Use of incremental peritoneal dialysis: impact on clinical outcomes and quality of life measure

BACKGROUND

Incremental peritoneal dialysis (PD) can be defined as a PD prescription that is less than the standard, full dose prescription and is typically used for patients initiating PD with residual kidney function. It has been suggested that use of incremental peritoneal dialysis may help preserve residual kidney function and may offer better quality of life due to the lower treatment burden, however published evidence is limited. In this study we assessed the associations between incremental peritoneal dialysis use and both clinical outcomes and quality of life measures in a large cohort of incident peritoneal dialysis patients in the US.

METHODS

We considered adult patients initiating peritoneal dialysis between 31 July, 2015 and 31 May, 2019 within a single dialysis organization. Patients with body weight < 40 kg, amputation, or an estimated glomerular filtration rate > 20 mL/min during the first 4 weeks on peritoneal dialysis were excluded. Patients were assigned to exposure groups based on peritoneal dialysis prescription during dialysis weeks 5-8. Incremental peritoneal dialysis was defined by treatment frequency, number of exchanges/day, and exchange volume (for continuous ambulatory peritoneal dialysis patients) or by treatment frequency and presence/absence of last fill (for automated peritoneal dialysis patients). Analyses were performed separately for continuous ambulatory peritoneal dialysis and automated peritoneal dialysis. For each analysis, incremental peritoneal dialysis patients were propensity score matched to eligible full-dose peritoneal dialysis patients. Patients were followed for a maximum of 12 months until censoring for loss to follow-up or study end. Outcomes were compared using Poisson models (mortality, hospitalization, peritoneal dialysis discontinuation), linear mixed models (estimated glomerular filtration rate), and paired t tests (KDQOL domain scores).

RESULTS

Among continuous ambulatory peritoneal dialysis patients, compared to full-dose peritoneal dialysis, incremental peritoneal dialysis use was associated with better KDQOL scores on 3 domains: physical composite score (42.5 vs 37.7, p = 0.03), burden of kidney disease (60.2 vs 45.6, p = 0.003), effects of kidney disease (79.4 vs 72.3, p = 0.05). Hospitalization and mortality rates were numerically lower (0.77 vs 1.12 admits/pt-year, p = 0.09 and 5.0 vs 10.2 deaths/100 pt-years, p = 0.22), while no associations were found with estimated glomerular filtration rate or peritoneal dialysis discontinuation rate. Use of incremental peritoneal dialysis was not associated with any discernable effects on outcomes in automated peritoneal dialysis patients.

CONCLUSION

These results suggest that there may be benefits of using incremental PD in the context of continuous ambulatory peritoneal dialysis, particularly with respect to quality of life as a prescription strategy when initiating peritoneal dialysis. While no significant benefits of incremental peritoneal dialysis were detected among patients initiating automated peritoneal dialysis, no detrimental effects of using incremental schedules were observed for either peritoneal dialysis type.

Predicting hospitalizations for patients with chronic kidney disease

OBJECTIVES

Patients with chronic kidney disease (CKD) are at higher risk of being admitted to the hospital than the general population. Hospitalizations in patients with CKD are associated with higher medical costs and increased morbidity and mortality. Identification of patients with CKD who are at greatest risk of hospitalization may hold promise to improve clinical outcomes and enable judicious allocation of health care resources.

STUDY DESIGN

Retrospective, observational cohort study.

METHODS

Medicare Part A and Part B claims from calendar years 2017 and 2018 from 50,000 unique patients with a diagnosis of stage 3 to 5 CKD were used for this study. Data were split into training (n = 40,000) and test (n = 10,000) sets. A variety of model types were built to predict all-cause hospitalization within 90 days.

RESULTS

The final model was a gradient-boosting machine with 399 input terms. The model demonstrated good ability to discriminate (area under the curve [AUC] for the receiver operating characteristic curve = 0.73), which was stable when tested in the test set (AUC = 0.73). The positive predictive value in the test set was 0.306, 0.240, and 0.216 at the 10%, 20%, and 30% thresholds, respectively. The sensitivity in the test set was 0.288, 0.453, and 0.609 at the 10%, 20%, and 30% thresholds, respectively.

CONCLUSIONS

We developed an algorithm that uses medical claims to identify Medicare patients with CKD stages 3 to 5 who are at highest risk of being hospitalized in the near term. This algorithm could be used as a decision support tool for clinical programs focusing on management of patient populations with CKD.

Dysnatremia and risk of bloodstream infection in dialysis patients

Background

Emerging data suggest that sodium disarrays including hyponatremia are potential risk factors for infection ensuing from impairments in host immunity, which may be exacerbated by coexisting conditions (i.e. mucosal membrane and cellular edema leading to breakdown of microbial barrier function). While dysnatremia and infection-related mortality are common in dialysis patients, little is known about the association between serum sodium levels and the risk of bloodstream infection in this population.

Methods

Among 823 dialysis patients from the national Biospecimen Registry Grant Program who underwent serum sodium testing over the period January 2008–December 2014, we examined the relationship between baseline serum sodium levels and subsequent rate of bloodstream infection. Bloodstream infection events were directly ascertained using laboratory blood culture data. Associations between serum sodium level and the incidence of bloodstream infection were estimated using expanded case mix–adjusted Poisson regression models.

Results

In the overall cohort, ∼10% of all patients experienced one or more bloodstream infection events during the follow-up period. Patients with both lower sodium levels <134 mEq/l and higher sodium levels ≥140 mEq/l had higher incident rate ratios (IRRs) of bloodstream infection in expanded case mix analyses (reference 136–<138 mEq/l), with adjusted IRRs of 2.30 [95% confidence interval (CI) 1.19–4.44], 0.77 (95% CI 0.32–1.84), 1.39 (95% CI 0.78–2.47), 1.88 (95% CI 1.08–3.28) and 1.96 (95% CI 1.08–3.55) for sodium levels <134, 134–<136, 138–<140, 140–<142 and ≥142 Eq/l, respectively.

Conclusions

Both lower and higher baseline serum sodium levels were associated with a higher rate of subsequent bloodstream infections in dialysis patients. Further studies are needed to determine whether correction of dysnatremia ameliorates infection risk in this population.

Urgent-start peritoneal dialysis: Association with outcomes

The majority of end-stage kidney disease (ESKD) patients start dialysis without adequate pre-dialysis planning. Of these patients, the vast majority initiate in-centre haemodialysis using a central venous catheter (ICHD-CVC). A minority utilise urgent-start peritoneal dialysis (USPD), whereby a peritoneal dialysis catheter is placed and used for dialysis without the usual 2-4-week waiting period. In this multicentre, retrospective study of adult patients initiating dialysis during 2018, we compared outcomes among patients utilising these two dialysis initiation routes. Patients who initiated dialysis via ICHD-CVC were matched 1:1 to patients who utilised USPD on the basis of aetiology of ESKD, race, diabetes status and insurance type. Hospitalisation and mortality were evaluated from dialysis initiation through the first of death, transplant, loss to follow-up or study end (30 June 2019). Outcomes were compared using models adjusted for age and sex. A total of 717 USPD patients were matched to ICHD-CVC patients. During follow-up, USPD patients were hospitalised at a rate of 1.21 admissions/patient-year (pt-yr) versus 1.51 admissions/pt-yr for ICHD-CVC. This corresponded to a 24% lower rate of hospitalisation among USPD patients (adjusted incidence rate ratio 0.76, 95% confidence interval [CI] 0.65-0.88). Mortality rates were 0.08 and 0.11 deaths/pt-yr among USPD patients and ICHD-CVC patients, respectively (adjusted hazard ratio 0.84, 95% CI 0.62, 1.15). These findings suggest that more widespread adoption of USPD may be beneficial among patients with limited pre-dialysis planning.

Comparative Effectiveness of mRNA-Based BNT162b2 Vaccine versus Adenovirus Vector-Based Ad26.COV2.S Vaccine for Prevention of COVID-19 among Dialysis Patients

Background Studies have demonstrated that mRNA-based SARS-CoV-2 vaccines are highly effective among dialysis patients. Because individual vaccines may be differentially available or acceptable to patients, it is important to understand comparative effectiveness relative to other vaccines, such those based on adenovirus technologies.

Methods In this retrospective study, we compared the clinical effectiveness of adenovirus vector-based Ad26.COV2.S (Janssen/Johnson & Johnson) to mRNA-based BNT162b2 (Pfizer/BioNTech) in a contemporary cohort of dialysis patients. Patients who received a first BNT162b2 dose were matched 1:1 to Ad26.COV2.S recipients based on date of first vaccine receipt, US state of residence, site of dialysis care (in-center versus home), prior history of COVID-19, and propensity score. The primary outcome was the comparative rate of COVID-19 diagnoses starting in the seventh week postvaccination. In a subset of consented Ad26.COV2.S patients, blood samples were collected ≥28 days after vaccination and anti-SARS-Cov-2 immunoglobulin G antibodies were measured

Results A total of 2572 matched pairs of patients qualified for analysis. Cumulative incidence rates of COVID-19 did not differ for BNT162b2 versus Ad26.COV2.S. No differences were observed in peri-COVID-19 hospitalizations and deaths among patients receiving BNT162b2 versus Ad26.COV2.S who were diagnosed with COVID-19 during follow-up. Results were similar when excluding patients with prior history of COVID-19, in subgroup analyses restricted to patients who completed the two-dose BNT162b2 regimen, and in patients receiving in-center hemodialysis. SARS-CoV-2 antibodies were detected in 59.4% of 244 patients who received Ad26.COV2.S.

Conclusions In a large real-world cohort of dialysis patients, no difference was detected in clinical effectiveness of BNT162b2 and Ad26.COV2.S over the first 6 months postvaccination, despite an inconsistent antibody response to the latter.

Real-World Effectiveness and Immunogenicity of BNT162b2 and mRNA-1273 SARS-CoV-2 Vaccines in Patients on Hemodialysis

BACKGROUND

Patients on hemodialysis have an elevated risk for COVID-19 but were not included in efficacy trials of SARS-CoV-2 vaccines.

