A case of distal limb arterial tortuosity and dilation: observations and potential clinical significance

Arterial tortuosity describes variation via bending of the arterial wall and has been noted in several arteries throughout the body. Tortuous blood vessels can cause nerve compression, as well as present difficulties to surgeons and radiologists. Here we present an unusual case of multi-vessel arterial tortuosity discovered in 78-year-old Hispanic male cadaver, independent of systemic pathology. The left ulnar and right tibial arteries were dissected, and using calibrated digital calipers, their external and internal diameters were measured both at the origin site and at the site of greatest dilation. Both wall thickness and the number of inflection points were also measured. Six bends were noticed in the ulnar artery and its diameter measured 8.11 mm at its widest, with a wall thickness of 0.88mm. On the lower extremity, the right tibial artery had three bends and its diameter measured 4.86 mm at its widest, with a wall thickness of 1.32 mm. This uncommon tortuosity is not only more prone to laceration during surgery, but the bending and thickening can be mistaken for tumors. Finally, fluid dynamics can be altered, resulting in an impact on blood pressure in the extremities. Thus, raising awareness is crucial to prevent both symptoms and iatrogenic complications.

Optimizing serum total carbon dioxide concentration during short and nocturnal frequent hemodialysis using lactate as dialysate buffer base

INTRODUCTION

Definitive clinical studies to determine the optimal dialysate lactate concentration to prescribe during frequent hemodialysis when using the NxStage System One dialysis delivery system at low dialysate flow rates have not been reported.

METHODS

We used clinical data from patients who transferred from in-center thrice-weekly hemodialysis (ICHD) to daily home hemodialysis using the NxStage System One and the H⁺ mobilization model to calculate acid generation rates in patient sub-groups during the FREEDOM study. Assuming those acid generation rates were representative, we then predicted using the H⁺ mobilization model the effect of using dialysate lactate concentrations of 40 and 45 mEq/L on predialysis serum total carbon dioxide (tCO₂ ) concentrations in patients who transfer from ICHD to short and nocturnal frequent hemodialysis prescriptions used in current clinical practice; the prescriptions evaluated varied by treatment frequency, dialysate volume per treatment, and treatment times.

FINDINGS

With frequencies of four to six treatments per week and treatment times of 170 to 210 minutes per treatment, the effect of dialysate lactate concentration was primarily dependent on weekly dialysate volume. For weekly dialysate volumes of 150 to 160 L per week, use of dialysate lactate concentrations of 45 mEq/L, but not 40 mEq/L, resulted in an increase of predialysis serum tCO₂ concentration. When longer treatment times typical of nocturnal frequent hemodialysis were evaluated, model predictions showed that the use of dialysate lactate concentration of 45 mEq/L may not be appropriate for many patients because of excessive increases in predialysis serum tCO₂ concentration. Reducing dialysate volume from 60 to 30 L may limit the increase in predialysis serum tCO₂ concentration when patients transfer from ICHD to nocturnal frequent hemodialysis.

DISCUSSION

Predictions from the H⁺ mobilization model show that dialysate lactate concentration and weekly dialysate volume are the primary prescription parameters for optimizing predialysis serum tCO₂ concentration during short and nocturnal frequent hemodialysis.

Effect of dialysate potassium and lactate on serum potassium and bicarbonate concentrations during daily hemodialysis at low dialysate flow rates

Background

Observational studies of hemodialysis patients treated thrice weekly have shown that serum and dialysate potassium and bicarbonate concentrations are associated with patient outcomes. The effect of more frequent hemodialysis on serum potassium and bicarbonate concentrations has rarely been studied, especially for treatments at low dialysate flow rate.

Methods

These post-hoc analyses evaluated data from patients who transferred from in-center hemodialysis (HD) to daily HD at low dialysate flow rates during the FREEDOM Study. The primary outcomes were the change in predialysis serum potassium and bicarbonate concentrations after transfer from in-center HD (mean during the last 3 months) to daily HD (mean during the first 3 months).

Results

After transfer from in-center HD to daily HD (data from 345 patients, 51 ± 15 years of age, mean ± standard deviation), predialysis serum potassium decreased (P < 0.001) by approximately 0.4 mEq/L when dialysate potassium concentration during daily HD was 1 mEq/L; no change occurred when dialysate potassium concentration during daily HD was 2 mEq/L. After transfer from in-center HD to daily HD (data from 284 patients, 51 ± 15 years of age), predialysis serum bicarbonate concentration decreased (P = 0.0022) by 1.0 ± 3.3 mEq/L when dialysate lactate concentration was 40 mEq/L but increased (P < 0.001) by 2.5 ± 3.5 mEq/L when dialysate lactate concentration was 45 mEq/L. These relationships were dependent on serum potassium and bicarbonate concentrations during in-center HD.

Conclusions

Control of serum potassium and bicarbonate concentrations during daily HD at low dialysate flow rates is readily achievable; the choice of dialysate potassium and lactate concentration can be informed when transfer is from in-center HD to daily HD.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1450-7) contains supplementary material, which is available to authorized users.

Contemporary Trends in Clinical Outcomes among Dialysis Patients with Medicare Coverage

BACKGROUND

The dialysis patient population in the United States continues to grow. Trends in rates of death and hospitalization among dialysis patients have important consequences for outpatient dialysis capacity and Medicare spending.

OBJECTIVES

To estimate contemporary trends in rates of death and hospitalization among dialysis patients in the United States, overall and within subgroups.

METHODS

We used Medicare Limited Data Sets (100% sample) in 2014-2017 to estimate trends in rates of death and hospitalization among dialysis patients with Medicare Parts A and B enrollment. We used seasonal autoregressive integrated moving average models to identify secular trends in the incidence of outcomes.

RESULTS

There were 631,075 unique patients; 222,924 deaths; and 1,876,779 hospital admissions. Weekly risks of both death and hospitalization exhibited strong seasonality. However, overall weekly risks of death were 34.9, 35.4, 35.2, and 35.7 deaths per 10,000 patients in 2014-2017, respectively (p = 0.47, from a likelihood ratio test of secular trend). The overall weekly risk of hospitalization was 3.08, 3.05, 3.11, and 3.11% in 2014, 2015, 2016, and 2017, respectively (p = 0.30). There were significant secular trends in risk of death in subgroups defined by black race and residency in South Atlantic states (p < 0.05). There were also secular trends in risk of hospitalization in subgroups defined by age 20-44 years, concurrent enrollment in Medicaid, and residency in South Central states.

CONCLUSION

For the first time since the beginning of this century, rates of both death and hospitalization among dialysis patients with Medicare fee-for-service coverage have stagnated. The reasons for this change are unknown and require detailed assessment. Persistent lack of change in clinical outcomes may alter the future expectations about dialysis patient population growth.

Excess Deaths Attributable to Influenza-Like Illness in the ESRD Population

BACKGROUND

Morbidity and mortality vary seasonally. Timing and severity of influenza seasons contribute to those patterns, especially among vulnerable populations such as patients with ESRD. However, the extent to which influenza-like illness (ILI), a syndrome comprising a range of potentially serious respiratory tract infections, contributes to mortality in patients with ESRD has not been quantified.

METHODS

We used data from the Centers for Disease Control and Prevention (CDC) Outpatient Influenza-like Illness Surveillance Network and Centers for Medicare and Medicaid Services ESRD death data from 2000 to 2013. After addressing the increasing trend in deaths due to the growing prevalent ESRD population, we calculated quarterly relative mortality compared with average third-quarter (summer) death counts. We used linear regression models to assess the relationship between ILI data and mortality, separately for quarters 4 and 1 for each influenza season, and model parameter estimates to predict seasonal mortality counts and calculate excess ILI-associated deaths.

