Large Dialysis Organization Research Articles

Racial and Ethnic Disparities in Use of and Outcomes with Home Dialysis in the United States.

Home dialysis, which comprises peritoneal dialysis (PD) or home hemodialysis (home HD), offers patients with ESRD greater flexibility and independence. Although ESRD disproportionately affects racial/ethnic minorities, data on disparities in use and outcomes with home dialysis are sparse. We analyzed data of patients who initiated maintenance dialysis between 2007 and 2011 and were admitted to any of 2217 dialysis facilities in 43 states operated by a single large dialysis organization, with follow-up through December 31, 2011 (n =: 162,050, of which 17,791 underwent PD and 2536 underwent home HD for ≥91 days). Every racial/ethnic minority group was significantly less likely to be treated with home dialysis than whites. Among individuals treated with in-center HD or PD, racial/ethnic minorities had a lower risk for death than whites; among individuals undergoing home HD, only blacks had a significantly lower death risk than whites. Blacks undergoing PD or home HD had a higher risk for transfer to in-center HD than their white counterparts, whereas Asians or others undergoing PD had a lower risk than whites undergoing PD. Blacks irrespective of dialysis modality, Hispanics undergoing PD or in-center HD, and Asians and other racial groups undergoing in-center HD were significantly less likely than white counterparts to receive a kidney transplant. In conclusion, there are racial/ethnic disparities in use of and outcomes with home dialysis in the United States. Disparities in kidney transplantation evident for blacks and Hispanics undergoing home dialysis are similar to those with in-center HD. Future studies should identify modifiable causes for these disparities.

Comparative Effectiveness of Iron and Erythropoiesis-Stimulating Agent Dosing on Health-Related Quality of Life in Patients Receiving Hemodialysis

The potential effects of iron-dosing strategies and erythropoiesis-stimulating agents (ESAs) on health-related quality of life (HRQoL) in the dialysis population are unclear. We examined the independent associations of bolus versus maintenance iron dosing and high versus low ESA dosing on HRQoL. Retrospective cohort design. Clinical data (2008-2010) from a large dialysis organization merged with data from the US Renal Data System. 13,039 patients receiving center-based hemodialysis were included. Iron and ESA dosing were assessed during 1-month (n=14,901) and 2-week (n=15,296) exposure periods. HRQoL was measured by the Kidney Disease Quality of Life (KDQOL) instrument (0-100 scale) during a 3-month follow-up period. Generalized linear mixed models, adjusting for several covariates, were used to estimate associations between iron and ESA dosing and HRQoL overall and for clinically relevant subgroups. For the 1-month exposure period, patients with lower baseline hemoglobin levels who received higher ESA dosing had higher physical health and kidney disease symptom scores (by 2.4 [95% CI, 0.6-4.2] and 5.6 [95% CI, 2.8-8.4] points, respectively) in follow-up than patients who received lower ESA dosing. For the 2-week exposure period, patients with low baseline hemoglobin levels who received bolus dosing had higher mental health scores (by 1.9 [95% CI, 0.0-3.8] points) in follow-up. Within the low-baseline-hemoglobin subgroup, individuals with a catheter or dialysis vintage less than 1 year who received higher ESA dosing had higher HRQoL scores in follow-up (by 5.0-9.9 points) and individuals with low baseline transferrin saturations who received bolus dosing had higher HRQoL scores in follow-up (by 2.6-5.8 points). Observational design; short duration of observation. For individuals with low baseline hemoglobin levels, higher ESA dosing and bolus iron dosing were associated with slightly higher HRQoL scores in follow-up. These differences became more pronounced and clinically relevant for specific subgroups.

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

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. We hypothesize that racial differences in LBM affect the mortality in HD patients. Chronic HD patients from a large dialysis organization in the United States. Estimated LBM (eLBM), self-identified racial subgroups. 5-year survival. 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. 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-<50.5kg), patients with the lowest eLBM (<41.3kg) 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 < 35kg/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 ≥ 35kg/m(2). Potential residual confounding. 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.

