the most important modifiable determinant of ΔPWV, suggesting that interventions to prevent arterial disease should focus on improved control of BP, particularly in those who evidence an early increase in PWV. These hypotheses should now be tested in prospective trials.

Patients' and kidney care team's perspectives of treatment burden and capacity in older people with chronic kidney disease: a qualitative study

OBJECTIVE

Chronic kidney disease (CKD) is often a multimorbid condition and progression to more severe disease is commonly associated with increased management requirements, including lifestyle change, more medication and greater clinician involvement. This study explored patients' and kidney care team's perspectives of the nature and extent of this workload (treatment burden) and factors that support capacity (the ability to manage health) for older individuals with CKD.

DESIGN

Qualitative semistructured interview and focus group study.

SETTING AND PARTICIPANTS

Adults (aged 60+) with predialysis CKD stages G3-5 (identified in two general practitioner surgeries and two renal clinics) and a multiprofessional secondary kidney care team in the UK.

RESULTS

29 individuals and 10 kidney team members were recruited. Treatment burden themes were: (1) understanding CKD, its treatment and consequences, (2) adhering to treatments and management and (3) interacting with others (eg, clinicians) in the management of CKD. Capacity themes were: (1) personal attributes (eg, optimism, pragmatism), (2) support network (family/friends, service providers), (3) financial capacity, environment (eg, geographical distance to unit) and life responsibilities (eg, caring for others). Patients reported poor provision of CKD information and lack of choice in treatment, whereas kidney care team members discussed health literacy issues. Patients reported having to withdraw from social activities and loss of employment due to CKD, which further impacted their capacity.

CONCLUSION

Improved understanding of and measures to reduce the treatment burden (eg, clear information, simplified medication, joined up care, free parking) associated with CKD in individuals as well as assessment of their capacity and interventions to improve capacity (social care, psychological support) will likely improve patient experience and their engagement with kidney care services.

Application of the Lomb-Scargle Periodogram to InvestigateHeart Rate Variability during Haemodialysis

Short-term cardiovascular compensatory responses to perturbations in the circulatory system caused by haemodialysis can be investigated by the spectral analysis of heart rate variability, thus providing an important variable for categorising individual patients' response, leading to a more personalised treatment. This is typically accomplished by resampling the irregular heart rate to generate an equidistant time series prior to spectral analysis, but resampling can further distort the data series whose interpretation can already be compromised by the presence of artefacts. The Lomb-Scargle periodogram provides a more direct method of spectral analysis as this method is specifically designed for large, irregularly sampled, and noisy datasets such as those obtained in clinical settings. However, guidelines for preprocessing patient data have been established in combination with equidistant time-series methods and their validity when used in combination with the Lomb-Scargle approach is missing from literature. This paper examines the effect of common preprocessing methods on the Lomb-Scargle power spectral density estimate using both real and synthetic heart rate data and will show that many common techniques for identifying and editing suspect data points, particularly interpolation and replacement, will distort the resulting power spectrum potentially misleading clinical interpretations of the results. Other methods are proposed and evaluated for use with the Lomb-Scargle approach leading to the main finding that suspicious data points should be excluded rather than edited, and where required, denoising of the heart rate signal can be reliably accomplished by empirical mode decomposition. Some additional methods were found to be particularly helpful when used in conjunction with the Lomb-Scargle periodogram, such as the use of a false alarm probability metric to establish whether spectral estimates are valid and help automate the assessment of valid heart rate records, potentially leading to greater use of this powerful technique in a clinical setting.

Quantitative assessment of renal structural and functional changes in chronic kidney disease using multi-parametric magnetic resonance imaging

Background

Multi-parametric magnetic resonance imaging (MRI) provides the potential for a more comprehensive non-invasive assessment of organ structure and function than individual MRI measures, but has not previously been comprehensively evaluated in chronic kidney disease (CKD).

Methods

We performed multi-parametric renal MRI in persons with CKD (n = 22, 61 ± 24 years) who had a renal biopsy and measured glomerular filtration rate (mGFR), and matched healthy volunteers (HV) (n = 22, 61 ± 25 years). Longitudinal relaxation time (T₁), diffusion-weighted imaging, renal blood flow (phase contrast MRI), cortical perfusion (arterial spin labelling) and blood-oxygen-level-dependent relaxation rate (R₂*) were evaluated.

