UK Renal Registry 19th Annual Report: Introduction

Cultural influences on physical activity and exercise beliefs in patients with chronic kidney disease: 'The Culture-CKD Study'-a qualitative study

OBJECTIVES

This study used a mixed-method approach to explore cultural and ethnic influences on the perception of, and decision to engage with or not to engage with, physical activity and exercise therapy in patients with chronic kidney disease (CKD).

DESIGN

Qualitative research was conducted through the use of semistructured interviews and focus groups. Self-reported physical activity levels were measured using the General Practice Physical Activity Questionnaire (GPPAQ), and self-efficacy for exercise with Bandura's Self-Efficacy for Exercise Scale.

SETTING

This study was conducted in a non-clinical setting of a single National Health Service Hospital Trust between April 2018 and July 2019.

PARTICIPANTS

Participants >18 years of age with a diagnosis of CKD, from black African, black Caribbean, South Asian or white ethnicity were eligible for the study. 84 patients with a diagnosis of CKD (stages 2-5), aged 25-79 (mean age 57) were recruited. Semistructured interviews (n=20) and six single-sex, ethnic-specific focus group discussions were undertaken (n=36).

OUTCOMES

Primary outcome was to explore the perceptions, attitudes and values about exercise and physical activity in different ethnic groups through qualitative interviews, analysed using an inductive thematic analysis approach. Questionnaires were analysed using Pearson correlation to determine if there was a significant relationship between the self-efficacy and GPPAQ levels.

RESULTS

Qualitative analysis provided four primary themes: I am who I am, Change of identity, Influences to physical activity and exercise and Support and education. Quantitative analysis using Pearson correlation revealed a significant correlation between GPPAQ levels of activity and self-efficacy to regulate exercise behaviour (r=-0.40, p=0.001).

CONCLUSION

Understanding the cultural, attitudes and beliefs of individuals with CKD from a variety of ethnic backgrounds is complex. Understanding of patients' experiences, thoughts and beliefs may be of relevance to clinicians when designing CKD exercise services.

TRIAL REGISTRATION NUMBER

NCT03709212; Pre-results.

Vitamin K for kidney transplant organ recipients: investigating vessel stiffness (ViKTORIES): study rationale and protocol of a randomised controlled trial

BACKGROUND

Renal transplant recipients (RTRs) exhibit increased vascular stiffness and calcification; these parameters are associated with increased cardiovascular risk. Activity of endogenous calcification inhibitors such as matrix gla protein (MGP) is dependent on vitamin K. RTRs commonly have subclinical vitamin K deficiency. The Vitamin K in kidney Transplant Organ Recipients: Investigating vEssel Stiffness (ViKTORIES) study assesses whether vitamin K supplementation reduces vascular stiffness and calcification in a diverse population of RTR.

METHODS AND ANALYSIS

ViKTORIES (ISRCTN22012044) is a single-centre, phase II, parallel-group, randomised, double-blind, placebo-controlled trial of the effect of vitamin K supplementation in 90 prevalent RTR. Participants are eligible if they have a functioning renal transplant for >1 year. Those on warfarin, with atrial fibrillation, estimated glomerular filtration rate <15 mL/min/1.73 m2 or contraindications to MRI are excluded. Treatment is with vitamin K (menadiol diphosphate) 5 mg three times per week for 1 year or matching placebo. All participants have primary and secondary endpoint measures at 0 and 12 months. The primary endpoint is ascending aortic distensibility on cardiac MR imaging. Secondary endpoints include vascular calcification (coronary artery calcium score by CT), cardiac structure and function on MR, carotid-femoral pulse wave velocity, serum uncarboxylated MGP, transplant function, proteinuria and quality of life. The study is powered to detect 1.0×10-3 mm Hg-1 improvement in ascending aortic distensibility in the vitamin K group relative to placebo at 12 months. Analyses will be conducted as between-group differences at 12 months by intention to treat.

DISCUSSION

This trial may identify a novel, inexpensive and low-risk treatment to improve surrogate markers of cardiovascular risk in RTR.

Flexibility in peritoneal dialysis prescription: Impact on technique survival

Background:

Patient burnout is a major cause of technique failure on peritoneal dialysis (PD). Reducing the PD prescription on an individual basis, dependent upon residual kidney function (RKF), may have a role in prolonging time on PD by reducing dialysis burden. This retrospective study aimed to determine the safety and impact of flexible PD prescribing on technique and patient survival.

