Association of Primary Versus Rotating Nephrologist Model of Care in Hemodialysis Programs with Patient Outcomes

SIGNIFICANCE STATEMENT

Nephrologist staffing models for patients receiving hemodialysis vary widely. Patients may be cared for continuously by a single primary nephrologist or by a group of nephrologists on a rotating basis. It remains unclear whether these differing care models influence clinical outcomes. In this population-based cohort study of more than 14,000 incident patients on maintenance hemodialysis from Ontario, Canada, we found no difference in mortality, kidney transplantation, home dialysis initiation, hospitalizations, or emergency department visits when care was provided by a single primary nephrologist or a rotating group of nephrologists. These results suggest that primary nephrologist models do not necessarily improve objective clinical outcomes, providing reassurance to patients, providers, and administrators that both models are acceptable options.

Patient Perspectives of Skeletal Muscle Cramping in Dialysis: A Focus Group Study

Key Points

This first step demonstrated content validity for a patient-reported outcome measure for skeletal muscle cramping in dialysis. This work lays the foundation for developing a patient-reported outcome measure for regulatory use to assess skeletal muscle cramping in people receiving dialysis.

Background

Skeletal muscle cramping is a common, painful, and debilitating symptom experienced by people receiving dialysis. Neither a standardized, patient-endorsed definition of skeletal muscle cramping nor full understanding of patients' perspectives of skeletal muscle cramping exist. We conducted focus groups, within a Kidney Health Initiative (KHI) project, to elicit skeletal muscle cramping experiences of people receiving dialysis as the basis for patient-reported outcome measure (PROM) development.

Methods

Eligible participants (English-speaking adults aged 18–85 years treated by dialysis and a skeletal muscle cramping episode within 30 days) were purposively recruited from a panel (L&E Research) of people receiving dialysis at home or in-center. Standard qualitative methods were used to conduct virtual 90-minute sessions discussing the following: skeletal muscle cramping clinical characteristics, participants' skeletal muscle cramping experiences, and feedback on a draft skeletal muscle cramping definition and a patient-facing conceptual model developed by the KHI project workgroup. We used qualitative thematic analysis.

Results

There were 20 diverse participants in three focus groups. Universally experienced skeletal muscle cramping attributes differed by dialysis setting in onset, worst pain rating, duration, and timing. Variably experienced attributes (applied to home and in-center dialysis) were gross and fine motor effect, sleep disruption, mood-related themes of fear, and annoyance/frustration/irritability. Avoidance/adaptive behaviors included reluctance or avoiding movement, adjusting what they ate or drink (e.g. , yellow mustard, pickles, pickle juice, and tonic water), heat application, massage, and cannabidiol use. The skeletal muscle cramping definition was endorsed, and insightful suggestions for conceptual model were collected.

Conclusions

This qualitative study of in-center and home patients' skeletal muscle cramping experiences identified universally and variably experienced attributes. The patient-endorsed skeletal muscle cramping definition can serve as a standard for assessment. These results provide the foundation to develop a PROM for regulatory use with people receiving maintenance dialysis who experience skeletal muscle cramping.

Protein Carbamylation and the Risk of ESKD in Patients with CKD

SIGNIFICANCE STATEMENT

Protein carbamylation, a nonenzymatic post-translational protein modification partially driven by elevated blood urea levels, associates with mortality and adverse outcomes in patients with ESKD on dialysis. However, little is known about carbamylation's relationship to clinical outcomes in the much larger population of patients with earlier stages of CKD. In this prospective observational cohort study of 3111 individuals with CKD stages 2-4, higher levels of carbamylated albumin (a marker of protein carbamylation burden) were associated with a greater risk of developing ESKD and other significant adverse clinical outcomes. These findings indicate that protein carbamylation is an independent risk factor for CKD progression. They suggest that further study of therapeutic interventions to prevent or reduce carbamylation is warranted.

