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

Following publication of the original article [1], the authors reported an error in Figs. 3 and S3.

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

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

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

BACKGROUND: Health-related quality of life (HRQOL) is a key outcome for dialysis patients, and its assessment is mandated by the Centers for Medicaid and Medicare Services. The Kidney Disease Quality of Life (KDQOL-36™) survey is widely used for this assessment. KDQOL-36™ completion rates, and the distributions of scores and item responses, have not been examined in a large, nationally representative cohort of dialysis patients. METHODS: This retrospective, observational study considered 413,951 survey opportunities contributed by adult patients who received dialysis at a large dialysis organization in the United States during calendar years 2014, 2015, and 2016 and were not Veterans Affairs beneficiaries. RESULTS: During the study period, 240,343 unique patients completed a total of 330,412 surveys (overall completion rate 79.8%). Mean domain scores on the physical component summary (PCS), mental component summary (MCS), burden of kidney disease (BKD), symptoms and problems of kidney disease (SPKD), and effects of kidney disease (EKD) subscales were 36.6, 49.0, 51.3, 78.1, and 73.0, respectively. Scores were similar across dialysis modalities. Patient perceptions of general health were not correlated (R < 0.05) with PCS or SPKD. The SPKD showed ceiling effects: among patients treated with in-center hemodialysis, for all 12 items, < 10% of patients were "extremely bothered," while > 65% of patients reported being "not at all" or only "somewhat bothered;" for 3 items, > 85% of patients gave these latter two responses. Interdialytic weight gain was not correlated with patient-reported shortness of breath, PCS, or SPKD. CONCLUSIONS: Survey completion rates for the KDQOL-36™ were high, and scores were similar across dialysis modalities. Ceiling effects were observed for SPKD. Revision of the KDQOL-36™ to address factors that are most important to contemporary dialysis patients may be warranted.

To eat or not to eat-international experiences with eating during hemodialysis treatment.

Providing food or nutrition supplements during hemodialysis (HD) may be associated with improved nutritional status and reduced mortality; however, despite these potential benefits, eating practices vary across countries, regions, and clinics. Understanding present clinic practices and clinician experiences with eating during HD may help outline best practices in this controversial area. Therefore, the objective of this study was to examine clinical practices and experiences related to eating during HD treatment. We surveyed clinicians about their clinic practices during the 2014 International Society of Renal Nutrition and Metabolism Conference. We received 73 responses from six continents. Respondents were primarily dietitians (71%) working at units housed in a hospital (63%). Sixty-one clinics (85%) allowed patients to eat during treatment, with 47 of these patients (65%) actively encouraging eating. Fifty-three clinics (73%) provided food during HD. None of the nine clinics from North America, however, provided food during treatment. The majority (47 clinics; 64%) provided supplements during treatment. Clinics in the hospital setting were more likely to provide food during treatment, whereas outpatient clinics were less likely to provide nutrition supplements (P≤ 0.05 for both). We also asked clinicians about their experience with six commonly cited reasons to restrict eating during treatment using a four-point scale. Clinicians responded they observed the following conditions "rarely" or "never": choking (98%), reduced Kt/V (98%), infection control issues (96%), spills or pests (83%), gastrointestinal issues (71%), and hypotension (62%). Our results indicate that while eating is common during treatment in some areas, disparities may exist in global practices, and most of the proposed negative sequelae of eating during HD are not frequently observed in clinical practice. Whether these disparities in practice can explain global differences in albumin warrants further research to help inform decisions regarding eating during HD.

Serum creatinine as a marker of muscle mass in chronic kidney disease: results of a cross-sectional study and review of literature.

BACKGROUND: Higher muscle mass is associated with better outcomes and longevity in patients with chronic disease states. Imaging studies such as dual-energy X-ray absorptiometry (DEXA) are among the gold standard methods for assessing body fat and lean body mass (LBM), approximately half of which is comprised of skeletal muscle mass. Elaborate imaging devices, however, are not commonly available in routine clinical practice and therefore easily accessible and cost-effective, but reliable muscle mass biomarkers are needed. One such marker is serum creatinine, derived from muscle-based creatine, which is inexpensive and ubiquitously available, and it can serve as a biomarker of skeletal muscle mass in human subjects. METHODS AND RESULTS: In 118 hemodialysis patients, we found that the 3-month averaged serum creatinine concentration correlated well with DEXA-measured LBM. The recent literature regarding serum creatinine as a surrogate of muscle mass is summarized, as is the literature concerning the use of other measures of muscle mass, such as plasma gelsolin and actin, and urinary creatinine excretion. We have also reviewed the role of dietary meat intake in serum creatinine variability along with several biomarkers of dietary meat intake (creatine, carnitine, carnosine, ophidine, anserine, 3-methyl-L-histidine and 1-methylhistidine). CONCLUSION: In summary, none of these biomarkers was studied in CKD patients. We advance the hypothesis that in both health and disease, under steady state, serum creatinine can serve as a reliable muscle mass biomarker if appropriate adjustment for full or residual kidney function and dietary meat intake is undertaken.

