Medical Director Practice of Advising Increased Dietary Protein Intake in Hemodialysis Patients With Hyperphosphatemia: Associations With Mortality in the Dialysis Outcomes and Practice Patterns Study.

OBJECTIVES: Patients undergoing hemodialysis (HD) may have poor nutritional status and hyperphosphatemia. Nephrologists sometimes manage hyperphosphatemia by prescribing phosphate binders and/or recommending restriction of dietary phosphate including protein-rich foods; the later may, however, adversely affect nutritional status. DESIGN AND METHODS: The analysis includes 8805 HD patients on dialysis ≥ 120 days in 12 countries in Dialysis Outcomes and Practice Patterns Study (DOPPS) phase 4 (2009-2011), from 248 facilities. The primary exposure variable was response to the following question: "For patients with serum albumin 3.0 g/dL and phosphate 6.0 mg/dL, do you recommend to (A) increase or (B) decrease/no change in dietary protein intake (DPI)?". The association between medical director's practice of recommending an increase in DPI and all-cause mortality was analyzed with Cox regression adjusted for potential confounders. Linear and logistic regressions were used to model the cross-sectional associations between DPI advice practice and intermediate markers of patient nutrition. RESULTS: Median follow-up was 1.6 years. In the case scenario, 91% of medical directors in North America had a practice of recommending DPI increase compared to 58% in Europe (range = 36%-83% across 7 countries) and 56% in Japan. The practice of advising DPI increase was weakly associated with lower mortality [HR (95% CI): 0.88 (0.76-1.02)]. The association tended to be stronger in patients with age 70+ years [HR (95% CI): 0.82 (0.69-0.97), P = .12 for interaction]. The practice of advising DPI increase was associated with 0.276 mg/dL higher serum creatinine levels (95% CI: 0.033-0.520) after adjustment for case mix. CONCLUSIONS: Medical director's practice of recommending an increase in DPI for HD patients with low albumin and high phosphate levels was associated with higher serum creatinine levels and potentially lower all-cause mortality. To recommend protein intake liberalization in parallel with phosphate management by physicians may be a critical practice for better nutritional status and outcomes in HD patients.

Peritoneal Dialysis-Related Infection Rates and Outcomes: Results From the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS).

RATIONALE & OBJECTIVE: Peritoneal dialysis (PD)-related peritonitis carries high morbidity for PD patients. Understanding the characteristics and risk factors for peritonitis can guide regional development of prevention strategies. We describe peritonitis rates and the associations of selected facility practices with peritonitis risk among countries participating in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS). STUDY DESIGN: Observational prospective cohort study. SETTING & PARTICIPANTS: 7,051 adult PD patients in 209 facilities across 7 countries (Australia, New Zealand, Canada, Japan, Thailand, United Kingdom, United States). EXPOSURES: Facility characteristics (census count, facility age, nurse to patient ratio) and selected facility practices (use of automated PD, use of icodextrin or biocompatible PD solutions, antibiotic prophylaxis strategies, duration of PD training). OUTCOMES: Peritonitis rate (by country, overall and variation across facilities), microbiology patterns. ANALYTICAL APPROACH: Poisson rate estimation, proportional rate models adjusted for selected patient case-mix variables. RESULTS: 2,272 peritonitis episodes were identified in 7,051 patients (crude rate, 0.28 episodes/patient-year). Facility peritonitis rates were variable within each country and exceeded 0.50/patient-year in 10% of facilities. Overall peritonitis rates, in episodes per patient-year, were 0.40 (95% CI, 0.36-0.46) in Thailand, 0.38 (95% CI, 0.32-0.46) in the United Kingdom, 0.35 (95% CI, 0.30-0.40) in Australia/New Zealand, 0.29 (95% CI, 0.26-0.32) in Canada, 0.27 (95% CI, 0.25-0.30) in Japan, and 0.26 (95% CI, 0.24-0.27) in the United States. The microbiology of peritonitis was similar across countries, except in Thailand, where Gram-negative infections and culture-negative peritonitis were more common. Facility size was positively associated with risk for peritonitis in Japan (rate ratio [RR] per 10 patients, 1.07; 95% CI, 1.04-1.09). Lower peritonitis risk was observed in facilities that had higher automated PD use (RR per 10 percentage points greater, 0.95; 95% CI, 0.91-1.00), facilities that used antibiotics at catheter insertion (RR, 0.83; 95% CI, 0.69-0.99), and facilities with PD training duration of 6 or more (vs <6) days (RR, 0.81; 95% CI, 0.68-0.96). Lower peritonitis risk was seen in facilities that used topical exit-site mupirocin or aminoglycoside ointment, but this association did not achieve conventional levels of statistical significance (RR, 0.79; 95% CI, 0.62-1.01). LIMITATIONS: Sampling variation, selection bias (rate estimates), and residual confounding (associations). CONCLUSIONS: Important international differences exist in the risk for peritonitis that may result from varied and potentially modifiable treatment practices. These findings may inform future guidelines in potentially setting lower maximally acceptable peritonitis rates.

