Nanopore tweezers show fractional-nucleotide translocation in sequence-dependent pausing by RNA polymerase.

RNA polymerases (RNAPs) carry out the first step in the central dogma of molecular biology by transcribing DNA into RNA. Despite their importance, much about how RNAPs work remains unclear, in part because the small (3.4 Angstrom) and fast (~40 ms/nt) steps during transcription were difficult to resolve. Here, we used high-resolution nanopore tweezers to observe the motion of single Escherichia coli RNAP molecules as it transcribes DNA ~1,000 times improved temporal resolution, resolving single-nucleotide and fractional-nucleotide steps of individual RNAPs at saturating nucleoside triphosphate concentrations. We analyzed RNAP during processive transcription elongation and sequence-dependent pausing at the yrbL elemental pause sequence. Each time RNAP encounters the yrbL elemental pause sequence, it rapidly interconverts between five translocational states, residing predominantly in a half-translocated state. The kinetics and force-dependence of this half-translocated state indicate it is a functional intermediate between pre- and post-translocated states. Using structural and kinetics data, we show that, in the half-translocated and post-translocated states, sequence-specific protein-DNA interaction occurs between RNAP and a guanine base at the downstream end of the transcription bubble (core recognition element). Kinetic data show that this interaction stabilizes the half-translocated and post-translocated states relative to the pre-translocated state. We develop a kinetic model for RNAP at the yrbL pause and discuss this in the context of key structural features.

Nanopores map the acid-base properties of a single site in a single DNA molecule.

Nanopores are increasingly powerful tools for single molecule sensing, in particular, for sequencing DNA, RNA and peptides. This success has spurred efforts to sequence non-canonical nucleic acid bases and amino acids. While canonical DNA and RNA bases have pKas far from neutral, certain non-canonical bases, natural RNA modifications, and amino acids are known to have pKas near neutral pHs at which nanopore sequencing is typically performed. Previous reports have suggested that the nanopore signal may be sensitive to the protonation state of an individual moiety. We sequenced ion currents with the MspA nanopore using a single stranded DNA containing a single non-canonical DNA base (Z) at various pH conditions. The Z-base has a near-neutral pKa ∼ 7.8. We find that the measured ion current is remarkably sensitive to the protonation state of the Z-base. We demonstrate how nanopores can be used to localize and determine the pKa of individual moieties along a polymer. More broadly, these experiments provide a path to mapping different protonation sites along polymers and give insight in how to optimize sequencing of polymers that contain moieties with near-neutral pKas.

Observing inhibition of the SARS-CoV-2 helicase at single-nucleotide resolution.

The genome of SARS-CoV-2 encodes for a helicase (nsp13) that is essential for viral replication and highly conserved across related viruses, making it an attractive antiviral target. Here we use nanopore tweezers, a high-resolution single-molecule technique, to gain detailed insight into how nsp13 turns ATP-hydrolysis into directed motion along nucleic acid strands. We measured nsp13 both as it translocates along single-stranded DNA or unwinds double-stranded DNA. Our data reveal nsp13's single-nucleotide steps, translocating at ∼1000 nt/s or unwinding at ∼100 bp/s. Nanopore tweezers' high spatiotemporal resolution enables detailed kinetic analysis of nsp13 motion. As a proof-of-principle for inhibition studies, we observed nsp13's motion in the presence of the ATPase inhibitor ATPγS. We construct a detailed picture of inhibition in which ATPγS has multiple mechanisms of inhibition. The dominant mechanism of inhibition depends on the application of assisting force. This lays the groundwork for future single-molecule inhibition studies with viral helicases.

Sequence-dependent mechanochemical coupling of helicase translocation and unwinding at single-nucleotide resolution.

We used single-molecule picometer-resolution nanopore tweezers (SPRNT) to resolve the millisecond single-nucleotide steps of superfamily 1 helicase PcrA as it translocates on, or unwinds, several kilobase-long DNA molecules. We recorded more than two million enzyme steps under various assisting and opposing forces in diverse adenosine tri- and diphosphate conditions to comprehensively explore the mechanochemistry of PcrA motion. Forces applied in SPRNT mimic forces and physical barriers PcrA experiences in vivo, such as when the helicase encounters bound proteins or duplex DNA. We show how PcrA's kinetics change with such stimuli. SPRNT allows for direct association of the underlying DNA sequence with observed enzyme kinetics. Our data reveal that the underlying DNA sequence passing through the helicase strongly influences the kinetics during translocation and unwinding. Surprisingly, unwinding kinetics are not solely dominated by the base pairs being unwound. Instead, the sequence of the single-stranded DNA on which the PcrA walks determines much of the kinetics of unwinding.

The Ottawa Statement implementation guidance document for cluster randomized trials in the hemodialysis setting.

Research teams are increasingly interested in using cluster randomized trial (CRT) designs to generate practice-guiding evidence for in-center maintenance hemodialysis. However, CRTs raise complex ethical issues. The Ottawa Statement on the Ethical Design and Conduct of Cluster Randomized Trials, published in 2012, provides 15 recommendations to address ethical issues arising within 7 domains: justifying the CRT design, research ethics committee review, identifying research participants, obtaining informed consent, gatekeepers, assessing benefits and harms, and protecting vulnerable participants. But applying the Ottawa Statement recommendations to CRTs in the hemodialysis setting is complicated by the unique features of the setting and population. Here, with the help of content experts and patient partners, we co-developed this implementation guidance document to provide research teams, research ethics committees, and other stakeholders with detailed guidance on how to apply the Ottawa Statement recommendations to CRTs in the hemodialysis setting, the result of a 4-year research project. Thus, our work demonstrates how the voices of patients, caregivers, and all stakeholders may be included in the development of research ethics guidance.