METHODS

We conducted a retrospective, observational study to estimate the real-world effectiveness and immunogenicity of two mRNA SARS-CoV-2 vaccines in a large, representative population of adult hemodialysis patients in the United States. In separate, parallel analyses, patients who began a vaccination series with BNT162b2 or mRNA-1273 in January and February 2021 were matched with unvaccinated patients and risk for outcomes were compared for days 1-21, 22-42, and ≥43 after first dose. In a subset of consented patients, blood samples were collected approximately 28 days after the second dose and anti-SARS-CoV-2 immunoglobulin G was measured.

RESULTS

A total of 12,169 patients received the BNT162b2 vaccine (matched with 44,377 unvaccinated controls); 23,037 patients received the mRNA-1273 vaccine (matched with 63,243 unvaccinated controls). Compared with controls, vaccinated patients' risk of being diagnosed with COVID-19 postvaccination became progressively lower during the study period (hazard ratio and 95% confidence interval for BNT162b2 was 0.21 [0.13, 0.35] and for mRNA-1273 was 0.27 [0.17, 0.42] for days ≥43). After a COVID-19 diagnosis, vaccinated patients were significantly less likely than unvaccinated patients to be hospitalized (for BNT162b2, 28.0% versus 43.4%; for mRNA-1273, 37.2% versus 45.6%) and significantly less likely to die (for BNT162b2, 4.0% versus 12.1%; for mRNA-1273, 5.6% versus 14.5%). Antibodies were detected in 98.1% (309/315) and 96.0% (308/321) of BNT162b2 and mRNA-1273 patients, respectively.

CONCLUSIONS

In patients on hemodialysis, vaccination with BNT162b2 or mRNA-1273 was associated with a lower risk of COVID-19 diagnosis and lower risk of hospitalization or death among those diagnosed with COVID-19. SARS-CoV-2 antibodies were detected in nearly all patients after vaccination. These findings support the use of these vaccines in this population.

Antibody Status, Disease History, and Incidence of SARS-CoV-2 Infection Among Patients on Chronic Dialysis

BACKGROUND

Although reinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rare among individuals with few coronavirus disease 2019 (COVID-19) risk factors, the ability of naturally acquired immunity to prevent reinfection among patients with ESKD is not known.

METHODS

This prospective study was conducted among adults with ESKD treated with in-center hemodialysis (ICHD) in the United States. Exposure was ascribed on the basis of the presence or absence of IgG against SARS-CoV-2 at baseline, and separately, a history of documented COVID-19 before study entry. Outcomes were assessed after an infection-free period, and were any SARS-CoV-2 infection (i.e., detected by protocolized PCR tests or during routine clinical surveillance), and clinically manifest COVID-19 (consisting of only the latter).

RESULTS

Of 2337 consented participants who met study inclusion criteria, 9.5% were anti-SARS-CoV-2 IgG positive at baseline; 3.6% had a history of COVID-19. Over 6679 patient-months of follow-up, 263 participants had evidence of any SARS-CoV-2 infection, including 141 who had clinically manifest COVID-19. Presence of anti-SARS-CoV-2 IgG (versus its absence) at baseline was associated with lower risk of any SARS-CoV-2 infection (incidence rate ratio, 0.55; 95% confidence interval, 0.32 to 0.95) and clinically manifest COVID-19 0.21 (95% confidence interval, 0.07 to 0.67).

CONCLUSION

Among patients with ESKD, naturally acquired anti-SARS-CoV-2 IgG positivity is associated with a 45% lower risk of subsequent SARS-CoV-2 infection, and a 79% lower risk of clinically manifest COVID-19. Because natural immunity is incomplete, patients with ESKD should be prioritized for SARS-CoV-2 vaccination, independent of their COVID-19 disease history.

Association of Chronic Condition Special Needs Plan With Hospitalization and Mortality Among Patients With End-Stage Kidney Disease

IMPORTANCE

While several studies have demonstrated the benefit of enrollment in chronic condition special needs plans (C-SNPs) for other chronic diseases (eg, diabetes), there is no evaluation of the association of C-SNPs with outcomes among patients with end-stage kidney disease (ESKD).

OBJECTIVE

To examine whether and to what degree C-SNP enrollment was associated with improved clinical outcomes and quality of life in patients with ESKD.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter cohort study included 2718 patients who were newly enrolled in an ESKD C-SNP between January 1, 2013, and September 30, 2017, and receiving dialysis from DaVita Kidney Care. Patients were followed up until death, loss to follow-up, or end of study (ie, December 31, 2018). Enrollees in C-SNP were matched via multiple clinical and demographic characteristics with 2 different control populations, as follows: (1) those in the same facilities (n = 2545) or (2) those in similar counties (n = 1986). Patients enrolled in CareMore C-SNPs (n = 206) were excluded from the study. Data analysis was conducted June to December 2019.

EXPOSURES

Standard ESKD care with dialysis plus access to an integrated care team who worked with the patient and the dialysis team, comprehensive health assessments done by the integrated care team, and access to select benefits (such as vision and dental care) as a C-SNP enrollee.

MAIN OUTCOMES AND MEASURES

Hospitalizations, mortality, laboratory values indicative of metabolic control, and Kidney Disease Quality of Life 36-item (KDQOL-36) survey scores.

RESULTS

The 2545 C-SNP enrollees in the facility-matched analysis had a mean (SD) age of 57.2 (12.9) years, and included 968 (38.0%) women, 1328 (52.2%) Hispanic individuals, and 553 (21.7%) African American individuals. The 1986 C-SNP enrollees in the county-matched analysis had a mean (SD) age of 57.8 (12.2) years, with 705 (35.5%) women, 1085 (54.6%) Hispanic individuals, and 472 (23.8%) African American individuals. Compared with patients not enrolled in C-SNP, enrollees had lower hospitalization rates, with incidence rate ratios of 0.90 (95% CI, 0.84-0.97; P = .006) in the facility-matched analysis and 0.76 (95% CI, 0.70-0.83; P < .001) in the county-matched analysis. Compared with patients not enrolled in C-SNP, enrollees had decreased mortality risk in the same facilities (hazard ratio, 0.77; 95% CI, 0.68-0.88; P < .001) and in the same counties (hazard ratio, 0.77; 95% CI, 0.66-0.88; P < .001). No significant differences were observed between C-SNP enrollees and matched patients in metabolic laboratory values or KDQOL-36 survey scores.

CONCLUSIONS AND RELEVANCE

This cohort study found a positive association of C-SNP enrollment with lower rates of hospitalization and mortality. The findings suggest that the additional services and benefits C-SNPs provide may improve outcomes compared with standard of care for patients with ESKD.

Effect of ultrafiltration profiling on outcomes among maintenance hemodialysis patients: a pilot randomized crossover trial

BACKGROUND

More rapid fluid removal during hemodialysis is associated with adverse cardiovascular outcomes and longer dialysis recovery times. The effect of ultrafiltration (UF) profiling, independent of concomitant sodium profiling, on markers of intradialytic hemodynamics and other outcomes has been inadequately studied.

METHODS

Four-phase, blinded crossover trial. Participants (UF rates > 10 mL/h/kg) were assigned in random order to receive hemodialysis with UF profiling (constantly declining UF rate, intervention) vs. hemodialysis with conventional UF (control). Each 3-week 9-treatment period was followed by a 1-week 3-treatment washout period. Participants crossed into each study arm twice (2 phases/arm); 18 treatments per treatment type. The primary outcomes were intradialytic hypotension, pre- to post-dialysis troponin T change, and change from baseline in left ventricular global longitudinal strain. Other outcomes included intradialytic symptoms and blood volume measured-plasma refill (post-dialysis volume status measure), among others. Each participant served as their own control.

RESULTS

On average, the 34 randomized patients (mean age 56 years, 24% female, mean dialysis vintage 6.3 years) had UF rates > 10 mL/h/kg in 56% of treatments during the screening period. All but 2 patients completed the 15-week study (prolonged hospitalization, kidney transplant). There was no significant difference in intradialytic hypotension, troponin T change, or left ventricular strain between hemodialysis with UF profiling and conventional UF. With UF profiling, participants had significantly lower odds of light-headedness and plasma refill compared to hemodialysis with conventional UF.

CONCLUSIONS

Ultrafiltration (UF) profiling did not reduce the odds of treatment-related cardiac stress but did reduce the odds of light-headedness and post-dialysis hypervolemia.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT03301740 (registered October 4, 2017).

Response to correspondence from Hays and colleagues concerning our paper entitled, use of the KDQOL-36™ for assessment of health-related quality of life among dialysis patients in the United States

In their correspondence, Hays et al. raise two main critiques of our recently published article entitled "Use of the KDQOL-36™ for assessment of health-related quality of life among dialysis patients in the United States." First, Hays et al. expressed concerns regarding the comparison of mean scores on five Kidney Disease Quality of Life (KDQOL) subscales, given that the Physical Component Summary (PCS) and Mental Component Summary (MCS) are scored on a different numeric scale compared to the other three subscales. Second, Hays et al. note that the correlations reported in our manuscript between the general health perceptions item ("In general, would you say your health is excellent, very good, good, fair, or poor") and the 5 KDQOL subscales were inconsistent with findings derived from other KDQOL datasets. Here, we respond to these two critiques.

Symptoms of Secondary Hyperparathyroidism in Patients Receiving Maintenance Hemodialysis: A Prospective Cohort Study

RATIONALE & OBJECTIVE

Although multiple lines of evidence suggest a negative impact of secondary hyperparathyroidism on patients with kidney failure treated by hemodialysis, it is uncertain whether patients can detect associated symptoms. The objective was to determine whether changes in parathyroid hormone (PTH) levels are associated with changes in symptoms within this patient population.

STUDY DESIGN

Prospective cohort.

SETTING & PARTICIPANTS

165 adults with hyperparathyroidism secondary to kidney failure diagnosed, a range of dialysis vintages, and receiving regular hemodialysis from a US single-provider organization.

EXPOSURE

Change in PTH levels over 24 weeks.

OUTCOMES

19 putative symptoms of secondary hyperparathyroidism measured up to 4 times using a self-administered questionnaire that assessed severity on a 5-level ordinal scale.

ANALYTICAL APPROACH

Longitudinal associations between changes in PTH levels and symptom severity were assessed using generalized additive models.