Prevalence, incidence, and risk factors for hepatitis C virus infection in hemodialysis patients.

Hepatitis C virus (HCV) infection is common in dialysis patients and is associated with increased morbidity and mortality. We used the Dialysis Outcomes and Practice Patterns Study (DOPPS, 1996-2015) to assess trends in the prevalence, incidence, and risk factors for HCV infection as defined by a documented diagnosis or antibody positivity. Among prevalent hemodialysis patients, HCV prevalence was nearly 10% in 2012-2015. Prevalence ranged from 4% in Belgium to as high as 20% in the Middle East, with intermediate prevalence in China, Japan, Italy, Spain, and Russia. HCV prevalence decreased over time in most countries participating in more than one phase of DOPPS, and prevalence was around 5% among patients who had recently (<4 months) initiated dialysis. The incidence of HCV infection decreased from 2.9 to 1.2 per 100 patient-years in countries participating in the initial phase of DOPPS. Although most units reported no seroconversions, 10% of units experienced 3 or more cases over a median of 1.1 years. High HCV prevalence in the hemodialysis unit was a powerful facility-level risk factor for seroconversion, but the use of isolation stations for HCV-positive patients was not associated with significantly lower seroconversion rates. Overall, despite a trend toward lower HCV prevalence among hemodialysis patients, the prevalence of HCV infection remains higher than in the general population. Combined with a high prevalence of HCV infection among patients with Stage 5 CKD, high rates of HCV seroconversion in a subset of hemodialysis units may contribute to this disparity.

Regional variation in the treatment and prevention of peritoneal dialysis-related infections in the Peritoneal Dialysis Outcomes and Practice Patterns Study.

BACKGROUND: Peritoneal dialysis (PD)-related infections lead to significant morbidity. The International Society for Peritoneal Dialysis (ISPD) guidelines for the prevention and treatment of PD-related infections are based on variable evidence. We describe practice patterns across facilities participating in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS). METHODS: PDOPPS, a prospective cohort study, enrolled nationally representative samples of PD patients in Australia/New Zealand (ANZ), Canada, Thailand, Japan, the UK and the USA. Data on PD-related infection prevention and treatment practices across facilities were obtained from a survey of medical directors'. RESULTS: A total of 170 centers, caring for >11 000 patients, were included. The proportion of facilities reporting antibiotic administration at the time of PD catheter insertion was lowest in the USA (63%) and highest in Canada and the UK (100%). Exit-site antimicrobial prophylaxis was variably used across countries, with Japan (4%) and Thailand (28%) having the lowest proportions. Exit-site mupirocin was the predominant exit-site prophylactic strategy in ANZ (56%), Canada (50%) and the UK (47%), while exit-site aminoglycosides were more common in the USA (72%). Empiric Gram-positive peritonitis treatment with vancomycin was most common in the UK (88%) and USA (83%) compared with 10-45% elsewhere. Empiric Gram-negative peritonitis treatment with aminoglycoside therapy was highest in ANZ (72%) and the UK (77%) compared with 10-45% elsewhere. CONCLUSIONS: Variation in PD-related infection prevention and treatment strategies exist across countries with limited uptake of ISPD guideline recommendations. Further work will aim to understand the impact these differences have on the wide variation in infection risk between facilities and other clinically relevant PD outcomes.