Peritoneal Equilibration Test and Patient Outcomes.

Although a peritoneal equilibration test yields data on three parameters (4-hour dialysate/plasma creatinine, 4- to 0-hour dialysate glucose, and 4-hour ultrafiltration volume), all studies have focused on the prognostic value of dialysate/plasma creatinine for patients undergoing peritoneal dialysis. Because dialysate 4- to 0-hour glucose and ultrafiltration volume may be superior in predicting daily ultrafiltration, the likely mechanism for the association of peritoneal equilibration test results with outcomes, we hypothesized that they are superior to dialysate/plasma creatinine for risk prediction. We examined unadjusted and adjusted associations of three peritoneal equilibration test parameters with all-cause mortality, technique failure, and hospitalization rate in 10,142 patients on peritoneal dialysis treated between January 1, 2007 and December 31, 2011 in 764 dialysis facilities operated by a single large dialysis organization in the United States, with a median follow-up period of 15.8 months; 87% were treated with automated peritoneal dialysis. Demographic and clinical parameters explained only 8% of the variability in dialysate/plasma creatinine. There was a linear association between dialysate/plasma creatinine and mortality (adjusted hazards ratio per 0.1 unit higher, 1.07; 95% confidence interval, 1.02 to 1.13) and hospitalization rate (adjusted incidence rate ratio per 0.1 unit higher, 1.05; 95% confidence interval, 1.03 to 1.06). Dialysate/plasma creatinine and dialysate glucose were highly correlated (r=-0.84) and yielded similar risk prediction. Ultrafiltration volume was inversely related with hospitalization rate but not with all-cause mortality. None of the parameters were associated with technique failure. Adding 4- to 0-hour dialysate glucose, ultrafiltration volume, or both did not result in any improvement in risk prediction with dialysate/plasma creatinine alone. This analysis from a large contemporary cohort treated primarily with automated peritoneal dialysis validates dialysate/plasma creatinine as a robust predictor of outcomes in patients treated with peritoneal dialysis.

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

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. 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. 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. 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.

Management of serum calcium reductions among patients on hemodialysis following cinacalcet initiation.

Cinacalcet is indicated for treatment of secondary hyperparathyroidism in patients receiving hemodialysis. Cinacalcet reduces serum calcium concentrations by decreasing parathyroid hormone secretion, but the frequency and degree of calcium reduction following cinacalcet initiation, subsequent physician response, and ultimate calcium recovery in clinical practice are not well described. Patients receiving hemodialysis at a large dialysis organization who enrolled in the organization's prescription benefits service and initiated cinacalcet at serum calcium ≥8.4 mg/dL were studied (N = 13 723). Patients were categorized by whether they experienced a reduction in calcium to <8.4 mg/dL and to what level (<7.5, 7.5-7.9, and 8.0-8.3 mg/dL). Baseline characteristics, frequency of subsequent intervention, and calcium recovery were compared. Of those who experienced a reduction in calcium to <8.4 mg/dL (n = 6437 [46.9%]), 6.6% had calcium <7.5 mg/dL and 24.5% had calcium 7.5-7.9 mg/dL, while the majority (68.9%) had a level of 8-8.3 mg/dL. Higher baseline parathyroid hormone and alkaline phosphatase were associated with lower resultant calcium. Among patients with calcium reductions, 45.6-63.5% received one or more directed clinical therapeutic responses, including 15.6-28.4% for whom cinacalcet was discontinued; the majority of patients recovered to calcium ≥8.4 mg/dL within 90 days of first detection. Only modest differences in recovery were noted between patients who did and did not receive any therapeutic response and patients who did and did not discontinue cinacalcet. Serum calcium reductions following cinacalcet initiation were common; declines <7.5 mg/dL were infrequent. Calcium recovery occurred in the majority of patients, with or without therapeutic intervention.