Methods:

All patients (186) from our centre starting PD from 1st January 2012 to 31st December 2016 were included. Data on dialysis prescription were collected for each patient from the time they had started PD, and dialysis adequacy measured regularly (3–6 monthly) using PD Adequest.

Results:

Median age at start of dialysis was 61 years. Only 49% started on PD 7 days a week and this dropped to 27% at 3 months following the first clearance test. Over 90% achieved creatinine clearance > 50 L/week/1.73 m2 up to 2 years of follow-up, with 87% achieving this standard at 3 years. Patient and technique survival at 1, 2 and 3 years were 91%, 81%, and 72%, and 89%, 87% and 78% respectively. Factors on univariate analysis affecting technique survival included increasing age (HR 0.98, p = 0.04, 95% CI (0.96–0.999)), two or more episodes of PD-associated peritonitis (HR 4.52, p = 0.00, 95% CI (1.87–10.91)) and increasing PD intensity (HR 3.30, p = 0.02, 95% CI (1.22–8.93)). After multivariate adjustment which included baseline kidney function, low PD intensity continued to be associated with better technique survival (HR 0.17, p = 0.03, 95% CI (0.03–0.85)).

Conclusion:

Tailoring the PD prescription to RKF enables days off dialysis while still maintaining recommended levels of small solute clearance. This approach reduces dialysis burden and is associated with higher technique survival.

Clinical practice guideline management of blood borne viruses within the haemodialysis unit

Some people who are receiving dialysis treatment have virus infection such as hepatitis B, hepatitis C and/or HIV that is present in their blood. These infections can be transmitted to other patients if blood is contaminated by the blood of another with a viral infection. Haemodialysis is performed by passing blood from a patient through a dialysis machine, and multiple patients receive dialysis within a dialysis unit. Therefore, there is a risk that these viruses may be transmitted around the dialysis session. This documents sets out recommendations for minimising this risk.There are sections describing how machines and equipment should be cleaned between patients. There are also recommendations for dialysing patients with hepatitis B away from patients who do not have hepatitis B. Patients should be immunised against hepatitis B, ideally before starting dialysis if this is possible. There are guidelines on how and when to do this, for checking whether immunisation is effective, and for administering booster doses of vaccine. Finally there is a section on the measures that should be taken if a patient receiving dialysis is identified as having a new infection of hepatitis B, hepatitis C or HIV.

Trends in kidney function testing in UK primary care since the introduction of the quality and outcomes framework: a retrospective cohort study using CPRD

OBJECTIVES

To characterise serum creatinine and urinary protein testing in UK general practices from 2005 to 2013 and to examine how the frequency of testing varies across demographic factors, with the presence of chronic conditions and with the prescribing of drugs for which kidney function monitoring is recommended.

DESIGN

Retrospective open cohort study.

SETTING

Routinely collected data from 630 UK general practices contributing to the Clinical Practice Research Datalink.

PARTICIPANTS

4 573 275 patients aged over 18 years registered at up-to-standard practices between 1 April 2005 and 31 March 2013. At study entry, no patients were kidney transplant donors or recipients, pregnant or on dialysis.

PRIMARY OUTCOME MEASURES

The rate of serum creatinine and urinary protein testing per year and the percentage of patients with isolated and repeated testing per year.

RESULTS

The rate of serum creatinine testing increased linearly across all age groups. The rate of proteinuria testing increased sharply in the 2009-2010 financial year but only for patients aged 60 years or over. For patients with established chronic kidney disease (CKD), creatinine testing increased rapidly in 2006-2007 and 2007-2008, and proteinuria testing in 2009-2010, reflecting the introduction of Quality and Outcomes Framework indicators. In adjusted analyses, CKD Read codes were associated with up to a twofold increase in the rate of serum creatinine testing, while other chronic conditions and potentially nephrotoxic drugs were associated with up to a sixfold increase. Regional variation in serum creatinine testing reflected country boundaries.

CONCLUSIONS

Over a nine-year period, there have been increases in the numbers of patients having kidney function tests annually and in the frequency of testing. Changes in the recommended management of CKD in primary care were the primary determinant, and increases persist even after controlling for demographic and patient-level factors. Future studies should address whether increased testing has led to better outcomes.

The prevalence of mild-to-moderate distress in patients with end-stage renal disease: results from a patient survey using the emotion thermometers in four hospital Trusts in the West Midlands, UK

OBJECTIVES

To assess the prevalence of mild-to-moderate distress in patients with end-stage renal disease (ESRD) and determine the association between distress and patient characteristics.

DESIGN

Cross-sectional survey using emotion thermometer and distress thermometer problem list.

SETTING

Renal units in four hospital Trusts in the West Midlands, UK.