The randomized controlled trial (NAVKIDS2) of a patient navigator program created for children with chronic kidney disease.

Patient navigators enable adult patients to circumnavigate complex health systems, improving access to health care and outcomes. Here, we aimed to evaluate the effects of a patient navigation program in children with chronic kidney disease (CKD). In this multi-center, randomized controlled trial, we randomly assigned children (aged 0-16 years) with CKD stages 1-5 (including children on dialysis or with kidney transplants), from low socioeconomic status backgrounds, and/or residing in remote areas, to receive patient navigation at randomization (immediate) or at six months (waitlist). The primary outcome was self-rated health (SRH) of participating children at six months, using intention to treat analysis. Secondary outcomes included caregivers' SRH and satisfaction with health care, children's quality of life, hospitalizations, and missed school days. Repeated measures of the primary outcome from baseline to six months were analyzed using cumulative logit mixed effects models. Semi-structured interviews were thematically evaluated. Of 398 screened children, 162 were randomized (80 immediate and 82 waitlist); mean age (standard deviation) of 8.8 (4.8) years with 64.8% male. SRH was not significantly different between the immediate and wait-listed groups at six months. There were also no differences across all secondary outcomes between the two groups. Caregivers' perspectives were reflected in seven themes: easing mental strain, facilitating care coordination, strengthening capacity to provide care, reinforcing care collaborations, alleviating family tensions, inability to build rapport and unnecessary support. Thus, in children with CKD, self-rated health may not improve in response to a navigator program, but caregivers gained skills related to providing and accessing care.

An Economic Evaluation of a Web-Based Management Support System for Children With Urinary Incontinence: The eADVICE Trial.

PURPOSE: Children who require specialist outpatient care typically wait substantial periods during which their condition may progress, making treatment more difficult and costly. Timely and effective therapy during this period may reduce the need for lengthy specialist care. This study evaluated the cost-effectiveness of an individualized, evidence-informed, web-based program for children with urinary incontinence awaiting a specialist appointment (Electronic Advice and Diagnosis Via the Internet following Computerized Evaluation [eADVICE]) compared to usual care. eADVICE was supervised by a primary physician and delivered by an embodied conversational agent. MATERIALS AND METHODS: A trial-based cost-effectiveness analysis was performed from the perspective of the health care funder as a substudy of eADVICE, a multicenter, waitlist-controlled, randomized trial. Outcomes measures were incremental cost per incremental change in continence status and quality of life on an intention-to-treat basis. Uncertainty was examined using cost-effectiveness planes, scenarios, and 1-way sensitivity analyses. Costs were valued in 2021 Australian dollars. RESULTS: The use of eADVICE was found to be cost saving and beneficial (dominant) over usual care, with a higher proportion of children dry over 14 days at 6 months (risk difference 0.13; 95%CI 0.02-0.23, P = .03) and mean health care costs reduced by $188 (95%CI $61-$315) per participant. CONCLUSIONS: An individualized, evidence-informed, web-based program delivered by an embodied conversational agent is likely cost saving for children with urinary incontinence awaiting a specialist appointment. The potential economic impact of such a program is favorable and substantial, and may be transferable to outpatient clinic settings for other chronic health conditions.

A Randomized Controlled Trial of a Web-Based Management Support System for Children With Urinary Incontinence: The eADVICE Trial.

PURPOSE: Children referred to specialist outpatient clinics by primary care providers often have long waiting times before being seen. We assessed whether an individualized, web-based, evidence-informed management support for children with urinary incontinence while waiting reduced requests for specialist appointments. MATERIALS AND METHODS: A multicenter, waitlisted randomized controlled trial was conducted for children (5-18 years) with urinary incontinence referred to tertiary pediatric continence clinics. Participants were randomized to the web-based eHealth program electronic Advice and Diagnosis Via the Internet following Computerized Evaluation (eADVICE), which used an embodied conversational agent to engage with the child at the time of referral (intervention) or 6 months later (control). The primary outcome was the proportion of participants requesting a clinic appointment at 6 months. Secondary outcomes included persistent incontinence, and the Paediatric incontinence Questionnaire (PinQ) score. RESULTS: From 2018 to 2020, 239 children enrolled, with 120 randomized to eADVICE and 119 to the control arm. At baseline, participants' mean age was 8.8 years (SD 2.2), 62% were males, mean PinQ score was 5.3 (SD 2.2), 36% had daytime incontinence, and 97% had nocturnal enuresis. At 6 months, 78% of eADVICE participants vs 84% of controls requested a clinic visit (relative risk 0.92, 95% CI 0.79, 1.06, P = .3), and 23% eADVICE participants vs 10% controls were completely dry (relative risk 2.23, 95% CI 1.10, 4.50, P = .03). The adjusted mean PinQ score was 3.5 for eADVICE and 3.9 for controls (MD -0.37, 95% CI -0.71, -0.03, P = .03). CONCLUSIONS: The eADVICE eHealth program for children awaiting specialist appointments doubled the proportion who were dry at 6 months and improved quality of life but did not reduce clinic appointment requests.

Causal Relationship Between Kidney Function and Cancer Risk: A Mendelian Randomization Study.