RESULTS

An estimated 1% absolute increase in quarterly ILI was associated with a 1.5% increase in relative mortality for quarter 4 and a 2.0% increase for quarter 1. The average number of annual deaths potentially attributable to ILI was substantial, about 1100 deaths per year.

CONCLUSIONS

We found an association between community ILI activity and seasonal variation in all-cause mortality in patients with ESRD, with ILI likely contributing to >1000 deaths annually. Surveillance efforts, such as timely reporting to the CDC of ILI activity within dialysis units during influenza season, may help focus attention on high-risk periods for this vulnerable population.

Identifying High-Risk Individuals for Chronic Kidney Disease: Results of the CHERISH Community Demonstration Project

BACKGROUND

Most people with chronic kidney disease (CKD) are not aware of their condition.

OBJECTIVES

To assess screening criteria in identifying a population with or at high risk for CKD and to determine their level of control of CKD risk factors.

METHOD

CKD Health Evaluation Risk Information Sharing (CHERISH), a demonstration project of the Centers for Disease Control and Prevention, hosted screenings at 2 community locations in each of 4 states. People with diabetes, hypertension, or aged ≥50 years were eligible to participate. In addition to CKD, screening included testing and measures of hemoglobin A1C, blood pressure, and lipids. -Results: In this targeted population, among 894 people screened, CKD prevalence was 34%. Of participants with diabetes, 61% had A1C < 7%; of those with hypertension, 23% had blood pressure < 130/80 mm Hg; and of those with high cholesterol, 22% had low-density lipoprotein < 100 mg/dL.

CONCLUSIONS

Using targeted selection criteria and simple clinical measures, CHERISH successfully identified a population with a high CKD prevalence and with poor control of CKD risk factors. CHERISH may prove helpful to state and local programs in implementing CKD detection programs in their communities.

Volume of urea cleared as a therapy dosing guide for more frequent hemodialysis

INTRODUCTION

With dialysis delivery systems that operate at low dialysate flow rates, prescriptions for more frequent hemodialysis (HD) employ dialysate volume as the primary parameter for small solute removal rather than blood-side urea dialyzer clearance (K). Such delivery systems, however, yield dialysate concentrations that almost completely saturate with blood (water), suggesting that the volume of urea cleared (the product of K and treatment time or Kt) can be readily estimated from the prescribed dialysate volume to target small solute removal. Methods For more frequent HD, we examined the volume of urea cleared per treatment required to achieve a minimal dose of small solute removal, comparing results based on body surface area (BSA) with those based on KDOQI clinical practice guidelines, that is, a weekly stdKt/V of 2.1. Estimates of the target volume of urea cleared were calculated for 4, 5, and 6 treatments per week, and compared for patients with different anthropometric estimates of total body water volume (V_ant ). BSA was assumed proportional to V_ant ^0.8 , and residual kidney function was neglected. Findings Whether based on BSA or weekly stdKt/V of 2.1, the target volume of urea cleared per treatment required to achieve a minimal dose of small solute removal was lower at higher treatment frequency. As with conventional thrice-weekly HD, target volumes of urea cleared for more frequent HD based on BSA were larger for patients with small V_ant and smaller for patients with large V_ant than those based on a weekly stdKt/V of 2.1. Discussion Prescription of more frequent HD using the volume of urea cleared per treatment, calculated from the prescribed dialysate volume, is simple in principle and can be readily implemented in clinical practice when using dialysis delivery systems that operate at low dialysate flow rates. Other aspects of dialysis adequacy require additional consideration.

Readmissions Following a Hospitalization for Cardiovascular Events in Dialysis Patients: A Retrospective Cohort Study

Background

Hospitalization for cardiovascular disease (CVD) is common among patients receiving maintenance dialysis, but patterns of readmissions following cardiovascular events are underexplored.

Methods and Results

In this retrospective analysis of prevalent, Medicare‐eligible patients receiving dialysis in 2012–2013, all live‐discharge hospitalizations attributed to CVD were ascertained. Rates of all‐cause, CVD‐related, and non–CVD‐related readmissions and death in the ensuing 10 and 30 days were calculated. Multinomial logistic modeling was used to assess the relationship between potential explanatory factors and outcomes of interest. Among 142 210 analyzed hospitalizations, mean age at time of index CVD hospitalization was 64.9±14.1 years; 50.4% of index hospitalizations were for women, and 41.4% were for white patients. Fully 15.6% and 34.2% of CVD hospitalizations resulted in readmission within 10 and 30 days, respectively; less than half of readmissions were CVD related (42.5%, 10 days; 43.1%, 30 days). Death within 30 days, regardless of readmission, occurred after 4.5% of index hospitalizations; 51.2% were attributed to CVD. Compared with ages 65 to 69 years, younger age tended to be associated with increased readmission risk (adjusted relative risk for ages 18–44 years: 1.55; 95% confidence interval, 1.48–1.63). Readmission risk did not differ between white and black patients, but risk of death without readmission was markedly lower for black patients (relative risk: 0.60; 95% confidence interval, 0.55–0.67).

Conclusions

Roughly 1 in 3 CVD hospitalizations resulted in 30‐day readmission; nearly 1 in 20 was followed by death within 30 days. Risk of death without readmission was higher for white than black patients, despite no difference in risk of readmission.

Relative risk of home hemodialysis attrition in patients using a telehealth platform

INTRODUCTION

Home hemodialysis (HHD) facilitates increased treatment frequency, which may improve patient outcomes. However, attrition due to technique failure limits the clinical effectiveness of the modality. Nx2me Connected Health is a telehealth platform that enables ongoing assessment of HHD patients using NxStage equipment, and that may reduce patient burden. We aimed to assess whether use of Nx2me was associated with risk of HHD attrition.

METHODS

We compared risks of all-cause attrition, dialysis cessation (i.e., death or transplant), and technique failure in Nx2me users and matched control patients, using a retrospective cohort study. We also compared the likelihood of HHD training graduation in patients who initiated use of Nx2me during training with the likelihood in matched control patients. Matching factors included date of HHD initiation, NxStage treatment duration at initiation of follow-up, and prescribed treatment frequency. We used stratified Fine-Gray and Cox regression to compare risks, with adjustment for demographic factors and vascular access modality, and stratification by matched cluster.

FINDINGS

We identified 606 Nx2me users; 49.5% initiated use of Nx2me in <3 months after initiation of HHD with NxStage equipment. Adjusted hazard ratios (AHRs) of all-cause attrition, dialysis cessation, and technique failure were 0.80 (95% confidence interval, 0.68-0.95), 1.10 (0.86-1.41), and 0.71 (0.57-0.87), respectively, for Nx2me users vs. matched controls. AHRs were similar in patients who initiated use of Nx2me in <3 months after initiation of HHD. The AHR of HHD training graduation was 1.61 (1.10-2.36) in patients who initiated use of Nx2me within 2 weeks of training initiation vs. matched controls.

DISCUSSION

Use of Nx2me was associated with lower risk of all-cause attrition, lower risk of technique failure, and higher likelihood of HHD training graduation. Further studies are needed to identify the mechanisms by which use of a telehealth platform may improve clinical outcomes and reduce patient burden.

