Rate of Deceased Kidney Donation From Potential In-Hospital Deaths in the US, 2003-2021

This cross-sectional study calculates deceased kidney donation rates in the US using deaths compatible with donation as the metric’s denominator.

Assessing trends and variability in outpatient dual testing for chronic kidney disease with urine albumin and serum creatinine, 2009-2018: a retrospective cohort study in the Veterans Health Administration System

BACKGROUND

Simultaneous urine testing for albumin (UAlb) and serum creatinine (SCr), that is, 'dual testing,' is an accepted quality measure in the management of diabetes. As chronic kidney disease (CKD) is defined by both UAlb and SCr testing, this approach could be more widely adopted in kidney care.

OBJECTIVE

We assessed time trends and facility-level variation in the performance of outpatient dual testing in the integrated Veterans Health Administration (VHA) system.

DESIGN, SUBJECTS AND MAIN MEASURES

This retrospective cohort study included patients with any inpatient or outpatient visit to the VHA system during the period 2009-2018. Dual testing was defined as UAlb and SCr testing in the outpatient setting within a calendar year. We assessed time trends in dual testing by demographics, comorbidities, high-risk (eg, diabetes) specialty care and facilities. A generalised linear mixed-effects model was applied to explore individual and facility-level predictors of receiving dual testing.

KEY RESULTS

We analysed data from approximately 6.9 million veterans per year. Dual testing increased, on average, from 17.4% to 21.2%, but varied substantially among VHA centres (0.3%-43.7% in 2018). Dual testing was strongly associated with diabetes (OR 10.4, 95% CI 10.3 to 10.5, p<0.0001) and not associated with VHA centre complexity level. However, among patients with high-risk conditions including diabetes, <50% received dual testing in any given year. As compared with white veterans, black veterans were less likely to be tested after adjusting for other individual and facility characteristics (OR 0.93, 95% CI 0.92 to 0.93, p<0.0001).

CONCLUSIONS

Dual testing for CKD in high-risk specialties is increasing but remains low. This appears primarily due to low rates of testing for albuminuria. Promoting dual testing in high-risk patients will help to improve disease management and patient outcomes.

Whole genome sequencing of 4,787 individuals identifies gene-based rare variants in age-related macular degeneration

Genome-wide association studies have contributed extensively to the discovery of disease-associated common variants. However, the genetic contribution to complex traits is still largely difficult to interpret. We report a genome-wide association study of 2394 cases and 2393 controls for age-related macular degeneration (AMD) via whole-genome sequencing, with 46.9 million genetic variants. Our study reveals significant single-variant association signals at four loci and independent gene-based signals in CFH, C2, C3, and NRTN. Using data from the Exome Aggregation Consortium (ExAC) for a gene-based test, we demonstrate an enrichment of predicted rare loss-of-function variants in CFH, CFI, and an as-yet unreported gene in AMD, ORMDL2. Our method of using a large variant list without individual-level genotypes as an external reference provides a flexible and convenient approach to leverage the publicly available variant datasets to augment the search for rare variant associations, which can explain additional disease risk in AMD.

Controlling Hypertension through Education and Coaching in Kidney Disease (CHECK-D): protocol of a cluster randomised controlled trial

INTRODUCTION

Chronic kidney disease (CKD) affects 30 million Americans. Early management focused on blood pressure (BP) control decreases cardiovascular morbidity and mortality. Less than 40% of patients with CKD achieve recommended BP targets due to many barriers. These barriers include a lack of understanding of the implications of their diagnosis and how to optimise their health.This cluster randomised control trial hypothesises that the combination of early primary care CKD education, and motivational interviewing (MI)-based health coach support, will improve patient behaviours aligned with BP control by increasing patient knowledge, self-efficacy and motivation. The results will aid in sustainable interventions for future patient-centric education and coaching support to improve quality and outcomes in patients with CKD stages 3-5. Outcomes in patients with CKD stages 3-5 receiving the intervention will be compared with similar patients within a control group. Continuous quality improvement (CQI) and systems methodologies will be used to optimise resource neutrality and leverage existing technology to support implementation and future dissemination. The innovative approach of this research focuses on the importance of a multidisciplinary team, including off-site patient coaching, that can intervene early in the CKD care continuum by supporting patients with education and coaching.

METHODS AND ANALYSIS

We will test impact of BP control when clinician-delivered education is followed by 12 months of MI-based health coaching. We will compare outcomes in 350 patients with CKD stages 3-5 between intervention and control groups in primary care. CQI and systems methodologies will optimise education and coaching for future implementation and dissemination.

ETHICS AND DISSEMINATION

This study was approved by the University of Michigan Institutional Review Boards (IRBMED) HUM00136011, HUM00150672 and SITE00000092 and the results of the study will be published on ClinicalTrials.gov, in peer-reviewed journals, as well as conference abstracts, posters and presentations.

TRIAL REGISTRATION NUMBER

NCT04087798.

Enhancing the Cardiovascular Safety of Hemodialysis Care Using Multimodal Provider Education and Patient Activation Interventions: Protocol for a Cluster Randomized Controlled Trial

BACKGROUND

End-stage kidney disease (ESKD) is treated with dialysis or kidney transplantation, with most patients with ESKD receiving in-center hemodialysis treatment. This life-saving treatment can result in cardiovascular and hemodynamic instability, with the most common form being low blood pressure during the dialysis treatment (intradialytic hypotension [IDH]). IDH is a complication of hemodialysis that can involve symptoms such as fatigue, nausea, cramping, and loss of consciousness. IDH increases risks of cardiovascular disease and ultimately hospitalizations and mortality. Provider-level and patient-level decisions influence the occurrence of IDH; thus, IDH may be preventable in routine hemodialysis care.