Results

MRI evidenced excellent reproducibility in CKD (coefficient of variation <10%). Significant differences between CKD and HVs included cortical and corticomedullary difference (CMD) in T₁, cortical and medullary apparent diffusion coefficient (ADC), renal artery blood flow and cortical perfusion. MRI measures correlated with kidney function in a combined CKD and HV analysis: estimated GFR correlated with cortical T₁ (r = −0.68), T₁ CMD (r = −0.62), cortical (r = 0.54) and medullary ADC (r = 0.49), renal artery flow (r = 0.78) and cortical perfusion (r = 0.81); log urine protein to creatinine ratio (UPCR) correlated with cortical T₁ (r = 0.61), T₁ CMD (r = 0.61), cortical (r = −0.45) and medullary ADC (r = −0.49), renal artery flow (r = −0.72) and cortical perfusion (r = −0.58). MRI measures (cortical T₁ and ADC, T₁ and ADC CMD, cortical perfusion) differed between low/high interstitial fibrosis groups at 30–40% fibrosis threshold.

Conclusion

Comprehensive multi-parametric MRI is reproducible and correlates well with available measures of renal function and pathology. Larger longitudinal studies are warranted to evaluate its potential to stratify prognosis and response to therapy in CKD.

A Feasibility Study of Non-Invasive Continuous Estimation of Brachial Pressure Derived From Arterial and Venous Lines During Dialysis

Objective: Intradialytic haemodynamic instability is a significant clinical problem, leading to end-organ ischaemia and contributing to morbidity and mortality in haemodialysis patients. Non-invasive continuous blood pressure monitoring is not currently part of routine practice but may aid detection and prevention of significant falls in blood pressure during dialysis. Brachial blood pressure is currently recorded intermittently during haemodialysis via a sphygmomanometer. Current methods of continuous non-invasive blood pressure monitoring tend to restrict movement, can be sensitive to external disturbances and patient movement, and can be uncomfortable for the wearer. Additionally, poor patient blood circulation can lead to unreliable measurements. In this feasibility study we performed an initial validation of a novel method and associated technology to continuously estimate blood pressure using pressure sensors in the extra-corporeal dialysis circuit, which does not require any direct contact with the person receiving dialysis treatment. Method: The paper describes the development of the measurement system and subsequent in vivo patient feasibility study with concurrent measurement validation by Finapres Nova physiological measurement device. Real-time physiological data is collected over the entire period of (typically 4-hour) dialysis treatment. Results: We identify a quasi-linear mathematical function to describe the relationship between arterial line pressure and brachial artery BP, which is confirmed in a patient study. The results from this observational study suggest that it is feasible to derive a continuous measurement of brachial pressure from continuous measurements of arterial and venous line pressures via an empirically based and updated mathematical model. Conclusion: The methodology presented requires no interfacing to proprietary dialysis machine systems, no sensors to be attached to the patient directly, and is robust to patient movement during treatment and also to the effects of the cyclical pressure waveforms induced by the hemodialysis peristaltic blood pump. This represents a key enabling factor to the development of a practical continuous blood pressure monitoring device for dialysis patients.

Dialysis-Induced Cardiovascular and Multiorgan Morbidity

Hemodialysis has saved many lives, albeit with significant residual mortality. Although poor outcomes may reflect advanced age and comorbid conditions, hemodialysis per se may harm patients, contributing to morbidity and perhaps mortality. Systemic circulatory "stress" resulting from hemodialysis treatment schedule may act as a disease modifier, resulting in a multiorgan injury superimposed on preexistent comorbidities. New functional intradialytic imaging (i.e., echocardiography, cardiac magnetic resonance imaging [MRI]) and kinetic of specific cardiac biomarkers (i.e., Troponin I) have clearly documented this additional source of end-organ damage. In this context, several factors resulting from patient-hemodialysis interaction and/or patient management have been identified. Intradialytic hypovolemia, hypotensive episodes, hypoxemia, solutes, and electrolyte fluxes as well as cardiac arrhythmias are among the contributing factors to systemic circulatory stress that are induced by hemodialysis. Additionally, these factors contribute to patients' symptom burden, impair cognitive function, and finally have a negative impact on patients' perception and quality of life. In this review, we summarize the adverse systemic effects of current intermittent hemodialysis therapy, their pathophysiologic consequences, review the evidence for interventions that are cardioprotective, and explore new approaches that may further reduce the systemic burden of hemodialysis. These include improved biocompatible materials, smart dialysis machines that automatically may control the fluxes of solutes and electrolytes, volume and hemodynamic control, health trackers, and potentially disruptive technologies facilitating a more personalized medicine approach.