RESULTS

The 165 participants studied represented 81% of enrollees (N=204) who had sufficiently complete data for analysis. Mean age was 56 years and 54% were women. Increases in PTH levels over time were associated (P<0.1) with worsening of bone aches and stiffness, joint aches, muscle soreness, overall pain, itchy skin, and tiredness, and the effects were more pronounced with larger changes in PTH levels.

LIMITATIONS

Findings may have been influenced by confounding by unmeasured comorbid conditions, concomitant medications, and multiple testing coupled with a P value threshold of 0.10.

CONCLUSIONS

In this exploratory study, we observed that among patients with secondary hyperparathyroidism, increases in PTH levels over time were associated with worsening of 1 or more cluster of symptoms. Replication of these findings in other populations is needed before concluding about the magnitude and shape of these associations. If replicated, these findings could inform clinically useful approaches for measuring patient-reported outcomes related to secondary hyperparathyroidism.

Serum-to-dialysate potassium gradient and its association with short-term outcomes in hemodialysis patients

Background

A high serum-to-dialysate potassium (K+) gradient at the start of dialysis leads to rapid lowering of serum K+ and may confer a greater risk of adverse events. Here, we examined the near-term association of K+ gradient with clinical outcomes.

Methods

This retrospective (2010-11) event-based study considered 830 741 patient-intervals, each defined by a pre-dialysis measurement of serum K+ made among adult Medicare Parts A and B enrollees who received in-center hemodialysis on a Monday/Wednesday/Friday schedule at a large US dialysis organization. K+ gradient was considered based on the difference in K+ concentration (serum-dialysate) on the date of measurement; analyses accounted for multiple observations per patient. Outcomes considered were: all-cause and cardiovascular hospital admissions, emergency department (ED) visits and deaths.

Results

Higher K+ gradient was associated with younger age, greater fistula use, lower comorbidity scores and better nutritional indices. Adjusting for patient differences, there was a dose-response relationship between higher K+ gradient and greater risks of all-cause hospitalization and ED visit. A similar trend was seen for cardiovascular hospitalization but did not achieve statistical significance. No associations were observed with mortality, potentially due to a low number of events.

Conclusions

Higher K+ gradient is independently associated with greater risk of all-cause hospitalizations and ED visits. Further research is needed to determine whether interventions that reduce the K+ gradient ameliorate this risk.

Ultrafiltration-profiled hemodialysis to reduce dialysis-related cardiovascular stress: Study protocol for a randomized controlled trial

Rapid fluid removal (ultrafiltration, UF) is associated with higher cardiovascular morbidity and mortality among individuals receiving maintenance hemodialysis (HD). Fluid removal rates that exceed vascular refill rates can result in hemodynamic instability, end-organ damage to the heart, kidneys, gut and brain, among other organs, and patient symptoms. There are no known evidence-based HD treatment strategies to reduce harm from higher UF rates. Ultrafiltration profiling, the practice of varying UF rates to maximize fluid removal during periods of greatest hydration and plasma oncotic pressure, has been proposed as an HD treatment intervention that may reduce UF rate-related complications. This study is a randomized 4-phase cross-over trial in which participants are successively alternated between study arms with intervening washout periods, and treatment order is randomized. After 4-week screening and 6-week baseline periods, participants are randomized to HD with conventional UF or HD with UF profiling for a period of 3 weeks followed by a 1-week washout period before crossing over. Participants cross into conventional UF and UF profiling phases twice (2 phases per arm). The primary outcomes of interest are intradialytic hypotension (nadir intradialytic systolic blood pressure <90 mmHg), pre-to post-HD change in troponin T (expressed as a percentage), change in left ventricular global longitudinal strain (an echocardiographic measure of left ventricular systolic function), and development of intradialytic left ventricular stunning (worsening of contractile function in ≥2 segments). This study will determine the impact of UF profiling on UF rate-related cardiovascular complications in prevalent, maintenance HD patients.

The TiME Trial: A Fully Embedded, Cluster-Randomized, Pragmatic Trial of Hemodialysis Session Duration

BACKGROUND

Data from clinical trials to inform practice in maintenance hemodialysis are limited. Incorporating randomized trials into dialysis clinical care delivery should help generate practice-guiding evidence, but the feasibility of this approach has not been established.

METHODS

To develop approaches for embedding trials into routine delivery of maintenance hemodialysis, we performed a cluster-randomized, pragmatic trial demonstration project, the Time to Reduce Mortality in ESRD (TiME) trial, evaluating effects of session duration on mortality (primary outcome) and hospitalization rate. Dialysis facilities randomized to the intervention adopted a default session duration ≥4.25 hours (255 minutes) for incident patients; those randomized to usual care had no trial-driven approach to session duration. Implementation was highly centralized, with no on-site research personnel and complete reliance on clinically acquired data. We used multiple strategies to engage facility personnel and participating patients.

RESULTS

The trial enrolled 7035 incident patients from 266 dialysis units. We discontinued the trial at a median follow-up of 1.1 years because of an inadequate between-group difference in session duration. For the primary analysis population (participants with estimated body water ≤42.5 L), mean session duration was 216 minutes for the intervention group and 207 minutes for the usual care group. We found no reduction in mortality or hospitalization rate for the intervention versus usual care.

CONCLUSIONS

Although a highly pragmatic design allowed efficient enrollment, data acquisition, and monitoring, intervention uptake was insufficient to determine whether longer hemodialysis sessions improve outcomes. More effective strategies for engaging clinical personnel and patients are likely required to evaluate clinical trial interventions that are fully embedded in care delivery.

Use of the KDQOL-36™ for assessment of health-related quality of life among dialysis patients in the United States

Background

Health-related quality of life (HRQOL) is a key outcome for dialysis patients, and its assessment is mandated by the Centers for Medicaid and Medicare Services. The Kidney Disease Quality of Life (KDQOL-36™) survey is widely used for this assessment. KDQOL-36™ completion rates, and the distributions of scores and item responses, have not been examined in a large, nationally representative cohort of dialysis patients.

Methods

This retrospective, observational study considered 413,951 survey opportunities contributed by adult patients who received dialysis at a large dialysis organization in the United States during calendar years 2014, 2015, and 2016 and were not Veterans Affairs beneficiaries.

Results

During the study period, 240,343 unique patients completed a total of 330,412 surveys (overall completion rate 79.8%). Mean domain scores on the physical component summary (PCS), mental component summary (MCS), burden of kidney disease (BKD), symptoms and problems of kidney disease (SPKD), and effects of kidney disease (EKD) subscales were 36.6, 49.0, 51.3, 78.1, and 73.0, respectively. Scores were similar across dialysis modalities. Patient perceptions of general health were not correlated (R < 0.05) with PCS or SPKD. The SPKD showed ceiling effects: among patients treated with in-center hemodialysis, for all 12 items, < 10% of patients were “extremely bothered,” while > 65% of patients reported being “not at all” or only “somewhat bothered;” for 3 items, > 85% of patients gave these latter two responses. Interdialytic weight gain was not correlated with patient-reported shortness of breath, PCS, or SPKD.

Conclusions

Survey completion rates for the KDQOL-36™ were high, and scores were similar across dialysis modalities. Ceiling effects were observed for SPKD. Revision of the KDQOL-36™ to address factors that are most important to contemporary dialysis patients may be warranted.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1295-0) contains supplementary material, which is available to authorized users.

Phosphate binder pill burden, adherence, and serum phosphorus control among hemodialysis patients converting to sucroferric oxyhydroxide

Background

Phosphate binders are widely used to achieve serum phosphorus control in patients with end-stage renal disease. However, the large pill burden associated with these medications may decrease adherence to therapy. In clinical trials, sucroferric oxyhydroxide (SO) demonstrated equivalent control of serum phosphorus to sevelamer, with a lower daily pill burden. We examined changes in phosphate binder pill burden, medication possession ratio (MPR), and phosphorus control among in-center hemodialysis (ICHD) patients converting to SO from another phosphate binder as part of routine care.

Materials and methods

Patients included in this retrospective analysis (N=490) were ≥18 years old, received ICHD at a large dialysis organization (LDO), and were enrolled in the LDO’s pharmacy service. Patients converting to SO were those who had supply of another phosphate binder, received a first prescription fill for SO, and subsequently did not refill the non-SO phosphate binder. Patients were followed over the 6 months before and 6 months following the first SO fill and were censored from the analysis upon modality change, loss to follow-up, discontinuation of SO, or fill of a prescription for another phosphate binder after SO initiation (number censored=361). Outcome measures assessed were total phosphate binder pill burden and MPR, serum phosphorus, and percentage of patients with serum phosphorus ≤5.5 mg/dL.

Results

Among patients converting to SO, mean phosphate binder pill burden was 10.8 pills/day during baseline; this decreased to 5.5 pills/day during follow-up (P<0.001). The percentage of patients with serum phosphorus ≤5.5 mg/dL increased from 22.0% to 30.0% (P<0.001). Among patients not using the LDO pharmacy’s automated refill management service (N=30), mean phosphate binder MPR increased from 0.68 during baseline to 0.80 during follow-up (P=0.01).

Conclusion

In a cohort of ICHD patients, conversion to SO was associated with a reduction in pill burden, better adherence, and improvements in phosphorus control.

Safety and efficacy of heparin during dialysis in the context of systemic anticoagulant and antiplatelet medications

Heparin is widely used to prevent coagulation during hemodialysis. Although systemic anticoagulants and antiplatelet agents are commonly prescribed in the hemodialysis population, the safety and efficacy of heparin in the presence of these medications is unclear. This retrospective cohort study considered adult hemodialysis patients treated in the United States (August 2015-July 2017). For each month, patients were ascribed a three-part exposure status (heparin use, anticoagulant use, antiplatelet agent use) based on electronic health records. Outcomes included anemia measures, peri-treatment bleeding and clotting, and hospitalization for gastrointestinal (GI) bleeding. Within systemic medication exposure categories, associations of heparin use were examined using adjusted generalized linear, negative binomial, or Poisson models. Across all systemic medication exposures, heparin use was associated with lower erythropoiesis stimulating agent (ESA) dose, higher hemoglobin levels, and lower monthly intravenous (IV) iron dose; lower rates of clotting during treatment and hospitalization for GI bleeding; and similar rates of peri-treatment bleeding. Associations with respect to ESA, IV iron, hemoglobin, and clotting were approximately twofold more potent in the absence of a systemic anticoagulant; the presence of an antiplatelet agent had little impact. Neither medication type influenced associations between heparin use and peri-treatment or GI bleeding. These results suggest that heparin use is safe and effective in the presence and absence of systemic anticoagulants and antiplatelet agents. Clinical judgment must be applied to assess bleeding risk in individual patients; however, the decision to withhold heparin should not solely be based upon the concurrent use of anticoagulant or antiplatet agents.