OBJECTIVE

This study aims to evaluate the independent and comparative effectiveness of 2 interventions-one directed at hemodialysis providers and another for patients-in reducing the rate of IDH at hemodialysis facilities. In addition, the study will assess the effects of interventions on secondary patient-centered clinical outcomes and examine factors associated with a successful implementation of the interventions.

METHODS

This study is a pragmatic, cluster randomized trial to be conducted in 20 hemodialysis facilities in the United States. Hemodialysis facilities will be randomized using a 2 × 2 factorial design, such that 5 sites will receive a multimodal provider education intervention, 5 sites will receive a patient activation intervention, 5 sites will receive both interventions, and 5 sites will receive none of the 2 interventions. The multimodal provider education intervention involved theory-informed team training and the use of a digital, tablet-based checklist to heighten attention to patient clinical factors associated with increased IDH risk. The patient activation intervention involves tablet-based, theory-informed patient education and peer mentoring. Patient outcomes will be monitored during a 12-week baseline period, followed by a 24-week intervention period and a 12-week postintervention follow-up period. The primary outcome of the study is the proportion of treatments with IDH, which will be aggregated at the facility level. Secondary outcomes include patient symptoms, fluid adherence, hemodialysis adherence, quality of life, hospitalizations, and mortality.

RESULTS

This study is funded by the Patient-Centered Outcomes Research Institute and approved by the University of Michigan Medical School's institutional review board. The study began enrolling patients in January 2023. Initial feasibility data will be available in May 2023. Data collection will conclude in November 2024.

CONCLUSIONS

The effects of provider and patient education on reducing the proportion of sessions with IDH and improving other patient-centered clinical outcomes will be evaluated, and the findings will be used to inform further improvements in patient care. Improving the stability of hemodialysis sessions is a critical concern for clinicians and patients with ESKD; the interventions targeted to providers and patients are predicted to lead to improvements in patient health and quality of life.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03171545; https://clinicaltrials.gov/ct2/show/NCT03171545.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/46187.

Proinflammatory Diets and Risk of ESKD in US Adults with CKD

Background

Inflammation may affect long-term kidney function. Diet may play a role in chronic inflammation. We hypothesized that proinflammatory diets increase the risk of progression to kidney failure with replacement therapy (KFRT), and systemic inflammation is a mediator of the effect of diet on progression to KFRT.

Methods

In the 1988-1994 National Health and Nutrition Examination Survey linked to the national ESKD registry, in adults with CKD (eGFR 15-59 ml/min per 1.73 m²), aged ≥20 years, we calculated the Adapted Dietary Inflammatory Index (ADII) at baseline from a 24-hour dietary recall and an inflammation score (IS) using average of z scores of four inflammation biomarkers. We explored the association of the ADII and IS with risk of incident KFRT using Cox proportional model, adjusting for sociodemographics, physical activity, Framingham risk score, eGFR, and urinary ACR. We evaluated whether, and to what extent, IS mediated the effect of the ADII on KFRT incidence, using causal mediation analysis.

Results

Of 1084 adults with CKD, 109 (10%) developed KFRT. The ADII was associated with increased risk of KFRT (relative hazard [RH] per SD increase (2.56): 1.4 [1.04-1.78]). IS was also associated with KFRT (RH: 1.12; 95% CI, 1.02 to 1.25). Approximately 36% of the association between the ADII and KFRT was explained by IS.

Conclusions

Among adults with CKD, a proinflammatory diet was associated with risk of KFRT, and that association was partially explained by an increase in inflammatory markers. Dietary interventions that reduce inflammation may offer an approach for preventing KFRT.

Occupational heat exposure and the risk of chronic kidney disease of nontraditional origin in the United States

Occupational heat exposure is linked to the development of kidney injury and disease in individuals who frequently perform physically demanding work in the heat. For instance, in Central America, an epidemic of chronic kidney disease of nontraditional origin (CKDnt) is occurring among manual laborers, whereas potentially related epidemics have emerged in India and Sri Lanka. There is growing concern that workers in the United States suffer with CKDnt, but reports are limited. One of the leading hypotheses is that repetitive kidney injury caused by physical work in the heat can progress to CKDnt. Whether heat stress is the primary causal agent or accelerates existing underlying pathology remains contested. However, the current evidence supports that heat stress induces tubular kidney injury, which is worsened by higher core temperatures, dehydration, longer work durations, muscle damaging exercise, and consumption of beverages containing high levels of fructose. The purpose of this narrative review is to identify occupations that may place US workers at greater risk of kidney injury and CKDnt. Specifically, we reviewed the scientific literature to characterize the demographics, environmental conditions, physiological strain (i.e., core temperature increase, dehydration, heart rate), and work durations in sectors typically experiencing occupational heat exposure, including farming, wildland firefighting, landscaping, and utilities. Overall, the surprisingly limited available evidence characterizing occupational heat exposure in US workers supports the need for future investigations to understand this risk of CKDnt.

Usability Evaluation of a Tablet-Based Intervention to Prevent Intradialytic Hypotension in Dialysis Patients During In-Clinic Dialysis: Mixed Methods Study

Background

Patients on hemodialysis receive dialysis thrice weekly for about 4 hours per session. Intradialytic hypotension (IDH)—low blood pressure during hemodialysis—is a serious but common complication of hemodialysis. Although patients on dialysis already participate in their care, activating patients toward IDH prevention may reduce their risk of IDH. Interactive, technology-based interventions hold promise as a platform for patient activation. However, little is known about the usability challenges that patients undergoing hemodialysis may face when using tablet-based informatics interventions, especially while dialyzing.

Objective

This study aims to test the usability of a patient-facing, tablet-based intervention that includes theory-informed educational modules and motivational interviewing–based mentoring from patient peers via videoconferencing.

Methods

We conducted a cross-sectional, mixed methods usability evaluation of the tablet-based intervention by using think-aloud methods, field notes, and structured observations. These qualitative data were evaluated by trained researchers using a structured data collection instrument to capture objective observational data. We calculated descriptive statistics for the quantitative data and conducted inductive content analysis using the qualitative data.