Acute kidney injury associated with COVID-19: A retrospective cohort study

BACKGROUND

Initial reports indicate a high incidence of acute kidney injury (AKI) in Coronavirus Disease 2019 (COVID-19), but more data are required to clarify if COVID-19 is an independent risk factor for AKI and how COVID-19-associated AKI may differ from AKI due to other causes. We therefore sought to study the relationship between COVID-19, AKI, and outcomes in a retrospective cohort of patients admitted to 2 acute hospitals in Derby, United Kingdom.

METHODS AND FINDINGS

We extracted electronic data from 4,759 hospitalised patients who were tested for COVID-19 between 5 March 2020 and 12 May 2020. The data were linked to electronic patient records and laboratory information management systems. The primary outcome was AKI, and secondary outcomes included in-hospital mortality, need for ventilatory support, intensive care unit (ICU) admission, and length of stay. As compared to the COVID-19-negative group (n = 3,374), COVID-19 patients (n = 1,161) were older (72.1 ± 16.1 versus 65.3 ± 20.4 years, p < 0.001), had a greater proportion of men (56.6% versus 44.9%, p < 0.001), greater proportion of Asian ethnicity (8.3% versus 4.0%, p < 0.001), and lower proportion of white ethnicity (75.5% versus 82.5%, p < 0.001). AKI developed in 304 (26.2%) COVID-19-positive patients (COVID-19 AKI) and 420 (12.4%) COVID-19-negative patients (AKI controls). COVID-19 patients aged 65 to 84 years (odds ratio [OR] 1.67, 95% confidence interval [CI] 1.11 to 2.50), needing mechanical ventilation (OR 8.74, 95% CI 5.27 to 14.77), having congestive cardiac failure (OR 1.72, 95% CI 1.18 to 2.50), chronic liver disease (OR 3.43, 95% CI 1.17 to 10.00), and chronic kidney disease (CKD) (OR 2.81, 95% CI 1.97 to 4.01) had higher odds for developing AKI. Mortality was higher in COVID-19 AKI versus COVID-19 patients without AKI (60.5% versus 27.4%, p < 0.001), and AKI was an independent predictor of mortality (OR 3.27, 95% CI 2.39 to 4.48). Compared with AKI controls, COVID-19 AKI was observed in a higher proportion of men (58.9% versus 51%, p = 0.04) and lower proportion with white ethnicity (74.7% versus 86.9%, p = 0.003); was more frequently associated with cerebrovascular disease (11.8% versus 6.0%, p = 0.006), chronic lung disease (28.0% versus 19.3%, p = 0.007), diabetes (24.7% versus 17.9%, p = 0.03), and CKD (34.2% versus 20.0%, p < 0.001); and was more likely to be hospital acquired (61.2% versus 46.4%, p < 0.001). Mortality was higher in the COVID-19 AKI as compared to the control AKI group (60.5% versus 27.6%, p < 0.001). In multivariable analysis, AKI patients aged 65 to 84 years, (OR 3.08, 95% CI 1.77 to 5.35) and ≥85 years of age (OR 3.54, 95% CI 1.87 to 6.70), peak AKI stage 2 (OR 1.74, 95% CI 1.05 to 2.90), AKI stage 3 (OR 2.01, 95% CI 1.13 to 3.57), and COVID-19 (OR 3.80, 95% CI 2.62 to 5.51) had higher odds of death. Limitations of the study include retrospective design, lack of urinalysis data, and low ethnic diversity of the region.

CONCLUSIONS

We observed a high incidence of AKI in patients with COVID-19 that was associated with a 3-fold higher odds of death than COVID-19 without AKI and a 4-fold higher odds of death than AKI due to other causes. These data indicate that patients with COVID-19 should be monitored for the development of AKI and measures taken to prevent this.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04407156.