A retrospective, longitudinal study estimating the association between interdialytic weight gain and cardiovascular events and death in hemodialysis patients.

BackgroundGreater interdialytic weight gain (IDWG) is associated with risk of all-cause mortality and hospitalization. Dialysis patients are also at greater risk of cardiovascular (CV) events than patients without kidney disease. This retrospective study examined the potential association between IDWG and specific types of CV events.MethodsData were obtained from United States Renal Data System claims and the electronic health records of Medicare patients who initiated hemodialysis between 01 January 2007 and 31 December 2008 at a large dialysis organization. Absolute IDWG was defined as predialysis weight minus postdialysis weight from the prior treatment, and relative IDWG was calculated as percentage of postdialysis weight with mean values for each, calculated over dialysis days 91 to 180. Patient outcomes were considered beginning on day 181, continuing until death, discontinuation of care, censoring, or study end (31 December 2009). Outcomes included all-cause mortality, CV mortality, hospitalization for nonfatal heart failure/volume overload, hospitalization for nonfatal myocardial infarction, MACE (a composite measure of nonfatal myocardial infarction, nonfatal ischemic stroke, or CV death), and MACE+ (events comprising MACE as well as arrhythmia, nonfatal hemorrhagic stroke, or hospitalization for heart failure). Associations between IDWG and outcomes over the exposure period were estimated using proportional hazards regression and adjusted for baseline characteristics.Results39,256 patients qualified for analysis. In general, associations of relative IDWG with outcomes were more potent, consistent, and monotonic than those for absolute IDWG. Relative IDWG > 3.5 % body weight was independently associated with all outcomes studied: point estimates ranged from 1.18 (myocardial infarction) to 1.26 (CV mortality) and were consistent among patients with and without diabetes, and with and without baseline heart failure. Absolute IDWG > 3 kg was associated with outcomes other than myocardial infarction: point estimates ranged from 1.11 (MACE) to 1.20 (heart failure).ConclusionsGreater IDWG is associated with an increased risk of CV morbid events. Strategies that mitigate IDWG may improve CV health and survival among hemodialysis patients.

Hypomagnesemia and Mortality in Incident Hemodialysis Patients

In the general population, low serum magnesium levels are associated with poor outcomes and death. While limited data suggest that low baseline magnesium levels may be associated with higher mortality in hemodialysis (HD) patients, the impact of changes in magnesium levels over time is unknown. We examined the association of time-varying serum magnesium levels with all-cause mortality using multivariable time-varying survival models adjusted for clinical characteristics and other time-varying laboratory measures. 9,359 maintenance HD patients treated in a large dialysis organization between 2007 and2011. Time-varying serum magnesium levels across 5 magnesium increments (<1.8, 1.8-<2.0, 2.0-<2.2, 2.2-<2.4, and≥2.4mg/dL). All-cause mortality. 2,636 individuals died over 5 years. Time-varying serum magnesium levels< 2.0mg/dL were associated with higher mortality after adjustment for demographics and comorbid conditions, including hypertension, diabetes, and malignancies (reference: magnesium, 2.2-<2.4mg/dL): adjusted HRs for serum magnesium level< 1.8 and 1.8 to<2.0mg/dL were 1.39 (95% CI, 1.23-1.58; P<0.001) and 1.20 (95% CI, 1.06-1.36; P=0.004), respectively. Some associations were attenuated to the null after incremental adjustment for laboratory test results, particularly serum albumin. However, among patients with serum albumin measurements, low albumin level (<3.5g/dL) and magnesium level< 2.0mg/dL were associated with an additional death risk (adjusted HR, 1.17; 95% CI, 1.05-1.31; P=0.004), whereas patients with high serum albumin levels (≥3.5g/dL) exhibited low death risk (adjusted HRs of 0.53 and 0.53 [P≤0.001] for magnesium< 2.0 and≥2.0mg/dL, respectively; reference: albumin< 3.5g/dL and magnesium≥ 2.0mg/dL). Causality cannot be determined, and residual confounding cannot be excluded given the observational study design. Lower serum magnesium levels are associated with higher mortality in HD patients, including those with hypoalbuminemia. Interventional studies are warranted to examine whether correction of hypomagnesemia ameliorates adverse outcomes in this population.