Results

Findings from 14 patients cluster around general constraints such as the use of one arm, dexterity issues, impaired vision, and lack of experience with touch screen devices. Our task-by-task usability results showed that specific sections with the greatest difficulty for users were logging into the intervention (difficulty score: 2.08), interacting with the quizzes (difficulty score: 1.92), goal setting (difficulty score: 2.28), and entering and exiting videoconference rooms (difficulty score: 2.07) that are used to engage with peers during motivational interviewing sessions.

Conclusions

In this paper, we present implications for designing informatics interventions for patients on dialysis and detail resulting changes to be implemented in the next version of this intervention. We frame these implications first through the context of the role the patients’ physical body plays when interacting with the intervention and then through the digital considerations for software and interface interaction.

Feeling better on hemodialysis: user-centered design requirements for promoting patient involvement in the prevention of treatment complications

OBJECTIVE

Hemodialysis patients frequently experience dialysis therapy sessions complicated by intradialytic hypotension (IDH), a major patient safety concern. We investigate user-centered design requirements for a theory-informed, peer mentoring-based, informatics intervention to activate patients toward IDH prevention.

METHODS

We conducted observations (156 hours) and interviews (n = 28) with patients in 3 hemodialysis clinics, followed by 9 focus groups (including participatory design activities) with patients (n = 17). Inductive and deductive analyses resulted in themes and design principles linked to constructs from social, cognitive, and self-determination theories.

RESULTS

Hemodialysis patients want an informatics intervention for IDH prevention that collapses distance between patients, peers, and family; harnesses patients' strength of character and resolve in all parts of their life; respects and supports patients' individual needs, preferences, and choices; and links "feeling better on dialysis" to becoming more involved in IDH prevention. Related design principles included designing for: depth of interpersonal connections; positivity; individual choice and initiative; and comprehension of connections and possible actions.

DISCUSSION

Findings advance the design of informatics interventions by presenting design requirements for outpatient safety and addressing key design opportunities for informatics to support patient involvement; these include incorporation of behavior change theories. Results also demonstrate the meaning of design choices for hemodialysis patients in the context of their experiences; this may have applicability to other populations with serious illnesses.

CONCLUSION

The resulting patient-facing informatics intervention will be evaluated in a pragmatic cluster-randomized controlled trial in 28 hemodialysis facilities in 4 US regions.

Prevalence of Chronic Kidney Disease Among Black Individuals in the US After Removal of the Black Race Coefficient From a Glomerular Filtration Rate Estimating Equation

This cross-sectional study examines whether removal of the Black race coefficient from a glomerular filtration rate (GFR) estimating equation is associated with a change in the estimated prevalence of chronic kidney disease (CKD) in the general Black population and among Black veterans in the US.

Angiotensin-Converting Enzyme Inhibitor or Angiotensin Receptor Blocker Use Among Hypertensive US Adults With Albuminuria

Since 2003, US hypertension guidelines have recommended ACE (angiotensin-converting enzyme) inhibitors or ARBs (angiotensin receptor blockers) as first-line antihypertensive therapy in the presence of albuminuria (urine albumin/creatinine ratio ≥300 mg/g). To examine national trends in guideline-concordant ACE inhibitor/ARB utilization, we studied adults participating in the National Health and Nutrition Examination Surveys 2001 to 2018 with hypertension (defined by self-report of high blood pressure, systolic blood pressure ≥140 mm Hg or diastolic ≥90 mm Hg, or use of antihypertensive medications). Among 20 538 included adults, the prevalence of albuminuria ≥300 mg/g was 2.8% in 2001 to 2006, 2.8% in 2007 to 2012, and 3.2% in 2013 to 2018. Among those with albuminuria ≥300 mg/g, no consistent trends were observed for the proportion receiving ACE inhibitor/ARB treatment from 2001 to 2018 among persons with diabetes, without diabetes, or overall. In 2013 to 2018, ACE inhibitor/ARB usage in the setting of albuminuria ≥300 mg/g was 55.3% (95% CI, 46.8%-63.6%) among adults with diabetes and 33.4% (95% CI, 23.1%-45.5%) among those without diabetes. Based on US population counts, these estimates represent 1.6 million adults with albuminuria ≥300 mg/g currently not receiving ACE inhibitor/ARB therapy, nearly half of whom do not have diabetes. ACE inhibitor/ARB underutilization represents a significant gap in preventive care delivery for adults with hypertension and albuminuria that has not substantially changed over time.

Population-based comparison of chronic kidney disease prevalence and risk factors among adults living in the Punjab, Northern India and the USA (2013-2015)

OBJECTIVES

India is witnessing a disturbing growth in non-communicable diseases (NCDs), including chronic kidney disease (CKD). Recently, a WHO STEPS survey was conducted in the state of Punjab, India to collect data from the adult population on NCD risk factors. We sought to compare the prevalence of CKD and its risk factors between this large state in northern India and the USA.

SETTING

Samples were drawn from both locations, Punjab, India and the USA, using multistage stratified sampling designs to collect data representative of the general population.

PARTICIPANTS

Data from 2002 participants in the Punjab survey (2014-2015) and 5057 in the USA (National Health and Nutrition Examination Survey (NHANES; 2013-2014), between the ages of 18-69 years were examined.

PRIMARY AND SECONDARY OUTCOME MEASURES

Modified Poisson regression was employed to compare prevalence between the two samples for markers of CKD and its risk factors. All analyses used sampling weights.