Symptom-burden in people living with frailty and chronic kidney disease

Background

Frailty is independently associated with worse health-related quality of life (HRQOL) in chronic kidney disease (CKD). However, the relationship between frailty and symptom experience is not well described in people living with CKD. This study’s aim was to evaluate the relationship between frailty and symptom-burden in CKD.

Methods

This study is a secondary analysis of a cross-sectional observational study, the QCKD study (ISRCTN87066351), in which participants completed physical activity, cardiopulmonary fitness, symptom-burden and HRQOL questionnaires. A modified version of the Frailty Phenotype, comprising 3 self-report components, was created to assess frailty status. Multiple linear regression was performed to assess the association between symptom-burden/HRQOL and frailty. Logistic regression was performed to assess the association between experiencing symptoms frequently and frailty. Principal Component Analysis was used to assess the experienced symptom clusters.

Results

A total of 353 patients with CKD were recruited with 225 (64%) participants categorised as frail. Frail participants reported more symptoms, had higher symptom scores and worse HRQOL scores. Frailty was independently associated with higher total symptom score and lower HRQOL scores. Frailty was also independently associated with higher odds of frequently experiencing 9 out of 12 reported symptoms. Finally, frail participants experienced an additional symptom cluster that included loss of appetite, tiredness, feeling cold and poor concentration.

Conclusions

Frailty is independently associated with high symptom-burden and poor HRQOL in CKD. Moreover, people living with frailty and CKD have a distinctive symptom experience. Proactive interventions are needed that can effectively identify and address problematic symptoms to mitigate their impact on HRQOL.

The PrEscription of intraDialytic exercise to improve quAlity of Life in patients with chronic kidney disease trial: study design and baseline data for a multicentre randomized controlled trial

Background

Exercise interventions designed to improve physical function and reduce sedentary behaviour in haemodialysis (HD) patients might improve exercise capacity, reduce fatigue and lead to improved quality of life (QOL). The PrEscription of intraDialytic exercise to improve quAlity of Life study aimed to evaluate the effectiveness of a 6-month intradialytic exercise programme on QOL and physical function, compared with usual care for patients on HD in the UK.

Methods

We conducted a prospective, pragmatic multicentre randomized controlled trial in 335 HD patients and randomly (1:1) assigned them to either (i) intradialytic exercise training plus usual care maintenance HD or (ii) usual care maintenance HD. The primary outcome of the study was the change in Kidney Disease Quality of Life Short Form (KDQOL-SF 1.3) Physical Component Score between baseline and 6 months. Additional secondary outcomes included changes in peak aerobic capacity, physical fitness, habitual physical activity levels and falls (International Physical Activity Questionnaire, Duke’s Activity Status Index and Tinetti Falls Efficacy Scale), QOL and symptom burden assessments (EQ5D), arterial stiffness (pulse wave velocity), anthropometric measures, resting blood pressure, clinical chemistry, safety and harms associated with the intervention, hospitalizations and cost-effectiveness. A nested qualitative study investigated the experience and acceptability of the intervention for both participants and members of the renal health care team.

Results

At baseline assessment, 62.4% of the randomized cohort were male, the median age was 59.3 years and 50.4% were white. Prior cerebrovascular events and myocardial infarction were present in 8 and 12% of the cohort, respectively, 77.9% of patients had hypertension and 39.4% had diabetes. Baseline clinical characteristics and laboratory data for the randomized cohort were generally concordant with data from the UK Renal Registry.

Conclusion

The results from this study will address a significant knowledge gap in the prescription of exercise interventions for patients receiving maintenance HD therapy and inform the development of intradialytic exercise programmes both nationally and internationally.

Trial Registration

ISRCTN N83508514; registered on 17 December 2014.

Prevalence of chronic kidney disease in adults in England: comparison of nationally representative cross-sectional surveys from 2003 to 2016

OBJECTIVES

To identify recent trends in chronic kidney disease (CKD) prevalence in England and explore their association with changes in sociodemographic, behavioural and clinical factors.

DESIGN

Pooled cross-sectional analysis.

SETTING

Health Survey for England 2003, 2009/2010 combined and 2016.

PARTICIPANTS

17 663 individuals (aged 16+) living in private households.