Insights From the 2016 Peer Kidney Care Initiative Report: Still a Ways to Go to Improve Care for Dialysis Patients

Although outcomes improved during the past decade for patients receiving maintenance dialysis, gains were few in certain key areas, as highlighted in the 2016 Peer Kidney Care Initiative Report. Overall incidence rates of dialysis therapy initiation in adults remained relatively stable (∼42 per 100,000 US population, 2009-2013), but rates varied more than 2-fold, from 26 to 54, across US geographic regions. Hospitalization rates in incident patients decreased from 261 hospitalizations per 100 patient-years in 2003 to 207 in 2012, but observation stay rates increased from 40 to 67, attenuating the decline in hospitalizations by half. Decreases in prevalent patient hospitalizations for heart failure, from 15.6 per 100 patient-years in 2004 to 9.5 in 2013, were partially offset by increases in hospitalizations for volume overload, from 3.0 in 2004 to 6.1 in 2013. Prevalent patient rates of hospitalizations for arrhythmias (∼4.6 per 100 patient-years) did not improve during the past decade, whereas sudden cardiac death as a proportion of total cardiovascular deaths increased from 53% to 73%. Hospitalization rates for pneumonia/influenza, at about 8.3 per 100 patient-years in prevalent patients, did not decrease during this period, while hospitalization rates for bacteremia/sepsis increased from 8.6 to 12.0. If decreases in mortality rates are to be sustained, novel approaches to these challenges will be required.

Association of Serum Potassium with All-Cause Mortality in Patients with and without Heart Failure, Chronic Kidney Disease, and/or Diabetes

BACKGROUND

The relationship between serum potassium, mortality, and conditions commonly associated with dyskalemias, such as heart failure (HF), chronic kidney disease (CKD), and/or diabetes mellitus (DM) is largely unknown.

METHODS

We reviewed electronic medical record data from a geographically diverse population (n = 911,698) receiving medical care, determined the distribution of serum potassium, and the relationship between an index potassium value and mortality over an 18-month period in those with and without HF, CKD, and/or DM. We examined the association between all-cause mortality and potassium using a cubic spline regression analysis in the total population, a control group, and in HF, CKD, DM, and a combined cohort.

RESULTS

27.6% had a potassium <4.0 mEq/L, and 5.7% had a value ≥5.0 mEq/L. A U-shaped association was noted between serum potassium and mortality in all groups, with lowest all-cause mortality in controls with potassium values between 4.0 and <5.0 mEq/L. All-cause mortality rates per index potassium between 2.5 and 8.0 mEq/L were consistently greater with HF 22%, CKD 16.6%, and DM 6.6% vs. controls 1.2%, and highest in the combined cohort 29.7%. Higher mortality rates were noted in those aged ≥65 vs. 50-64 years. In an adjusted model, all-cause mortality was significantly elevated for every 0.1 mEq/L change in potassium <4.0 mEq/L and ≥5.0 mEq/L. Diuretics and renin-angiotensin-aldosterone system inhibitors were related to hypokalemia and hyperkalemia respectively.

CONCLUSION

Mortality risk progressively increased with dyskalemia and was differentially greater in those with HF, CKD, or DM.

Use of the Medicare database in epidemiologic and health services research: a valuable source of real-world evidence on the older and disabled populations in the US

Medicare is the federal health insurance program for individuals in the US who are aged ≥65 years, select individuals with disabilities aged <65 years, and individuals with end-stage renal disease. The Centers for Medicare and Medicaid Services grants researchers access to Medicare administrative claims databases for epidemiologic and health outcomes research. The data cover beneficiaries’ encounters with the health care system and receipt of therapeutic interventions, including medications, procedures, and services. Medicare data have been used to describe patterns of morbidity and mortality, describe burden of disease, compare effectiveness of pharmacologic therapies, examine cost of care, evaluate the effects of provider practices on the delivery of care and patient outcomes, and explore the health impacts of important Medicare policy changes. Considering that the vast majority of US citizens ≥65 years of age have Medicare insurance, analyses of Medicare data are now essential for understanding the provision of health care among older individuals in the US and are critical for providing real-world evidence to guide decision makers. This review is designed to provide researchers with a summary of Medicare data, including the types of data that are captured, and how they may be used in epidemiologic and health outcomes research. We highlight strengths, limitations, and key considerations when designing a study using Medicare data. Additionally, we illustrate the potential impact that Centers for Medicare and Medicaid Services policy changes may have on data collection, coding, and ultimately on findings derived from the data.

Impact of Renal Disease on Patients with Hepatitis C: A Retrospective Analysis of Disease Burden, Clinical Outcomes, and Health Care Utilization and Cost

BACKGROUND/AIMS

Few studies explore the magnitude of the disease burden and health care utilization imposed by renal disease among patients with hepatitis C virus (HCV). We aimed to describe the characteristics, outcomes, and health care utilization and costs of patients with HCV with and without renal impairment.

METHODS

This retrospective analysis used 2 administrative claims databases: the US commercially insured population in Truven Health MarketScan® data (aged 20-64 years), and the US Medicare fee-for-service population in the Medicare 20% sample (aged ≥65 years). Baseline characteristics and comorbid conditions were identified from claims during 2011; patients were followed for up to 1 year (beginning January 1, 2012) to identify health outcomes of interest and health care utilization and costs.

RESULTS

In the MarketScan and Medicare databases, 35,965 and 10,608 patients with HCV were identified, 8.5 and 26.5% with evidence of renal disease (chronic kidney disease [CKD] or end-stage renal disease [ESRD]). Most comorbid conditions and unadjusted outcome rates increased across groups from patients with no evidence of renal disease to non-ESRD CKD to ESRD. Health care utilization followed a similar pattern, as did the costs.

CONCLUSIONS

Our findings suggest that HCV patients with concurrent renal disease have significantly more comorbidity, a higher likelihood of negative health outcomes, and higher health care utilization and costs.

The Healthy People 2020 Objectives for Kidney Disease: How Far Have We Come, and Where Do We Need to Go?

The Healthy People 2020 initiative established goals for patients with CKD and ESRD. We assessed United States progress toward some of these key goals. Using data from the Centers for Medicare and Medicaid Services ESRD database, we created yearly cohorts of patients on incident and prevalent dialysis from 2000 to 2013. Change in event rate or proportion change over the study years was modeled using Poisson regression with adjustment for age, race, sex, and primary cause of ESRD. For all-cause mortality in prevalent patients, Healthy People 2020 sought approximately 0.8% relative annual improvement; actual improvement was 2.7%. Improvement was greatest for patients ages 18-44 years old (3.8%; P<0.01 versus 2.8% for ages 65-74 years old) and 2.3% even for patients ages ≥75 years old. For mortality in incident patients, the relative annual decrease was 2.1% overall, a twofold improvement over the goal; mortality decreased nearly twice as much in black as in white patients (3.2% versus 1.8%; P<0.001). Geographic variation was substantial; the relative annual decrease was 0.6% in the Midwest and more than fourfold greater (2.7%) in the South. Cardiovascular mortality in prevalent patients decreased dramatically at 5.0% per year, far exceeding the annual goal of approximately 0.8%; the decrease was greatest in patients ages ≥75 years old (5.5%; P<0.001 versus ages 65-74 years old; 5.1%). The relative annual increase in percentages of patients with a fistula at dialysis initiation was 2.4%, roughly three times the goal; the increase was greater for black than white patients (3.2% versus 2.3%; P<0.01). Adjusted regional differences varied greater than twofold: 2.0% for the South versus 4.1% for the Midwest. Thus, although gains have been substantial, not all groups have benefitted equally. Goal development for Healthy People 2030 should consider changes in goal paradigms, such as tailoring by geographic region and incorporating patient-centered goals.