RESULTS

The average age in the Punjab sample was significantly lower than the USA (38.3 vs 42.5 years, p<0.0001). While smoking and obesity were higher in the USA, hypertension was much more common in Punjab (48.2% vs 33.4%, p<0.0001). Significant differences were seen in the prevalence of CKD, with lower prevalence of eGFR <60 mL/min/1.73 m² (2.0% vs 3.8%, p<0.0001), but markedly higher prevalence of albuminuria (46.7% vs 8.9%, p<0.0001) in Punjab. These differences could not be explained by traditional risk factors such as diabetes and hypertension.

CONCLUSIONS

We report a strikingly high prevalence of albuminuria in Punjab, India, compared with the USA. This requires further study and may have enormous public health implications for future burden of progressive CKD, end-stage kidney disease, morbidity, mortality and specifically for elevated risk or presence of cardiovascular disease in the northern state of Punjab, India.Funding came from the National Health Mission, Punjab, India, JST and the Centers for Disease Control and Prevention, Atlanta, Georgia, USA.

Body mass index change and estimated glomerular filtration rate decline in a middle-aged population: health check-based cohort in Japan

BACKGROUND

Obesity is a growing public health problem worldwide. We evaluated the mediators and association between changes in obesity metrics and renal outcomes in the general population.

METHODS

Using the Japanese nationwide health check-based cohort from April 2011 to March 2019, we selected individuals aged 40-74 years, with a baseline estimated glomerular filtration rate (eGFR) ≥45 mL/min/1.73 m², whose body mass index (BMI) change was assessed. The primary outcome was combined 30% decline in eGFR, eGFR <15 mL/min/1.73 m² and end-stage renal disease.

RESULTS

During 245 147 person-years' follow-up among 50 604 participants (mean eGFR, 83.7 mL/min/1.73 m²; mean BMI, 24.1 kg/m²), 645 demonstrated eGFR decline (incidence rate 2.6/1000 person-years, 95% CI: 2.4 to 2.8). We observed continued initial changes in BMI for over 6 years and a U-shaped association between BMI change and eGFR decline. Compared with 0% change in BMI, adjusted HRs for changes of -10%, -4%, 4% and 10% were 1.53 (95% CI: 1.15 to 2.04), 1.14 (95% CI: 1.01 to 1.30), 1.16 (95% CI: 1.02 to 1.32) and 1.87 (95% CI: 1.25 to 2.80), respectively. The percentage of excess risk of BMI increase (>4%) mediated by three risk factors (blood pressure, haemoglobin A1c and total cholesterol), was 13.3%.

CONCLUSION

In the middle-aged Japanese population, both, increase and decrease in BMI were associated with subsequent eGFR decline. Changes in risk factors mediated a small proportion of the association between BMI increase and eGFR decline. Our findings support the clinical significance of monitoring BMI as a renal risk factor.

Burden and Cost of Caring for US Veterans With CKD: Initial Findings From the VA Renal Information System (VA-REINS)

Kidney disease is a common, complex, costly, and life-limiting condition. Most kidney disease registries or information systems have been limited to single institutions or regions. A national US Department of Veterans Affairs (VA) Renal Information System (VA-REINS) was recently developed. We describe its creation and present key initial findings related to chronic kidney disease (CKD) without kidney replacement therapy (KRT). Data from the VA's Corporate Data Warehouse were processed and linked with national Medicare data for patients with CKD receiving KRT. Operational definitions for VA user, CKD, acute kidney injury, and kidney failure were developed. Among 7 million VA users in fiscal year 2014, CKD was identified using either a strict or liberal operational definition in 1.1 million (16.4%) and 2.5 million (36.3%) veterans, respectively. Most were identified using an estimated glomerular filtration rate laboratory phenotype, some through proteinuria assessment, and very few through International Classification of Diseases, Ninth Revision coding. The VA spent ∼$18 billion for the care of patients with CKD without KRT, most of which was for CKD stage 3, with higher per-patient costs by CKD stage. VA-REINS can be leveraged for disease surveillance, population health management, and improving the quality and value of care, thereby enhancing VA's capacity as a patient-centered learning health system for US veterans.

US Trends in Prevalence of Sleep Problems and Associations with Chronic Kidney Disease and Mortality

BACKGROUND

To better understand the relation between sleep problems and CKD, we examined temporal trends in the prevalence of self-reported sleep problems in adults in the United States and their associations with CKD and all-cause mortality.

METHODS

Using data from 27,365 adult participants in five biannual National Health and Examination Surveys (2005-2006 through 2013-2014), we studied five self-reported sleep problems-trouble sleeping, sleep disorder, nocturia (urinating ≥2 times/night), inadequate sleep (<7 hours/night), and excessive sleep (>9 hours/night)-plus a composite index. We conducted three types of analysis: temporal trends in the prevalence of each sleep measure by CKD status, using model-based standardization; cross-sectional analysis of associations between four CKD measures and each sleep measure, using logistic regression; and survival analysis of the association between each sleep measure and mortality, using Cox regression.

RESULTS

The prevalence of trouble sleeping and sleep disorder increased over the five surveys by 4% and 3%, respectively, whereas the other sleep problems remained relatively stable. All sleep problems, except inadequate sleep, were more common during the study period among adults with CKD than without CKD (40% versus 21% for nocturia; 5% versus 2% for excessive sleep; 30% versus 25% for trouble sleeping; 12% versus 8% for sleep disorder). Both eGFR <30 ml/min per 1.73 m² and albuminuria were positively associated with nocturia and excessive sleep. Excessive sleep and nocturia were also associated with higher mortality (adjusted hazard ratio for >9 versus 7-9 hours/night=1.7; 95% CI, 1.3 to 2.1; and for nocturia=1.2; 95% CI, 1.1 to 1.4).

CONCLUSIONS

The high prevalence of sleep problems among persons with CKD and their associations with mortality suggest their potential importance to clinical practice. Future work could examine the health effects of identifying and treating sleep problems in patients with CKD.