PARTICIPANTS

Adult patients with stage 5 chronic kidney disease who were: (1) On prerenal replacement therapy. (2) On dialysis for less than 2 years. (3) On dialysis for 2 years or more (4) With a functioning transplant.

OUTCOMES

The prevalence of mild-to-moderate distress, and the incidence of distress thermometer problems and patient support needs.

RESULTS

In total, 1040/3730 surveys were returned (27.9%). A third of survey respondents met the criteria for mild-to-moderate distress (n=346; 33.3%). Prevalence was highest in patients on dialysis for 2 years or more (n=109/300; 36.3%) and lowest in transplant patients (n=118/404; 29.2%). Prevalence was significantly higher in younger versus older patients (χ²=14.33; p=0.0008), in women versus men (χ²=6.63; p=0.01) and in black and minority ethnic patients versus patients of white ethnicity (χ²=10.36; p=0.013). Over 40% of patients (n=141) reported needing support. More than 95% of patients reported physical problems and 91.9% reported at least one emotional problem.

CONCLUSIONS

Mild-to-moderate distress is common in patients with ESRD, and there may be substantial unmet support needs. Regular screening could help identify patients whose distress may otherwise remain undetected. Further research into differences in distress prevalence over time and at specific transitional points across the renal disease pathway is needed, as is work to determine how best to support patients requiring help.

Validation of differentially methylated microRNAs identified from an epigenome-wide association study; Sanger and next generation sequencing approaches

Objectives

Altered DNA methylation and microRNA profiles are associated with diabetic kidney disease. This study compared different sequencing approaches to define the genetic and epigenetic architecture of sequences surrounding microRNAs associated with diabetic kidney disease.

Results

We compared Sanger and next generation sequencing to validate microRNAs associated with diabetic kidney disease identified from an epigenome-wide association study (EWAS). These microRNAs demonstrated differential methylation levels in cases with diabetic kidney disease compared to controls with long duration of type 1 diabetes and no evidence of kidney disease (P_adjusted < 10⁻⁵). Targeted next generation sequencing analysis of genomic DNA and matched cell-line transformed DNA samples identified four genomic variants within the microRNAs, two within miR-329-2 and two within miR-429. Sanger sequencing of genomic DNA replicated these findings and confirmed the altered methylation status of the CpG sites identified by the EWAS in bisulphite-treated DNA. This investigation successfully fine-mapped the genetic sequence around key microRNAs. Variants have been detected which may affect their methylation status and methylated CpG sites have been confirmed. Additionally, we explored both the fidelity of next generation sequencing analysis and the potential efficacy of cell-line transformed DNA samples in place of finite patient samples in discovery genetic and epigenetic research.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3872-x) contains supplementary material, which is available to authorized users.

Renal biopsy: it is time for pragmatism and consensus

To obtain truly informed consent, we must be able to advise our patients accurately about the relative risk and benefit of any treatment plan. Percutaneous renal biopsy remains the gold standard investigation in the evaluation of intrinsic renal disease. There have been significant improvements in practice over the past decades with regards to percutaneous renal biopsy. Across centres, we appear now to have reached agreement on many aspects of this procedure, such as the need for blood pressure control, avoidance of coagulopathy, use of spring-loaded needles under direct imaging guidance and a need to monitor for complications. The authors from Rush University Medical Centre provide reassurance that renal biopsy in the modern era remains a safe procedure with a low rate of significant bleeding. There remain areas of divergence in practice that may have unintended and deleterious consequences: administration of desmopressin and discontinuation of aspirin, for example, both carry a risk of thrombosis. It is our opinion that it is time to reach consensus on our interpretation of the available data and to draw up guidelines to standardize our biopsy practice internationally.

Recapitulating kidney development: Progress and challenges

Decades of research into the molecular and cellular regulation of kidney morphogenesis in rodent models, particularly the mouse, has provided both an atlas of the mammalian kidney and a roadmap for recreating kidney cell types with potential applications for the treatment of kidney disease. With advances in both our capacity to maintain nephron progenitors in culture, reprogram to kidney cell types and direct the differentiation of human pluripotent stem cells to kidney endpoints, renal regeneration via cellular therapy or tissue engineering may be possible. Human kidney models also have potential for disease modelling and drug screening. Such applications will rely upon the accuracy of the model at the cellular level and the capacity for stem-cell derived kidney tissue to recapitulate both normal and diseased kidney tissue. In this review, we will discuss the available cell sources, how well they model the human kidney and how far we are from application either as models or for tissue engineering.