The IMPACT (Incident Management of Patients, Actions Centered on Treatment) program: a quality improvement approach for caring for patients initiating long-term hemodialysis.

BACKGROUND: Patients beginning dialysis therapy are at risk of death and illness. The IMPACT (Incident Management of Patients, Actions Centered on Treatment) quality improvement program was developed to improve incident hemodialysis patient outcomes through standardized care. STUDY DESIGN: Quality improvement report. SETTING & PARTICIPANTS: Patients who started hemodialysis therapy between September 2007 and December 2008 at DaVita facilities using the IMPACT program (n = 1,212) constituted the intervention group. Propensity score-matched patients who initiated hemodialysis therapy in the same interval at DaVita facilities not using the IMPACT program (n = 2,424) made up the control group. QUALITY IMPROVEMENT PLAN: IMPACT intervention included a structured intake process and monitoring reports; patient enrollment in a 90-day patient education program and 90-day patient management pathway. OUTCOMES: Mean dialysis adequacy (Kt/V), hemoglobin and albumin levels, percentage of patients using preferred vascular access (arteriovenous fistula or graft), and mortality at each quarter. RESULTS: Compared with the non-IMPACT group, the IMPACT group was associated with a higher proportion of patients dialyzing with a preferred access at 90 days (0.50 [95% CI, 0.47-0.53] vs 0.47 [95% CI, 0.45-0.49]; P = 0.1) and 360 days (0.63 [95% CI, 0.61-0.66] vs 0.48 [95% CI, 0.46-0.50]; P < 0.001) and a lower mortality rate at 90 days (24.8 [95% CI, 19.0-30.7] vs 31.9 [95% CI, 27.1-36.6] deaths/100 patient-years; P = 0.08) and 360 days (17.8 [95% CI, 15.2-20.4] vs 25.1 [95% CI, 20.7-25.2] deaths/100 patient-years; P = 0.01). LIMITATIONS: The study does not determine the care processes responsible for the improved outcomes. CONCLUSIONS: Intense management of incident dialysis patients with the IMPACT quality improvement program was associated with significantly decreased first-year mortality. Focused attention to the care of incident patients is an important part of a dialysis program.

Novel equations to estimate lean body mass in maintenance hemodialysis patients.

BACKGROUND: Lean body mass (LBM) is an important nutritional measure representing muscle mass and somatic protein in hemodialysis patients, for whom we developed and tested equations to estimate LBM. STUDY DESIGN: A study of diagnostic test accuracy. SETTING & PARTICIPANTS: The development cohort included 118 hemodialysis patients with LBM measured using dual-energy x-ray absorptiometry (DEXA) and near-infrared (NIR) interactance. The validation cohort included 612 additional hemodialysis patients with LBM measured using a portable NIR interactance technique during hemodialysis. INDEX TESTS: 3-month averaged serum concentrations of creatinine, albumin, and prealbumin; normalized protein nitrogen appearance; midarm muscle circumference (MAMC); handgrip strength; and subjective global assessment of nutrition. REFERENCE TEST: LBM measured using DEXA in the development cohort and NIR interactance in validation cohorts. RESULTS: In the development cohort, DEXA and NIR interactance correlated strongly (r = 0.94, P < 0.001). DEXA-measured LBM correlated with serum creatinine level, MAMC, and handgrip strength, but not with other nutritional markers. Three regression equations to estimate DEXA-measured LBM were developed based on each of these 3 surrogates and sex, height, weight, and age (and urea reduction ratio for the serum creatinine regression). In the validation cohort, the validity of the equations was tested against the NIR interactance-measured LBM. The equation estimates correlated well with NIR interactance-measured LBM (R² ≥ 0.88), although in higher LBM ranges, they tended to underestimate it. Median (95% confidence interval) differences and interquartile range for differences between equation estimates and NIR interactance-measured LBM were 3.4 (-3.2 to 12.0) and 3.0 (1.1-5.1) kg for serum creatinine and 4.0 (-2.6 to 13.6) and 3.7 (1.3-6.0) kg for MAMC, respectively. LIMITATIONS: DEXA measurements were obtained on a nondialysis day, whereas NIR interactance was performed during hemodialysis treatment, with the likelihood of confounding by volume status variations. CONCLUSIONS: Compared with reference measures of LBM, equations using serum creatinine level, MAMC, or handgrip strength and demographic variables can estimate LBM accurately in long-term hemodialysis patients.