Association of Continuation of Loop Diuretics at Hemodialysis Initiation with Clinical Outcomes

BACKGROUND AND OBJECTIVES

Loop diuretics are commonly used to manage nondialysis-dependent CKD. Despite benefits of augmented urine output, loop diuretics are often discontinued after dialysis initiation. Here, we assessed the association of the early decision to continue loop diuretics at hemodialysis start with clinical outcomes during the first year of dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We considered all patients on in-center hemodialysis at a large dialysis organization (2006-2013) with Medicare Part A and D benefits who had an active supply of a loop diuretic at dialysis initiation (n=11,297). Active therapy was determined on the basis of whether loop diuretic prescription was refilled after dialysis initiation and within 30 days of exhaustion of prior supply. Patients were followed under an intention-to-treat paradigm for up to 12 months for rates of death, hospitalization, and intradialytic hypotension and mean monthly values of interdialytic weight gain, serum potassium, predialysis systolic BP, and ultrafiltration rates.

RESULTS

We identified 5219 patients who refilled a loop diuretic and 6078 eligible controls who did not. After adjustments for patient mix and clinical differences, continuation of loop diuretics was associated with lower hospitalization (adjusted incidence rate ratio, 0.93; 95% confidence interval, 0.89 to 0.98) and intradialytic hypotension (adjusted incidence rate ratio, 0.95; 95% confidence interval, 0.92 to 0.99) rates, no difference in death rate (adjusted hazard ratio, 0.92; 95% confidence interval, 0.84 to 1.01), and lower interdialytic weight gain (P=0.03).

CONCLUSIONS

Continuation of loop diuretics after hemodialysis initiation was associated with lower rates of hospitalization and intradialytic hypotension as well as lower interdialytic weight gain, but there was no difference in mortality over the first year of dialysis.

The Impact of Midodrine on Outcomes in Patients with Intradialytic Hypotension

BACKGROUND

Intradialytic hypotension (IDH) is a frequent complication of hemodialysis, and is associated with significant morbidity and mortality. Off-label use of the alpha-1 andrenergic receptor agonist midodrine to reduce the frequency and severity of IDH is common. However, limited data exist to support this practice. This study sought to examine real-world efficacy of midodrine with respect to relevant clinical and hemodynamic outcomes.

METHODS

Here, we compared a variety of clinical and hemodynamic outcomes among adult patients who were prescribed midodrine (n = 1,046) and matched controls (n = 2,037), all of whom were receiving in-center hemodialysis treatment at dialysis facilities in the United States (July 2015 - September 2016). Mortality, all-cause hospitalization, cardiovascular hospitalization, and hemodynamic outcomes were considered from the month following the initiation of midodrine (or corresponding month for controls) until censoring for discontinuation of dialysis, transplant, loss to follow-up, or study end (September 30, 2016). Rate outcomes were compared using Poisson models and quantitative outcomes using linear mixed models; all models were adjusted for imbalanced patient characteristics.

RESULTS

Compared to non-use, midodrine use was associated with higher rates of death (adjusted incidence rate ratio 1.37, 95% CI 1.15-1.62), all-cause hospitalization (1.31, 1.19-1.43) and cardiovascular hospitalization (1.41, 1.17-1.71). During follow-up, midodrine use tended to be associated with lower pre-dialysis systolic blood pressure (SBP), lower nadir SBP, greater fall in SBP during dialysis, and a greater proportion of treatments affected by IDH.

CONCLUSION

Although residual confounding may have influenced the results, the associations observed here are not consistent with a potent beneficial effect of midodrine with respect to either clinical or hemodynamic outcomes.

Anemia and mortality in patients with nondialysis-dependent chronic kidney disease

BACKGROUND

A combination of safety concerns and labeling changes impacted use of erythropoiesis-stimulating agents (ESAs) in renal anemia. Data regarding contemporary utilization in pre-dialysis chronic kidney disease (CKD) are lacking.

METHODS

Electronic healthcare records and medical claims data of pre-dialysis CKD patients were aggregated from a large US managed care provider (2011-13). ESA use patterns, characteristics, and outcomes of ESA-treated/untreated patients were quantified.

RESULTS

At baseline, 109/32,308 patients (0.3%) were ESA users. Treated patients were older, had more advanced CKD (58.8% vs 5.4% with stage 4/5 vs 3) and greater prevalence of comorbid diabetes, hypertension, heart failure, and peripheral vascular disease. An additional 266 patients initiated ESA: hemoglobin at initiation was 8-10 g/dL in 193 of these and >10 g/dL in the remainder; 61.7% had stage 4/5 CKD; prevalence of cardiovascular disease was high (50.8% heart failure; 25.2% prior myocardial infarction; 24.1% prior stroke). During follow-up, rates of death and cardiovascular events were higher in baseline ESA users and ESA naives versus non-users.

CONCLUSIONS

ESA use in pre-dialysis CKD patients was exceedingly rare and directed disproportionately to older, sicker patients; these patients had high rates of death and cardiovascular events. These data provide context for contemporary use of ESA in pre-dialysis CKD.

Thyroid Status and Death Risk in US Veterans With Chronic Kidney Disease

OBJECTIVE

Given that patients with non-dialysis-dependent chronic kidney disease (NDD-CKD) have a disproportionately higher prevalence of hypothyroidism compared with their non-CKD counterparts, we sought to determine the association between thyroid status, defined by serum thyrotropin (TSH) levels, and mortality among a national cohort of patients with NDD-CKD.

PATIENTS AND METHODS

Among 227,422 US veterans with stage 3 NDD-CKD with 1 or more TSH measurements during the period October 1, 2004, to September 30, 2012, we first examined the association of thyroid status, defined by TSH categories of less than 0.5, 0.5 to 5.0 (euthyroidism), and more than 5.0 mIU/L, with all-cause mortality. We then evaluated 6 granular TSH categories: less than 0.1, 0.1 to less than 0.5, 0.5 to less than 3.0, 3.0 to 5.0, more than 5.0 to 10.0, and more than 10.0 mIU/L. We concurrently examined thyroid status, thyroid-modulating therapy, and mortality in sensitivity analyses.

RESULTS

In expanded case-mix adjusted Cox analyses, compared with euthyroidism, baseline and time-dependent TSH levels of more than 5.0 mIU/L were associated with higher mortality (adjusted hazard ratios [aHRs] [95% CI], 1.19 [1.15-1.24] and 1.23 [1.19-1.28], respectively), as were baseline and time-dependent TSH levels of less than 0.5 mIU/L (aHRs [95% CI], 1.18 [1.15-1.22] and 1.41 [1.37-1.45], respectively). Granular examination of thyroid status showed that incrementally higher TSH levels of 3.0 mIU/L or more were associated with increasingly higher mortality in baseline and time-dependent analyses, and TSH categories of less than 0.5 mIU/L were associated with higher mortality (reference, 0.5-<3.0 mIU/L) in baseline analyses. In time-dependent analyses, untreated and undertreated hypothyroidism and untreated hyperthyroidism were associated with higher mortality (reference, spontaneous euthyroidism), whereas hypothyroidism treated-to-target showed lower mortality.

CONCLUSION

Among US veterans with NDD-CKD, high-normal TSH (≥3.0 mIU/L) and lower TSH (<0.5 mIU/L) levels were associated with higher death risk. Interventional studies identifying the target TSH range associated with the greatest survival in patients with NDD-CKD are warranted.

Longitudinal trends in serum ferritin levels and associated factors in a national incident hemodialysis cohort

Background

The rise in serum ferritin levels among US maintenance hemodialysis patients has been attributed to higher intravenous iron administration and other changes in practice. We examined ferritin trends over time in hemodialysis patients and whether iron utilization patterns and other factors [erythropoietin-stimulating agent (ESA) prescribing patterns, inflammatory markers] were associated with ferritin trajectory.

Methods

In a 5-year (January 2007–December 2011) cohort of 81 864 incident US hemodialysis patients, we examined changes in ferritin averaged over 3-month intervals using linear mixed effects models adjusted for intravenous iron dose, malnutrition and inflammatory markers. We then examined ferritin trends across strata of baseline ferritin level, dialysis initiation year, cumulative iron and ESA use in the first dialysis year and baseline hemoglobin level.

Results

In models adjusted for iron dose, malnutrition and inflammation, mean ferritin levels increased over time in the overall cohort and across the three lower baseline ferritin strata. Among patients initiating dialysis in 2007, mean ferritin levels increased sharply in the first versus second year of dialysis and again abruptly increased in the fifth year independent of iron dose, malnutrition and inflammatory markers; similar trends were observed among patients who initiated dialysis in 2008 and 2009. In analyses stratified by cumulative iron use, mean ferritin increased among groups receiving iron, but decreased in the no iron group. In analyses stratified by cumulative ESA dose and baseline hemoglobin, mean ferritin increased over time.

Conclusions

While ferritin trends correlated with patterns of iron use, increases in ferritin over time persisted independent of intravenous iron and ESA exposure, malnutrition and inflammation.

Serum sodium and mortality in a national peritoneal dialysis cohort

Background

Sodium disarrays are common in peritoneal dialysis (PD) patients, and may be associated with adverse outcomes in this population. However, few studies of limited sample size have examined the association of serum sodium with mortality in PD patients, with inconsistent results. We hypothesized that both hypo- and hypernatremia are associated with higher death risk in a nationally representative cohort of US PD patients.