RATIONALE & OBJECTIVE: Patients treated with kidney replacement therapy experience a 1.5 to 2-fold increased risk of cancer and cancer mortality compared to the general population. Whether this excess risk extends to people with earlier stages of chronic kidney disease is unclear. This study explored the potentially causal relationship between reduced kidney function and cancer. STUDY DESIGN: Two-sample Mendelian randomization (MR). SETTING & PARTICIPANTS: Genome Wide Association Study (GWAS) summary statistics for estimated glomerular filtration rate (eGFR) (n=567,460) and urinary albuminuria (UACR) (n=127,865) from the CKDGen consortium and cancer outcomes from the UK Biobank (n=407,329). EXPOSURES: eGFR and UACR. OUTCOMES: Overall cancer incidence, cancer-related mortality, and site-specific colorectal, lung, and urinary tract cancer incidence. ANALYTICAL APPROACH: Univariable and multivariable MR were conducted for all outcomes using inverse-variance weighted methods. RESULTS: The mean eGFR and median UACR were 91.4 mL/min/1.73m2 and 9.32 mg/g in the CKDGen and 90.4 mL/min/1.73m2 and 9.29 mg/g in the UK Biobank. There were 98,093 cases of cancer, 6,664 colorectal, 3584 lung, and 3,271 urinary tract. There were 15,850 cases of cancer-related death, The genetic instruments for eGFR and UACR comprised 34 and 38 variants, respectively. Genetically predicted kidney function (eGFR and UACR) was not associated with overall cancer risk or cancer death. No associations of genetically predicted eGFR and UACR with overall cancer incidence were observed; odds ratio (95%CI; p-value) of 0.88 (0.40-1.97; p=0.76) and 0.90 (0.78-1.04; p=0.16), respectively. An adjusted generalized additive model for eGFR and cancer demonstrated evidence of non-linearity. There was no evidence of a causal association between eGFR and cancer in a stratified MR. LIMITATIONS: To avoid overlapping samples a smaller GWAS for UACR was used, reducing the strength of the instrument and potentially introducing population stratification. CONCLUSIONS: These findings did not demonstrate a causal association of kidney function with overall cancer incidence or cancer-related death.

Experiences of Indigenous Patients Receiving Dialysis: Systematic Review of Qualitative Studies.

RATIONALE & OBJECTIVE: Indigenous People suffer a high burden of kidney disease. Those receiving maintenance dialysis have worse outcomes compared with similarly treated non-Indigenous patients. We characterized the experiences of Indigenous patients receiving dialysis in British-colonized countries to gain insights into which aspects of kidney care may benefit from improvement. STUDY DESIGN: A systematic review of published qualitative interview studies. SETTING & STUDY POPULATIONS: Indigenous Peoples aged 18 years and over, receiving hemodialysis or peritoneal dialysis in British-colonized countries. SELECTION CRITERIA FOR STUDIES: Search terms for Indigenous Peoples, dialysis, and qualitative research were entered into Medline, Embase, PsycINFO, and CINAHL and searched from inception to January 5, 2023. DATA EXTRACTION: Characteristics of each study were extracted into Microsoft Excel for quality assessment. ANALYTICAL APPROACH: Data were analyzed using thematic synthesis. RESULTS: The analysis included 28 studies involving 471 participants from Australia, New Zealand, Canada, and the United States. We identified four themes: centrality of family and culture (continuing dialysis for family, gaining autonomy through shared involvement, balancing primary responsibility to care for family); marginalization due to structural and social inequities (falling through gaps in primary care intensifying shock, discriminated against and judged by specialists, alienated and fearful of hospitals, overwhelmed by travel, financial and regimental burdens); vulnerability in accessing health care (need for culturally responsive care, lack of language interpreters, without agency in decision-making, comorbidities compounding complexity of self-management); and distress from separation from community (disenfranchisement and sorrow when away for dialysis, inability to perpetuate cultural continuity, seeking a kidney transplant). LIMITATIONS: We only included articles published in English. CONCLUSIONS: Indigenous patients receiving dialysis experience inequities in health care that compound existing accessibility issues caused by colonization. Improving the accessibility and cultural responsiveness of dialysis and kidney transplant services in collaboration with Indigenous stakeholders holds promise to enhance the experience of Indigenous patients receiving dialysis. PLAIN-LANGUAGE SUMMARY: Worldwide Indigenous populations suffer a high incidence of chronic disease leading to lower life expectancy, particularly for kidney disease, an insidious condition requiring long-term dialysis treatment. By listening to Indigenous dialysis patients' stories, we hoped to understand how to improve their experience. We gathered 28 qualitative research studies from four countries reporting Indigenous adults' experiences of dialysis. They described lacking awareness of kidney disease, poor access to health services, systemic racism, inadequate cultural safety, and being dislocated from family, community, and culture. These findings indicate that respectful collaboration with Indigenous Peoples to craft and implement policy changes holds promise to improve prevention, integrate culturally responsive health care practices, and provide better access to local dialysis services and opportunities for kidney transplants.

Patient, Parental, and Health Professional Perspectives on Growth in Children With CKD.

RATIONALE & OBJECTIVE: Growth failure is a common problem among children with chronic kidney disease (CKD). Reduced height is associated with psychosocial burden, social stigma, and impaired quality of life. This study aimed to describe the aspects of growth impairment that are most impactful from the perspectives of children with CKD, their parents, and health professionals. STUDY DESIGN: Qualitative study. SETTINGS & PARTICIPANTS: 120 children with CKD (aged 8-21 years), 250 parents, and 445 health professionals from 53 countries participated in 16 focus groups, two consensus workshops, and a Delphi survey. ANALYTICAL APPROACH: A thematic analysis of all qualitative data concerning growth from the Standardized Outcomes in Nephrology - Children and Adolescents (SONG-Kids) initiative. RESULTS: We identified five themes: diminishing psychological wellbeing (compared to and judged by peers, tired of explaining to others, damaging self-esteem), constrained life participation and enjoyment (deprived of normal school experiences, excluded from sports or competing at a disadvantage, impaired quality of life in adulthood); grappling with impacts of symptoms and treatment (difficulty understanding short stature and accessing help, lack of appetite, uncertainty regarding bone pains, medication side effects, burden of growth hormone treatment); facilitating timely interventions and optimizing outcomes (early indicator of disease, assessing management, maximizing transplant outcomes, minimizing morbidity); and keeping growth and health priorities in perspective (quality of life and survival of utmost priority, achieved adequate height). LIMITATIONS: Only English-speaking participants were included. CONCLUSIONS: Impaired growth may diminish psychological wellbeing, self-esteem, and participation in daily activities for children with CKD. Balancing different treatments that can affect growth complicates decision-making. These findings may inform the psychosocial support needed by children with CKD and their caregivers to address concerns about growth.