Association between adjuvant chemotherapy and risk of acute kidney injury in elderly women diagnosed with early-stage breast cancer

PURPOSE

We studied elderly Medicare enrollees newly diagnosed with early-stage breast cancer to examine the association between adjuvant chemotherapy and acute kidney injury (AKI).

METHODS

Using the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we conducted a retrospective cohort study including women diagnosed with stages I-III breast cancer at ages 66-89 years between 1992 and 2007. We performed one-to-one matching on time-dependent propensity score on the day of adjuvant chemotherapy initiation within 6 months after the first cancer-directed surgery based on the estimated probability of chemotherapy initiation at each day for each patient, using a Cox proportional hazards model. We estimated the cumulative incidence of AKI using Kaplan-Meier methods. We used Cox proportional hazards models to evaluate the association between chemotherapy and the risk of AKI, and compared the risk among major chemotherapy types.

RESULTS

The study included 28,048 women. The 6-month cumulative incidence of AKI was 0.80% for chemotherapy-treated patients, compared with 0.30% for untreated patients (P < 0.001). Adjuvant chemotherapy was associated with a nearly threefold increased risk of AKI [hazard ratio (HR) 2.73; 95% CI 1.8-4.1]. Compared with anthracycline-based chemotherapy, the HRs (95% CIs) were 1.66 (0.94-2.91), 0.88 (0.53-1.47), and 1.15 (0.57-2.32) for taxane-based, CMF, and other chemotherapy, respectively.

CONCLUSION

Our findings showed that adjuvant chemotherapy was associated with increased risk of AKI in elderly women diagnosed with early-stage breast cancer. The risk seemed to vary by regimen type, but the differences were not statistically significant.

Geographic variation of parathyroidectomy in patients receiving hemodialysis: a retrospective cohort analysis

Background

Secondary hyperparathyroidism (SHPT) is associated with adverse outcomes in patients receiving maintenance dialysis. Parathyroidectomy is a treatment for SHPT; whether parathyroidectomy utilization varies geographically in the US is unknown.

Methods

A retrospective cohort analysis was undertaken to identify all patients aged 18 years or older who were receiving in-center hemodialysis between 2007 and 2009, were covered by Medicare Parts A and B, and had been receiving hemodialysis for at least 1 year. Parathyroidectomy was identified from inpatient claims using relevant International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes. Patient characteristics and End-Stage Renal Disease Network (a proxy for geography) were ascertained. Adjusted odds ratios for parathyroidectomy were estimated from a logistic model.

Results

A total of 286,569 patients satisfied inclusion criteria, of whom 4435 (1.5%) underwent PTX. After adjustment for a variety of patient characteristics, there was a 2-fold difference in adjusted odds of parathyroidectomy between the most- and least-frequently performing regions. Adjusted odds ratios were more than 20% higher than average in four networks, and more than 20% lower in four networks.

Conclusions

Parathyroidectomy use varies substantially by geography in the US; the factors responsible should be further investigated.

Facility-level CKD-MBD composite score and risk of adverse clinical outcomes among patients on hemodialysis

BACKGROUND

Patients receiving hemodialysis with values outside of target levels for parathyroid hormone (PTH: 150-600 pg/mL), calcium (Ca: 8.4-10.2 mg/dL), and phosphate (P: 3.5-5.5 mg/dL) are at elevated morbidity and mortality risk. We examined whether patients receiving care in dialysis facilities where greater proportions of patients have at least two values out of target have a higher risk of adverse clinical outcomes.

METHODS

The study cohort consisted of 39,085 prevalent hemodialysis patients in 1298 DaVita dialysis facilities as of September 1, 2009, followed from January 1, 2010, until an outcome, a censoring event, or December 31, 2010. We determined the quintile of the distribution across facilities of the proportion of patients with at least two of three parameters out of, or above, target over a 4-month baseline period. The primary composite outcome was cardiovascular hospitalization or death. Secondary outcomes included death, cardiovascular hospitalization, and parathyroidectomy. Poisson regression models were used to estimate the association of facility quintile with outcomes.

RESULTS

Facility quintile was associated with a 7 % increased risk of cardiovascular hospitalization or death (quintile 5 versus 1, RR 1.07, 95 % CI 1.01-1.13) using the out-of-target measure of exposure and a 12 % increased risk (RR 1.12, 95 % CI 1.06-1.19) using the above-target measure. No association was seen for death using either measure. Patients in facility quintiles 3-5 (versus 1) were at increased parathyroidectomy risk (RR ranged from 2.05, 95 % CI 1.10-3.82, for quintile 3 to 2.73, 95 % CI 1.50-4.98, for quintile 5).

CONCLUSIONS

Facility level analysis of a large prevalent sample of US patients on hemodialysis demonstrates that patients in facilities with the least control of PTH, Ca, and P had the greatest risk of parathyroidectomy or the combination of cardiovascular hospitalization or death.

Epoetin Alfa and Outcomes in Dialysis amid Regulatory and Payment Reform

Erythropoiesis-stimulating agents (ESAs) are commonly used to treat anemia in patients with CKD, including those receiving dialysis, although clinical trials have identified risks associated with ESA use. We evaluated the effects of changes in dialysis payment policies and product labeling instituted in 2011 on mortality and major cardiovascular events across the United States dialysis population in an open cohort study of patients on dialysis from January 1, 2005, through December 31, 2012, with Medicare as primary payer. We compared observed rates of death and major cardiovascular events in 2011 and 2012 with expected rates calculated on the basis of rates in 2005-2010, accounting for differences in patient characteristics and influenza virulence. An abrupt decline in erythropoietin dosing and hemoglobin concentration began in late 2010. Observed rates of all-cause mortality, cardiovascular mortality, and myocardial infarction in 2011 and 2012 were consistent with expected rates. During 2012, observed rates of stroke, venous thromboembolic disease (VTE), and heart failure were lower than expected (absolute deviation from trend per 100 patient-years [95% confidence interval]: -0.24 [-0.08 to -0.37] for stroke, -2.43 [-1.35 to -3.70] for VTE, and -0.77 [-0.28 to -1.27] for heart failure), although non-ESA-related changes in practice and Medicare payment penalties for rehospitalization may have confounded the results. This initial evidence suggests that action taken to mitigate risks associated with ESA use and changes in payment policy did not result in a relative increase in death or major cardiovascular events and may reflect improvements in stroke, VTE, and heart failure.

Geovariation in Fracture Risk among Patients Receiving Hemodialysis

BACKGROUND AND OBJECTIVES

Fractures are a major source of morbidity and mortality in patients receiving dialysis. We sought to determine whether rates of fractures and tendon ruptures vary geographically.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data from the US Renal Data System were used to create four yearly cohorts, 2007-2010, including all eligible prevalent patients on hemodialysis in the United States on January 1 of each year. A secondary analysis comprising patients in a large dialysis organization conducted over the same period permitted inclusion of patient-level markers of mineral metabolism. Patients were grouped into 10 regions designated by the Centers for Medicare and Medicaid Services and divided by latitude into one of three bands: south, <35°; middle, 35° to <40°; and north, ≥40°. Poisson regression was used to calculate unadjusted and adjusted region-level rate ratios for events.