Mineral and bone disorder management in hemodialysis patients: comparing PTH control practices in Japan with Europe and North America: the Dialysis Outcomes and Practice Patterns Study (DOPPS).

BACKGROUND: High-circulating level of parathyroid hormone (PTH) is associated with elevated mortality in dialysis patients. The Japanese Society for Dialysis Therapy guideline suggests a lower PTH target than other international guidelines; thus, PTH control may differ in Japan compared with other regions, and be associated with mortality. METHODS: We analyzed data from hemodialysis patients with ≥3 measurements of PTH during the first 9 months after enrollment in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4-5 (2009-2015). PTH control was assessed by the mean, slope, and mean squared error (MSE) of all PTH measurements over the 9-month run-in period. Distribution of each PTH control was assessed by regions (Europe/Australia/New Zealand [Eur/ANZ], Japan and North America) and dialysis vintage. Mortality rates were compared across PTH control categories using Cox regression models. RESULTS: Mean PTH was lower in Japan than in other regions across dialysis vintage categories. In patients with dialysis vintage < 90 days, PTH level was more likely to decline > 5% per month in Japan (48% of patients) versus Eur/ANZ (35%) and North America (35%). In patients with dialysis vintage > 1 year, Japanese patients maintained steady PTH, while patients in Eur/ANZ and North America were more likely to experience a PTH increase. Mean PTH was associated with mortality in the overall samples (highest mortality rate for PTH > 600 pg/mL, hazard ratio, 1.35; 95% confidence interval, 1.20 to 1.52 vs PTH 200-399 pg/mL), and the association was obvious in the prevalent patients (hazard ratio, 1.44; 95% confidence interval, 1.26 to 1.65). PTH slope and MSE did not show significant association with mortality in the overall sample as well as in subjects stratified both by region and dialysis vintage. CONCLUSION: PTH control in hemodialysis patients, as measured by keeping a stable PTH level over 9 months, was observed in Japan contrasted with other regions. High PTH mean, but not increased PTH slope and MSE, was associated with mortality especially in prevalent patients.

Unique hemoglobin A1c level distribution and its relationship with mortality in diabetic hemodialysis patients.

Diabetic hemodialysis patients with hemoglobin A1c (HbA1c) levels below 6.5% and over 8.0% face a higher mortality risk. To determine the optimal glycemic control in Japanese patients, we examined the association between HbA1c and mortality in 2,300 Japanese diabetic patients on maintenance hemodialysis with HbA1c levels determined at enrollment in the Japanese Dialysis Outcomes and Practice Patterns Study (JDOPPS) phases 2-5, using Cox regression analysis with adjustment for baseline age, sex, dialysis vintage, 12 general comorbidities, hemoglobin, albumin and creatinine levels, and insulin use; stratification by JDOPPS phase; and facility clustering taken into account. Overall, 54% of patients had HbA1c levels under 6.0, including 14% with HbA1c levels under 5.0. Insulin or oral diabetes medications were used less frequently in patients with higher HbA1c levels. The dependence of mortality on HbA1c level was U shaped. When the group with the lowest mortality (HbA1c 6.0-7.0) was used as a reference, the hazard ratios for HbA1c categories under 5.0, 5.0-6.0, 7.0 to under 8.0, and 8.0 and greater were, respectively, 1.56 (95% confidence interval, 1.05-2.33), 1.26 (0.92-1.71), 1.23 (0.79-1.89), and 2.10 (1.32-3.33) in the adjusted model. The HbA1c level was not associated with self-reported hypoglycemic episodes in JDOPPS phase 5. The HbA1c levels in diabetic hemodialysis patients differ considerably between Japan and those reported from Western countries. Thus, our findings highlight the importance of domestic guidelines for glycemic control by race and country.