PRIMARY AND SECONDARY OUTCOME MEASURES

Prevalence of estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 and albuminuria (measured by albumin-creatinine ratio) during 2009/2010 and 2016 and trends in eGFR between 2003 and 2016. eGFR was estimated using serum creatinine Chronic Kidney Disease Epidemiology Collaboration and Modification of Diet in Renal Disease equations.

RESULTS

GFR <60 mL/min/1.73 m2 prevalence was 7.7% (95% CI 7.1% to 8.4%), 7.0% (6.4% to 7.7%) and 7.3%(6.5% to 8.2%) in 2003, 2009/2010 and 2016, respectively. Albuminuria prevalence was 8.7% (8.1% to 9.5%) in 2009/2010 and 9.8% (8.7% to 10.9%) in 2016. Prevalence of CKD G1-5 (eGFR <60 mL/min/1.73 m2 or albuminuria) was 12.6% (11.8% to 13.4%) in 2009/2010 and 13.9% (12.8% to 15.2%) in 2016. Prevalence of diabetes and obesity increased during 2003-2016 while prevalence of hypertension and smoking fell. The age-adjusted and gender-adjusted OR of eGFR <60 mL/min/1.73 m2 for 2016 versus 2009/2010 was 0.99 (0.82 to 1.18) and fully adjusted OR was 1.13 (0.93 to 1.37). There was no significant period effect on the prevalence of albuminuria or CKD G1-5 from 2009/2010 to 2016 in age and gender or fully adjusted models.

CONCLUSION

The fall in eGFR <60 mL/min/1.73 m2 seen from 2003 to 2009/2010 did not continue to 2016. However, absolute CKD burden is likely to rise with population growth and ageing, particularly if diabetes prevalence continues to increase. This highlights the need for greater CKD prevention efforts and continued surveillance.

Health-related quality of life, functional impairment and comorbidity in people with mild-to-moderate chronic kidney disease: a cross-sectional study

OBJECTIVES

To determine the associations between comorbidities, health-related quality of life (HRQoL) and functional impairment in people with mild-to-moderate chronic kidney disease (CKD) in primary care.

DESIGN

Cross-sectional analysis at 5-year follow-up in a prospective cohort study.

SETTING

Thirty-two general practitioner surgeries in England.

PARTICIPANTS

1008 participants with CKD stage 3 (of 1741 people recruited at baseline in the Renal Risk in Derby study) who survived to 5 years and had complete follow-up data for HRQoL and functional status (FS).

PRIMARY AND SECONDARY OUTCOME MEASURES

HRQoL assessed using the 5-level EQ-5D version (EQ-5D-5L, with domains of mobility, self-care, usual activities, pain/discomfort and anxiety/depression and index value using utility scores calculated from the English general population), and FS using the Karnofsky Performance Status scale (functional impairment defined as Karnofksy score ≤70). Comorbidity was defined by self-reported or doctor-diagnosed condition, disease-specific medication or blood result.