Socioeconomic Status of Counties Where Dialysis Clinics Are Located Is an Important Factor in Comparing Dialysis Providers

This study assessed the hypothesis that the clinic site of service socioeconomic status (SES) represents an unmeasured confounder for clinical outcome comparisons between dialysis clinics and provider types, using data from the federal pay-for-performance program for end-stage renal disease. A total of 6506 dialysis facilities were categorized by clinic SES status (rurality and poverty status). Clinics were then grouped by provider type (chain size and tax status). Lastly, performance penalties were determined by each of these classifications. Findings were that 7.4% of dialysis clinics could be classified as being in rural locations, and 20.6% could be classified as being in high-poverty locations. Large dialysis organizations served more rural (65%) and high-poverty areas (metropolitan, 69%; micropolitan, 75%; rural, 75%) compared to other providers (medium, small, hospital/university). For-profit providers accounted for a majority of dialysis clinics in rural areas (78%) and high poverty areas (metropolitan, 84%; micropolitan, 85%; rural, 90%). This study found that dialysis clinic performance penalties did vary by SES, with poorer outcomes observed for clinic locations with lower SES. This finding, along with the nonrandom distribution of provider types by SES status, suggests that clinic and provider location SES may need to be considered when comparing providers.

Managing oral phosphate binder medication expenditures within the Medicare bundled end-stage renal disease prospective payment system: economic implications for large U.S. dialysis organizations.

From January 2016, payment for oral-only renal medications (including phosphate binders and cinacalcet) was expected to be included in the new Medicare bundled end-stage renal disease (ESRD) prospective payment system (PPS). The implementation of the ESRD PPS has generated concern within the nephrology community because of the potential for inadequate funding and the impact on patient quality of care. To estimate the potential economic impact of the new Medicare bundled ESRD PPS reimbursement from the perspective of a large dialysis organization in the United States. We developed an interactive budget impact model to evaluate the potential economic implications of Medicare payment changes to large dialysis organizations treating patients with ESRD who are receiving phosphate binders. In this analysis, we focused on the budget impact of the intended 2016 integration of oral renal drugs, specifically oral phosphate binders, into the PPS. We also utilized the model to explore the budgetary impact of a variety of potential shifts in phosphate binder market shares under the bundled PPS from 2013 to 2016. The base model predicts that phosphate binder costs will increase to $34.48 per dialysis session in 2016, with estimated U.S. total costs for phosphate binders of over $682 million. Based on these estimates, a projected Medicare PPS $33.44 reimbursement rate for coverage of all oral-only renal medications (i.e., phosphate binders and cinacalcet) would be insufficient to cover these costs. A potential renal drugs and services budget shortfall for large dialysis organizations of almost $346 million was projected. Our findings suggest that large dialysis organizations will be challenged to manage phosphate binder expenditures within the planned Medicare bundled rate structure. As a result, large dialysis organizations may have to make treatment choices in light of potential inadequate funding, which could have important implications for the quality of care for patients with ESRD.

