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.

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.

Public health and prevention research within the Medical Research Future Fund.

OBJECTIVE: To explore the amount and type of research funded under relevant Medical Research Future Fund (MRFF) Initiatives that addressed public health and prevention from 2018 to July 2023. METHODS: Projects funded by six MRFF Initiatives, with objectives relevant to public health and public health nominated as "field of research" by >25% of applicants, were evaluated against a set of public health research criteria and were categorised based on levels of prevention. RESULTS: Fifty-seven per cent of 249 funded projects were categorised as public health research. Projects with curative features, focusing on tertiary (32%) and quaternary (4%) prevention, were as common as projects with earlier preventive features, focussed on primordial (7%) and primary (28%) prevention. The Preventive and Public Health Research Initiative had the lowest proportion of public health research (48%) of the six evaluated Initiatives and a dominance of curative (39%) and non-preventive (26%) research over preventive research (30%). CONCLUSION: This study highlighted variable levels of public health research across public-health-relevant MRFF Initiatives and generally low proportions of primary and primordial prevention. A greater emphasis on primordial and primary prevention research in public-health-relevant Initiatives could advance prevention in Australia. IMPLICATIONS FOR PUBLIC HEALTH: There appears to be scope for improvement in the prioritisation of upstream prevention research in public-health-relevant MRFF Initiatives and projects. Addressing this may enhance the benefit of MRFF to Australian public health.

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.

Socioeconomic Position and Health Among Children and Adolescents With CKD Across the Life-Course.

Children and adolescents in families of lower socioeconomic position (SEP) experience an inequitable burden of reduced access to healthcare and poorer health. For children living with chronic kidney disease (CKD), disadvantaged SEP may exacerbate their considerable disease burden. Across the life-course, CKD may also compromise the SEP of families and young people, leading to accumulating health and socioeconomic disadvantage. This narrative review summarizes the current evidence on relationships of SEP with kidney care and health among children and adolescents with CKD from a life-course approach, including impacts of family SEP on kidney care and health, and bidirectional impacts of CKD on SEP. It highlights relevant conceptual models from social epidemiology, current evidence, clinical and policy implications, and provides directions for future research. Reflecting the balance of available evidence, we focus primarily on high-income countries (HICs), with an overview of key issues in low- and middle-income countries (LMICs). Overall, a growing body of evidence indicates sobering socioeconomic inequities in health and kidney care among children and adolescents with CKD, and adverse socioeconomic impacts of CKD. Dedicated efforts to tackle inequities are critical to ensuring that all young people with CKD have the opportunity to live long and flourishing lives. To prevent accumulating disadvantage, the global nephrology community must advocate for local government action on upstream social determinants of health; and adopt a life-course approach to kidney care that proactively identifies and addresses unmet social needs, targets intervening factors between SEP and health, and minimizes adverse socioeconomic outcomes across financial, educational and vocational domains.

Patient-Centered Research and Outcomes in Cancer and Kidney Transplantation.

Cancer has been identified by kidney transplant recipients as a critically important outcome. The co-occurrence of cancer and kidney transplantation represents a complex intersection of diseases, symptoms, and competing priorities for treatments. Research that focuses on biochemical parameters and clinical events may not capture the priorities of patients. Patient-centered research can improve the relevance and efficiency of research and is particularly pertinent in the setting of cancer and kidney transplantation to facilitate shared decision-making in complex clinical situations. In addition, patient-reported outcomes can facilitate the assessment of patients' experiences, symptom burden, treatment side effects, and quality of life. This review discusses patient-centered research in the context of kidney transplantation and cancer, including consumer involvement in research and patient-centered outcomes and their measures and inclusion in core outcome sets.

Intra-generational social mobility and mortality among older men in the Concord Health and Ageing in Men Project: A cohort study.

Objectives: We examined associations between intra-generational social mobility (reflected in life-course socioeconomic trajectories) and mortality, among older men. Methods: Data came from a prospective Australian community-based cohort of older men. Social mobility was defined by socioeconomic indicators from three points in the life-course: educational attainment (late adolescence-early adulthood), occupation (mid-life), and current sources of income (older age). We defined indicators of social mobility trajectory (6 categories; reflecting the direction of social mobility) and social mobility status (2 categories; mobile or non-mobile). We used Cox regression to examine associations with mortality, adjusting for age, country of birth, and living arrangement. Results: We followed 1568 men (mean age 76.8, SD 5.4) for a mean duration of 9.1 years, with 797 deaths recorded. Moving upward was the predominant social mobility trajectory (36.0%), followed by mixed trajectories (25.1%), downward (15.1%), stable low (12.2%), stable high (7.6%), and stable middle (4.0%). Men with downward (Hazard ratio 1.58, 95% CI 1.13 to 2.19) and stable low socioeconomic trajectories (1.77, 1.25 to 2.50) had higher mortality risks than men with stable high socioeconomic trajectories, while men with upward trajectories had similar risks to those with stable high trajectories. 76.2% of the participants were classified as having mobile status; no associations were evident between binary social mobility status and mortality. Discussions: These findings suggest cumulative and persistent exposure to disadvantaged socioeconomic conditions across the life-course, rather than social mobility, is associated with increased mortality. For each stage of the life-course, addressing socioeconomic disadvantage may reduce inequities in mortality.