BACKGROUND

Protein carbamylation, a post-translational protein modification partially driven by elevated blood urea levels, associates with adverse outcomes in ESKD. However, little is known about protein carbamylation's relationship to clinical outcomes in the much larger population of patients with earlier stages of CKD.

METHODS

To test associations between protein carbamylation and the primary outcome of progression to ESKD, we measured baseline serum carbamylated albumin (C-Alb) in 3111 patients with CKD stages 2-4 enrolled in the prospective observational Chronic Renal Insufficiency Cohort study.

RESULTS

The mean age of study participants was 59 years (SD 10.8); 1358 (43.7%) were female, and 1334 (42.9%) were White. The mean eGFR at the time of C-Alb assessment was 41.8 (16.4) ml/minute per 1.73 m 2 , and the median C-Alb value was 7.8 mmol/mol (interquartile range, 5.8-10.7). During an average of 7.9 (4.1) years of follow-up, 981 (31.5%) individuals developed ESKD. In multivariable adjusted Cox models, higher C-Alb (continuous or quartiles) independently associated with an increased risk of ESKD. For example, compared with quartile 1 (C-Alb ≤5.80 mmol/mol), those in quartile 4 (C-Alb >10.71 mmol/mol) had a greater risk for ESKD (adjusted hazard ratio, 2.29; 95% confidence interval, 1.75 to 2.99), and the ESKD incidence rate per 1000 patient-years increased from 15.7 to 88.5 from quartile 1 to quartile 4. The results remained significant across numerous subgroup analyses, when treating death as a competing event, and using different assessments of eGFR.

CONCLUSIONS

Having a higher level of protein carbamylation as measured by circulating C-Alb is an independent risk factor for ESKD in individuals with CKD stages 2-4.

PODCAST

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Predictive Models for Kidney Recovery and Death in Patients Continuing Dialysis as Outpatients after Starting in Hospital

BACKGROUND

For patients who initiate dialysis during a hospital admission and continue to require dialysis after discharge, outpatient dialysis management could be improved by better understanding the future likelihood of recovery to dialysis independence and the competing risk of death.

METHODS

We derived and validated linked models to predict the subsequent recovery to dialysis independence and death within 1 year of hospital discharge using a population-based cohort of 7657 patients in Ontario, Canada. Predictive variables included age, comorbidities, length of hospital admission, intensive care status, discharge disposition, and prehospital admission eGFR and random urine albumin-to-creatinine ratio. Models were externally validated in 1503 contemporaneous patients from Alberta, Canada. Both models were created using proportional hazards survival analysis, with the "Recovery Model" using Fine-Gray methods. Probabilities generated from both models were used to develop 16 distinct "Recovery and Death in Outpatients" (ReDO) risk groups.

RESULTS

ReDO risk groups in the derivation group had significantly distinct 1-year probabilities for recovery to dialysis independence (first quartile: 10% [95% confidence interval (CI), 9% to 11%]; fourth quartile: 73% [70% to 77%]) and for death (first quartile: 12% [11% to 13%]; fourth quartile: 46% [43% to 50%]). In the validation group, model discrimination was modest (c-statistics [95% CI] for recovery and for death quartiles were 0.70 [0.67 to 0.73] and 0.66 [0.62 to 0.69], respectively), but calibration was excellent (integrated calibration index [95% CI] was 7% [5% to 9%] and 4% [2% to 6%] for recovery and death, respectively).

CONCLUSIONS

The ReDO models generated accurate expected probabilities of recovery to dialysis independence and death in patients who continued outpatient dialysis after initiating dialysis in hospital. An online tool on the basis of the models is available at https://qxmd.com/calculate/calculator_874 .

Inclement Weather and Risk of Missing Scheduled Hemodialysis Appointments among Patients with Kidney Failure

BACKGROUND

Nonadherence to hemodialysis appointments could potentially result in health complications that can influence morbidity and mortality. We examined the association between different types of inclement weather and hemodialysis appointment adherence.