Facility Dialysate Calcium Practices and Clinical Outcomes Among Patients Receiving Hemodialysis: A Retrospective Observational Study

Some US dialysis facilities have reduced default dialysate calcium concentrations from 2.5 mEq/L to lower levels. There has been no rigorous systematic examination of the effects of such a reduction on clinical and biochemical outcomes. Retrospective cohort study. Medicare-eligible patients who received in-center hemodialysis at a large dialysis organization in January 2008 to December 2010. Facility conversion from predominant use (≥75% patients) of 2.50-mEq/L dialysate calcium to predominant use of lower dialysate calcium concentrations versus maintenance of predominant use of 2.50-mEq/L dialysate calcium. All-cause and cause-specific mortality and hospitalization, laboratory markers of metabolic bone disease, and drug utilization. Hierarchical mixed linear and Poisson models were fit to compare pre- to postconversion differences in outcomes between converter and matched control facilities. Results, expressed as relative rate ratios (RRRs) and delta-delta (change in mean values), were estimated for early (months 0-2) and late (months 3-12) postconversion to allow for possible latent effects. Facility conversion was associated with greater rates of hospitalization for heart failure exacerbation (late RRR, 1.27 [95% CI, 1.06-1.51]), hypocalcemia (early RRR, 1.19 [95% CI, 1.05-1.35]; late RRR, 1.39 [95% CI, 1.20-1.60]), and intradialytic hypotension (early RRR, 1.07 [95% CI, 1.02-1.11]; late RRR, 1.05 [95% CI, 1.01-1.10]), but no differences were observed for all-cause mortality or hospitalization rates. Facility conversion was also associated with comparative temporal decreases in serum calcium level, increases in serum phosphate and parathyroid hormone levels, and increases in use of phosphate binders, vitamin D, and calcimimetics. Possible residual confounding, generalizability beyond Medicare patients uncertain. There are potential safety concerns associated with the default use of dialysate calcium concentrations < 2.50 mEq/L, as well as biochemical evidence of poorer disease control despite associated greater medication use. Individualization of dialysate calcium concentration rather than predominant use of dialysate calcium concentrations < 2.50 mEq/L should be considered.

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

BackgroundCinacalcet 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.MethodsUnited 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.ResultsFor 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.ConclusionsShort-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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12882-015-0030-8) contains supplementary material, which is available to authorized users.

End-stage renal disease in autosomal dominant polycystic kidney disease: a comparison of dialysis-related utilization and costs with other chronic kidney diseases.

BackgroundAutosomal dominant polycystic kidney disease (ADPKD) is the leading inheritable cause of end-stage renal disease (ESRD) and one of the leading causes of ESRD overall. ADPKD patients differ from the overall dialysis population; however, there is little published data regarding health care costs for ADPKD patients on dialysis.MethodsThis retrospective observational cohort study was designed to quantify health care utilization and costs for ADPKD patients with ESRD who received initial services at a single large dialysis organization between January 1, 2007 and December 31, 2009. Parallel results and baseline patient characteristics for control patients with ESRD etiologies other than ADPKD were performed for reference. Dialysis-related utilization and health care costs for patients with ADPKD in ESRD overall and during time horizons that correspond to Medicare-eligibility benchmarks were analyzed. Baseline patient characteristics were described for all patients and included demographics, comorbid illnesses, and clinical characteristics. Dialysis-related utilization, hospitalization rates, and health care costs were considered longitudinally.ResultsTotal health care costs for ADPKD patients were high at US$51,048 per patient-year based on the overall analysis. Total health care costs were lower for ADPKD patients than for control patients on dialysis. Patients with ADPKD were generally younger, had a lower Charlson Comorbidity Index, and had lower rates of comorbid conditions, which may have contributed to the lower overall costs seen for patients with ADPKD.ConclusionHealth care resource utilization and costs for patients with ADPKD in ESRD requiring dialysis were high, and therapeutic interventions that can prevent or delay the progression to ESRD may increase dialysis-free life for patients with ADPKD.

Consequences of hemolytic uremic syndrome among hemodialysis patients.