Interdialytic Weight Gain: Trends, Predictors, and Associated Outcomes in the International Dialysis Outcomes and Practice Patterns Study (DOPPS).

BACKGROUND: High interdialytic weight gain (IDWG) is associated with adverse outcomes in hemodialysis (HD) patients. We identified temporal and regional trends in IDWG, predictors of IDWG, and associations of IDWG with clinical outcomes. STUDY DESIGN: Analysis 1: sequential cross-sections to identify facility- and patient-level predictors of IDWG and their temporal trends. Analysis 2: prospective cohort study to assess associations between IDWG and mortality and hospitalization risk. SETTING & PARTICIPANTS: 21,919 participants on HD therapy for 1 year or longer in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 2 to 5 (2002-2014). PREDICTORS: Analysis 1: study phase, patient demographics and comorbid conditions, HD facility practices. Analysis 2: relative IDWG, expressed as percentage of post-HD weight (<0%, 0%-0.99%, 1%-2.49%, 2.5%-3.99% [reference], 4%-5.69%, and ≥5.7%). OUTCOMES: Analysis 1: relative IDWG as a continuous variable using linear mixed models; analysis 2: mortality; all-cause and cause-specific hospitalization using Cox regression, adjusting for potential confounders. RESULTS: From phase 2 to 5, IDWG declined in the United States (-0.29kg; -0.5% of post-HD weight), Canada (-0.25kg; -0.8%), and Europe (-0.22kg; -0.5%), with more modest declines in Japan and Australia/New Zealand. Among modifiable factors associated with IDWG, the most notable was facility mean dialysate sodium concentration: every 1-mEq/L greater dialysate sodium concentration was associated with 0.13 (95% CI, 0.11-0.16) greater relative IDWG. Compared to relative IDWG of 2.5% to 3.99%, there was elevated risk for mortality with relative IDWG≥5.7% (adjusted HR, 1.23; 95% CI, 1.08-1.40) and elevated risk for fluid-overload hospitalization with relative IDWG≥4% (HRs of 1.28 [95% CI, 1.09-1.49] and 1.64 [95% CI, 1.27-2.13] for relative IDWGs of 4%-5.69% and ≥5.7%, respectively). LIMITATIONS: Possible residual confounding. No dietary salt intake data. CONCLUSIONS: Reductions in IDWG during the past decade were partially explained by reductions in dialysate sodium concentration. Focusing quality improvement strategies on reducing occurrences of high IDWG may improve outcomes in HD patients.

International Comparisons to Assess Effects of Payment and Regulatory Changes in the United States on Anemia Practice in Patients on Hemodialysis: The Dialysis Outcomes and Practice Patterns Study.

For years, erythropoiesis-stimulating agent (ESA) use among patients on dialysis was much higher in the United States than in Europe or Japan. Sweeping changes to dialysis reimbursement and regulatory policies for ESA in the United States in 2011 were expected to reduce ESA use and hemoglobin levels. We used the Dialysis Outcomes and Practice Patterns Study (DOPPS) data from 7129 patients in 223 in-center hemodialysis facilities (average per month) to estimate and compare time trends in ESA dose and hemoglobin levels among patients on hemodialysis in the United States, Germany, Italy, Spain, the United Kingdom, and Japan. From 2010 to 2013, substantial declines in ESA use and hemoglobin levels occurred in the United States but not in other DOPPS countries. Between August of 2010 and April of 2013, mean weekly ESA dose in the United States decreased 40.4% for black patients and 38.0% for nonblack patients; mean hemoglobin decreased from 11.5 g/dl in black patients and 11.4 g/dl in nonblack patients to 10.6 g/dl in both groups. In 2010 and 2013, adjusted weekly ESA doses per kilogram were 41% and 11% lower, respectively, in patients in Europe and 60% and 18% lower, respectively, in patients in Japan than in nonblack patients in the United States. Adjusted hemoglobin levels in 2010 and 2013 were 0.07 g/dl lower and 0.56 g/dl higher, respectively, in patients in Europe and 0.93 and 0.01 g/dl lower, respectively, in patients in Japan than in nonblack patients in the United States. In conclusion, ESA dosing reductions in the United States likely reflect efforts in response to changes in reimbursement policy and regulatory guidance.