RESULTS

Overall, 327,615 patients on hemodialysis were included. Mean (SD) age was 61.8 (15.0) years old, 52.7% were white, and 55.0% were men. During 716,962 person-years of follow-up, 44,014 fractures and tendon ruptures occurred, the latter being only 0.3% of overall events. Event rates ranged from 5.36 to 7.83 per 100 person-years, a 1.5-fold rate difference across regions. Unadjusted region-level rate ratios varied from 0.83 (95% confidence interval, 0.81 to 0.85) to 1.20 (95% confidence interval, 1.18 to 1.23), a 1.45-fold rate difference. After adjustment for a wide range of case mix variables, a 1.33-fold variation in rates remained. Rates were higher in north and middle bands than the south (north rate ratio, 1.18; 95% confidence interval, 1.13 to 1.23; middle rate ratio, 1.13; 95% confidence interval, 1.10 to 1.17). Latitude explained 11% of variation, independent of region. A complementary analysis of 87,013 patients from a large dialysis organization further adjusted for circulating mineral metabolic parameters and protein energy wasting yielded similar results.

CONCLUSIONS

Rates of fractures vary geographically in the United States dialysis population, even after adjustment for known patient characteristics. Latitude seems to contribute to this phenomenon, but additional analyses exploring whether other factors might influence variation are warranted.

Improving Outcomes in Patients Receiving Dialysis: The Peer Kidney Care Initiative

The past decade has witnessed a marked reduction in mortality rates among patients receiving maintenance dialysis. However, the reasons for this welcome development are uncertain, and greater understanding is needed to translate advances in care into additional survival gains. To fill important knowledge gaps and to enable dialysis provider organizations to learn from one another, with the aim of advancing patient care, the Peer Kidney Care Initiative (Peer) was created in 2014 by the chief medical officers of 14 United States dialysis provider organizations and the Chronic Disease Research Group. Areas of particular clinical importance were targeted to help shape the public health agenda in CKD and ESRD. Peer focuses on the effect of geographic variation on outcomes, the implications of seasonality for morbidity and mortality, the clinical significance of understudied disorders affecting dialysis patients, and the debate about how best to monitor and evaluate progress in care. In the realm of geovariation, Peer has provided key observations on regional variation in the rates of ESRD incidence, hospitalization, and pre-ESRD care. Regarding seasonality, Peer has reported on variation in both infection-related and non-infection-related hospitalizations, suggesting that ambient environmental conditions may affect a range of health outcomes in dialysis patients. Specific medical conditions that Peer highlights include Clostridium difficile infection, which has become strikingly more common in patients in the year after dialysis initiation, and chronic obstructive pulmonary disease, the treatments for which have the potential to contribute to sudden cardiac death. Finally, Peer challenges the nephrology community to consider alternatives to standardized mortality ratios in assessing progress in care, positing that close scrutiny of trends over time may be the most effective way to drive improvements in patient care.

Effects of the prospective payment system on anemia management in maintenance dialysis patients: implications for cost and site of care

Background

The 2011 expanded Prospective Payment System (PPS) and contemporaneous Food and Drug Administration label revision for erythropoiesis-stimulating agents (ESAs) were associated with changes in ESA use and mean hemoglobin levels among patients receiving maintenance dialysis. We aimed to investigate whether these changes coincided with increased red blood cell transfusions or changes to Medicare-incurred costs or sites of anemia management care in the period immediately before and after the introduction of the PPS, 2009–2011.

Methods

From US Medicare end-stage renal disease (ESRD) data (Parts A and B claims), maintenance hemodialysis patients from facilities that initially enrolled 100 % into the ESRD PPS were identified. Dialysis and anemia-related costs per-patient-per-month (PPPM) were calculated at the facility level, and transfusion rates were calculated overall and by site of care (outpatient, inpatient, emergency department, observation stay).

Results

More than 4100 facilities were included. Transfusions in both the inpatient and outpatient environments increased. In the inpatient environment, PPPM use increased by 11–17 % per facility in each quarter of 2011 compared with 2009; in the outpatient environment, PPPM use increased overall by 5.0 %. Site of care for transfusions appeared to have shifted. Transfusions occurring in emergency departments or during observation stays increased 13.9 % and 26.4 %, respectively, over 2 years.

Conclusions

Inpatient- and emergency-department-administered transfusions increased, providing some evidence for a partial shift in the cost and site of care for anemia management from dialysis facilities to hospitals. Further exploration into the economic implications of this increase is necessary.

Shaping Public Health Initiatives in Kidney Diseases: The Peer Kidney Care Initiative

BACKGROUND

While broad-based societal efforts to improve public health have targeted disorders such as cardiovascular disease and cancer for several decades, efforts devoted to kidney disease have developed only more recently. The Peer Kidney Care Initiative, a novel effort designed to address knowledge gaps in the care of patients with kidney disease, examines key disease processes, the roles of geography and seasonality on outcomes, and longitudinal trends in outcomes over time.

SUMMARY

Admissions for gastrointestinal bleeds increased approximately 28% between 2004 and 2011 in prevalent patients. Infection with Clostridium difficile increased nearly 70% between 2003 and 2010 in patients within a year of initiation. Admissions for heart failure in prevalent patients decreased approximately 25% between 2004 and 2012, but admissions for volume overload increased a nearly equal amount. Incidence rates varied substantially by geographic region, such that unadjusted rates in the highest region were nearly double than those in the lowest. There was seasonal variation in all-cause mortality of approximately 15-20% in both incident and prevalent patients, suggesting a link between cardiovascular events and seasonally related environmental conditions. New cases of end-stage renal disease fell from 385 per million population in 2003 to 344 in 2012, a decline of approximately 10%.

KEY MESSAGES

Peer complements existing kidney disease epidemiologic efforts by examining specific actionable disease entities, exploring geographic variation in care, highlighting the role of seasonality on outcomes, and emphasizing the importance of trending outcomes over time as overall societal progress is being made.

Multinational Assessment of Accuracy of Equations for Predicting Risk of Kidney Failure: A Meta-analysis

IMPORTANCE

Identifying patients at risk of chronic kidney disease (CKD) progression may facilitate more optimal nephrology care. Kidney failure risk equations, including such factors as age, sex, estimated glomerular filtration rate, and calcium and phosphate concentrations, were previously developed and validated in 2 Canadian cohorts. Validation in other regions and in CKD populations not under the care of a nephrologist is needed.

OBJECTIVE

To evaluate the accuracy of the risk equations across different geographic regions and patient populations through individual participant data meta-analysis.

DATA SOURCES

Thirty-one cohorts, including 721,357 participants with CKD stages 3 to 5 in more than 30 countries spanning 4 continents, were studied. These cohorts collected data from 1982 through 2014.

STUDY SELECTION

Cohorts participating in the CKD Prognosis Consortium with data on end-stage renal disease.

DATA EXTRACTION AND SYNTHESIS

Data were obtained and statistical analyses were performed between July 2012 and June 2015. Using the risk factors from the original risk equations, cohort-specific hazard ratios were estimated and combined using random-effects meta-analysis to form new pooled kidney failure risk equations. Original and pooled kidney failure risk equation performance was compared, and the need for regional calibration factors was assessed.

MAIN OUTCOMES AND MEASURES

Kidney failure (treatment by dialysis or kidney transplant).

RESULTS

During a median follow-up of 4 years of 721,357 participants with CKD, 23,829 cases kidney failure were observed. The original risk equations achieved excellent discrimination (ability to differentiate those who developed kidney failure from those who did not) across all cohorts (overall C statistic, 0.90; 95% CI, 0.89-0.92 at 2 years; C statistic at 5 years, 0.88; 95% CI, 0.86-0.90); discrimination in subgroups by age, race, and diabetes status was similar. There was no improvement with the pooled equations. Calibration (the difference between observed and predicted risk) was adequate in North American cohorts, but the original risk equations overestimated risk in some non-North American cohorts. Addition of a calibration factor that lowered the baseline risk by 32.9% at 2 years and 16.5% at 5 years improved the calibration in 12 of 15 and 10 of 13 non-North American cohorts at 2 and 5 years, respectively (P = .04 and P = .02).