Methods

We sought to examine the association of serum sodium over time and mortality among 4687 adult incident PD patients from a large US dialysis organization who underwent one or more serum sodium measurements within the first 3 months of dialysis over January 2007 to December 2011. We examined the association of time-dependent and baseline sodium with all-cause mortality as a proxy of short- and long-term sodium-mortality associations, respectively. Hazard ratios were estimated using Cox models with three adjustment levels: minimally adjusted, case-mix adjusted, and case-mix + laboratory adjusted.

Results

In time-dependent analyses, sodium levels <140 mEq/L were associated with incrementally higher death risk in case-mix models (ref: 140 to <142 mEq/L); following laboratory covariate adjustment, associations between lower sodium and higher mortality remained significant for levels <136 mEq/L. In analyses using baseline values, sodium levels <140 mEq/L were associated with higher mortality risk across all models (ref: 140 to <142 mEq/L).

Conclusions

In PD patients, lower time-dependent and baseline sodium levels were independently associated with higher death risk. Further studies are needed to determine whether correction of dysnatremia improves longevity in this population.

Cluster-Randomized Trial of Devices to Prevent Catheter-Related Bloodstream Infection

Central venous catheters (CVCs) contribute disproportionately to bloodstream infection (BSI) and, by extension, to infection-related hospitalization, mortality, and health care costs in patients undergoing dialysis. Recent product advancements may reduce BSIs, but a sufficiently powered comparative-effectiveness study is needed to facilitate evidence-based patient care decisions. In a 13-month, prospective, cluster-randomized, open-label trial, we compared BSI rates in facilities using ClearGuard HD antimicrobial barrier caps (ClearGuard group) with those in facilities using Tego hemodialysis connectors plus Curos disinfecting caps (Tego+Curos group). Forty DaVita dialysis facilities in the United States were pair-matched by BSI rate, number of patients using CVCs, and geographic location, and then cluster randomized 1:1. We enrolled all adult patients undergoing dialysis with CVCs at these facilities, except those allergic to heparin or chlorhexidine. Overall, 1671 patients participated in the study, accruing >183,000 CVC-days. The study outcome was positive blood culture (PBC) rate as an indicator of BSI rate. We calculated results at the cluster level and adjusted for the facility cluster effect. During a 3-month run-in period immediately before study interventions, the groups had similar BSI rates (P=0.8). During the 13-month intervention period that immediately followed, the ClearGuard group had a BSI rate significantly lower than that of the Tego+Curos group (0.28 versus 0.75 PBCs per 1000 CVC-days, respectively; P=0.001). No device-related adverse events were reported. In conclusion, compared with Tego connectors plus Curos caps, ClearGuard HD antimicrobial barrier caps significantly lowered the rate of catheter-related BSIs in patients undergoing hemodialysis using CVCs, representing an important advancement in hemodialysis patient care.

Vocational activity and health insurance type among patients with end-stage renal disease: association with outcomes

It is widely thought that patients with end-stage renal disease who remain vocationally active and/or commercially insured following dialysis initiation have better clinical outcomes and higher quality of life than those who do not. However, scientifically robust data are lacking. Here, we examined whether vocational status (active, N = 1848; inactive, N = 10,001) and, separately, insurance status (commercial, N = 4858; Medicare/self-pay, N = 13,329; Medicaid, N = 3528) were associated with clinical outcomes and Kidney Disease Quality of Life (KDQOL) scores among a cohort of patients who initiated dialysis at a large US dialysis organization during 2015-2016. Outcomes were considered from the day after index (31 days after dialysis initiation for vocational status and 1 day after initiation for insurance status) until the earliest of death, discontinuation of dialysis, transplant, loss to follow-up, or end of study (30 September 2016). Comparisons were made using intention-to-treat principles and generalized linear models adjusted for imbalanced patient characteristics, including sociodemographic variables. Vocational inactivity (vs. vocational activity) was independently associated with higher rates of mortality and hospitalization, lower rates of transplant, and lower KDQoL scores in 4 of 5 domains. Similar trends were observed when comparing Medicare/self-pay or Medicaid insurance to commercial insurance. Vocational activity, and separately, commercial insurance, were independently associated with better clinical and quality of life outcomes compared to other insurance and vocational categories. These findings may inform patient and physician education, and guide advocacy efforts.

Effects of Oral Nutritional Supplements on Mortality, Missed Dialysis Treatments, and Nutritional Markers in Hemodialysis Patients

OBJECTIVE

Protein-energy wasting is common in end-stage renal disease patients undergoing dialysis and is strongly associated with mortality and adverse outcomes. Intradialytic oral nutritional supplements (ONS) reduce risk of mortality in these patients. Large studies characterizing the impact of ONS on other outcomes are lacking. We assessed the associations between administration of ONS and clinical and nutritional outcomes.

DESIGN

Retrospective evaluation of a pilot program providing ONS to patients at a large dialysis organization in the United States. The pilot program provided ONS to in-center hemodialysis patients with serum albumin ≤3.5 g/dL at 408 facilities.

SUBJECTS

ONS patients were compared to matched controls with serum albumin ≤3.5 g/dL, identified from facilities not participating in the ONS program (n = 3,374 per group).

INTERVENTION

Receipt of ONS.

MAIN OUTCOME MEASURES

Death, missed dialysis treatments, hospitalizations, serum albumin, normalized protein catabolic rate, and postdialysis body weight were abstracted from large dialysis organization electronic medical records.

RESULTS

There was a 69% reduction in deaths (hazard ratio = 0.31; 95% confidence interval = 0.25-0.39), and 33% fewer missed dialysis treatments (incidence rate ratio = 0.77; 95% confidence interval = 0.73-0.82) among ONS patients compared to controls (P < .001 for both). The effects of ONS on nutritional indices were mixed: serum albumin was lower, whereas normalized protein catabolic rate values, a surrogate for dietary protein intake, and postdialysis body weights were higher for ONS patients compared to controls during follow-up.

CONCLUSIONS

Our evaluation confirmed the beneficial effects of ONS in reducing mortality and improving some indices of nutritional status for hypoalbuminemic hemodialysis patients. We also report the novel finding that ONS can reduce the number of missed dialysis treatments. These results support the use of intradialytic ONS as an effective intervention to improve the outcomes in hemodialysis patients with low serum albumin.

Association between Testosterone and Mortality Risk among U.S. Males Receiving Dialysis

BACKGROUND

Among the general population, low circulating testosterone levels are associated with higher risk of cardiovascular disease and death. While testosterone deficiency is common in dialysis patients, studies of testosterone and mortality in this population are ambiguous and overlapping. We hypothesized that lower testosterone levels are associated with higher mortality in male dialysis patients.

METHODS

We examined a nationally representative cohort of male dialysis patients from a large US dialysis organization who underwent one or more total testosterone measurements from 1/2007 to 12/2011. The association between total testosterone categorized as quartiles and all-cause mortality was studied using Cox models adjusted for expanded case-mix and laboratory covariates. We also examined total testosterone as a continuous predictor of all-cause mortality using restricted cubic splines.

RESULTS

Among 624 male dialysis patients, 51% of patients demonstrated testosterone deficiency (total testosterone <300 ng/dL); median (IQR) total testosterone levels were 297 (190-424) ng/mL. In expanded case-mix + laboratory adjusted Cox analyses, we observed a graded association between lower testosterone levels and higher mortality risk (ref: quartile 3): adjusted hazard ratios (95% CI) 2.32 (1.33-4.06), 1.80 (0.99-3.28), and 0.68 (0.32-1.42) for Quartiles 1, 2, and 4, respectively. In adjusted spline analyses, the lower testosterone-higher mortality risk association declined with higher testosterone levels until the value reached a threshold of 400 ng/dL above which risk plateaued.

CONCLUSION

Lower testosterone levels were independently associated with higher mortality risk in male dialysis patients. Further studies are needed to determine underlying mechanisms, and whether testosterone replacement ameliorates death risk in this population.

Thyroid Status, Quality of Life, and Mental Health in Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

In the general population, there is increasing recognition of the effect of thyroid function on patient-centered outcomes, including health-related quality of life and depression. Although hypothyroidism is highly prevalent in hemodialysis patients, it is unknown whether thyroid status is a risk factor for impaired health-related quality of life or mental health in this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined the association of thyroid status, defined by serum thyrotropin, with health-related quality of life and depressive symptoms over time in a prospective cohort of 450 patients on hemodialysis from 17 outpatient dialysis facilities from May of 2013 to May of 2015 who underwent protocolized thyrotropin testing, Short-Form 36 surveys, and Beck Depression Inventory-II questionnaires every 6 months. We examined the association of baseline and time-dependent thyrotropin categorized as tertiles and continuous variables with eight Short-Form 36 domains and Beck Depression Inventory-II scores using expanded case mix plus laboratory adjusted linear mixed effects models.

RESULTS

In categorical analyses, the highest baseline thyrotropin tertile was associated with a five-point lower Short-Form 36 domain score for energy/fatigue (P=0.04); the highest time-dependent tertile was associated with a five-point lower physical function score (P=0.03; reference: lowest tertile). In continuous analyses, higher baseline serum thyrotropin levels (+Δ1 mIU/L) were associated with lower role limitations due to physical health (β=-1.3; P=0.04), energy/fatigue (β=-0.8; P=0.03), and pain scores (β=-1.4; P=0.002), equivalent to five-, three-, and five-point lower scores, respectively, for every 1-SD higher thyrotropin. Higher time-dependent thyrotropin levels were associated with lower role limitations due to physical health scores (β=-1.0; P=0.03), equivalent to a three-point decline for every 1-SD higher thyrotropin. Baseline and time-dependent thyrotropin were not associated with Beck Depression Inventory-II scores.

CONCLUSIONS

In patients on hemodialysis, higher serum thyrotropin levels are associated with impaired health-related quality of life across energy/fatigue, physical function, and pain domains. Studies are needed to determine if thyroid-modulating therapy improves the health-related quality of life of hemodialysis patients with thyroid dysfunction.