Functional Dependence and Mortality in the International Dialysis Outcomes and Practice Patterns Study (DOPPS).

BACKGROUND: Patients receiving long-term dialysis have among the highest mortality and hospitalization rates. In the nonrenal literature, functional dependence is recognized as a contributor to subsequent disability, recurrent hospitalization, and increased mortality. A higher burden of functional dependence with progressive worsening of kidney function has been observed in several studies, suggesting that functional dependence may contribute to both morbidity and mortality in dialysis patients. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 7,226 hemodialysis patients from 12 countries in the DOPPS (Dialysis Outcomes and Practice Patterns Study) phase 4 (2009-2011) with self-reported data for functional status. PREDICTOR: Patients' ability to perform 13 basic and instrumental activities of daily living was summarized to create an overall functional status score (range, 1.25 [most dependent] to 13 [functionally independent]). OUTCOME: Cox regression was used to estimate the association between functional status and all-cause mortality, adjusting for several demographic and clinical risk factors for mortality. Median follow-up was 17.2 months. RESULTS: The proportion of patients who could perform each activity of daily living task without assistance ranged from 97% (eating) to 47% (doing housework). 36% of patients could perform all 13 tasks without assistance (functional status = 13), and 14% of patients had high functional dependence (functional status < 8). Functionally independent patients were younger and had many indicators of better health status, including higher quality of life. Compared with functionally independent patients, the adjusted HR for mortality was 2.37 (95% CI, 1.92-2.94) for patients with functional status < 8. LIMITATIONS: Possible nonresponse bias and residual confounding. CONCLUSIONS: We found a high burden of functional dependence across all age groups and across all DOPPS countries. When adjusting for several known mortality risk factors, including age, access type, cachexia, and multimorbidity, functional dependence was a strong consistent predictor of mortality.

Sex-specific differences in hemodialysis prevalence and practices and the male-to-female mortality rate: the Dialysis Outcomes and Practice Patterns Study (DOPPS).

BACKGROUND: A comprehensive analysis of sex-specific differences in the characteristics, treatment, and outcomes of individuals with end-stage renal disease undergoing dialysis might reveal treatment inequalities and targets to improve sex-specific patient care. Here we describe hemodialysis prevalence and patient characteristics by sex, compare the adult male-to-female mortality rate with data from the general population, and evaluate sex interactions with mortality. METHODS AND FINDINGS: We assessed the Human Mortality Database and 206,374 patients receiving hemodialysis from 12 countries (Australia, Belgium, Canada, France, Germany, Italy, Japan, New Zealand, Spain, Sweden, the UK, and the US) participating in the international, prospective Dialysis Outcomes and Practice Patterns Study (DOPPS) between June 1996 and March 2012. Among 35,964 sampled DOPPS patients with full data collection, we studied patient characteristics (descriptively) and mortality (via Cox regression) by sex. In all age groups, more men than women were on hemodialysis (59% versus 41% overall), with large differences observed between countries. The average estimated glomerular filtration rate at hemodialysis initiation was higher in men than women. The male-to-female mortality rate ratio in the general population varied from 1.5 to 2.6 for age groups <75 y, but in hemodialysis patients was close to one. Compared to women, men were younger (mean = 61.9 ± standard deviation 14.6 versus 63.1 ± 14.5 y), were less frequently obese, were more frequently married and recipients of a kidney transplant, more frequently had coronary artery disease, and were less frequently depressed. Interaction analyses showed that the mortality risk associated with several comorbidities and hemodialysis catheter use was lower for men (hazard ratio [HR] = 1.11) than women (HR = 1.33, interaction p<0.001). This study is limited by its inability to establish causality for the observed sex-specific differences and does not provide information about patients not treated with dialysis or dying prior to a planned start of dialysis. CONCLUSIONS: Women's survival advantage was markedly diminished in hemodialysis patients. The finding that fewer women than men were being treated with dialysis for end-stage renal disease merits detailed further study, as the large discrepancies in sex-specific hemodialysis prevalence by country and age group are likely explained by factors beyond biology. Modifiable variables, such as catheter use, showing significant sex interactions suggest interventional targeting. Please see later in the article for the Editors' Summary.