Cramping, crashing, cannulating, and clotting: a qualitative study of patients' definitions of a "bad run" on hemodialysis

BACKGROUND

Hemodialysis sessions frequently become unstable from complications such as intradialytic hypotension and untoward symptoms. Previous patient safety initiatives promote prevention of treatment complications; yet, they have placed little specific focus on avoidable session instability. A patient-centered definition of session instability grounded in patient experiences, and an understanding of patient perceptions of causes and solutions to instability, may enable such efforts.

METHODS

Twenty-five participants participated in three focus groups and/or a survey. They were purposively sampled for variation in region of residence, and sensitivity to patient well-being. Focus group recordings were analyzed using descriptive coding, in vivo coding, and thematic analysis.

RESULTS

Patients define unstable sessions ("bad runs") as those in which they experience severe discomfort or unanticipated events that interfere with their ability to receive therapy. Bad runs were characterized primarily by cramping, low blood pressure ("crashing"), cannulation-related difficulties ("bad sticks"), and clotting of the dialysis circuit or vascular access. Patients believed that cramping and crashing could be explained by both patient and clinician behavior: patient fluid consumption and providers' fluid removal goals. Patients felt that the responsibility for cannulation-related problems lay with dialysis staff, and they asked for different staff or self-cannulated as solutions. Clotting was viewed as an idiosyncratic issue with one's body, and perceived solutions were clinician-driven. Patients expressed concern about "bad runs" on their ability to achieve fluid balance.

CONCLUSIONS

Findings point to novel priorities for efforts to enhance hemodialysis session stability, and areas in which patients can be supported to become involved in such efforts.

Elevated serum anion gap in adults with moderate chronic kidney disease increases risk for progression to end-stage renal disease

Acid retention associated with reduced glomerular filtration rate (GFR) exacerbates nephropathy progression in partial nephrectomy models of chronic kidney disease (CKD) and might be reflected in patients with CKD with reduced estimated GFR (eGFR) by increased anion gap (AG). We explored the presence of AG and its association with CKD in 14,924 adults aged ≥20 yr with eGFR ≥ 15 ml·min-1·1.73 m-2 enrolled in the National Health and Nutrition Examination Survey III, 1988-1994, using multivariable regression analysis. The model was adjusted for sociodemographic characteristics, diabetes, and hypertension. We further examined the association between AG and incident end-stage renal disease (ESRD) using frailty models, adjusting for demographics, clinical factors, body mass index, serum albumin, bicarbonate, eGFR, and urinary albumin-to-creatinine ratio by following 558 adults with moderate CKD for 12 yr via the United States Renal Data System. Laboratory measures determined AG using the traditional, albumin-corrected, and full AG definitions. Individuals with moderate CKD (eGFR: 30-59 ml·min-1·1.73 m-2) had a greater AG than those with eGFR ≥ 60 ml·min-1·1.73 m-2 in multivariable regression analysis with adjustment for covariates. We found a graded relationship between the adjusted mean for all three definitions of AG and eGFR categories (P trend < 0.0001). During followup, 9.2% of adults with moderate CKD developed ESRD. Those with AG in the highest tertile had a higher risk of ESRD after adjusting for covariates in a frailty model [relative hazard (95% confidence interval) for traditional AG: 1.76 (1.16-2.32)] compared with those in the middle tertile. The data suggest that high AG, even after adjusting for serum bicarbonate, is a contributing acid-base mechanism to CKD progression in adults with moderate chronic kidney disease.

Poor accordance to a DASH dietary pattern is associated with higher risk of ESRD among adults with moderate chronic kidney disease and hypertension

The Dietary Approaches to Stop Hypertension (DASH) diet lowers blood pressure, an important risk factor for chronic kidney disease (CKD) and end-stage renal disease (ESRD). However, it is unclear whether adherence to a DASH diet confers protection against future ESRD, especially among those with pre-existing CKD and hypertension. We examined whether a DASH diet is associated with lower risk of ESRD among 1,110 adults aged ≥ 20 years with hypertension and CKD (estimated glomerular filtration rate, eGFR 30-59 ml/min/1.73 m²) enrolled in the National Health and Nutrition Examination Survey (1988-1994). Baseline DASH diet accordance score was assessed using a 24-hour dietary recall questionnaire. ESRD was ascertained by linkage to the U.S. Renal Data System registry. We used the Fine-Gray competing risks method to estimate the relative hazard (RH) for ESRD after adjusting for sociodemographics, clinical and nutritional factors, eGFR, and albuminuria. Over a median follow-up of 7.8 years, 18.4% of subjects developed ESRD. Compared to the highest quintile of DASH diet accordance, there was a greater risk of ESRD among subjects in quintiles 1 (RH=1.7; 95% CI 1.1-2.7) and 2 (RH 2.2; 95% CI 1.1-4.1). Significant interactions were observed with diabetes status and race/ethnicity, with the strongest association between DASH diet adherence and ESRD risk observed in individuals with diabetes and in non-Hispanic blacks. Low accordance to a DASH diet is associated with greater risk of ESRD in adults with moderate CKD and hypertension, particularly in non-Hispanic blacks and persons with diabetes.

County-level air quality and the prevalence of diagnosed chronic kidney disease in the US Medicare population

BACKGROUND

Considerable geographic variation exists in the prevalence of chronic kidney disease across the United States. While some of this variability can be explained by differences in patient-level risk factors, substantial variability still exists. We hypothesize this may be due to understudied environmental exposures such as air pollution.

METHODS

Using data on 1.1 million persons from the 2010 5% Medicare sample and Environmental Protection Agency air-quality measures, we examined the association between county-level particulate matter ≤2.5 μm (PM2.5) and the prevalence of diagnosed CKD, based on claims. Modified Poisson regression was used to estimate associations (prevalence ratios [PR]) between county PM2.5 concentration and individual-level diagnosis of CKD, adjusting for age, sex, race/ethnicity, hypertension, diabetes, and urban/rural status.