Association of Glycemic Status During Progression of Chronic Kidney Disease With Early Dialysis Mortality in Patients With Diabetes

OBJECTIVE

Although early trials suggested that intensive glycemic targets reduce the number of complications with diabetes, contemporary trials indicate no cardiovascular benefit and potentially higher mortality risk. As patients with advanced chronic kidney disease (CKD) transitioning to treatment with dialysis were excluded from these studies, the optimal glycemic level in this population remains uncertain. We hypothesized that glycemic status, defined by hemoglobin A_1c (HbA--_1c) and random glucose levels, in the pre-end-stage renal disease (ESRD) period is associated with higher 1-year post-ESRD mortality among patients with incident diabetes who have ESRD.

RESEARCH DESIGN AND METHODS

Among 17,819 U.S. veterans with diabetic CKD transitioning to dialysis from October 2007 to September 2011, we examined the association of mean HbA--_1c and random glucose levels averaged over the 1-year pre-ESRD transition period with mortality in the first year after dialysis initiation. All-cause mortality hazard ratios (HRs) were estimated using multivariable survival models. Secondary analyses examined cardiovascular mortality using competing risks methods.

RESULTS

HbA--_1c levels ≥8% (≥64 mmol/mol) were associated with higher mortality in the first year after dialysis initiation (reference value 6% to <7% [42-53 mmol/mol]): adjusted HRs [aHRs] 1.19 [95% CI 1.07-1.32] and 1.48 (1.31-1.67) for HbA--_1c 8% to <9% [64-75 mmol/mol] and ≥9% [≥75 mmol/mol], respectively). Random glucose levels ≥200 mg/dL were associated with higher mortality (reference value 100 to <125 mg/dL): aHR 1.34 [95% CI 1.20-1.49]). Cumulative incidence curves showed that incrementally higher mean HbA--_1c and random glucose levels were associated with increasingly higher cardiovascular mortality.

CONCLUSIONS

In patients with diabetes and CKD transitioning to dialysis, higher mean HbA--_1c and random glucose levels during the pre-ESRD prelude period were associated with higher 1-year post-ESRD mortality. Clinical trials are warranted to examine whether modulating glycemic status improves survival in this population.

In-center hemodialysis absenteeism: prevalence and association with outcomes

Objective

The aim of this study was to determine the rate of missed treatments among hemodialysis (HD) patients, and the association between treatment nonadherence and clinical outcomes.

Data source

The data used in this study were based on electronic medical records and Medicare claims.

Study design

This is a retrospective, observational study.

Principal findings

HD patients miss 9.9% of all treatments. Approximately half of the missed treatments are due to observable medical events, predominantly hospitalizations, while half result from nonadherence (“absence”). A single absence is associated with a 1.4-fold greater risk of hospitalization, and a 2.2-fold greater risk of death in the subsequent 30 days.

Conclusion

Treatment nonadherence is common among HD patients and is associated with adverse outcomes. Interventions that improve adherence may improve patient health and reduce costs.

Thyroid Status and Mortality in a Prospective Hemodialysis Cohort

CONTEXT AND OBJECTIVE

Compared with the general population, hemodialysis patients have a substantially higher risk of hypothyroidism, as defined by an elevated serum thyrotropin (TSH) level, and cardiovascular mortality. Whereas an elevated TSH is associated with cardiovascular disease and death in the general population, associations among dialysis patients have been inconsistent.

DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME

We examined 541 hemodialysis patients from 17 southern California dialysis centers in the prospective Hypothyroidism, Cardiovascular Health, and Survival study who underwent protocolized measurement of repeated serum TSH levels every 6 months from 2013 to 2015. Associations between TSH tertiles (<1.28, 1.28 to <2.14, and 2.14 to 86.7 mIU/L) and mortality were estimated using time-dependent Cox models with four adjustment levels. In sensitivity analyses, we excluded patients receiving thyroid hormone supplementation.

RESULTS

Compared with the lowest TSH tertile, the highest TSH tertile was associated with a 2.2- to 2.5-fold higher mortality risk in unadjusted, case-mix, expanded case-mix+laboratory, and expanded case-mix+laboratory+medication models [hazard ratios (95% confidence interval), 2.54 (1.32 to 4.89), 2.53 (1.30 to 4.93), 2.19 (1.11 to 4.32), and 2.28 (1.45 to 3.58), respectively]. We observed a consistent trend between higher TSH tertiles and numerically higher mortality risk across all models. Similar findings were observed in analyses excluding patients receiving thyroid hormone supplementation.

CONCLUSION

In time-dependent analyses, TSH levels in the high-normal to high range were independently associated with higher death risk in hemodialysis patients. Further studies are indicated to determine whether normalization of TSH levels with thyroid hormone supplementation improves survival in this population.

Sodium modelling to reduce intradialytic hypotension during haemodialysis for acute kidney injury in the intensive care unit

AIM

Intradialytic hypotension often complicates haemodialysis for patients with acute kidney injury (AKI) and may impact renal recovery. Sodium modelling is sometimes used as prophylaxis against intradialytic hypotension in the chronic haemodialysis population, but there is little evidence for its use among critically ill patients with AKI.

METHODS

A retrospective cohort with AKI requiring intermittent haemodialysis in the intensive care unit from 2001 to 2008 was used to study the association of prophylactic sodium modelling and multiple outcomes. Outcomes included a composite of in-hospital death or dialysis dependence at hospital discharge, as well as intradialytic hypotension, ultrafiltration goal achievement and net ultrafiltration volume. Associations were estimated using logistic regression, mixed linear models and generalized estimating equations adjusting for demographic and clinical characteristics.

RESULTS

One hundred and ninety-one individuals who underwent 892 sessions were identified; sodium modelling was prescribed in 27.1% of the sessions. In adjusted analyses, sodium modelling was not significantly associated with intradialytic hypotension (P = 0.67) or with the ultrafiltration goal achievement (P = 0.06). Sodium modelling during the first dialysis session was numerically associated with lower risk for the composite of in-hospital death or dialysis dependence: adjusted odds ratio (95% confidence interval) 0.39 (0.15-1.02; P = 0.06); however, this association did not reach statistical significance.

CONCLUSION

We did not observe statistically significant associations between sodium modelling and improved outcomes among AKI patients receiving intermittent dialysis in the intensive care unit. However, suggestive findings warrant further study.

Serum Potassium and Short-term Clinical Outcomes Among Hemodialysis Patients: Impact of the Long Interdialytic Interval

BACKGROUND

Hyperkalemia is common among hemodialysis patients and is associated with morbidity and mortality. The long interdialytic interval is likewise associated with adverse outcomes. However, the interplay among serum potassium, dialysis cycle phase, and clinical outcomes has not been examined.

STUDY DESIGN

Retrospective observational study.

SETTING & PARTICIPANTS

52,734 patients receiving in-center hemodialysis at a large dialysis organization during 2010 and 2011 contributed 533,889 potassium measurements (230,634 on Monday; 285,522 on Wednesday; 17,733 on Friday).

PREDICTOR

Serum potassium concentration, day of the week of potassium measurement.

OUTCOMES

Death, hospitalization, emergency department (ED) visit.

RESULTS

There was a significant association between higher serum potassium and risk of hospitalization within 96 hours that was of greater magnitude on Fridays (389 hospitalizations) than Mondays or Wednesdays (4,582 and 4,629 hospitalizations, respectively; P for interaction = 0.008). Serum potassium of 5.5 to <6.0 (vs the referent category of 4.0-<4.5 mEq/L) was associated with increased risk of hospitalization on Fridays, with an adjusted OR of 1.68 (95% CI, 1.22-2.30). However, serum potassium of 5.5 to <6.0 mEq/L was associated with only mild elevation of risk on Mondays and no significantly increased risk on Wednesdays (adjusted ORs of 1.12 [95% CI, 1.00-1.24] and 1.04 [95% CI, 0.94-1.16], respectively). Associations of elevated serum potassium (6.0-<6.5 mEq/L or greater) with death and ED visit were significant, but did not differ based on day of the week.

LIMITATIONS

There were insufficient observations to detect effect modification by day of the week for deaths, ED visits, and specific causes of hospitalizations. Confounding may have influenced results.

CONCLUSIONS

Higher serum potassium is associated with increased short-term risk of hospitalization, ED visit, and death. The association between serum potassium and hospitalization risk is modified by day of the week, consistent with a contribution of accumulated potassium to adverse outcomes following the long interdialytic interval. Further work is needed to determine whether directed interventions ameliorate this risk.

Dialysate temperature of 36 °C: association with clinical outcomes

Dialysate cooling, either individualized based upon patient body temperature, or to a standardized temperature below 37 °C, has been proposed to minimize hemodynamic insults and improve outcomes among hemodialysis patients. However, low dialysate temperatures (35-35.5 °C) are associated with patient discomfort, and individualized dialysate cooling is difficult to operationalize. Here, we tested whether a standardized dialysate temperature of 36 °C (dT36) was associated with improved clinical outcomes compared to the default temperature of 37 °C (dT37). Because patients with known hemodynamic instability may be selectively prescribed dT36, we minimized selection bias by considering only incident adult in-center hemodialysis patients who, between Jan 2011 and Dec 2013 received their first-ever hemodialysis treatment at a large dialysis organization. Exposure status was based on the treatment order for this first-ever treatment. 313 dT36 patients were identified and propensity-score matched (1:5) to 1565 dT37 controls. Death, hospitalization, and missed hemodialysis treatments were considered from the date of first-ever hemodialysis treatment until the earliest of death, loss to follow-up, crossover (month in which prescribed dialysate temperature was consistent with patient's exposure group for <80% of treatments), or study end (June 2015). During follow-up, rates of death, hospitalization and missed hemodialysis treatments did not differ between the two groups. This study therefor showed no benefit of dT36 vs. dT37 with respect to these clinical outcomes. Our results do not favor conversion to a default dialysate temperature of 36 °C. Individualized dialysate cooling may provide a more reliable approach to achieve the hemodynamic benefits associated with reduced dialysate temperature.

The clinical and economic burden of pneumonia in patients enrolled in Medicare receiving dialysis: a retrospective, observational cohort study

Background

End-stage renal disease (ESRD) patients receiving dialysis are at particular risk for infection. We assessed the clinical and economic burden of pneumonia in a population of Medicare-enrolled ESRD patients with respect to incidence and case fatality rates, rates of all-cause and cardiovascular hospitalization, and costs.