METHODS

We analyzed health records of 60,135 patients with kidney failure who received in-center hemodialysis treatment at Fresenius Kidney Care clinics across the Northeastern US counties during 2001-2019. County-level daily meteorological data on rainfall, hurricane and tropical storm events, snowfall, snow depth, and wind speed were extracted using National Oceanic and Atmosphere Agency data sources. A time-stratified case-crossover study design with conditional Poisson regression was used to estimate the effect of inclement weather exposures within the Northeastern US region. We applied a distributed lag nonlinear model framework to evaluate the delayed effect of inclement weather for up to 1 week.

RESULTS

We observed positive associations between inclement weather and missed appointment (rainfall, hurricane and tropical storm, snowfall, snow depth, and wind advisory) when compared with noninclement weather days. The risk of missed appointments was most pronounced during the day of inclement weather (lag 0) for rainfall (incidence rate ratio [RR], 1.03 per 10-mm rainfall; 95% confidence interval [CI], 1.02 to 1.03) and snowfall (RR, 1.02; 95% CI, 1.01 to 1.02). Over 7 days (lag 0-6), hurricane and tropical storm exposures were associated with a 55% higher risk of missed appointments (RR, 1.55; 95% CI, 1.22 to 1.98). Similarly, 7-day cumulative exposure to sustained wind advisories was associated with 29% higher risk (RR, 1.29; 95% CI, 1.25 to 1.31), while wind gusts advisories showed a 34% higher risk (RR, 1.34; 95% CI, 1.29 to 1.39) of missed appointment.

CONCLUSIONS

Inclement weather was associated with higher risk of missed hemodialysis appointments within the Northeastern United States. Furthermore, the association between inclement weather and missed hemodialysis appointments persisted for several days, depending on the inclement weather type.

Dynamics of Plasma Refill Rate and Intradialytic Hypotension During Hemodialysis: Retrospective Cohort Study With Causal Methodology

Key Points

Directly studying plasma refill rate (PRR) during hemodialysis (HD) can offer insight into physiologic mechanisms that change throughout HD. PRR at the start and during HD is associated with intradialytic hypotension, independent of ultrafiltration rate. A rising PRR during HD may be an early indicator of compensatory mechanisms for impending circulatory instability.

Background

Attaining the optimal balance between achieving adequate volume removal while preserving organ perfusion is a challenge for patients receiving maintenance hemodialysis (HD). Current strategies to guide ultrafiltration are inadequate.

Methods

We developed an approach to calculate the plasma refill rate (PRR) throughout HD using hematocrit and ultrafiltration data in a retrospective cohort of patients receiving maintenance HD at 17 dialysis units from January 2017 to October 2019. We studied whether (1 ) PRR is associated with traditional risk factors for hemodynamic instability using logistic regression, (2 ) low starting PRR is associated with intradialytic hypotension (IDH) using Cox proportional hazard regression, and (3 ) time-varying PRR throughout HD is associated with hypotension using marginal structural modeling.

Results

During 180,319 HD sessions among 2554 patients, PRR had high within-patient and between-patient variability. Female sex and hypoalbuminemia were associated with low PRR at multiple time points during the first hour of HD. Low starting PRR has a higher hazard of IDH, whereas high starting PRR was protective (hazard ratio [HR], 1.26, 95% confidence interval [CI], 1.18 to 1.35 versus HR, 0.79, 95% CI, 0.73 to 0.85, respectively). However, when accounting for time-varying PRR and time-varying confounders, compared with a moderate PRR, while a consistently low PRR was associated with increased risk of hypotension (odds ratio [OR], 1.09, 95% CI, 1.02 to 1.16), a consistently high PRR had a stronger association with hypotension within the next 15 minutes (OR, 1.38, 95% CI, 1.30 to 1.45).

Conclusions

We present a straightforward technique to quantify plasma refill that could easily integrate with devices that monitor hematocrit during HD. Our study highlights how examining patterns of plasma refill may enhance our understanding of circulatory changes during HD, an important step to understand how current technology might be used to improve hemodynamic instability.