BackgroundHemolytic uremic syndrome (HUS) is characterized by hemolytic anemia, low platelets, and renal impairment and is mediated by thrombotic microangiopathy (TMA). A common perception is that HUS becomes dormant in dialysis patients with end-stage renal disease (ESRD). We analyzed patients in a large dialysis organization to understand the potential consequences and burden of HUS.MethodsWe identified patients with ESRD ascribed to HUS and those with ESRD ascribed to another cause (control patients) who received hemodialysis or peritoneal dialysis from 01 January 2007 to 31 December 2012. Outcomes were survival, hospitalization, and longitudinal laboratory values associated with TMA, including lactate dehydrogenase, red cell distribution width (RDW), platelets, and hemoglobin.ResultsHUS patients (n = 217) were propensity-score matched 1:5 to control patients (n = 1,085) for age, gender, race, dry weight, insurance, access, comorbidities, and Charlson comorbidity index. Compared to control patients, HUS patients had significantly greater risk for hospitalizations overall (RR = 2.3, p = 0.004) and hospitalization for hematologic (RR = 5.6, p = 0.001), cardiovascular (RR = 2.1, p = 0.02), and pancreatic (RR = 7.9, p = 0.04) causes. HUS patients also had evidence of ongoing TMA: higher lactate dehydrogenase and RDW, lower platelets and hemoglobin, and more frequent lactate dehydrogenase spikes.ConclusionsDialysis patients with HUS were at significantly higher risk than matched control patients for hospitalizations due to cardiovascular, hematologic, and pancreatic disease, which were associated with ongoing TMA. Additional studies are needed to determine whether targeted therapy for HUS reduces hospitalizations.

The economic impact of improving phosphate binder therapy adherence and attainment of guideline phosphorus goals in hemodialysis patients: a Medicare cost-offset model.

Hyperphosphatemia (serum phosphorus>5.5mg/dL) in hemodialysis patients is a key factor in mineral and bone disorders and is associated with increased hospitalization and mortality risks. Treatment with oral phosphate binders offers limited benefit in achieving target serum phosphorus concentrations due to high daily pill burden (7-10 pills/day) and associated poor medication adherence. The economic value of improving phosphate binder adherence and increasing percent time in range (PTR) for target phosphorus concentrations has not been previously assessed in dialysis patients. The current retrospective analysis was conducted to summarize health care cost savings to United States (US) payers associated with improved phosphate binder adherence and increased PTR for target phosphorus concentrations in adult end-stage renal disease (ESRD) patients receiving hemodialysis therapy. Phosphate binder adherence and PTR were derived from hemodialysis patients who were treated at a large dialysis organization between January 2007 and December 2011. Cost model inputs were derived from US Renal Data System data between July 2007 and December 2009. A cost-offset model was constructed to estimate monthly and annual incremental health care costs (total Medicare; inpatient, outpatient, and Medicare Part B) associated with different levels of phosphate binder adherence and PTR. Model inputs included number of ESRD patients, population adherence to phosphate binders, PTR associated with adherence to phosphate binders, and per-patient per-month cost associated with PTR. A base case model estimated monthly and annual costs of phosphate binder therapy in the population using estimated model inputs. The estimated adherence rate was used to determine number of patients in compliant and noncompliant groups. Monthly costs were calculated as the sum of per-patient per-month cost times the number of patients in adherent and nonadherent groups. Annual costs were monthly costs times 12 and assumed the same level of adherence, PTR, and per-patient per-month costs over time. To study the impact of improving phosphate binder adherence and PTR on cost outcomes, we hypothetically and simultaneously increased both base phosphate binders adherence and PTR for adherent patients (adherence/PTR: 10/20%, 20/40%, 30/60%). Monthly and annual costs were derived for each scenario and compared against the results of the base case model. One-way sensitivity analysis was performed to test model robustness. The base case model estimated total Medicare and inpatient costs of $5,152,342 and $1,435,644, respectively (N=1,000). When base case model costs were compared to results of each extended model scenario, overall Medicare cost savings (range 0.3-1.9%) and inpatient cost savings (range 1.2-5.7%) were observed. The one-way sensitivity analysis indicated that results were sensitive to PTR for adherent and nonadherent patients and the factor used to increase adherence rate and PTR associated with adherence in the hypothetical scenarios. However, cost savings in overall Medicare costs and inpatient costs were still noted. Increasing phosphate binder adherence and improving phosphorus control were associated with increased cost savings in total Medicare costs and inpatient costs.