Methods

Patients received dialysis between 01 January 2009 and 31 December 2011 and were enrolled in Medicare Parts A and B. Pneumonia episodes were identified from institutional and supplier claims. Patients were considered at-risk from first date of Medicare coverage and were censored upon transplant, withdrawal from dialysis, recovery of renal function, loss of Medicare benefits, or death. Linear mixed-effects models were used to assess hospitalization rates and costs over the 3 months prior to and 12 months following pneumonia episodes.

Results

The pneumonia incidence rate for the study period was 21.4 events/100 patient-years; the majority of episodes (90.1%) required inpatient treatment. The 30-day case fatality rate was 10.7%. Compared to month -3 prior to event, rates of all-cause and cardiovascular hospitalization were higher in the month of the pneumonia episode (IRR, 4.61 and 4.30). All-cause admission rates remained elevated through month 12; cardiovascular admission rates remained elevated through month 6. Mean per-patient per-month costs were $10,976 higher in the month of index episode compared to month -3, largely driven by increased inpatient costs, and remained elevated through end of 12-month follow-up.

Conclusion

Pneumonia episodes are frequent among ESRD patients and result in hospitalizations and greater overall costs to Medicare over the following year.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0412-6) contains supplementary material, which is available to authorized users.

Dialysate Potassium, Serum Potassium, Mortality, and Arrhythmia Events in Hemodialysis: Results From the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Sudden death is a leading cause of death in patients on maintenance hemodialysis therapy. During hemodialysis sessions, the gradient between serum and dialysate levels results in rapid electrolyte shifts, which may contribute to arrhythmias and sudden death. Controversies exist about the optimal electrolyte concentration in the dialysate; specifically, it is unclear whether patient outcomes differ among those treated with a dialysate potassium concentration of 3 mEq/L compared to 2 mEq/L.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

55,183 patients from 20 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 1 to 5 (1996-2015).

PREDICTOR

Dialysate potassium concentration at study entry.

OUTCOMES

Cox regression was used to estimate the association between dialysate potassium concentration and both all-cause mortality and an arrhythmia composite outcome (arrhythmia-related hospitalization or sudden death), adjusting for potential confounders.

RESULTS

During a median follow-up of 16.5 months, 24% of patients died and 7% had an arrhythmia composite outcome. No meaningful difference in clinical outcomes was observed for patients treated with a dialysate potassium concentration of 3 versus 2 mEq/L (adjusted HRs were 0.96 [95% CI, 0.91-1.01] for mortality and 0.98 [95% CI, 0.88-1.08] for arrhythmia composite). Results were similar across predialysis serum potassium levels. As in prior studies, higher serum potassium level was associated with adverse outcomes. However, dialysate potassium concentration had only minimal impact on serum potassium level measured predialysis (+0.09 [95% CI, 0.05-0.14] mEq/L serum potassium per 1 mEq/L greater dialysate potassium concentration).

LIMITATIONS

Data were not available for delivered (vs prescribed) dialysate potassium concentration and postdialysis serum potassium level; possible unmeasured confounding.

CONCLUSIONS

In combination, these results suggest that approaches other than altering dialysate potassium concentration (eg, education on dietary potassium sources and prescription of potassium-binding medications) may merit further attention to reduce risks associated with high serum potassium levels.

Identification of volume overload hospitalizations among hemodialysis patients using administrative claims: a validation study

BACKGROUND

High rates of volume overload hospitalizations may indicate inadequate dialysis facility fluid management. Administrative claims databases are often used to study such outcomes, but these data are generated for billing purposes and may not capture clinical nuance. It is unknown if volume overload admissions can be correctly identified in administrative data and if a single claims-based definition for volume overload can be used across epidemiologic surveillance studies, observational studies of exposure-outcome associations and quality assessments. We conducted a validation study to assess the accuracy of claims-based definitions for volume overload hospitalizations among hemodialysis patients.

METHODS

Data were taken from a random sample of 315 adult hemodialysis patients admitted to University of North Carolina Hospitals from January 2010 through June 2013. Standardized chart reviews were conducted to clinically adjudicate the presence or absence of volume overload at hospital admission. Claims-based definitions were constructed from varying combinations of fluid-related ICD-9 discharge diagnosis codes including fluid overload, pulmonary edema, pleural effusion, and heart failure. Using clinically adjudicated volume overload hospitalizations as the reference standard, validity metrics and their 95 % confidence intervals (CIs) were estimated for each definition.

RESULTS

Of the 315 hospital admissions, 77 (24.4 %) were clinically adjudicated as volume overload hospitalizations. The prevalence of claims-identified volume overload admissions varied across definitions, ranging from 1.6 to 37.1 %. When definitions were constructed with discharge diagnosis codes present in any billing position, volume overload hospitalizations defined by fluid overload, pleural effusion or heart failure diagnosis codes had the highest sensitivity, 81.8 % (95 % CI: 71.4 %, 89.7 %). Volume overload hospitalizations defined by pulmonary edema diagnosis codes had the highest specificity, 98.3 % (95 % CI: 95.8 %, 99.5 %). Definitions constructed with discharge diagnosis codes present in any billing position (versus the primary position) captured more false positive events.

CONCLUSIONS

Prevalence and validity estimates of volume overload hospitalizations vary across claims-based definitions. A universal claims-based definition for volume overload hospitalizations may not apply to all clinical and research scenarios. Investigators and regulators need to consider the implications of misclassifying events when evaluating and monitoring hemodialysis patient volume overload admissions with administrative data. Claims-based definitions should be selected accordingly.

The association between cinacalcet use and missed in-center hemodialysis treatment rate

PURPOSE

Missed in-center hemodialysis treatments (MHT) are a general indicator of health status in hemodialysis patients. This analysis was conducted to estimate the association between cinacalcet use and MHT rate.

METHODS

We studied patients receiving hemodialysis and prescription benefits services from a large dialysis organization. Incident cinacalcet users were propensity score matched to controls on 31 demographic, clinical, and laboratory variables. We applied inverse probability (IP) of censoring and crossover weights to account for informative censoring. Weighted negative binomial modeling was used to estimate MHT rates and pooled logistics models were used to estimate the association between cinacalcet use and MHT.

RESULTS

Baseline demographic and clinical variables included serum calcium, phosphorus, parathyroid hormone, and vitamin D use, and were balanced between 15,474 new cinacalcet users and 15,474 matched controls. In an analysis based on intention-to-treat principles, 40.8% of cinacalcet users and 46.5% of nonusers were censored. MHT rate was 13% lower among cinacalcet initiators versus controls: IP of censoring weighted incidence rate ratio was 0.87 (95% confidence interval [CI]: 0.84-0.90 p < 0.001). In analyses based on as-treated principles, 72.8% and 61.5% of cinacalcet users and nonusers, respectively, crossed over or were censored. MHT rate was 15% lower among cinacalcet initiators versus controls: IP of censoring/crossover weighted incidence rate ratio was 0.85 (95%CI: 0.82-0.87 p < 0.001).

CONCLUSIONS

After controlling for indication and differential censoring, cinacalcet treatment was associated with lower MHT rates, which may reflect better health status. Copyright © 2016 John Wiley & Sons, Ltd.

Spectrum and Burden of Erythropoiesis-Stimulating Agent Hyporesponsiveness Among Contemporary Hemodialysis Patients

BACKGROUND

Hemodialysis patients with erythropoiesis-stimulating agent (ESA) hyporesponsiveness have been a topic of active research. However, there have been no studies of ESA hyporesponsiveness among US patients following the dramatic change in anemia management that resulted from the 2011 changes in ESA product labeling and bundling of dialysis remuneration.

STUDY DESIGN

Retrospective observational study.

SETTING & PARTICIPANTS

We studied prevalent hemodialysis patients treated at a large dialysis organization in calendar years 2012 to 2013 (N=98,972).

PREDICTOR

ESA hyporesponsiveness, defined as 2 consecutive hemoglobin measurements < 10g/dL (every other week) with contemporaneous ESA dose > 7,700U/treatment. Patients with ESA hyporesponsiveness were identified during the first quarter of 2012 and followed up through 2013 using intention-to-treat principles.

OUTCOMES

Associations between the study exposure (ESA hyporesponsiveness) and mortality, missed hemodialysis treatments, ESA and iron use, and hemoglobin levels were determined using generalized estimating equations adjusting for imbalanced baseline covariates.

RESULTS

At baseline, 12,361 (12.5%) patients were identified as having ESA hyporesponsiveness. The mean hemoglobin level among patients with ESA hyporesponsiveness was ∼1g/dL lower than in patients without ESA hyporesponsiveness at baseline, narrowing over follow-up to 0.4g/dL. Initially, mean ESA use was approximately 3-fold greater for patients with ESA hyporesponsiveness than for those without ESA hyporesponsiveness, decreasing to 2-fold greater at study end; iron use and missed hemodialysis treatment rates were also greater among patients with ESA hyporesponsiveness throughout. ESA hyporesponsiveness was associated with enhanced mortality risk versus non-ESA hyporesponsiveness: adjusted incidence rate ratios were estimated at 2.24 (95% CI, 1.93-2.60) in the second quarter, gradually decreasing to 1.48 (95% CI, 1.18-1.84) by study end.

LIMITATIONS

It is possible that an alternative ESA hyporesponsiveness definition may be optimal. As such, the associations we observed may be conservative estimates of true relationships.

CONCLUSIONS

When using a contemporary definition at one point in time, ESA hyporesponsiveness was potently and persistently associated with greater mortality, greater iron and ESA use, and lower hemoglobin levels compared to non-ESA hyporesponsiveness.

Mean platelet volume and mortality risk in a national incident hemodialysis cohort

BACKGROUND

Higher mean platelet volume (MPV) is an indicator of larger, reactive platelets, and has been associated with a higher risk of thrombosis and cardiovascular events in the general population. Hemodialysis patients have a higher risk for cardiovascular death and predisposition to platelet dysfunction (thrombosis and bleeding diathesis), but the relationship between MPV and mortality in this population is unknown.