Improving Diverse and Equitable Involvement of Patients and Caregivers in Research in CKD: Report of a Better Evidence and Translation-Chronic Kidney Disease (BEAT-CKD) Workshop.

Patient and caregiver involvement can enhance the uptake and impact of research, but the involvement of patients and caregivers who are underserved and marginalized is often limited. A better understanding of how to make involvement in research more broadly accessible, supportive, and inclusive for patients with chronic kidney disease (CKD) and caregivers is needed. We conducted a national workshop involving patients, caregivers, clinicians, and researchers from across Australia to identify strategies to increase the diversity of patients and caregivers involved in CKD research. Six themes were identified. Building trust and a sense of safety was considered pivotal to establishing meaningful relationships to support knowledge exchange. Establishing community and connectedness was expected to generate a sense of belonging to motivate involvement. Balancing stakeholder goals, expectations, and responsibilities involved demonstrating commitment and transparency by researchers. Providing adequate resources and support included strategies to minimize the burden of involvement for patients and caregivers. Making research accessible and relatable was about nurturing patient and caregiver interest by appealing to intrinsic motivators. Adapting to patient and caregiver needs and preferences required tailoring the approach for individuals and the target community. Strategies and actions to support these themes may support more diverse and equitable involvement of patients and caregivers in research in CKD.

Outcomes for clinical trials involving adults with chronic kidney disease: a multinational Delphi survey involving patients, caregivers and health professionals.

BACKGROUND: Many outcomes of high priority to patients and clinicians are infrequently and inconsistently reported across trials in chronic kidney disease (CKD), which generates research waste and limits evidence-informed decision making. We aimed to generate consensus among patients/caregivers and health professionals on critically important outcomes for trials in CKD prior to kidney failure and the need for kidney replacement therapy, and to describe the reasons for their choices. METHODS: This was an online two-round international Delphi survey. Adult patients with CKD (all stages and diagnoses), caregivers and health professionals who could read English, Spanish or French were eligible. Participants rated the importance of outcomes using a Likert scale (7-9 indicating critical importance) and a Best-Worst Scale. The scores for the two groups were assessed to determine absolute and relative importance. Comments were analysed thematically. RESULTS: In total, 1399 participants from 73 countries completed Round 1 of the Delphi survey, including 628 (45%) patients/caregivers and 771 (55%) health professionals. In Round 2, 790 participants (56% response rate) from 63 countries completed the survey including 383 (48%) patients/caregivers and 407 (52%) health professionals. The overall top five outcomes were: kidney function, need for dialysis/transplant, life participation, cardiovascular disease and death. In the final round, patients/caregivers indicated higher scores for most outcomes (17/22 outcomes), and health professionals gave higher priority to mortality, hospitalization and cardiovascular disease (mean difference >0.3). Consensus was based upon the two groups yielding median scores of ≥7 and mean scores >7, and the proportions of both groups rating the outcome as 'critically important' being >50%. Four themes reflected the reasons for their priorities: imminent threat of a health catastrophe, signifying diminishing capacities, ability to self-manage and cope, and tangible and direct consequences. CONCLUSION: Across trials in CKD, the outcomes of highest priority to patients, caregivers and health professionals were kidney function, need for dialysis/transplant, life participation, cardiovascular disease and death.

Hypertension and Cardiovascular Risk Among Children with Chronic Kidney Disease.

PURPOSE OF REVIEW: Cardiovascular disease is the most common cause of mortality across the lifespan of children with chronic kidney disease (CKD). Hypertension is a common and important contributor, but other factors such as obesity, dyslipidemia and mineral bone disease play a role. This narrative review focusses on studies published in the past five years that have investigated hypertension and cardiovascular risk among children with CKD. RECENT FINDINGS: Cohort studies such as Chronic Kidney Disease in Children (CKiD) and Cardiovascular Comorbidity in Children with CKD (4C) have continued to develop our understanding of blood pressure (BP) phenotypes, and of progressive changes in the structure and function of the heart and blood vessels occurring in children with CKD. Metabolic risk factors, such as dyslipidemia, may represent an under-recognized component of care. Trial data are less common than observational evidence, but support lifestyle interventions currently used, mainly the low sodium dietary approaches to stop hypertension (DASH) diet. The findings of the recently reported Hypertension Optimal Treatment in Children with Chronic Kidney Disease trial (HOT-KID) are described in relation to the use of office BP treatment targets. Cardiovascular health is critical to the long-term outcomes of children with CKD. Recognizing and treating hypertension remains a critical component to improving outcomes, along with measures to improve concurrent cardiovascular risk factors. Some cardiovascular changes may not be reversible with transplantation and further research is needed for children at all stages of CKD.

School attendance and sport participation amongst children with chronic kidney disease: a cross-sectional analysis from the Kids with CKD (KCAD) study.