CONCLUSIONS AND RELEVANCE

Kidney failure risk equations developed in a Canadian population showed high discrimination and adequate calibration when validated in 31 multinational cohorts. However, in some regions the addition of a calibration factor may be necessary.

End-stage renal disease from hemolytic uremic syndrome in the United States, 1995-2010

Management of hemolytic uremic syndrome (HUS) has evolved rapidly, and optimal treatment strategies are controversial. However, it is unknown whether the burden of end-stage renal disease (ESRD) from HUS has changed, and outcomes on dialysis in the United States are not well described. We retrospectively examined data for patients initiating maintenance renal replacement therapy (RRT) (n = 1,557,117), 1995-2010, to define standardized incidence ratios (SIRs) and outcomes of ESRD from HUS) (n = 2241). Overall ESRD rates from HUS in 2001-2002 were 0.5 cases/million per year and were higher for patients characterized by age 40-64 years (0.6), ≥65 years (0.7), female sex (0.6), and non-Hispanic African American race (0.7). Standardized incidence ratios remained unchanged (P ≥ 0.05) between 2001-2002 and 2009-2010 in the overall population. Compared with patients with ESRD from other causes, patients with HUS were more likely to be younger, female, white, and non-Hispanic. Over 5.4 years of follow-up, HUS patients differed from matched controls with ESRD from other causes by lower rates of death (8.3 per 100 person-years in cases vs. 10.4 in controls, P < 0.001), listing for renal transplant (7.6 vs. 8.6 per 100 person-years, P = 0.04), and undergoing transplant (6.9 vs. 9 per 100 person-years, P < 0.001). The incidence of ESRD from HUS appears not to have risen substantially in the last decade. However, given that HUS subtypes could not be determined in this study, these findings should be interpreted with caution.

Changes in secondary hyperparathyroidism-related biochemical parameters and medication use following parathyroidectomy

BACKGROUND

Little is known about changes in parathyroid hormone (PTH), calcium and phosphorous levels after parathyroidectomy in hemodialysis patients. We studied the effects of parathyroidectomy on these biochemical values in a large cohort of patients receiving maintenance hemodialysis.

METHODS

This retrospective cohort study included patients identified in both the United States Renal Data System and the database of a large dialysis organization who underwent parathyroidectomy in 2007-09, were aged ≥ 18 years, had Medicare Parts A and B as primary payer and had received hemodialysis for ≥ 1 year pre-parathyroidectomy. Descriptive statistics were calculated for continuous variables; categorical variables were used to characterize the population and evaluate monthly laboratory and medication use; median values were calculated for laboratory measures.

RESULTS

Among 1402 parathyroidectomy patients, mean age was 48.9 years, 52.4% were males, 58.8% were African American and mean dialysis duration was 7.5 years. Median PTH levels increased over the year before parathyroidectomy from 1039 to 1661 pg/mL and decreased afterward to 98 pg/mL at 1 month; levels remained ≥ 897 pg/mL for 10% of patients. Median calcium levels fell from 9.6 mg/dL before to 7.9 mg/dL 1 month after parathyroidectomy; levels were ≤ 7.1 mg/dL for 25% and remained ≤ 7.2 mg/dL for the lowest 25% at 3 months. Median phosphorous level was 6.8 mg/dL immediately before parathyroidectomy, decreased to 3.8 mg/dL immediately after and reached 5.8 mg/dL at 1 year.

CONCLUSIONS

While PTH levels dropped after parathyroidectomy for most patients, surgery was sometimes ineffective in reducing levels and sometimes led to over-suppression. Hypocalcemia could be profound and long lasting, suggesting the need for prolonged vigilance.

Trends in anemia management practices in patients receiving hemodialysis and peritoneal dialysis: a retrospective cohort analysis

BACKGROUND/AIMS

Recent changes in clinical practice guidelines and reimbursement policies may have affected the use of anemia-related medications and red blood cell (RBC) transfusions in peritoneal dialysis (PD) and hemodialysis (HD) patients. We sought to compare patterns of erythropoiesis-stimulating agents (ESA) and intravenous (IV) iron use, achieved hemoglobin levels, and RBC transfusion use in PD and HD patients.

METHODS

In quarterly cohorts of prevalent dialysis patients receiving persistent therapy (>3 months), 2007-2011, with Medicare Parts A and B coverage, we assessed ESA and IV iron use and dose, RBC transfusions, and hemoglobin levels. Quarterly transfusion rates were calculated.

RESULTS

Observable PD and HD patients numbered 14,958 and 221,866 in Q1/2007 and 17,842 and 256,942 in Q4/2011. Adjusted ESA use was lower in PD (71.4-80.1%) than in HD (86.9-92.0%) patients, decreasing from 80.1% (Q1/2010) to 71.4% (Q4/2011) in PD patients, and from 92.0 to 86.9% in HD patients. The mean adjusted ESA dose decreased by 67.5% in PD and 58.4% in HD patients. IV iron use tended to increase, peaking at 39.3% for PD (Q3/2011) and 80.5% for HD (Q2/2011) patients. Adjusted mean hemoglobin levels fell from 11.7 to 10.6 mg/dl in PD and from 12.0 to 10.7 mg/dl in HD ESA users; adjusted transfusion rates increased from 2.4 to 3.0 per 100 patient-months in PD and from 2.6 to 3.3 in HD patients.

CONCLUSIONS

In patients receiving persistent dialysis, dose and frequency of ESA administrations decreased during the period 2007-2011. Mean hemoglobin levels decreased by more than 1 g/dl, while transfusion rates increased by approximately 25%.

United States Renal Data System public health surveillance of chronic kidney disease and end-stage renal disease

The United States Renal Data System (USRDS) began in 1989 through US Congressional authorization under National Institutes of Health competitive contracting. Its history includes five contract periods, two of 5 years, two of 7.5 years, and the fifth, awarded in February 2014, of 5 years. Over these 25 years, USRDS reporting transitioned from basic incidence and prevalence of end-stage renal disease (ESRD), modalities, and overall survival, as well as focused special studies on dialysis, in the first two contract periods to a comprehensive assessment of aspects of care that affect morbidity and mortality in the second two periods. Beginning in 1999, the Minneapolis Medical Research Foundation investigative team transformed the USRDS into a total care reporting system including disease severity, hospitalizations, pediatric populations, prescription drug use, and chronic kidney disease and the transition to ESRD. Areas of focus included issues related to death rates in the first 4 months of treatment, sudden cardiac death, ischemic and valvular heart disease, congestive heart failure, atrial fibrillation, and infectious complications (particularly related to dialysis catheters) in hemodialysis and peritoneal dialysis patients; the burden of congestive heart failure and infectious complications in pediatric dialysis and transplant populations; and morbidity and access to care. The team documented a plateau and decline in incidence rates, a 28% decline in death rates since 2001, and changes under the 2011 Prospective Payment System with expanded bundled payments for each dialysis treatment. The team reported on Bayesian methods to calculate mortality ratios, which reduce the challenges of traditional methods, and introduced objectives under the Health People 2010 and 2020 national health care goals for kidney disease.

Abstract P3-07-30: Association between adjuvant chemotherapy and risk of chronic kidney disease in elderly women diagnosed with early stage breast cancer

Background: Chronic kidney disease (CKD) and cancer are major public health problems in the elderly population. With the development of cancer screening and efficacious treatments including chemotherapy (chemo), the number of cancer survivors has been increasing. In elderly cancer patients (pts), little is known about CKD as a late effect of chemo. This study examined the association between adjuvant chemo and risk of CKD in elderly women diagnosed with early stage breast cancer (BC).