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.

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.

Overadjustment bias in systematic reviews and meta-analyses of socio-economic inequalities in health: a meta-research scoping review.

BACKGROUND: Overadjustment bias occurs when researchers adjust for an explanatory variable on the causal pathway from exposure to outcome, which leads to biased estimates of the causal effect of the exposure. This meta-research review aimed to examine how previous systematic reviews and meta-analyses of socio-economic inequalities in health have managed overadjustment bias. METHODS: We searched Medline and Embase until 16 April 2021 for systematic reviews and meta-analyses of observational studies on associations between individual-level socio-economic position and health outcomes in any population. A set of criteria were developed to examine methodological approaches to overadjustment bias adopted by included reviews (rated Yes/No/Somewhat/Unclear). RESULTS: Eighty-four reviews were eligible (47 systematic reviews, 37 meta-analyses). Regarding approaches to overadjustment, whereas 73% of the 84 reviews were rated as Yes for clearly defining exposures and outcomes, all other approaches were rated as Yes for <55% of reviews; for instance, 5% clearly defined confounders and mediators, 2% constructed causal diagrams and 35% reported adjusted variables for included studies. Whereas only 2% included overadjustment in risk of bias assessment, 54% included confounding. Of the 37 meta-analyses, 16% conducted sensitivity analyses related to overadjustment. CONCLUSIONS: Our findings suggest that overadjustment bias has received insufficient consideration in systematic reviews and meta-analyses of socio-economic inequalities in health. This is a critical issue given that overadjustment bias is likely to result in biased estimates of health inequalities and accurate estimates are needed to inform public health interventions. There is a need to highlight overadjustment bias in review guidelines.

Mendelian randomization for nephrologists.

Confounding is a major limitation of observational studies. Mendelian randomization (MR) is a powerful study design that uses genetic variants as instrumental variables to enable examination of the causal effect of an exposure on an outcome in observational data. With the emergence of large-scale genome-wide association studies in nephrology over the past decade, MR has become a popular method to establish causal inferences. However, MR is a complex and challenging methodology that requires careful consideration to ensure robust results. This review article aims to summarize the basic concepts of MR, its application and relevance in nephrology, and the methodological challenges and limitations as well as discuss the current guidelines for design and reporting. With reference to a clinically relevant example of examining the causal relationship between the estimated glomerular filtration rate and cancer, this review outlines the key steps to conducting an MR study, including the key considerations and potential pitfalls at each step. These include defining the clinical question, selecting the data sources, identifying and refining appropriate genetic variants by considering linkage disequilibrium and associations with potential confounders, harmonization of variants across data sets, validation of the genetic instrument by assessing its strength, estimation of the causal effects, confirming the validity of the findings, and interpreting and reporting results.

Sex and Gender Disparities in Living Kidney Donation: A Scoping Review.

Background: Women are more likely than men to be living kidney donors. We summarized the evidence concerning the reasons behind sex and gender disparities in living kidney donation (LKD). Methods: A scoping review of quantitative and qualitative evidence on reasons for sex and gender disparities in LKD was conducted from inception to March 2023. Results: Of 1123 studies screened, 45 were eligible for inclusion. Most studies were from North America, Europe, and Central Asia (n = 33, 73%). A predominance of women as living donors (55%-65%) was observed in 15 out of 18 (83%) studies. Reasons for sex and gender disparities in LKD included socioeconomic, biological, and cognitive or emotional factors. A gendered division of roles within the families was observed in most studies, with men being the primary income earner and women being the main caregiver. Fear of loss of income was a barrier to male donation. Human leukocyte antigen sensitization through pregnancy in female recipients precluded male partner donation, whereas female donation was supported by altruism and a positive attitude toward LKD. Conclusions: Sex imbalance in LKD is prevalent, with a predominance of women as living donors. Such disparities are driven by societal and cultural perceptions of gender roles, pregnancy-induced sensitization, and attitudes toward donation and at least some of these factors are modifiable. Donor compensation to support predonation assessments and income loss, implementation of innovative desensitization treatments, promotion of paired kidney exchange program, and targeted educational initiatives to promote equitable living donation may help to close the gender gap in LKD.