BACKGROUND: School attendance and life participation, particularly sport, is a high priority for children with chronic kidney disease (CKD). This study is aimed at assessing the association between CKD stage, sports participation, and school absences in children with CKD. METHODS: Using data from the binational Kids with CKD study (ages 6-18 years, n = 377), we performed multivariable regression to evaluate the association between CKD stage, school absences, and sports participation. RESULTS: Overall, 62% of participants played sport with the most frequent sport activities engaged in being swimming (17%) and soccer (17%). Compared to children with CKD 1-2, the incidence rate ratios (IRR) (95% CI) for sports participation amongst children with CKD 3-5, dialysis, or transplant were 0.84 (0.64-1.09), 0.59 (0.39-0.90), and 0.75 (0.58-0.96), respectively. The median (IQR) days of school absences within a four-week period were 1 day (0-1), with children on dialysis reporting the highest number of school absences (9 days (5-15)), followed by transplant recipients (2 days (1-7)), children with CKD 3-5 (1 day (0-3)), and with CKD 1-2 (1 day (0-3)). Duration of CKD modified the association between CKD stage and school absences, with children with a transplant experiencing a higher number of missed school days with increasing duration of CKD, but not in children with CKD 1-5 or on dialysis (p-interaction < 0.01). CONCLUSIONS: Children receiving dialysis and with a kidney transplant had greater school absences and played fewer sports compared to children with CKD stages 1-2. Innovative strategies to improve school attendance and sport participation are needed to improve life participation of children with CKD.

Longitudinal associations between socioeconomic position and overall health of children with chronic kidney disease and their carers.

BACKGROUND: Disadvantaged socioeconomic position (SEP) is an important predictor of poor health in children with chronic kidney disease (CKD). The time course over which SEP influences the health of children with CKD and their carers is unknown. METHODS: This prospective longitudinal study included 377 children, aged 6-18 years with CKD (stages I-V, dialysis, and transplant), and their primary carers. Mixed effects ordinal regression was performed to assess the association between SEP and carer-rated child health and carer self-rated health over a 4-year follow-up. RESULTS: Adjusted for CKD stage, higher family household income (adjusted odds ratio (OR) (95% CI) 3.3, 1.8-6.0), employed status of primary carers (1.7, 0.9-3.0), higher carer-perceived financial status (2.6, 1.4-4.8), and carer home ownership (2.2, 1.2-4.0) were associated with better carer-rated child health. Household income also had a differential effect on the carer's self-rated health over time (p = 0.005). The predicted probabilities for carers' overall health being 'very good' among lower income groups at 0, 2, and 4 years were 0.43 (0.28-0.60), 0.34 (0.20-0.51), and 0.25 (0.12-0.44), respectively, and 0.81 (0.69-0.88), 0.84 (0.74-0.91), and 0.88 (0.76-0.94) for carers within the higher income group. CONCLUSIONS: Carers and their children with CKD in higher SEP report better overall child and carer health compared with those in lower SEP. Carers of children with CKD in low-income households had poorer self-rated health compared with carers in higher-income households at baseline, and this worsened over time. These cumulative effects may contribute to health inequities between higher and lower SEP groups over time. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information.

Corticosteroid therapy for nephrotic syndrome in children.

BACKGROUND: In nephrotic syndrome, protein leaks from the blood into the urine through the glomeruli, resulting in hypoproteinaemia and generalised oedema. While most children with nephrotic syndrome respond to corticosteroids, 80% experience a relapsing course. Corticosteroids have reduced the death rate to around 3%; however, corticosteroids have well-recognised potentially serious adverse events such as obesity, poor growth, hypertension, diabetes mellitus, osteoporosis, cataracts, glaucoma and behavioural disturbances. This is an update of a review first published in 2000 and updated in 2002, 2005, 2007, 2015 and 2020. OBJECTIVES: The aim of this review was to assess the benefits and harms of different corticosteroid regimens in children with steroid-sensitive nephrotic syndrome (SSNS). The benefits and harms of therapy were studied in two groups of children: 1) children in their initial episode of SSNS and 2) children who experience a relapsing course of SSNS. SEARCH METHODS: We contacted the Information Specialist and searched the Cochrane Kidney and Transplant Register of Studies up to 9 July 2024 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov. SELECTION CRITERIA: Randomised controlled trials (RCTs) performed in children (one to 18 years) during their initial or subsequent episode of SSNS, comparing different durations, total doses or other dose strategies using any corticosteroid agent. DATA COLLECTION AND ANALYSIS: Summary estimates of effects were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. MAIN RESULTS: In this 2024 update, we included five new studies, resulting in 54 studies randomising 4670 children. Risk of bias methodology was often poorly performed, with only 31 studies and 28 studies respectively assessed to be at low risk for random sequence generation and allocation concealment. Ten studies were at low risk of performance bias (blinding of participants and personnel), and 12 studies were at low risk of detection bias (blinding of outcome assessment); nine of these studies were placebo-controlled RCTs. Twenty-seven studies (fewer than 50%) were at low risk for attrition bias, and 26 studies were at low risk for reporting bias (selective outcome reporting). In studies at low risk of selection bias evaluating children in their initial episode of SSNS, there is little or no difference in the number of children with frequent relapses when comparing two months of prednisone with three months or more (RR 0.96, 95% CI 0.83 to 1.10; 755 children, 5 studies; I2 = 0%; high certainty evidence) or when comparing three months with five to seven months of therapy (RR 0.99, 95% CI 0.74 to 1.33; 376 children, 3 studies; I2 = 35%; high certainty evidence). In analyses of studies at low risk of selection bias, there is little or no difference in the number of children with any relapse by 12 to 24 months when comparing two months of prednisone with three months or more (RR 0.93, 95% CI 0.81 to 1.06; 808 children; 6 studies; I2 = 47%) or when comparing three months with five to seven months of therapy (RR 0.88, 95% CI 0.70 to 1.11; 377 children, 3 studies; I2 = 53%). Little or no difference was noted in adverse events between the different treatment durations. Amongst children with relapsing SSNS, four small studies (177 children) utilising lower doses of prednisone compared with standard regimens found little or no differences between groups in the numbers with relapse (RR 1.01, 95% CI 0.85 to 1.20; I2 = 0%). A fifth study (117 children) reported little or no difference between two weeks and four weeks of alternate-day prednisone after remission with daily prednisone. A recent large, well-designed study with 271 children found that administering daily prednisone compared with alternate-day prednisone or no prednisone during viral infection did not reduce the risk of relapse. In contrast, four previous small studies in children with frequently relapsing disease had reported that daily prednisone during viral infections compared with alternate-day prednisone or no treatment reduced the risk of relapse. AUTHORS' CONCLUSIONS: There are four well-designed studies randomising 823 children, which have demonstrated that there is no benefit of prolonging prednisone therapy beyond two to three months in the first episode of SSNS. Small studies in children with relapsing disease have identified no differences in efficacy using lower induction doses or shorter durations of prednisone therapy. Large, well-designed studies are required to confirm these findings. While previous small studies had suggested that changing from alternate-day to daily prednisone therapy at the onset of infection reduced the likelihood of relapse, a much larger and well-designed study found no reduction in the number relapsing when administering daily prednisone at the onset of infection.