Risk Stratification to Predict Renal Survival in Anti-Glomerular Basement Membrane Disease

SIGNIFICANCE STATEMENT

Most patients with anti-glomerular basement membrane (GBM) disease present with rapidly progressive glomerulonephritis, and more than half develop ESKD. Currently, no tools are available to aid in the prognostication or management of this rare disease. In one of the largest assembled cohorts of patients with anti-GBM disease (with 174 patients included in the final analysis), the authors demonstrated that the renal risk score for ANCA-associated vasculitis is transferable to anti-GBM disease and the renal histology is strongly predictive of renal survival and recovery. Stratifying patients according to the percentage of normal glomeruli in the kidney biopsy and the need for RRT at the time of diagnosis improves outcome prediction. Such stratification may assist in the management of anti-GBM disease.

BACKGROUND

Prospective randomized trials investigating treatments and outcomes in anti-glomerular basement membrane (anti-GBM) disease are sparse, and validated tools to aid prognostication or management are lacking.

METHODS

In a retrospective, multicenter, international cohort study, we investigated clinical and histologic parameters predicting kidney outcome and sought to identify patients who benefit from rescue immunosuppressive therapy. We also explored applying the concept of the renal risk score (RRS), currently used to predict renal outcomes in ANCA-associated vasculitis, to anti-GBM disease.

RESULTS

The final analysis included 174 patients (out of a total of 191). Using Cox and Kaplan-Meier methods, we found that the RRS was a strong predictor for ESKD. The 36-month renal survival was 100%, 62.4%, and 20.7% in the low-risk, moderate-risk, and high-risk groups, respectively. The need for renal replacement therapy (RRT) at diagnosis and the percentage of normal glomeruli in the biopsy were independent predictors of ESKD. The best predictor for renal recovery was the percentage of normal glomeruli, with a cut point of 10% normal glomeruli providing good stratification. A model with the predictors RRT and normal glomeruli ( N ) achieved superior discrimination for significant differences in renal survival. Dividing patients into four risk groups led to a 36-month renal survival of 96.4% (no RRT, N ≥10%), 74.0% (no RRT, N <10%), 42.3% (RRT, N ≥10%), and 14.1% (RRT, N <10%), respectively.

CONCLUSIONS

These findings demonstrate that the RRS concept is transferrable to anti-GBM disease. Stratifying patients according to the need for RRT at diagnosis and renal histology improves prediction, highlighting the importance of normal glomeruli. Such stratification may assist in the management of anti-GBM disease.

PODCAST

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Mortality Risk of Patients Treated in Dialysis Facilities with Payment Reductions under ESRD Quality Incentive Program

BACKGROUND

The Centers for Medicare & Medicaid Services End-Stage Renal Disease Quality Incentive Program (ESRD QIP) measures quality of care delivered by dialysis facilities and imposes Medicare payment reductions for quality lapses. We assessed the association between payment reductions and patient mortality, a quality indicator not included in the ESRD QIP measure set.

METHODS

Association between mortality and ESRD QIP facility payment reduction based on the year of performance was expressed as the unadjusted rate and patient case-mix-adjusted hazard ratio. We also measured association between mortality and 1-year changes in payment reductions. Retrospective patient cohorts were defined by their treating dialysis facility on the first day of each year (2010-2018).

RESULTS

Facility performance resulted in payment reductions for 5%-42% of dialysis facilities over the 9 study years. Patients experienced progressively higher mortality at each payment reduction level. Across all years, unadjusted mortality was 17.3, 18.1, 18.9, 20.3, and 23.9 deaths per 100 patient-years for patients in facilities that received 0%, 0.5%, 1%, 1.5%, and 2% payment reductions, respectively. The adjusted hazard ratio showed a similar stepwise pattern by the level of payment reduction: 1.0 (reference), 1.08 (95% confidence interval [CI], 1.07 to 1.09), 1.15 (95% CI, 1.13 to 1.16), 1.19 (95% CI, 1.16 to 1.21), and 1.34 (95% CI, 1.29 to 1.39). Strength of the association increased from 2010 to 2016. Patients treated in facilities that improved over 1 year generally experienced lower mortality; patients in facilities that performed worse on ESRD QIP measures generally experienced higher mortality.