Methods: This retrospective cohort study used the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare data. Women diagnosed with stages I-III breast cancer (BC) at ages 66-89 years between 1992-2007 were included. We preformed 1-1 sequential matching on time-dependent propensity score on the day of adjuvant chemo initiation within 6 months after the first surgery. Follow-up (F/U) began on the matching date and ended at CKD diagnosis, death, change in enrollment status, or December 31, 2009. For pts in the matched untreated cohort, F/U time was also censored at chemo initiation. Chemo was identified in claims through billing codes indicating drugs or administration. Regimens of interest included anthracyclines (A), CMF, taxanes (T, no anthracyclines), and others. CKD was identified through diagnosis codes in Medicare claims. The cumulative incidence of CKD was assessed using the Kaplan-Meier method. The association between adjuvant chemo and risk of CKD was evaluated using a Cox proportional hazards model. The analyses were repeated by regimen type.

Results: The matched study cohorts included 28,048 pts. The mean (standard deviation) F/U time was 5.1 (3.4) years for the chemo cohort and 3.3 (3.6) years for the matched no-chemo cohort. CKD rate (standard error) was 29.0 (0.6) and 29.3 (0.8) per 1000 patient-years in chemo and no-chemo pts, respectively. Overall, there was no significant difference in the cumulative incidence of CKD between the two cohorts (chemo vs. no-chemo, 47.2% vs. 49%; P=0.91). Adjuvant chemo was not associated with increased risk of developing CKD (HR 1.00, 95% CI 0.93-1.07). Of chemo-treated pts, 53%, 31%, 7%, and 8% received an A-based, a CMF, a T-based, and other regimens, respectively. Though the association between adjuvant chemo and risk of CKD varied across regimen types, these associations were not statistically significant (Table).

Regimen TypeTotal, nMean (SD) F/U time, yearsRate of CKD (1000 pt-yrs)Adjusted HR (95% CI)*No chemo140243.3 (3.6)29.3ReferenceA-based74654.8 (3.0)27.70.96 (0.88-1.04)CMF43896.0 (3.9)29.11.04 (0.95-1.14)T-based10302.8 (1.8)39.40.91 (0.74-1.12)Other11405.1 (4.0)31.21.04 (0.89-1.22)*Adjusted for patient baseline characteristics and trastuzumab use

Conclusion: Adjuvant chemo in elderly women with BC may not impose additional risk for CKD. This finding suggests that patients’ underlying risk factors for CKD such as diabetes, hypertension, etc. should be considered in the discussions between clinicians and pts regarding potential risk of CKD development after chemo treatment and choice of chemo treatment.

Citation Format: Shuling Li, Jiannong Liu, Beth A Virnig, Allan J Collins. Association between adjuvant chemotherapy and risk of chronic kidney disease in elderly women diagnosed with early stage breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-07-30.

Abstract P3-07-29: Association between adjuvant chemotherapy and risk of acute kidney injury in elderly women diagnosed with early stage breast cancer

Background: Acute kidney injury (AKI) is a serious complication of cancer and its treatment, causing delay or interruptions in cancer therapy and increased risk of adverse outcomes including premature death. Little is known from large population-based cohort studies about the association between chemotherapy (chemo) and risk of AKI in elderly cancer patients (pts).

Methods: This retrospective cohort study used the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare data. Women diagnosed with stages I-III breast cancer (BC) at ages 66-89 years between 1992-2007 were included. We performed 1-1 sequential matching on time-dependent propensity score on the day of adjuvant chemo initiation within 6 months (mos) after the first surgery. Follow-up (F/U) began on the matching date and ended at AKI occurrence, chronic kidney disease diagnosis, death, change in enrollment status, or 6 mos after the matching date. For pts in the matched untreated cohort, F/U time was also censored at chemo initiation. Chemo was identified in claims through billing codes indicating drugs or administration. Regimens of interest included anthracyclines (A), CMF, taxanes (T, no anthracyclines), and others. AKI was identified in hospital claims. The cumulative incidence of AKI was assessed using the Kaplan-Meier method. The association between adjuvant chemo and risk of AKI was evaluated using a Cox proportional hazards model. The analyses were repeated by regimen type.

Results: The matched study cohorts included 28,048 pts. The mean (standard deviation) F/U time was 6.0 (0.8) mos for the chemo cohort and 4.3 (2.5) mos for the matched no-chemo cohort. The cumulative incidence of AKI at mos 1, 3, and 6 was 0.24%, 0.50%, and 0.80% for pts receiving chemo, compared with 0.05%, 0.17%, and 0.30% for no-chemo pts (P&lt;0.001). Adjuvant chemo was associated with a 2.7-fold increased risk of AKI (HR 2.7, 95% CI 1.8-4.1; P&lt;0.001), despite a very low overall incidence rate (16 and 6 per 1000 person-years in chemo and no-chemo pts, respectively). Further examination of distribution of other diseases coded on hospital claims in AKI pts showed that septicemia occurred in 40% of chemo-treated pts with AKI and in only 17% of untreated pts with AKI. Of chemo-treated pts, 53%, 31%, 7%, and 8% received an A-based, a CMF, a T-based, and other regimens, respectively. Each regimen was significantly associated with increased risk of AKI, with the strongest association for a T-based regimen (HR 4.2, 95% CI 2.2-7.8), the weakest for a CMF regimen (HR 2.2, 95% CI, 1.3-3.8), and intermediate associations for an A-based regimen (HR 2.5, 95% CI 1.6-4.1) and others (HR 3.0, 95% CI 1.5-6.2), but the effect of these regimens did not significantly differ from each other.

Conclusion: Adjuvant chemo is associated with increased risk of AKI in elderly women diagnosed with early stage BC. This association may be partially explained by septicemia caused by infection/neutropenia due to use of myelosuppressive chemotherapeutic agents, highlighting the importance of preventing serious complications of chemo in preventing AKI.

Citation Format: Shuling Li, Jiannong Liu, Beth A Virnig, Allan J Collins. Association between adjuvant chemotherapy and risk of acute kidney injury in elderly women diagnosed with early stage breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-07-29.

Parathyroid hormone change after cinacalcet initiation and one-year clinical outcome risk: a retrospective cohort study

BACKGROUND

Cinacalcet reduces parathyroid hormone (PTH) levels in patients receiving hemodialysis, but no non-experimental studies have evaluated the association between changes in PTH levels following cinacalcet initiation and clinical outcomes. We assessed whether short-term change in PTH levels after first cinacalcet prescription could serve as a surrogate marker for improvements in longer-term clinical outcomes.

METHODS

United States Renal Data System data were linked with data from a large dialysis organization. We created a point prevalent cohort of adult hemodialysis patients with Medicare as primary payer who initiated cinacalcet November 1, 2004-February 1, 2007, and were on cinacalcet for ≥ 40 days. We grouped patients into quartiles of PTH change after first cinacalcet prescription. We used Cox proportional hazard modeling to evaluate associations between short-term PTH change and time to first composite event (hospitalization for cardiovascular events or mortality) within 1 year. Overall models and models stratified by baseline PTH levels were adjusted for several patient-related factors.

RESULTS

For 2485 of 3467 included patients (72%), PTH levels decreased after first cinacalcet prescription; for 982 (28%), levels increased or were unchanged. Several characteristics differed between PTH change groups, including age and mineral-and-bone-disorder laboratory values. In adjusted models, we did not identify an association between greater short-term PTH reduction and lower composite event rates within 1 year, overall or in models stratified by baseline PTH levels.