Sociodemographic Drivers of Donor and Recipient Gender Disparities in Living Kidney Donation in Australia.

Background: Females account for 60% of all living kidney donors worldwide. We defined the proportion of female to male donors for living donor kidney transplantation stratified by recipient gender, and explored the factors associated with female kidney donation. Methods: Data from the ANZDATA (Australian and New Zealand Dialysis and Transplantation) and ANZOD (Australian and New Zealand Organ Donor) registries (2002-2019) were used to identify the sociodemographic characteristics and their interactions associated with living donation from female donors. We derived the predicted probabilities from adjusted logistic models using marginal means. Results: Of 3523 living donor pairs, 2203 (63%) recipients were male, and 2012 (57%) donors were female. Male recipients were more likely to receive kidneys from female donors than male donors. Donor and recipient sex association was modified by donor-recipient relationship (P < 0.01), with sensitivity analysis suggesting that spousal donor-recipient pairs drive this interaction. Older recipients residing in regional or remote areas were more likely to receive kidneys from female donors compared with those from major cities (aged ≥60 years: 0.67 [0.63-0.71] vs. aged <60 years: 0.57 [0.53-0.60]). Conclusions: Factors associated with female donation include recipient sex, with spousal donors contributing to the interaction between recipient gender and donor-recipient relationship. Recipient age and location of residence have interactive effects on the likelihood of living donor transplantation from female donors.

Scope and Consistency of Cancer Outcomes Reported in Randomized Trials in Kidney Transplant Recipients.

Introduction: Cancer is an important outcome in kidney transplantation, but the scope and consistency of how cancer is defined and reported in trials involving kidney transplant recipients has not been evaluated. This study aimed to assess the range and variability of cancer outcomes in trials involving kidney transplant recipients. Methods: The ClinicalTrials.gov database was searched from February 2000 to July 2021 to identify all randomized controlled trials (RCTs) in adult kidney transplant recipients, and which included cancer as a specified outcome. The definition of cancer, types of cancer (if any), timepoint(s) of measurement and method of aggregation were extracted for each cancer outcome. Results: Of the 819 trials in kidney transplantation, only 84 (10%) included 1 or more cancer outcomes. Of these, 72 of 84 (86%) trials included cancer as a secondary outcome and 12 of 84 (14%) considered cancer as a primary outcome. The most frequent description of cancer was "malignancy" (n = 44, 43%), without reference to diagnostic criteria, histology, grade, or stage. The 2 most common cancer types were posttransplant lymphoproliferative disorder (PTLD) (n = 20, 20%) and nonmelanoma skin cancer (n = 10, 10%). Several methods of aggregation were identified, including incidence or rate (n = 47, 46%), frequency or proportion (n = 30, 29%), and time to event (n = 5, 5%). Approximately half the cancer outcomes were measured at a single time point (n = 44, 52%). Conclusion: Cancer is an infrequently reported outcome and is inconsistently defined in trials of kidney transplant recipients. Consistent reporting of cancer outcomes using standardized definitions would provide important information on the impact of cancer in patients after kidney transplantation.

Baseline characteristics of participants in the NAVKIDS2 trial: a patient navigator program in children with chronic kidney disease.

BACKGROUND: Children with chronic kidney disease (CKD) require multidisciplinary care to meet their complex healthcare needs. Patient navigators are trained non-medical personnel who assist patients and caregivers to overcome barriers to accessing health services through care coordination. This trial aims to determine the effectiveness of a patient navigator program in children with CKD. METHODS: The NAVKIDS2 trial is a multi-center, waitlisted, randomized controlled trial of patient navigators in children with CKD conducted at five sites across Australia. Children (0-16 years) with CKD from low socioeconomic status rural or remote areas were randomized to an intervention group or a waitlisted control group (to receive intervention after 6 months). The study primary and secondary endpoints include the self-rated health (SRH) (primary), and utility-based quality of life, progression of kidney dysfunction of the child, SRH, and satisfaction with healthcare of the caregiver at 6 months post-randomization. RESULTS: The trial completed recruitment in October 2021 with expected completion of follow-up by October 2022. There were 162 patients enrolled with 80 and 82 patients randomized to the immediate intervention and waitlisted groups, respectively. Fifty-eight (36%) participants were from regional/remote areas, with a median (IQR) age of 9.5 (5.0, 13.0) years, 46% were of European Australian ethnicity, and 65% were male. A total of 109 children (67%) had CKD stages 1-5, 42 (26%) were transplant recipients, and 11 (7%) were receiving dialysis. CONCLUSION: The NAVKIDS2 trial is designed to evaluate the effectiveness of patient navigation in children with CKD from families experiencing socioeconomic disadvantage. A higher resolution version of the Graphical abstract is available as Supplementary information.