RESULTS

Mean age was 75.8 years. The numbers reporting some problems in EQ-5D-5L domains were: 582 (57.7%) for mobility, 166 (16.5%) for self-care, 466 (46.2%) for usual activities, 712 (70.6%) for pain/discomfort and 319 (31.6%) for anxiety/depression. Only 191 (18.9%) reported no problems in any domain. HRQoL index values showed greater variation among those with lower FS (eg, for those with Karnofsky score of 60, the median (IQR) EQ-5D index value was 0.45 (0.24 to 0.68) compared with 0.94 (0.86 to 1) for those with Karnofsky score of 90). Overall, 234 (23.2%) had functional impairment.In multivariable logistic regression models, functional impairment was independently associated with experiencing problems for all EQ-5D-5L domains (mobility: OR 16.87 (95% CI 8.70 to 32.79, p<0.001, self-care: OR 13.08 (95% CI 8.46 to 20.22), p<0.001, usual activities: OR 8.27 (95% CI 5.43 to 12.58), p<0.001, pain/discomfort: OR 2.94 (95% CI 1.86 to 4.67), p<0.001, anxiety/depression: 3.08 (95% CI 2.23 to 4.27), p<0.001). Higher comorbidity count and obesity were independently associated with problems in mobility, self-care, usual activities and pain/discomfort: for three or more comorbidities versus none: (mobility: OR 2.10 (95% CI 1.08 to 4.10, p for trend 0.002), self-care: OR 2.64 (95% CI 0.72 to 9.67, p for trend 0.05), usual activities: OR 4.20 (95% CI 2.02 to 8.74, p for trend <0.001), pain/discomfort: OR 3.06 (95% CI 1.63 to 5.73, p for trend <0.001)), and for obese (body mass index (BMI) ≥30 kg/m2) versus BMI <25 kg/m2: (mobility: OR 2.44 (95% CI 1.61 to 3.69, p for trend <0.001), self-care: OR 1.98 (95% CI 1.06 to 3.71, p for trend 0.003), usual activities: OR 1.82 (95% CI 1.19 to 2.76, p for trend 0.019), pain/discomfort: OR 2.37 (95% CI 1.58 to 3.55, p for trend <0.001)). Female sex, lower FS and lower educational attainment were independently associated with anxiety/depression (ORs 1.60 (95% CI 1.18 to 2.16, p 0.002), 3.08 (95% CI 2.23 to 4.27, p<0.001) and 1.67 (95% CI 1.10 to 2.52, p 0.009), respectively). Older age, higher comorbidity count, albuminuria (≥30 mg/mmol vs <3 mg/mmol), lower educational attainment (no formal qualifications vs degree level) and obesity were independently associated with functional impairment (ORs 1.07 (95% CI 1.04 to 1.09, p<0.001), 2.18 (95% CI 0.80 to 5.96, p for trend <0.001), 1.74 (95% CI 0.82 to 3.68, p for trend 0.005), 2.08 (95% CI 1.26 to 3.41, p for trend <0.001) and 4.23 (95% CI 2.48 to 7.20), respectively).

CONCLUSIONS

The majority of persons with mild-to-moderate CKD reported reductions in at least one HRQoL domain, which were independently associated with comorbidities, obesity and functional impairment.

TRIAL REGISTRATION NUMBER

National Institute for Health Research Clinical Research Portfolio Study Number 6632.

Peritoneal Ultrafiltration for Heart Failure: Lessons from a Randomized Controlled Trial

Peritoneal ultrafiltration (PuF) has been employed for severe heart failure (HF), but evidence for its benefit is lacking. The Peritoneal Dialysis for Heart Failure (PDHF) study was a multicenter prospective randomized controlled trial which aimed to investigate this issue. The trial stopped early due to inadequate recruitment. We describe methods, trial activity, and lessons learned.The trial aimed to recruit 130 participants with severe diuretic-resistant HF (New York Heart Association [NYHA] 3/4) and chronic kidney disease (CKD) stage 3/4 on optimal medical treatment for ≥ 4 weeks from 6 UK centers. Participants were randomized to either continuation of conventional HF treatment or to additionally receiving PuF (1 overnight exchange using Icodextrin dialysate). Primary outcome was change in 6-minute walk test (6MWT) between baseline and 28 weeks (end of trial). Secondary outcomes were changes in patient reported quality of life as assessed by the Kansas City Cardiomyopathy Questionnaire, short form 36 (SF 36) health survey results, hospitalization, and mortality.Over a 2-year period, 290 patients were screened from which only 20 met inclusion criteria and 10 were recruited. Reasons for ineligibility were fluctuating estimated glomerular filtration rate (eGFR), suboptimal HF treatment, frailty, and patients being too unwell for randomization. Barriers to recruitment included patient frailty, with some participants considered only when they were at end of life, unwillingness to engage in an invasive therapy, and suboptimal coordination between cardiology and renal services. This is a challenging patient group in which to perform research, and lessons learned from the peritoneal dialysis (PD)-HF trial will be helpful in the planning of future studies in this area.