Association of mortality risk with various definitions of intradialytic hypotension.

Intradialytic hypotension is a serious and frequent complication of hemodialysis; however, there is no evidence-based consensus definition of intradialytic hypotension. As a result, coherent evaluation of the effects of intradialytic hypotension is difficult. We analyzed data from 1409 patients in the HEMO Study and 10,392 patients from a single large dialysis organization to investigate the associations of commonly used intradialytic hypotension definitions and mortality. Intradialytic hypotension definitions were selected a priori on the basis of literature review. For each definition, patients were characterized as having intradialytic hypotension if they met the corresponding definition in at least 30% of baseline exposure period treatments or characterized as control otherwise. Overall and within subgroups of patients with predialysis systolic BP<120 or 120-159 mmHg, an absolute nadir systolic BP<90 mmHg was most potently associated with mortality. Within the subgroup of patients with predialysis BP≥160 mmHg, nadir BP<100 mmHg was most potently associated with mortality. Intradialytic hypotension definitions that considered symptoms, interventions, and decreases in BP during dialysis were not associated with outcome, and when added to nadir BP, symptom and intervention criteria did not accentuate associations with mortality. Our results suggest that nadir-based definitions best capture the association between intradialytic hypotension and mortality.

Use of the Tego needlefree connector is associated with reduced incidence of catheter-related bloodstream infections in hemodialysis patients.

Background and objectivesCatheter-related bloodstream infections (CRBSIs) are common in hemodialysis patients using central venous catheters, and catheter occlusion also occurs frequently. The Tego needlefree connector was developed to reduce the incidence of these complications; however, existing studies of its effectiveness and safety are limited.Materials and methodsThis retrospective analysis compared outcomes among patients of a large dialysis organization receiving in-center hemodialysis using a central venous catheter with either the Tego connector or standard catheter caps between October 1 and June 30, 2013. Incidence rates for intravenous (IV) antibiotic starts, receipt of an IV antibiotic course, positive blood cultures, mortality, and missed dialysis treatments were calculated, and incidence-rate ratios (IRRs) were estimated using Poisson regression models. Utilization of erythropoiesis-stimulating agents (ESAs) and thrombolytics was described for each patient-month and compared using mixed linear models. Models were run without adjustment, adjusted for covariates that were imbalanced between cohorts, or fully adjusted for all potential confounders.ResultsThe analysis comprised 10,652 Tego patients and 6,493 controls. Tego use was independently associated with decreased risk of CRBSI, defined by initiation of IV antibiotics (adjusted IRR 0.92, 95% confidence interval [CI] 0.87–0.97) or initiation of IV antibiotic course (adjusted IRR 0.89, 95% CI 0.84–0.95). Tego use was independently associated with decreased rate of missed dialysis treatments (adjusted IRR 0.98, 95% CI 0.97–1.00); no significant difference between Tego and control cohorts was observed with respect to mortality. Tego use was associated with decreased likelihood of thrombolytic use (adjusted per-month probability of 5.6% versus 6.2% for controls) and lower utilization of ESAs in study months 7–9.ConclusionUse of the Tego connector may reduce the risk of CRBSI and result in lower utilization of thrombolytics, antibiotics, and ESAs, as well as fewer missed dialysis treatments.