Associations of frequency and duration of patient-doctor contact in hemodialysis facilities with mortality.

It is unknown whether regular patient-doctor contact (PDC) contributes to better outcomes for patients undergoing hemodialysis. Here, we analyzed the associations between frequency and duration of PDC during hemodialysis treatments with clinical outcomes among 24,498 patients from 778 facilities in the international Dialysis Outcomes and Practice Patterns Study (DOPPS). The typical facility PDC frequency, estimated by facility personnel, was high (more than once per week) for 55% of facilities, intermediate (once per week) for 24%, and low (less than once per week) for 21%. The mean ± SD estimated duration of a typical interaction between patient and physician was 7.7 ± 5.6 minutes. PDC frequency and duration varied across DOPPS phases and countries; the proportion of facilities with high PDC frequency was 17% in the United States and 73% across the other countries. Compared with high PDC frequency, the adjusted hazard ratio (HR) for all-cause mortality was 1.06 (95% confidence interval [CI], 0.96 to 1.17) for intermediate PDC frequency and 1.11 (95% CI, 1.01 to 1.23) for low PDC frequency (P=0.03 for trend). Furthermore, each 5-minutes-shorter duration of PDC was associated with a 5% higher risk for death, on average (HR, 1.05; 95% CI, 1.01 to 1.09), adjusted for PDC frequency and other covariates. Multivariable analyses also suggested modest inverse associations between both PDC frequency and duration with hospitalization but not with kidney transplantation. Taken together, these results suggest that policies supporting more frequent and longer duration of PDC may improve patient outcomes in hemodialysis.

A multinational cohort study of in-center daily hemodialysis and patient survival.

Increasing hemodialysis frequency from three to six times per week improves left-ventricular mass and health-related quality of life; however, effects on survival remain uncertain. To study this, we identified 556 patients in the International Quotidian Dialysis Registry who received daily hemodialysis (more than five times per week) between 2001 and 2010. Using propensity score-based matching, we matched 318 of these patients to 575 contemporaneous patients receiving conventional (three times weekly) hemodialysis in the Dialysis Outcomes and Practice Patterns Study. All patients had session times of <5 h, and received dialysis in the clinic or hospital setting. Mortality rates between groups were compared using Cox proportional hazards regression. Mean dialysis frequency in the daily group was 5.8 sessions per week. Mean weekly treatment time was 15.7 h for daily and 11.9 h for conventional patients. During 1382 patient-years of follow-up, 170 patients died. Those receiving daily hemodialysis had a significantly higher mortality rate than those receiving conventional hemodialysis (15.6 and 10.9 deaths per 100 patient-years, respectively: hazard ratio 1.6). Similar results were found in prespecified subgroup and sensitivity analyses. Unlike previous studies, we found that in-center daily hemodialysis was not associated with any mortality benefit. Thus, decisions to undertake daily hemodialysis should be based on quality-of-life improvements, rather than on claims of improved survival.

The DOPPS Practice Monitor for US dialysis care: trends through August 2011.

We have examined trends in hemodialysis practice from August 2010 to August 2011, a time frame spanning the implementation of the bundled PPS, a major ESA label change by the FDA, and announcements from CMS on the proposed and final rules for the first year of the Quality Incentive Program (QIP) plus the proposed rules for the second and third years of the QIP. Although many hemodialysis practices have remained stable during this 1-year time period, substantial changes have been seen. These include a decline in epoetin dose and hemoglobin levels, an increase in IV iron use and serum ferritin levels, and an increase in PTH levels. The rates of decline in hemoglobin and epoetin dosing levels were greatest in the 2 months after the ESA label change in June 2011. Trends in anemia care in ensuing months, with more follow-up time after the label change, will be of great interest. In view of declining hemoglobin levels, a mechanism for comprehensive monitoring of transfusion rates is warranted to understand this important aspect of care for hemodialysis patients. Regarding clinical outcomes, no trend in all-cause mortality has been evident during this 1-year time period. Additional follow-up is warranted to understand if findings reported here persist over time, and require confirmation with national data as these become available. Trends in clinical care may not necessarily affect patient outcomes, and careful evaluation is required to understand effects on patient outcomes.