Sodium-glucose linked transporter-2 inhibitor renal outcome modification in type 2 diabetes: Evidence from studies in patients with high or low renal risk

Data from three completed cardiovascular outcome trials (CVOTs), EMPA-REG OUTCOME, CANVAS Program and DECLARE-TIMI 58, add to the evidence supporting the potential renoprotective effects of sodium-glucose linked transporter-2 (SGLT2) inhibitors in patients with type 2 diabetes. Despite recommendations in recent guidelines, it is difficult to support a view that definitive evidence for renoprotection exists from these SGLT2 inhibitor CVOT results. To date, the only dedicated trial to report definitive data on the renal impact of SGLT2 inhibition is CREDENCE. Notably, the total number of patient-relevant renal endpoint events (dialysis, transplant or renal death) observed in CREDENCE was significantly higher than the total for all three CVOTs collectively (183 events/4401 patients vs. 69 events/34 322 patients, respectively), which shows the increased statistical power of CREDENCE for these renal endpoints. Treatment with canagliflozin was associated with a 30% relative risk reduction (RRR) in the primary composite endpoint of end-stage kidney disease, doubling of serum creatinine, or death from renal or cardiovascular causes and a 34% RRR for the renal-specific elements of this primary endpoint (P <0.001). Canagliflozin has therefore become the first US-approved SGLT2 inhibitor to include an indication for RRR, in addition to type 2 diabetes glycaemic control and cardiovascular risk reduction. While confirmatory of the exploratory data from CVOTs, CREDENCE provides the first robust data on the effects of canagliflozin on patient-relevant renal endpoints. Extrapolation to a conclusion of a SGLT2 inhibitor class effect cannot be made until additional renal trials with other SGLT2 inhibitors are reported.

Quantitative assessment of renal structural and functional changes in chronic kidney disease using multi-parametric magnetic resonance imaging

BACKGROUND

Multi-parametric magnetic resonance imaging (MRI) provides the potential for a more comprehensive non-invasive assessment of organ structure and function than individual MRI measures, but has not previously been comprehensively evaluated in chronic kidney disease (CKD).

METHODS

We performed multi-parametric renal MRI in persons with CKD (n = 22, 61 ± 24 years) who had a renal biopsy and measured glomerular filtration rate (mGFR), and matched healthy volunteers (HV) (n = 22, 61 ± 25 years). Longitudinal relaxation time (T1), diffusion-weighted imaging, renal blood flow (phase contrast MRI), cortical perfusion (arterial spin labelling) and blood-oxygen-level-dependent relaxation rate (R2*) were evaluated.

RESULTS

MRI evidenced excellent reproducibility in CKD (coefficient of variation <10%). Significant differences between CKD and HVs included cortical and corticomedullary difference (CMD) in T1, cortical and medullary apparent diffusion coefficient (ADC), renal artery blood flow and cortical perfusion. MRI measures correlated with kidney function in a combined CKD and HV analysis: estimated GFR correlated with cortical T1 (r = -0.68), T1 CMD (r = -0.62), cortical (r = 0.54) and medullary ADC (r = 0.49), renal artery flow (r = 0.78) and cortical perfusion (r = 0.81); log urine protein to creatinine ratio (UPCR) correlated with cortical T1 (r = 0.61), T1 CMD (r = 0.61), cortical (r = -0.45) and medullary ADC (r = -0.49), renal artery flow (r = -0.72) and cortical perfusion (r = -0.58). MRI measures (cortical T1 and ADC, T1 and ADC CMD, cortical perfusion) differed between low/high interstitial fibrosis groups at 30-40% fibrosis threshold.

CONCLUSION

Comprehensive multi-parametric MRI is reproducible and correlates well with available measures of renal function and pathology. Larger longitudinal studies are warranted to evaluate its potential to stratify prognosis and response to therapy in CKD.

An updated overview of diabetic nephropathy: Diagnosis, prognosis, treatment goals and latest guidelines

Diabetic nephropathy (DN) is a major healthcare challenge. It occurs in up to 50% of those living with diabetes, is a major cause of end-stage kidney disease (ESKD) that requires treatment with dialysis or renal transplantation, and is associated with significantly increased cardiovascular morbidity and mortality. DN is a clinical syndrome characterized by persistent albuminuria and a progressive decline in renal function, but it is increasingly recognized that the presentation and clinical course of kidney disease in diabetes is heterogeneous. The term diabetic kidney disease (DKD) is now commonly used to encompass the spectrum of people with diabetes who have either albuminuria or reductions in renal function. In this article, the clinical presentation and approach to diagnosis of DKD will be discussed, as will its prognosis. The general principles of management of DKD will also be reviewed with reference to current international guidelines.