Angiotensin-converting-enzyme inhibitors and angiotensin receptor blockers for preventing the progression of diabetic kidney disease.

BACKGROUND: Guidelines suggest that adults with diabetes and kidney disease receive treatment with angiotensin-converting-enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB). This is an update of a Cochrane review published in 2006. OBJECTIVES: We compared the efficacy and safety of ACEi and ARB therapy (either as monotherapy or in combination) on cardiovascular and kidney outcomes in adults with diabetes and kidney disease. SEARCH METHODS: We searched the Cochrane Kidney and Transplants Register of Studies to 17 March 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov. SELECTION CRITERIA: We included studies evaluating ACEi or ARB alone or in combination, compared to each other, placebo or no treatment in people with diabetes and kidney disease. DATA COLLECTION AND ANALYSIS: Two authors independently assessed the risk of bias and extracted data. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. MAIN RESULTS: One hundred and nine studies (28,341 randomised participants) were eligible for inclusion. Overall, the risk of bias was high. Compared to placebo or no treatment, ACEi may make little or no difference to all-cause death (24 studies, 7413 participants: RR 0.91, 95% CI 0.73 to 1.15; I2 = 23%; low certainty) and with similar withdrawals from treatment (7 studies, 5306 participants: RR 1.03, 95% CI 0.90 to 1.19; I2 = 0%; low certainty). ACEi may prevent kidney failure (8 studies, 6643 participants: RR 0.61, 95% CI 0.39 to 0.94; I2 = 0%; low certainty). Compared to placebo or no treatment, ARB may make little or no difference to all-cause death (11 studies, 4260 participants: RR 0.99, 95% CI 0.85 to 1.16; I2 = 0%; low certainty). ARB have uncertain effects on withdrawal from treatment (3 studies, 721 participants: RR 0.85, 95% CI 0.58 to 1.26; I2 = 2%; low certainty) and cardiovascular death (6 studies, 878 participants: RR 3.36, 95% CI 0.93 to 12.07; low certainty). ARB may prevent kidney failure (3 studies, 3227 participants: RR 0.82, 95% CI 0.72 to 0.94; I2 = 0%; low certainty), doubling of serum creatinine (SCr) (4 studies, 3280 participants: RR 0.84, 95% CI 0.72 to 0.97; I2 = 32%; low certainty), and the progression from microalbuminuria to macroalbuminuria (5 studies, 815 participants: RR 0.44, 95% CI 0.23 to 0.85; I2 = 74%; low certainty). Compared to ACEi, ARB had uncertain effects on all-cause death (15 studies, 1739 participants: RR 1.13, 95% CI 0.68 to 1.88; I2 = 0%; low certainty), withdrawal from treatment (6 studies, 612 participants: RR 0.91, 95% CI 0.65 to 1.28; I2 = 0%; low certainty), cardiovascular death (13 studies, 1606 participants: RR 1.15, 95% CI 0.45 to 2.98; I2 = 0%; low certainty), kidney failure (3 studies, 837 participants: RR 0.56, 95% CI 0.29 to 1.07; I2 = 0%; low certainty), and doubling of SCr (2 studies, 767 participants: RR 0.88, 95% CI 0.52 to 1.48; I2 = 0%; low certainty). Compared to ACEi plus ARB, ACEi alone has uncertain effects on all-cause death (6 studies, 1166 participants: RR 1.08, 95% CI 0.49 to 2.40; I2 = 20%; low certainty), withdrawal from treatment (2 studies, 172 participants: RR 0.78, 95% CI 0.33 to 1.86; I2 = 0%; low certainty), cardiovascular death (4 studies, 994 participants: RR 3.02, 95% CI 0.61 to 14.85; low certainty), kidney failure (3 studies, 880 participants: RR 1.36, 95% CI 0.79 to 2.32; I2 = 0%; low certainty), and doubling of SCr (2 studies, 813 participants: RR 1.14, 95% CI 0.70 to 1.85; I2 = 0%; low certainty). Compared to ACEi plus ARB, ARB alone has uncertain effects on all-cause death (7 studies, 2607 participants: RR 1.02, 95% CI 0.76 to 1.37; I2 = 0%; low certainty), withdrawn from treatment (3 studies, 1615 participants: RR 0.81, 95% CI 0.53 to 1.24; I2 = 0%; low certainty), cardiovascular death (4 studies, 992 participants: RR 3.03, 95% CI 0.62 to 14.93; low certainty), kidney failure (4 studies, 2321 participants: RR 1.15, 95% CI 0.67 to 1.95; I2 = 29%; low certainty), and doubling of SCr (3 studies, 2252 participants: RR 1.18, 95% CI 0.85 to 1.64; I2 = 0%; low certainty). Comparative effects of different ACEi or ARB and low-dose versus high-dose ARB were rarely evaluated. No study compared different doses of ACEi. Adverse events of ACEi and ARB were rarely reported. AUTHORS' CONCLUSIONS: ACEi or ARB may make little or no difference to all-cause and cardiovascular death compared to placebo or no treatment in people with diabetes and kidney disease but may prevent kidney failure. ARB may prevent the doubling of SCr and the progression from microalbuminuria to macroalbuminuria compared with a placebo or no treatment. Despite the international guidelines suggesting not combining ACEi and ARB treatment, the effects of ACEi or ARB monotherapy compared to dual therapy have not been adequately assessed. The limited data availability and the low quality of the included studies prevented the assessment of the benefits and harms of ACEi or ARB in people with diabetes and kidney disease. Low and very low certainty evidence indicates that it is possible that further studies might provide different results.

