Dealing with time-dependent exposures and confounding when defining and estimating attributable fractions-Revisiting estimands and estimators.

The population-attributable fraction (PAF) is commonly interpreted as the proportion of events that can be ascribed to a certain exposure in a certain population. Its estimation is sensitive to common forms of time-dependent bias in the face of a time-dependent exposure. Predominant estimation approaches based on multistate modeling fail to fully eliminate such bias and, as a result, do not permit a causal interpretation, even in the absence of confounding. While recently proposed multistate modeling approaches can successfully eliminate residual time-dependent bias, and moreover succeed to adjust for time-dependent confounding by means of inverse probability of censoring weighting, inadequate application, and misinterpretation prevails in the medical literature. In this paper, we therefore revisit recent work on previously proposed PAF estimands and estimators in settings with time-dependent exposures and competing events and extend this work in several ways. First, we critically revisit the interpretation and applied terminology of these estimands. Second, we further formalize the assumptions under which a causally interpretable PAF estimand can be identified and provide analogous weighting-based representations of the identifying functionals of other proposed estimands. This representation aims to enhance the applied statistician's understanding of different sources of bias that may arise when the aim is to obtain a valid estimate of a causally interpretable PAF. To illustrate and compare these representations, we present a real-life application to observational data from the Ghent University Hospital ICUs to estimate the fraction of ICU deaths attributable to hospital-acquired infections.

Mental health and professional outcomes in parents of children with chronic kidney disease.

BACKGROUND: This study evaluated parenting stress, anxiety, and depression symptoms and their associated factors in parents of children with chronic kidney disease (CKD). METHODS: This cross-sectional study compared parents of patients with CKD (0-18 years) with a matched control group of parents of healthy children. Both groups completed the Parenting Stress Index - Short Form, the Hospital Anxiety and Depression Scale, and a sociodemographic questionnaire. RESULTS: The study group consisted of 45 parents (median age 39; 32 mothers) of CKD patients (median age 8; 36% female). Nearly 75% of children had CKD stages 2, 3, or 4, and 44.5% had congenital anomaly of the kidney and urinary tract. Five children (11%) were on dialysis, and 4 (9%) had a functioning kidney graft. Compared with parents of healthy children, more stress and anxiety symptoms were reported. Since the CKD diagnosis, 47% of parents perceived a deterioration of their own health, and 40% reduced work on a structural basis. Higher levels of stress, anxiety, and depression symptoms were associated with a more negative perception of own health, and more child medical comorbidities and school absence. CONCLUSIONS: This study showed higher levels of parenting stress and anxiety symptoms in parents of children with CKD compared with parents of healthy children. This was associated with a less positive perception of their own health, especially if the child had more medical comorbidities or more absence from school. Psychosocial interventions to reduce the parental burden should be integrated in the standard care of pediatric nephrology departments.

Towards a better uptake of home dialysis in Europe: understanding the present and looking to the future.

Use of peritoneal dialysis and home haemodialysis remains low in Europe, with the highest use in Scandinavian countries and the lowest in Eastern and Central Europe despite the advantages for people on dialysis and economic advantages for healthcare systems. This is partly due to the impact of the haemodialysis industry resulting in proliferation of haemodialysis units and nephrologist reimbursement related to use of haemodialysis. Equally important is the bias against home dialysis at both clinician and healthcare system levels. The underlying causes of this bias are discussed in relation to a mechanistic view of the human body, lack of compassion, failure to adjust dialysis provision for older age and frailty, proliferation of small dialysis centres, and complexity of decision-making and clinical care. For home dialysis to flourish, we need to foster a change in attitude to and vision of the aims of healthcare so that enabling meaningful activities of people requiring dialysis, as explored in the Standardized Outcomes in Nephrology initiative, rather than achieving biological numbers become the focus of care delivery.

Factors influencing renal replacement therapy modality choice from the nephrologist's perspective.