RESULTS

Prevalence of diagnosed CKD ranged from 0% to 60% by county (median = 16%). As a continuous variable, PM2.5 concentration shows adjusted PR of diagnosed CKD = 1.03 (95% CI: 1.02-1.05; p<0.001) for an increase of 4 μg/m3 in PM2.5. Investigation by quartiles shows an elevated prevalence of diagnosed CKD for mean PM2.5 levels ≥14 μg/m3 (highest quartile: PR = 1.05, 95% CI: 1.03-1.07), which is consistent with current ambient air quality standard of 12 μg/m3, but much lower than the level typically considered healthy for sensitive groups (~40 μg/m3).

CONCLUSION

A positive association was observed between county-level PM2.5 concentration and diagnosed CKD. The reliance on CKD diagnostic codes likely identified associations with the most severe CKD cases. These results can be strengthened by exploring laboratory-based diagnosis of CKD, individual measures of exposure to multiple pollutants, and more control of confounding.

Temporal Trends and Factors Associated with Medication Prescription Patterns in Peritoneal Dialysis Patients

INTRODUCTION

Patients on peritoneal dialysis (PD) suffer from a high burden of comorbidities, which are managed with multiple medications. Determinants of prescription patterns are largely unknown in this population. This study assesses temporal changes and factors associated with medication prescription in a nationally representative population of patients on PD under the universal coverage healthcare system in Brazil.

METHODS

Incident patients recruited in the Brazilian Peritoneal Dialysis Study (BRAZPD) from December 2004 to January 2011, stratified by prior hemodialysis (HD) treatment, were included in the analysis. Multivariable logistic regression was used to assess the association between medication prescription and socioeconomic factors. Yearly prevalent cross-sections were calculated to estimate prescription over time.

RESULTS

Medication prescription was in general higher among patients who had previously received HD, compared with those who started renal replacement therapy (RRT) directly on PD. Prescription increased from baseline to 6 months of PD therapy, particularly in those who did not previously receive HD. After accounting for patient characteristics, significant associations were found between socioeconomic factors, geographic region, and medication prescription patterns. Finally, the prescription of all cardioprotective and anemia medications and phosphate binders increased significantly over time.

CONCLUSION

In a PD population under universal coverage in a developing country, there was an increase in drug prescription during the first 6 months on PD, and a trend toward more liberal prescription of medications in later years. Independent from patient characteristics and comorbidities, socioeconomic factors influenced drug prescriptions that likely impact patient outcome, calling for public health action to decrease potential inequities in management of comorbidities in PD patients.

Mortality risk of chronic kidney disease: A comparison between the adult populations in urban China and the United States

BACKGROUND

Chronic kidney disease (CKD) is a risk factor for all-cause mortality in the United States, but the evidence from China is limited. We investigate whether prognosis of CKD (mortality) differs between the two countries. In particular, we sought to compare the strength of association between CKD stage and all-cause mortality, by country.

METHODS

Mortality-linked data from China National Survey of Chronic Kidney Disease (urban population, n = 25,269) and US NHANES (2005-2010, n = 15,209) for adults >20 years old were analyzed. The Chinese cohort was followed until Dec 31, 2013, while the NHANES cohort until Dec 31, 2011. CKD was defined by eGFR <60ml/min/1.73m2 or albuminuria (defined as ACR ≥30mg/g). Weighted Cox models were used to evaluate the association between the two CKD indicators and mortality. Both stratified and combined models (with country interactions) were explored.

RESULTS

The Chinese sample had a lower proportion of eGFR<60 ml/min/1.73m2 (3.7% vs. 6.9%) and albuminuria (7.6% vs. 9.0%), compared to the US. Higher rates of mortality were observed with higher stages of CKD in both countries. HRs for mortality in the more advanced CKD categories reached 2.18 (1.14-4.15) in China and 1.66 (1.18-2.32) in the US in the absence of albuminuria, and 2.30 (1.13-4.68) and 3.04 (2.33-3.96) in the presence of albuminuria. No significant interactions were detected between country and these categories.

CONCLUSION

The association between albuminuria and reduced eGFR and all-cause mortality was similar in both countries, with albuminuria being associated with the larger effect size compared to lower eGFR.

Effect of Moderate-Intensity Exercise Training on Peak Oxygen Consumption in Patients With Hypertrophic Cardiomyopathy: A Randomized Clinical Trial

IMPORTANCE

Formulating exercise recommendations for patients with hypertrophic cardiomyopathy is challenging because of concern about triggering ventricular arrhythmias and because a clinical benefit has not been previously established in this population.

OBJECTIVE

To determine whether moderate-intensity exercise training improves exercise capacity in adults with hypertrophic cardiomyopathy.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial involving 136 patients with hypertrophic cardiomyopathy was conducted between April 2010 and October 2015 at 2 academic medical centers in the United States (University of Michigan Health System and Stanford University Medical Center). Date of last follow-up was November 2016.

INTERVENTIONS

Participants were randomly assigned to 16 weeks of moderate-intensity exercise training (n = 67) or usual activity (n = 69).

MAIN OUTCOMES AND MEASURES

The primary outcome measure was change in peak oxygen consumption from baseline to 16 weeks.

RESULTS

Among the 136 randomized participants (mean age, 50.4 [SD, 13.3] years; 42% women), 113 (83%) completed the study. At 16 weeks, the change in mean peak oxygen consumption was +1.35 (95% CI, 0.50 to 2.21) mL/kg/min among participants in the exercise training group and +0.08 (95% CI, -0.62 to 0.79) mL/kg/min among participants in the usual-activity group (between-group difference, 1.27 [95% CI, 0.17 to 2.37]; P = .02). There were no occurrences of sustained ventricular arrhythmia, sudden cardiac arrest, appropriate defibrillator shock, or death in either group.