Non-immunosuppressive treatment for IgA nephropathy.

BACKGROUND: IgA nephropathy (IgAN) is the most common primary glomerular disease, with approximately 20% to 40% of patients progressing to kidney failure within 25 years. Non-immunosuppressive treatment has become a mainstay in the management of IgAN by improving blood pressure (BP) management, decreasing proteinuria, and avoiding the risks of long-term immunosuppressive management. Due to the slowly progressive nature of the disease, clinical trials are often underpowered, and conflicting information about management with non-immunosuppressive treatment is common. This is an update of a Cochrane review, first published in 2011. OBJECTIVES: To assess the benefits and harms of non-immunosuppressive treatment for treating IgAN in adults and children. We aimed to examine all non-immunosuppressive therapies (e.g. anticoagulants, antihypertensives, dietary restriction and supplementation, tonsillectomy, and herbal medicines) in the management of IgAN. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to December 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs of non-immunosuppressive agents in adults and children with biopsy-proven IgAN were included. DATA COLLECTION AND ANALYSIS: Two authors independently reviewed search results, extracted data and assessed study quality. Results were expressed as mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI) using random-effects meta-analysis. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. MAIN RESULTS: This review includes 80 studies (4856 participants), of which 24 new studies (2018 participants) were included in this review update. The risk of bias within the included studies was mostly high or unclear for many of the assessed methodological domains, with poor reporting of important key clinical trial methods in most studies. Antihypertensive therapies were the most examined non-immunosuppressive therapy (37 studies, 1799 participants). Compared to placebo or no treatment, renin-angiotensin system (RAS) inhibition probably decreases proteinuria (3 studies, 199 participants: MD - 0.71 g/24 h, 95% CI -1.04 to -0.39; moderate certainty evidence) but may result in little or no difference to kidney failure or doubling of serum creatinine (SCr), or complete remission of proteinuria (low certainty evidence). Death, remission of haematuria, relapse of proteinuria or > 50% increase in SCr were not reported. Compared to symptomatic treatment, RAS inhibition (3 studies, 168 participants) probably decreases proteinuria (MD -1.16 g/24 h, 95% CI -1.52 to -0.81) and SCr (MD -9.37 µmol/L, 95% CI -71.95 to -6.80) and probably increases creatinine clearance (2 studies, 127 participants: MD 23.26 mL/min, 95% CI 10.40 to 36.12) (all moderate certainty evidence); however, the risk of kidney failure is uncertain (1 study, 34 participants: RR 0.20, 95% CI 0.01 to 3.88; very low certainty evidence). Death, remission of proteinuria or haematuria, or relapse of proteinuria were not reported. The risk of adverse events may be no different with RAS inhibition compared to either placebo or symptomatic treatment (low certainty evidence). In low certainty evidence, tonsillectomy in people with IgAN in addition to standard care may increase remission of proteinuria compared to standard care alone (2 studies, 143 participants: RR 1.90, 95% CI 1.45 to 2.47) and remission of microscopic haematuria (2 studies, 143 participants: RR 1.93, 95% CI 1.47 to 2.53) and may decrease relapse of proteinuria (1 study, 73 participants: RR 0.70, 95% CI 0.57 to 0.85) and relapse of haematuria (1 study, 72 participants: RR 0.70, 95% CI 0.51 to 0.98). Death, kidney failure and a > 50% increase in SCr were not reported. These trials have only been conducted in Japanese people with IgAN, and the findings' generalisability is unclear. Anticoagulant therapy, fish oil, and traditional Chinese medicines exhibited small benefits to kidney function in patients with IgAN when compared to placebo or no treatment. However, compared to standard care, the kidney function benefits are no longer evident. Antimalarial therapy compared to placebo in one study reported an increase in a > 50% reduction of proteinuria (53 participants: RR 3.13 g/24 h, 95% CI 1.17 to 8.36; low certainty evidence). Although, there was uncertainty regarding adverse events from this study due to very few events. AUTHORS' CONCLUSIONS: Available RCTs focused on a diverse range of interventions. They were few, small, and of insufficient duration to determine potential long-term benefits on important kidney and cardiovascular outcomes and harms of treatment. Antihypertensive agents appear to be the most beneficial non-immunosuppressive intervention for IgAN. The antihypertensives examined were predominantly angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. The benefits of RAS inhibition appear to outweigh the harms in patients with IgAN. The certainty of the evidence of RCTs demonstrating a benefit of tonsillectomy to patients with Japanese patients with IgAN was low. In addition, these findings are inconsistent across observational studies in people with IgAN of other ethnicities; hence, tonsillectomy is not widely recommended, given the potential harm of therapy. The RCT evidence is insufficiently robust to demonstrate efficacy for the other non-immunosuppressive treatments evaluated here.