METHODS

Among a 5-year cohort (1/2007-12/2011) of 149,118 incident hemodialysis patients from a large national dialysis organization, we examined the association between MPV and all-cause mortality. In primary analyses, we granularly analyzed MPV across five categories: 7.2-7.5, >7.5-9.5, >9.5-11.5, >11.5-13.5, and >13.5-15.0fL. In secondary analyses, we examined MPV categorized as low, normal, and high based on thresholds in the general population: 7.2-7.5, >7.5-11.5, and >11.5fL, respectively. Associations between baseline and time-dependent MPV with mortality were estimated using traditional and time-dependent Cox models in order to determine long-term and short-term exposure-mortality associations, respectively, using three adjustment levels: unadjusted, case-mix, and case-mix+laboratory models.

RESULTS

In primary analyses, higher baseline and time-dependent MPV levels were associated with incrementally higher death risk in case-mix+laboratory analyses (reference: >9.5-11.5fL). In secondary analyses, high baseline and time-dependent MPV levels were associated with higher mortality, whereas low MPV was associated with lower death risk across all multivariable models (reference: normal MPV).

CONCLUSIONS

Hemodialysis patients with higher MPV have heightened mortality risk. Further studies are needed to determine the pathophysiologic basis for the higher risk, and if modification of MPV ameliorates mortality in this population.

Residual Kidney Function Decline and Mortality in Incident Hemodialysis Patients

In patients with ESRD, residual kidney function (RKF) contributes to achievement of adequate solute clearance. However, few studies have examined RKF in patients on hemodialysis. In a longitudinal cohort of 6538 patients who started maintenance hemodialysis over a 4-year period (January 2007 through December 2010) and had available renal urea clearance (CL_urea) data at baseline and 1 year after hemodialysis initiation, we examined the association of annual change in renal CL_urea rate with subsequent survival. The median (interquartile range) baseline value and mean±SD annual change of CL_urea were 3.3 (1.9-5.0) and -1.1±2.8 ml/min per 1.73 m², respectively. Greater CL_urea rate 1 year after hemodialysis initiation associated with better survival. Furthermore, we found a gradient association between loss of RKF and all-cause mortality: changes in CL_urea rate of -6.0 and +3.0 ml/min per 1.73 m² per year associated with case mix-adjusted hazard ratios (95% confidence intervals) of 2.00 (1.55 to 2.59) and 0. 61 (0.50 to 0.74), respectively (reference: -1.5 ml/min per 1.73 m² per year). These associations remained robust against adjustment for laboratory variables and ultrafiltration rate and were consistent across strata of baseline CL_urea, age, sex, race, diabetes status, presence of congestive heart failure, and hemoglobin, serum albumin, and serum phosphorus levels. Sensitivity analyses using urine volume as another index of RKF yielded consistent associations. In conclusion, RKF decline during the first year of dialysis has a graded association with all-cause mortality among incident hemodialysis patients. The clinical benefits of RKF preservation strategies on mortality should be determined.

Prognostic Value of Serial Changes in High-Sensitivity Cardiac Troponin I and T over 3 Months Using Reference Change Values in Hemodialysis Patients

INTRODUCTION

Serial changes in cardiac troponin in hemodialysis (HD) patients have uncertain clinical implications. We evaluated associations of adverse outcomes in HD patients with reference change value (RCV) data and tertile concentrations for cardiac troponin I (cTnI) and cTnT measured by high-sensitivity (hs) assays.

METHODS

RCV data and tertiles for hs-cTnI and hs-cTnT were determined from plasma samples collected 3 months apart in 677 stable outpatient HD patients and assessed for their associations with adverse outcomes using adjusted Cox models. Primary outcomes were all-cause mortality and sudden cardiac death (SCD).

RESULTS

During a median follow-up of 23 months, 18.6% of patients died. RCVs were: hs-cTnI +37% and −30%; hs-cTnT +25% and −20%. Patients with serial hs-cTnI and hs-cTnT changes &gt;RCV (increase or decrease) had all-cause mortality of 25.2% and 23.8% respectively, compared to 15.0% and 16.5% with changes ≤RCV [adjusted hazard ratios (aHRs): 1.9, P = 0.0003 and 1.7, P = 0.0066), respectively]. Only hs-cTnI changes &gt;RCV were predictive of SCD (aHR 2.6, P = 0.005). hs–Cardiac troponin changes &gt;RCV improved all-cause mortality prognostication compared to changes ≤RCV in tertile 2: hs-cTnI aHR, 2.70 (P = 0.003); hs-cTnT aHR, 1.98 (P = 0.043). The aHR of changes in hs-cTnI in tertile 2 &gt;RCV for SCD was 5.62 (P = 0.039).

CONCLUSIONS

Changes over 3 months in hs-cTnI and hs-cTnT of &gt;RCV identified patients at greater risk of all-cause mortality, and for hs-cTnI were also predictive of SCD. Among patients with middle tertile cardiac troponin concentrations, hs-cTnI changes &gt;RCV provided additive prognostic value for both SCD and all-cause mortality, whereas those for hs-cTnT provided additive prognostic value only for all-cause mortality.

Association between Serum Potassium and Outcomes in Patients with Reduced Kidney Function

BACKGROUND AND OBJECTIVES

Patients with CKD are more likely than others to have abnormalities in serum potassium (K(+)). Aside from severe hyperkalemia, the clinical significance of K(+) abnormalities is not known. We sought to examine the association of serum K(+) with mortality and hospitalization rates within narrow eGFR strata to understand how the burden of hyperkalemia varies by CKD severity. Associations were examined between serum K(+) and discontinuation of medications that block the renin-angiotensin-aldosterone system (RAAS), which are known to increase serum K(+).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A cohort of patients with CKD (eGFR<60 ml/min per 1.73 m(2)) with serum K(+) data were studied (n=55,266) between January 1, 2009, and June 30, 2013 (study end). Serum K(+), eGFR, and covariates were considered on a time-updated basis. Mortality, major adverse cardiovascular events (MACE), hospitalization, and discontinuation of RAAS blockers were considered per time at risk.

RESULTS

During the study, serum K(+) levels of 5.5-5.9 and ≥6.0 mEq/L were most prevalent at lower eGFR: they were present, respectively, in 1.7% and 0.2% of patient-time for eGFR of 50-59 ml/min per 1.73 m(2) versus 7.6% and 1.8% of patient-time for eGFR<30 ml/min per 1.73 m(2). Serum K(+) level <3.5 mEq/L was present in 1.2%-1.4% of patient-time across eGFR strata. The median follow-up time was 2.76 years. There was a U-shaped association between serum K(+) and mortality; pooled adjusted incidence rate ratios were 3.05 (95% confidence interval, 2.53 to 3.68) and 3.31 (95% confidence interval, 2.52 to 4.34) for K(+) levels <3.5 mEq/L and ≥6.0 mEq/L, respectively. Within eGFR strata, there were U-shaped associations of serum K(+) with rates of MACE, hospitalization, and discontinuation of RAAS blockers.

CONCLUSIONS

Both hyperkalemia and hypokalemia were independently associated with higher rates of death, MACE, hospitalization, and discontinuation of RAAS blockers in patients with CKD who were not undergoing dialysis. Future studies are needed to determine whether interventions targeted at maintaining normal serum K(+) improve outcomes in this population.

Medicare Advantage associated with lower mortality for incident dialysis patients

Physicians across the care continuum are increasingly aligned around the belief that coordinated care can improve patient outcomes. As the principal caregivers for one of the most medically fragile patient groups in healthcare, nephrologists are especially attuned to the potential value of integrated care. Medicare Advantage (MA) offers one way to test this hypothesis. By law, end-stage renal disease patients currently cannot enroll into an MA plan, but if they develop ESRD while in such a plan, they may continue to be enrolled. The contrast between these patients and their counterparts who carry Medicare fee for service (MFFS) thereby represents a natural experiment that affords an opportunity to examine whether enrollment in a coordinated care system may improve outcomes. In order to promote (unbiased) comparison of patients in a non-randomized context, we propensity score-matched incident dialysis patients enrolled in MA versus those in MFFS. The data demonstrate that patients who were enrolled in an MA plan upon initiation of dialysis had a 9% lower mortality rate than their MFFS counterparts. This beneficial association of MA enrollment was found to be sustained over the first two years of dialysis treatment.

Lean Body Mass and Survival in Hemodialysis Patients and the Roles of Race and Ethnicity

BACKGROUND

Lean body mass (LBM) represents the "fat-free" muscle mass in hemodialysis (HD) patients and is an important nutritional measure. Previous studies have found that both higher LBM and body mass index (BMI) were related to greater survival in HD patients. Additional studies have shown differences in survival across racial-ethnic groups of HD patients. However, the association of LBM and mortality across racial-ethnic subgroups has not been examined.

OBJECTIVE

We hypothesize that racial differences in LBM affect the mortality in HD patients.

SETTING AND SUBJECTS

Chronic HD patients from a large dialysis organization in the United States.

PREDICTORS

Estimated LBM (eLBM), self-identified racial subgroups.

MAIN OUTCOME MEASURE

5-year survival.

STUDY DESIGN

We examined the association between baseline eLBM and survival using Cox proportional hazard models adjusted for demographics, comorbidities, and laboratory measures. Associations were examined across subgroups of race-ethnicity (non-Hispanic white, African American, and Hispanic) and BMI.

RESULTS

The final cohort included 117,683 HD patients, who were 62 ± 15 (mean ± standard deviation) years old, 43% women and 59% with diabetes mellitus. Higher eLBM was linearly associated with lower mortality. Compared with the reference group (48.4-<50.5 kg), patients with the lowest eLBM (<41.3 kg) had a 1.4-fold higher risk of mortality (hazard ratio: 1.37; 95% confidence interval: 1.30-1.44) in the fully adjusted model. A similar linear association was seen among patients with BMI < 35 kg/m(2) and in non-Hispanic whites and African American subgroups. However, higher eLBM was not associated with improved survival in Hispanic patients or patients with BMI ≥ 35 kg/m(2).

LIMITATION

Potential residual confounding.

CONCLUSIONS

Higher eLBM is associated with a lower mortality risk in HD patients, especially among non-Hispanic white and African American groups. Hispanic patients do not demonstrate a similar inverse relationship. The association between LBM and mortality among different racial groups of HD patients deserves additional study.