Fibroblast Growth Factor 23 and Mortality Among Prevalent Hemodialysis Patients in the Japan Dialysis Outcomes and Practice Patterns Study.

INTRODUCTION: Elevated fibroblast growth factor 23 (FGF23) levels have been strongly associated with mortality in the predialysis and incident hemodialysis populations, but few studies have examined this relationship in a large cohort of prevalent hemodialysis patients and in particular among persons with high dialysis vintage. To address this, we analyzed data from the Japan Dialysis Outcomes and Practice Patterns Study (J-DOPPS). METHODS: We included 1122 prevalent hemodialysis patients from the J-DOPPS phase 5 (2012-2015) who had FGF23 measurements. We evaluated the association of FGF23 levels with all-cause mortality and cardiovascular composite outcome using Cox regression adjusted for potential confounders. RESULTS: At study enrollment, median dialysis vintage was 5.8 years (interquartile range, 2.7-12.4 years) and median FGF23 level was 2113 pg/ml (interquartile range, 583-6880 pg/ml). During 3-year follow-up, 154 of the 1122 participants died. In adjusted analyses, higher FGF23 was associated with a greater hazard of death (hazard ratio per doubling of FGF23, 1.12; 95% confidence interval, 1.03-1.21); however, the association became weaker as the dialysis vintage increased and finally disappeared in the highest tertile (>9.4 years). Similar patterns of effect modification by dialysis vintage were observed for cardiovascular composite outcome and in time-dependent models. CONCLUSION: Elevated FGF23 was associated with mortality and cardiovascular events in prevalent hemodialysis patients, but the association was attenuated at longer dialysis vintages. This novel finding suggests that long-term hemodialysis patients may be less susceptible to the detrimental effects of FGF23 or correlated biological processes, and additional studies are needed to gain understanding of these possibilities.

Estimating the Fraction of First-Year Hemodialysis Deaths Attributable to Potentially Modifiable Risk Factors: Results from the DOPPS.

PURPOSE: Mortality among first-year hemodialysis (HD) patients remains unacceptably high. To address this problem, we estimate the proportions of early HD deaths that are potentially preventable by modifying known risk factors. METHODS: We included 15,891 HD patients (within 60 days of starting HD) from 21 countries in the Dialysis Outcomes and Practice Patterns Study (1996-2015), a prospective cohort study. Using Cox regression adjusted for potential confounders, we estimated the fraction of first-year deaths attributable to one or more of twelve modifiable risk factors (the population attributable fraction, AF) identified from the published literature by comparing predicted survival based on risk factors observed vs counterfactually set to reference levels. RESULTS: The highest AFs were for catheter use (22%), albumin <3.5 g/dL (19%), and creatinine <6 mg/dL (12%). AFs were 5%-9% for no pre-HD nephrology care, no residual urine volume, systolic blood pressure <130 or ≥160 mm Hg, phosphorus <3.5 or ≥5.5 mg/dL, hemoglobin <10 or ≥12 g/dL, and white blood cell count >10,000/µL. AFs for ferritin, calcium, and PTH were <3%. Overall, 65% (95% CI: 59%-71%) of deaths were attributable to these 12 risk factors. Additionally, the AF for C-reactive protein >10 mg/L was 21% in facilities where it was routinely measured. CONCLUSION: A substantial proportion of first-year HD deaths could be prevented by successfully modifying a few risk factors. Highest priorities should be decreasing catheter use and limiting malnutrition/inflammation whenever possible.