Antihypertensive treatment for kidney transplant recipients.

BACKGROUND: The comparative effects of specific blood pressure (BP) lowering treatments on patient-important outcomes following kidney transplantation are uncertain. Our 2009 Cochrane review found that calcium channel blockers (CCBs) improved graft function and prevented graft loss, while the evidence for other BP-lowering treatments was limited. This is an update of the 2009 Cochrane review. OBJECTIVES: To compare the benefits and harms of different classes and combinations of antihypertensive drugs in kidney transplant recipients. SEARCH METHODS: We contacted the Information Specialist and searched the Cochrane Kidney and Transplant Register of Studies up to 3 July 2024 using search terms relevant to this review. Studies in the Register were identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs evaluating any BP-lowering agent in recipients of a functioning kidney transplant for at least two weeks were eligible. DATA COLLECTION AND ANALYSIS: Two authors independently assessed the risks of bias and extracted data. Treatment estimates were summarised using the random-effects model and expressed as relative risk (RR) or mean difference (MD) with 95% confidence intervals (CI). Evidence certainty was assessed using Grades of Recommendation, Assessment, Development and Evaluation (GRADE) processes. The primary outcomes included all-cause death, graft loss, and kidney function. MAIN RESULTS: Ninety-seven studies (8706 participants) were included. One study evaluated treatment in children. The overall risk of bias was unclear to high across all domains. Compared to placebo or standard care alone, CCBs probably reduce all-cause death (23 studies, 3327 participants: RR 0.83, 95% CI 0.72 to 0.95; I2 = 0%; moderate certainty evidence) and graft loss (24 studies, 3577 participants: RR 0.84, 95% CI 0.75 to 0.95; I2 = 0%; moderate certainty evidence). CCBs may make little or no difference to estimated glomerular filtration rate (eGFR) (11 studies, 2250 participants: MD 1.89 mL/min/1.73 m2, 95% CI -0.70 to 4.48; I2 = 48%; low certainty evidence) and acute rejection (13 studies, 906 participants: RR 10.8, 95% CI 0.85 to 1.35; I2 = 0%; moderate certainty evidence). CCBs may reduce systolic BP (SBP) (3 studies, 329 participants: MD -5.83 mm Hg, 95% CI -10.24 to -1.42; I2 = 13%; low certainty evidence) and diastolic BP (DBP) (3 studies, 329 participants: MD -3.98 mm Hg, 95% CI -5.98 to -1.99; I2 = 0%; low certainty evidence). CCBs have uncertain effects on proteinuria. Compared to placebo or standard care alone, angiotensin-converting-enzyme inhibitors (ACEi) may make little or no difference to all-cause death (7 studies, 702 participants: RR 1.13, 95% CI 0.58 to 2.21; I2 = 0%; low certainty evidence), graft loss (6 studies, 718 participants: RR 0.75, 95% CI 0.49 to 1.13; I2 = 0%; low certainty evidence), eGFR (4 studies, 509 participants: MD -2.46 mL/min/1.73 m2, 95% CI -7.66 to 2.73; I2 = 64%; low certainty evidence) and acute rejection (4 studies, 388 participants: RR 1.75, 95% CI 0.76 to 4.04; I2 = 0%; low certainty evidence). ACEi may reduce proteinuria (5 studies, 441 participants: MD -0.33 g/24 hours, 95% CI -0.64 to -0.01; I2 = 67%; low certainty evidence) but had uncertain effects on SBP and DBP. Compared to placebo or standard care alone, angiotensin receptor blockers (ARB) may make little or no difference to all-cause death (6 studies, 1041 participants: RR 0.69, 95% CI 0.36 to 1.31; I2 = 0%; low certainty evidence), eGRF (5 studies, 300 participants: MD -1.91 mL/min/1.73 m2, 95% CI -6.20 to 2.38; I2 = 57%; low certainty evidence), and acute rejection (4 studies, 323 participants: RR 1.00, 95% CI 0.44 to 2.29; I2 = 0%; low certainty evidence). ARBs may reduce graft loss (6 studies, 892 participants: RR 0.35, 95% CI 0.15 to 0.84; I2 = 0%; low certainty evidence), SBP (10 studies, 1239 participants: MD -3.73 mm Hg, 95% CI -7.02 to -0.44; I2 = 63%; moderate certainty evidence) and DBP (9 studies, 1086 participants: MD -2.75 mm Hg, 95% CI -4.32 to -1.18; I2 = 47%; moderate certainty evidence), but has uncertain effects on proteinuria. The effects of CCBs, ACEi or ARB compared to placebo or standard care alone on cardiovascular outcomes (including fatal or nonfatal myocardial infarction, fatal or nonfatal stroke) or other adverse events were uncertain. The comparative effects of ACEi plus ARB dual therapy, alpha-blockers, and mineralocorticoid receptor antagonists compared to placebo or standard care alone were rarely evaluated. Head-to-head comparisons of ACEi, ARB or thiazide versus CCB, ACEi versus ARB, CCB or ACEi versus alpha- or beta-blockers, or ACEi plus CCB dual therapy versus ACEi or CCB monotherapy were scarce. No studies reported outcome data for cancer or life participation. AUTHORS' CONCLUSIONS: For kidney transplant recipients, the use of CCB therapy to reduce BP probably reduces death and graft loss compared to placebo or standard care alone, while ARB may reduce graft loss. The effects of ACEi and ARB compared to placebo or standard care on other patient-centred outcomes were uncertain. The effects of dual therapy, alpha-blockers, and mineralocorticoid receptor antagonists compared to placebo or standard care alone and the comparative effects of different treatments were uncertain.