CONCLUSIONS

Patient mortality was associated with ESRD QIP facility payment reductions in dose-response and temporal patterns.

The ASCENT Intervention to Improve Access and Reduce Racial Inequalities in Kidney Waitlisting: A Randomized, Effectiveness-Implementation Trial

BACKGROUND

The US kidney allocation system (KAS) changed in 2014, but dialysis facility staff (including nephrologists, social workers, nurse managers, and facility administrators) had low awareness of how this policy change could affect their patients' access to transplant. We assessed the effectiveness of a multicomponent and multilevel educational and outreach intervention targeting US dialysis facilities with low waitlisting, with a goal of increasing waitlisting and reducing Black versus White racial disparities in waitlisting.

METHODS

The Allocation System Changes for Equity in Kidney Transplantation (ASCENT) study was a cluster-randomized, pragmatic, multilevel, effectiveness-implementation trial including 655 US dialysis facilities with low waitlisting, randomized to receive either the ASCENT intervention (a performance feedback report, a webinar, and staff and patient educational videos) or an educational brochure. Absolute and relative differences in coprimary outcomes (1-year waitlisting and racial differences in waitlisting) were reported among incident and prevalent patients.

RESULTS

Among 56,332 prevalent patients, 1-year waitlisting decreased for patients in control facilities (2.72%-2.56%) and remained the same for patients in intervention facilities (2.68%-2.75%). However, the proportion of prevalent Black patients waitlisted in the ASCENT interventions increased from baseline to 1 year (2.52%-2.78%), whereas it remained the same for White patients in the ASCENT intervention facilities (2.66%-2.69%). Among incident patients in ASCENT facilities, 1-year waitlisting increased among Black patients (from 0.87% to 1.07%) but declined among White patients (from 1.54% to 1.27%). Significant racial disparities in waitlisting were observed at baseline, with incident Black patients in ASCENT facilities less likely to waitlist compared with White patients (adjusted odds ratio [aOR], 0.56; 95% confidence interval [CI], 0.35 to 0.92), but 1 year after the intervention, this racial disparity was attenuated (aOR, 0.84; 95% CI, 0.49 to 1.42).

CONCLUSIONS

The ASCENT intervention may have a small effect on extending the reach of the new KAS policy by attenuating racial disparities in waitlisting among a population of US dialysis facilities with low waitlisting.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

National Institutes of Health ( NCT02879812 ).

PODCAST

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Risk Amplifiers for Vascular Disease and CKD in South Asians: When Intrinsic β-Cell Dysfunction Meets a High-Carbohydrate Diet

South Asians, comprising almost one fourth of the world population, are at higher risk of type 2 diabetes mellitus, hypertension, cardiovascular disease, and CKD compared with other ethnic groups. This has major public health implications in South Asia and in other parts of the world to where South Asians have immigrated. The interplay of various modifiable and nonmodifiable risk factors confers this risk. Traditional models of cardiometabolic disease progression and CKD evaluation may not be applicable in this population with a unique genetic predisposition and phenotype. A wider understanding of dietary and lifestyle influences, genetic and metabolic risk factors, and the pitfalls of conventional equations estimating kidney function in this population are required in providing care for kidney diseases. Targeted screening of this population for metabolic and vascular risk factors and individualized management plan for disease management may be necessary. Addressing unhealthy dietary patterns, promoting physical activity, and medication management that adheres to cultural factors are crucial steps to mitigate the risk of cardiovascular disease and CKD in this population. In South Asian countries, a large rural and urban community-based multipronged approach using polypills and community health workers to decrease the incidence of these diseases may be cost-effective.