CONCLUSIONS AND RELEVANCE

In this preliminary study involving patients with hypertrophic cardiomyopathy, moderate-intensity exercise compared with usual activity resulted in a statistically significant but small increase in exercise capacity at 16 weeks. Further research is needed to understand the clinical importance of this finding in patients with hypertrophic cardiomyopathy, as well as the long-term safety of exercise at moderate and higher levels of intensity.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01127061.

Genome sequencing elucidates Sardinian genetic architecture and augments association analyses for lipid and blood inflammatory markers

We report ∼17.6 million genetic variants from whole-genome sequencing of 2,120 Sardinians; 22% are absent from previous sequencing-based compilations and are enriched for predicted functional consequences. Furthermore, ∼76,000 variants common in our sample (frequency >5%) are rare elsewhere (<0.5% in the 1000 Genomes Project). We assessed the impact of these variants on circulating lipid levels and five inflammatory biomarkers. We observe 14 signals, including 2 major new loci, for lipid levels and 19 signals, including 2 new loci, for inflammatory markers. The new associations would have been missed in analyses based on 1000 Genomes Project data, underlining the advantages of large-scale sequencing in this founder population.

Ancestry estimation and control of population stratification for sequence-based association studies

Estimating individual ancestry is important in genetic association studies where population structure leads to false positive signals, although assigning ancestry remains challenging with targeted sequence data. We propose a new method for the accurate estimation of individual genetic ancestry, based on direct analysis of off-target sequence reads, and implement our method in the publicly available LASER software. We validate the method using simulated and empirical data and show that the method can accurately infer worldwide continental ancestry when used with sequencing data sets with whole-genome shotgun coverage as low as 0.001×. For estimates of fine-scale ancestry within Europe, the method performs well with coverage of 0.1×. On an even finer scale, the method improves discrimination between exome-sequenced study participants originating from different provinces within Finland. Finally, we show that our method can be used to improve case-control matching in genetic association studies and to reduce the risk of spurious findings due to population structure.

Prevalence of CKD and its relationship to eGFR-related genetic loci and clinical risk factors in the SardiNIA study cohort

The prevalence of CKD and of renal failure vary worldwide, yet parallel increases in leading risk factors explain only part of the differential prevalence. We measured CKD prevalence and eGFR, and their relationship with traditional and additional risk factors, in a Sardinian founder population cohort. The eGFR was calculated using equations from the CKD Epidemiology Collaboration and Modification of Diet in Renal Disease studies. With use of the Kidney Disease Improving Global Outcomes guidelines, a cross-sectional analysis of 4842 individuals showed that CKD prevalence was 15.1%, including 3.6% of patients in the high-risk and 0.46% in the very-high-risk categories. Longitudinal analyses performed on 4074 of these individuals who completed three visits with an average follow-up of 7 years revealed that, consistent with other populations, average eGFR slope was -0.79 ml/min per 1.73 m(2) per year, but 11.4% of the participants had an eGFR decline >2.3 ml/min per 1.73 m(2) per year (fast decline). A genetic score was generated from 13 reported eGFR- and CKD-related loci, and univariable and multivariable analyses were applied to assess the relationship between clinical, ultrasonographic, and genetic variables with three outcomes: CKD, change in eGFR, and fast eGFR decline. Genetic risk score, older age, and female sex independently correlated with each outcome. Diabetes was associated with CKD prevalence, whereas hypertension and hyperuricemia correlated more strongly with fast eGFR decline. Diabetes, hypertension, hyperuricemia, and high baseline eGFR were associated with a decline of eGFR. Along with differential health practices, population variations in this spectrum of risk factors probably contributes to the variable CKD prevalence worldwide.

Dialysis Outcomes and Practice Patterns Study estimate of patient life-years attributable to modifiable haemodialysis practices in Sweden

OBJECTIVE

To examine the association of adherence to Swedish Society of Nephrology guidelines on haemodialysis treatment and patient outcomes in Sweden.

MATERIAL AND METHODS

A prevalent cross-sectional sample of Swedish haemodialysis patients was obtained from the Dialysis Outcomes and Practice Patterns Study (DOPPS II, 2002-2004), an international, prospective, cohort study that investigates relationships between patient outcomes and haemodialysis practices. The sample was used to estimate life-years gained through adherence to six potentially modifiable practice patterns: dialysis dose, anaemia, serum phosphorus, serum calcium, serum albumin and catheter use for vascular access. Cox proportional hazards regression models were used to calculate the relative risk of mortality for all patients outside each guideline.

RESULTS

The practices resulting in the largest patient-year gains were increasing patient albumin above 35 g/l and reducing facility catheter use to below 10%. Compliance with the albumin target levels could save approximately 441 life-years (or as many as 904 years). Similarly, by 2010, 409 life-years (or as many as 837 years) could be saved if vascular access target levels were achieved.

CONCLUSION

The analysis suggests potential opportunities to improve haemodialysis patient care in Sweden. Estimates of life-years saved may serve as motivation for the improvement of patient care through adherence to published guidelines supported by international data from the DOPPS.

Key comorbid conditions that are predictive of survival among hemodialysis patients

BACKGROUND AND OBJECTIVES

Abstracting information about comorbid illnesses from the medical record can be time-consuming, particularly when a large number of conditions are under consideration. We sought to determine which conditions are most prognostic and whether comorbidity continues to contribute to a survival model once laboratory and clinical parameters have been accounted for.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Comorbidity data were abstracted from the medical records of Dialysis Outcomes and Practice Pattern Study (DOPPS) I, II, and III participants using a standardized questionnaire. Models that were composed of different combinations of comorbid conditions and case-mix factors were compared for explained variance (R(2)) and discrimination (c statistic).