BACKGROUND: Peritoneal dialysis (PD) offers quality of life and empowerment for persons with end-stage kidney disease (ESKD). Nevertheless, the prevalence of PD is low in Belgium and Europe in general. Reimbursement, patient mix and late referral have been quoted as underlying reasons. However, to date no one-size-fits-all solution increasing uptake of PD has been successfully implemented. We aimed to understand the nephrologist's perspective, beliefs, and experiences on dialysis modality selection and to clarify underlying process-level and intrinsic motivations steering final decisions. METHODS: Using purposeful sampling, Belgian nephrologists (non-/academic, geographical spread, age, gender) were selected. We conducted semi-structured interviews, and audiotapes were transcribed verbatim. Meaningful units were grouped into (sub-)themes, and a conceptual framework was developed using grounded theory according to Charmaz as guidance. RESULTS: Twenty-nine nephrologists were interviewed. We identified four themes: Trust and belief (in PD as a technique; own expertise, knowledge and team; in behavior of patient, family practitioner), feeling of control (paternalism; insecurity; prejudice), vision of care and approach (shared decision making; troubleshooting attitude; flexibility and creativity; complacency), and organizational issues (predialysis; access; financial; and assisted PD). CONCLUSIONS: Based on these interviews, it is apparent that next to already identified singular issues such as late referral, predialysis education, patient mix and financial incentives, more intrinsic factors also impact uptake of home-based therapies. These factors intertwine and relate both to process-level topics and to attitudes and culture of the nephrologists within the team.

Indoxyl Sulfate Contributes to Impaired Height Velocity in (Pre)School Children.

Introduction: Growth failure is considered the most important clinical outcome parameter in childhood chronic kidney disease (CKD). Central to the pathophysiology of growth failure is the presence of a chronic proinflammatory state, presumed to be partly driven by the accumulation of uremic toxins. In this study, we assessed the association between uremic toxin concentrations and height velocity in a longitudinal multicentric prospective pediatric CKD cohort of (pre)school-aged children and children during pubertal stages. Methods: In a prospective, multicentric observational study, a selection of uremic toxin levels of children (aged 0-18 years) with CKD stage 1 to 5D was assessed every 3 months (maximum 2 years) along with clinical growth parameters. Linear mixed models with a random slope for age and a random intercept for child were fitted for height (in cm and SD scores [SDS]). A piecewise linear association between age and height was assumed. Results: Data analysis included data from 560 visits of 81 children (median age 9.4 years; 2/3 male). In (pre)school aged children (aged 2-12 years), a 10% increase in concurrent indoxyl sulfate (IxS, total) concentration resulted in an estimated mean height velocity decrease of 0.002 SDS/yr (P < 0.05), given that CKD stage, growth hormone (GH), bicarbonate concentration, and dietary protein intake were held constant. No significant association with height velocity was found in children during pubertal stages (aged >12 years). Conclusion: The present study demonstrated that, especially IxS contributes to a lower height velocity in (pre)school children, whereas we could not find a role for uremic toxins with height velocity during pubertal stages.

Challenges in posttransplantation care for kidney transplant recipients: A qualitative study highlighting gaps in psychological, social and exercise support.

BACKGROUND: Kidney transplantation offers meaningful health improvements compared to dialysis, yet the quality of life and life expectancy of kidney transplant recipients still lag behind those of their healthy peers. Physical inactivity and poor physical fitness are prevalent among kidney transplant recipients, affecting overall life participation. OBJECTIVES: To explore challenges hindering life participation for kidney transplant recipients and reveal facilitators and barriers to integrating rehabilitation into their daily lives. DESIGN: An explorative study using a qualitative method. PARTICIPANTS: Fourteen purposively selected kidney transplant recipients. APPROACH: Semistructured, individual interviews were conducted posttransplantation. The following topics were covered: living with chronic kidney disease, pretransplantation challenges, posttransplantation recovery, engagement in various activities, including physical activity, and the need for supervised exercise rehabilitation programmes. Interviews were recorded and transcribed verbatim, and an inductive thematic analysis approach was used. FINDINGS: Data saturation occurred after analysing 12 interviews, revealing two main themes: the impact on life participation and the impact on physical and mental functioning. Participants expressed the need for comprehensive posttransplant care, including mental health support, family education and guidance on returning to work. Structured support in managing physical fitness, tailored to individual preferences, was also recognised as important. CONCLUSIONS: The study underscores the necessity for a biopsychosocial approach to posttransplant care that addresses the multifaceted challenges faced by kidney transplant recipients. A multidisciplinary approach, tailored support, education and individualised exercise programmes are crucial for enhancing their overall well-being and integrating rehabilitation into their daily lives, considering both physical and psychosocial aspects.

Detection and Scoring of Extracorporeal Circuit Clotting During Hemodialysis.

Maintaining patency of the extracorporeal hemodialysis (HD) circuit is a prerequisite to perform HD. Unfractionated heparin and low-molecular-weight heparins are the most used anticoagulants in maintenance HD, but their administration comes with a major trade-off of bleeding complications. This narrative review article discusses technical factors impacting on HD circuit patency, such as tubings, dialyzer membranes, priming practices, and treatment settings. Strategies for monitoring extracorporeal circuit clotting during and after treatment are also reviewed, as these are essential tools for optimizing anticoagulation.