Abstract P019: Identifying Laboratory Markers of Incident Myocardial Infarction through Electronic Health Records

Background: Patients on hemodialysis (HD) are at high risk of cardiac events including myocardial infarction (MI). Electronic health records (EHRs) present a unique opportunity to observe biomedical changes in patients over time. Purpose: To assess whether there were any distinct changes in laboratory values prior to an incident MI. Methods: Using EHR data from a large dialysis organization, we identified 6,468 patients with an incident MI and selected an equal number of patients receiving dialysis on the same date without an MI. We abstracted six months of 12 regularly collected laboratory measures for their potential utility as a marker for incident MI: albumin, calcium, co2, creatinine, ferritin, hemoglobin, iron saturation, phosphorus, platelet, potassium, single pool Kt/V and white blood cell count. We used natural cubic spline regression to determine whether the trajectory of the laboratory values differed amongst patients with and without an incident MI. Results: Of the 12 laboratory measures, 7 showed a distinct change between patients with and without MI, 14 to 28 days before the incident event. Three measures were related to inflammation (white blood cell count, iron saturation, and ferritin; see Figure 1), 3 measures were related to malnutrition (albumin, creatinine, phosphorous), along with single pool kt/v. Conclusion: Distinct changes in routinely collected laboratories are observed prior to an MI. Future studies based on our results will focus on whether these changes can be used in real-time to predict MI risk in HD patients.

Revisiting the association between altitude and mortality in dialysis patients

It was recently reported that residential altitude is inversely associated with all-cause mortality among incident dialysis patients; however, no adjustment was made for key case-mix and laboratory variables. We re-examined this question in a contemporary patient database with comprehensive clinical and laboratory data. In a contemporary 8-year cohort of 144,892 maintenance dialysis patients from a large dialysis organization, we examined the relationship between residential altitude and all-cause mortality. Using data from the US Geological Survey, the average residential altitudes per approximately 43,000 US zip codes were compiled and linked to the residential zip codes of each patient. Mortality risks for these patients were estimated by Cox proportional hazard ratios. The study population's mean ± standard deviation age was 61 ± 15 years. Forty-five percent of patients were women, and 57% of patients had diabetes. In fully adjusted analysis, those residing in the highest altitude strata (≥ 6000 ft) had a lower all-cause mortality risk in fully adjusted analyses: death hazard ratio: 0.92 (95% confidence interval, 0.86-0.99), as compared with patients in the reference group (<250 ft). Residential altitude is inversely associated in all-cause mortality risk in maintenance dialysis patients notwithstanding the unknown and unmeasured confounders.

Association of pre-transplant blood pressure with post-transplant outcomes.

Previous studies have indicated U-shaped associations between blood pressure (BP) and mortality in dialysis patients. We hypothesized that a similar association exists between pre-transplant BP and post-transplant outcomes in dialysis patients who undergo successful kidney transplantation. Data from the Scientific Registry of Transplant Recipients were linked to the five-yr cohort of a large dialysis organization in the United States. We identified all dialysis patients who received a kidney transplant during this period. Unadjusted and multivariate adjusted predictors of transplant outcomes were examined. A total of 13 881 patients included in our study were 47 ± 14 yr old and included 42% women. There was no association between pre-transplant systolic BP and post-transplant mortality, although a decreased risk trend was observed in those with low post-dialysis systolic BP. Compared to patients with pre-dialysis diastolic BP 70 to <80 mmHg, patients with pre-dialysis diastolic BP <50 mmHg experienced lower risk of post-transplant death (hazard ratios [HR]: 0.74, 95% CI: 0.55-0.99). However, compared to patients with post-dialysis diastolic BP 70 to <80 mmHg, patients with post-dialysis diastolic BP ≥100 mmHg experienced higher risk of death (HR: 3.50, 95% CI: 1.57-7.84). In addition, very low (<50 mmHg for diastolic BP and <110 mmHg for systolic BP) pre-transplant BP was associated with lower risk of graft loss. Low post-dialysis systolic BP and low pre-dialysis diastolic BP are associated with lower post-transplant risk of death, whereas very high post-dialysis diastolic BP is associated with higher mortality in kidney transplant recipients. BP variations in dialysis patients prior to kidney transplantation may have a bearing on post-transplant outcome, which warrants additional studies.