CONCLUSIONS

Short-term change in PTH levels after first cinacalcet prescription does not appear to be a useful surrogate for longer-term improvements in cardiovascular or survival risk.

One-year mortality rates in US children with end-stage renal disease

BACKGROUND/AIMS

Few published data describe survival rates for pediatric end-stage renal disease (ESRD) patients. We aimed to describe one-year mortality rates for US pediatric ESRD patients over a 15-year period.

METHODS

In this retrospective cohort study, we used the US Renal Data System database to identify period-prevalent cohorts of patients aged younger than 19 for each year during the period 1995-2010. Yearly cohorts averaged approximately 1,200 maintenance dialysis patients (60% hemodialysis, 40% peritoneal dialysis) and 1,100 transplant recipients. Patients were followed for up to 1 year and censored at change in modality, loss to follow-up, or death. We calculated the unadjusted model-based mortality rates per time at risk, within each cohort year, by treatment modality (hemodialysis, peritoneal dialysis, transplant) and patient characteristics; percentage of deaths by cause; and overall adjusted odds of mortality by characteristics and modality.

RESULTS

Approximately 50% of patients were in the age group 15-18, 55% were male, and 45% were female. The most common causes of ESRD were congenital/reflux/obstructive causes (55%) and glomerulonephritis (30%). One-year mortality rates showed evidence of a decrease in the number of peritoneal dialysis patients (6.03 per 100 patient-years, 1995; 2.43, 2010; p = 0.0263). Mortality rates for transplant recipients (average 0.68 per 100 patient-years) were consistently lower than the rates for all dialysis patients (average 4.36 per 100 patient-years).

CONCLUSIONS

One-year mortality rates differ by treatment modality in pediatric ESRD patients.

End-stage renal disease attributed to acute tubular necrosis in the United States, 2001-2010

BACKGROUND/AIMS

Though end-stage renal disease (ESRD) is increasingly attributed to acute tubular necrosis (ATN), contemporary trends in the rates of incidence and recovery of renal function are poorly defined. Hence, we set out to describe the clinical epidemiology of ESRD due to ATN between 2001 and 2010.

METHODS

We examined United States Renal Data System data (n = 1,070,490) for 2001 through 2010 to calculate the incidence rates and rates of renal recovery and death for patients with ESRD due to ATN treated with renal replacement therapy (RRT, n = 27,603).

RESULTS

Standardized incidence ratios increased between 2001-2002 and 2009-2010 in the overall population (ratio 2.14), having risen in all demographic subgroups examined. Recovery of renal function was more likely in patients with ATN than in matched controls (cumulative incidence 23% vs. 2% at 12 weeks, 34% vs. 4% at 1 year), as was death (cumulative incidence 38% vs. 27% at 1 year). Hazards ratios for renal recovery increased stepwise with year of RRT inception to 1.34 (95% confidence interval 1.24-1.45) for 2009-2010 (vs. 2001-2002). In contrast, hazards ratios for death declined stepwise to 0.83 (0.79-0.87) in 2009-2010.

CONCLUSION

While the incidence of ESRD attributed to ATN has increased, prospects of renal recovery and survival have also increased. Despite substantial mortality risk on RRT, renal recovery is not a rare occurrence.

ESRD from lupus nephritis in the United States, 1995-2010

BACKGROUND AND OBJECTIVES

While ESRD from lupus nephritis (ESLN) increased in the United States after the mid-1990s and racial disparities were apparent, current trends are unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Retrospective US Renal Data System data (n=1,557,117) were used to calculate standardized incidence ratios (standardized to 1995-1996) and outcomes of ESLN (n=16,649). For events occurring after initiation of RRT, follow-up ended on June 30, 2011.

RESULTS

Overall ESLN rates (95% confidence intervals [95% CIs]) in 1995-1996 were 3.1 (2.9 to 3.2) cases per million per year. Rates were higher for subgroups characterized by African-American race (11.1 [95% CI, 10.3 to 11.9]); other race (4.9 [95% CI, 4.0 to 5.8]); female sex (4.9 [95% CI, 4.6 to 5.2]); and ages 20-29 years (4.9 [95% CI, 4.4 to 5.4]), 30-44 years (4.6 [95% CI, 4.2 to 5.0]), and 45-64 years (4.0 [95% CI, 3.7 to 4.4]). Standardized incidence ratios for the overall population in subsequent biennia were 1.19 (1.14 to 1.24) in 1997-1998, 1.17 (1.12 to 1.22) in 1999-2000, 1.17 (1.12 to 1.22) in 2001-2002, 1.21 (1.16 to 1.26) in 2003-2004, 1.18 (1.13 to 1.23) in 2005-2006, 1.16 (1.11 to 1.21) in 2007-2008, and 1.05 (1.01 to 1.09) in 2009-2010, respectively. During a median (interquartile range) follow-up of 4.4 (6.3) years, 42.6% of patients with ESLN died, 45.3% were listed for renal transplant, and 28.7% underwent transplantation. Patients with ESLN were more likely than matched controls to be listed for and to undergo transplantation, and mortality rates were similar. Among patients with ESLN, African Americans were less likely to undergo transplantation (adjusted hazard ratio, 0.54 [0.51 to 0.58]) and more likely to die prematurely (adjusted hazard ratio, 1.23 [1.17 to 1.30]).

CONCLUSIONS

While ESLN appears to have stopped increasing in the last decade, racial disparities in outcomes persist.

Clinical outcomes after parathyroidectomy in a nationwide cohort of patients on hemodialysis

BACKGROUND AND OBJECTIVES

Patients receiving dialysis undergo parathyroidectomy to improve laboratory parameters in resistant hyperparathyroidism with the assumption that clinical outcomes will also improve. However, no randomized clinical trial data demonstrate the benefits of parathyroidectomy. This study aimed to evaluate clinical outcomes up to 1 year after parathyroidectomy in a nationwide sample of patients receiving hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using data from the US Renal Data System, this study identified prevalent hemodialysis patients aged ≥18 years with Medicare as primary payers who underwent parathyroidectomy from 2007 to 2009. Baseline characteristics and comorbid conditions were assessed in the year preceding parathyroidectomy; clinical events were identified in the year preceding and the year after parathyroidectomy. After parathyroidectomy, patients were censored at death, loss of Medicare coverage, kidney transplant, change in dialysis modality, or 365 days. This study estimated cause-specific event rates for both periods and rate ratios comparing event rates in the postparathyroidectomy versus preparathyroidectomy periods.

RESULTS

Of 4435 patients who underwent parathyroidectomy, 2.0% died during the parathyroidectomy hospitalization and the 30 days after discharge. During the 30 days after discharge, 23.8% of patients were rehospitalized; 29.3% of these patients required intensive care. In the year after parathyroidectomy, hospitalizations were higher by 39%, hospital days by 58%, intensive care unit admissions by 69%, and emergency room/observation visits requiring hypocalcemia treatment by 20-fold compared with the preceding year. Cause-specific hospitalizations were higher for acute myocardial infarction (rate ratio, 1.98; 95% confidence interval, 1.60 to 2.46) and dysrhythmia (rate ratio 1.4; 95% confidence interval1.16 to 1.78); fracture rates did not differ (rate ratio 0.82; 95% confidence interval 0.6 to 1.1).

CONCLUSIONS

Parathyroidectomy is associated with significant morbidity in the 30 days after hospital discharge and in the year after the procedure. Awareness of clinical events will assist in developing evidence-based risk/benefit determinations for the indication for parathyroidectomy.