RESULTS

Seventeen comorbid conditions account for 96% of the total explained variance that would result if 45 comorbidities that were expected to be predictive of survival were added to a demographics-adjusted survival model. These conditions together had more discriminatory power (c statistic 0.67) than age alone (0.63) or serum albumin (0.60) and were equivalent to a combination of routine laboratory and clinical parameters (0.67). The strength of association of the individual comorbidities lessened when laboratory/clinical parameters were added, but all remained significant. The total R(2) of a model adjusted for demographics and laboratory/clinical parameters increased from 0.13 to 0.17 upon addition of comorbidity.

CONCLUSIONS

A relatively small list of comorbid conditions provides equivalent discrimination and explained variance for survival as a more extensive characterization of comorbidity. Comorbidity adds to the survival model a modest amount of independent prognostic information that cannot be substituted by clinical/laboratory parameters.

[DOPPS estimate of guideline impact on survival in hemodialysis in Italy]

Knowing the relative risk (RR) of mortality associated with being outside the guideline targets and the percentage of patients in this situation, it is possible to estimate the number of patient life years that could be gained from adhering to guideline recommendations. We used a prevalent cross-sectional sample of 576 Italian patients from the Dialysis Outcomes and Practices Patterns Study (DOPPS) phase II (2002-2004) to determine the percentage of patients who failed to meet the Italian Society of Nephrology's targets for dialysis dose (spKt/V ≥ 1.3), anemia management (hemoglobin ≥ 11 g/dL), and mineral metabolism (serum calcium and phosphorus: ≤ 2.6 and ≤ 1.8 mmol/L, respectively), and the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (K/DOQI) targets for nutritional status (serum albumin ≥ 4 g/dL) and vascular access (facility catheter use ≤ 10%). We used a larger random sample of DOPPS patients to establish the adjusted RRs of mortality associated with the 6 examined targets. The percentage of patients outside the targets and the adjusted RRs were 34% and 1.12 for dialysis dose, 37.7% and 1.20 for anemia management, 40.8% and 1.14 for phosphorus, 14.4% and 1.22 for calcium, 62.5% and 1.46 for albumin, and 40.1% and 1.20 for facility catheter use. The adjusted sum of life years potentially gained by complete adherence to all 6 guidelines was 25,156 over a period of 5 years (2006-2010); a more conservative estimate, modeling life years potentially gained by bringing half of all patients outside targets within them, was 13,382. In conclusion, this analysis suggests opportunities to improve hemodialysis patient care in Italy. The magnitude of potential savings in life years should encourage greater adherence to guidelines and practices that are significantly associated with better survival.

Outcome and prognosis factors in HIV-infected hemodialysis patients

HIV-infected patients who are on hemodialysis have a worse prognosis than noninfected patients who are on hemodialysis. Their outcome in the highly active antiretroviral therapy (HAART) era remains unclear. Outcomes in patients who were enrolled in the French Dialysis in HIV/AIDS (DIVA) cohort were determined in a 2-yr prospective follow-up. All HIV-infected patients who were on hemodialysis in France on January 1, 2002, were included and followed prospectively until January 1, 2004. Patients' survival was examined by Kaplan-Meier method, and mortality risk factors were examined using uni- and multicovariate analyses. Survival was compared with that of 584 hemodialysis patients who did not have HIV or diabetes and were enrolled in the French Dialysis Outcomes and Practice Patterns Study II (DOPPS II) in the same period (after standardization for the average age, gender, and ethnicity of the DIVA cohort). A total of 27,577 patients were receiving hemodialysis in France at the beginning of the study; 164 (0.59%) were infected with HIV, 72% were male, mean age was 44.8 +/- 10.9 yr, and 65% were black. The 2-yr survival rate was 89 +/- 2% and statistically indistinguishable from the survival of the French cohort extracted from the DOPPS II study. Significant mortality risk factors were low CD4 cell count (hazard ratio [HR] 1.4/100 CD4 cells per mm(3) lower), high viral load (HR 2.5/1 Log per ml), absence of HAART (HR 2.7), and a history of opportunistic infection (HR 3.7), the last two being independent (HR 2.6 and 3.6, respectively). Survival of HIV-infected patients who are hemodialysis has greatly improved. A prospective cohort of paired hemodialysis patients with and without HIV is required to compare better their mortality in the HAART era.

[The Dialysis Outcomes and Practice Patterns Study (DOPPS): results of the Italian cohort]

BACKGROUND

The Dialysis Outcomes and Practice Patterns Study (DOPPS) is an international prospective, longitudinal, observational study examining the relationship between dialysis unit practices and outcomes for hemodialysis (HD) patients in seven developed countries France, Germany, Italy, Spain, United Kingdom, Japan and the United States. Results of the DOPPS in Italy are the subject of this report.

METHODS

A national representative sample of 20 dialysis units (21 in Germany) was randomly selected in each of the European DOPPS countries (Euro-DOPPS). In these units, the HD in-center patients were included on a facility census, and their survival rates continuously monitored. A representative sample of incident (269 in Italy, 1553 in the Euro-DOPPS) and prevalent (600 in Italy, 3038 in the Euro-DOPPS) patients was randomly selected from the census for more detailed longitudinal investigation with regard to medical history, laboratory values and hospital admission.

RESULTS

Comparing the Italian and Euro-DOPPS cohorts we found comparable mean age for prevalent patients (61.4 vs. 59.5 yrs), but incident patients were older in Italy. Italian prevalent patients had less cardiovascular disease, more satisfactory nutritional status and more frequent use of native vascular access. These data were associated with a comparable mortality (15.7 vs. 16.3 deaths/100 patient yrs), but morbidity was lower in Italy. Kt/V levels were comparable in the two cohorts (1.32 vs. 1.37), but 35% of Italian patients showed a Kt/V below the recommended target. Moreover, hemoglobin levels were below 11 g/dL in 60% of Italian patients.

CONCLUSIONS

The DOPPS results bring to light several positive aspects and the opportunity for further possible improvements for Italian patients, but at the same time highlight some critical points that could represent a risk for dialysis quality.