Comparing body composition assessment tests in long-term hemodialysis patients.

BACKGROUND: Protein-energy wasting is common in chronic kidney disease and is associated with decreases in body muscle and fat stores and poor outcomes. The accuracy and reliability of field methods to measure body composition is unknown in this population. STUDY DESIGN: Cross-sectional observational study. SETTING & PARTICIPANTS: 118 maintenance hemodialysis patients were seen at the General Clinical Research Center at Harbor-UCLA Medical Center, Torrance, CA. INDEX TESTS: Triceps skinfold, near-infrared interactance, and bioelectrical impedance analysis using the Segal, Kushner, and Lukaski equations. REFERENCE TEST: Dual-energy x-ray absorptiometry (DEXA). RESULTS: Participants (42% women, 52% with diabetes, 40% African Americans, and 38% Hispanics) were aged 49.4 +/- 11.5 (mean +/- SD) years, and had undergone dialysis therapy for 41.1 +/- 32.9 months. Body mass index was 27.0 +/- 6.0 kg/m(2). Using DEXA as the reference test, the bioelectrical impedance analysis-Kushner equation, triceps skinfold, and near-infrared interactance were most accurate of the index tests in estimating total-body fat percentage, whereas bioelectrical impedance analysis-Segal equation and bioelectrical impedance analysis-Lukaski equation overestimated total body fat percentage. Bland-Altman analyses and difference plots showed that bioelectrical impedance analysis-Kushner and near-infrared interactance were most similar to the reference test. Bioelectrical impedance analysis-Kushner, triceps skinfold, and near-infrared interactance had the smallest mean differences from DEXA, especially in women (1.6%, 0.7%, and 1.2%, respectively). Similar results were observed in African American participants (n = 47). LIMITATIONS: Measurements were performed 1 day after a hemodialysis treatment, leading to more fluid retention, which may have affected the reference and index tests differently. CONCLUSIONS: Using DEXA as the reference test, both near-infrared interactance and bioelectrical impedance analysis-Kushner method yield more consistent estimates of total body fat percentage in maintenance hemodialysis patients compared with the other index tests. Near-infrared interactance is not affected by skin color. Field methods with portable devices may provide adequate precision.

American Dietetic Association and the National Kidney Foundation Standards of Practice and Standards of Professional Performance for registered dietitians (generalist, specialty, and advanced) in nephrology care.

The American Dietetic Association (ADA) Renal Dietitians Practice Group (RPG) and the National Kidney Foundation Council on Renal Nutrition (NKF CRN), under the guidance of the ADA Quality Management Committee and Scope of Dietetics Practice Framework Sub-Committee, have developed the Standards of Practice (SOP) and Standards of Professional Performance (SOPP) for Registered Dietitians (Generalist, Specialty, and Advanced) in Nephrology Care (Supplementary Figures 1, 2, and 3 are available only online at www.jrnjournal.org). The SOP and SOPP documents are based upon the 2008 Revised Standards of Practice in Nutrition Care and Standards of Professional Performance for Registered Dietitians (RDs)(1), which are part of ADA's Scope of Dietetics Practice Framework(2). The 2008 Revised SOP in Nutrition Care and SOPP, along with the Code of Ethics(3), guide the practice and performance of RDs in all settings.

Association of serum total iron-binding capacity and its changes over time with nutritional and clinical outcomes in hemodialysis patients.

Serum transferrin, estimated by total iron-binding capacity (TIBC), may be a marker of protein-energy wasting (PEW) in maintenance hemodialysis (MHD) patients. We hypothesized that low TIBC or its fall over time is associated with poor clinical outcomes. In 807 MHD patients in a prospective 5-year cohort, associations of TIBC and its changes over time with outcomes were examined after adjustment for case-mix and markers of iron stores and malnutrition-inflammation including serum interleukin-6, iron and ferritin. Patients with serum TIBC >or=250 mg/dl had higher body mass index, triceps and biceps skinfolds and mid-arm muscle circumference and higher serum levels of iron but lower ferritin and inflammatory markers. Some SF-36 quality of life (QoL) components were worse in the lowest and/or highest TIBC groups. Mortality was incrementally higher in lower TIBC levels (p-trend <0.001). Adjusted death hazard ratio was 1.75 (95% CI: 1.00-3.05, p = 0.05) for TIBC <150 compared to TIBC of 200-250 mg/dl. A fall in TIBC >20 mg/dl over 6 months was associated with a death hazard ratio of 1.57 (95% CI: 1.04-2.36, p = 0.03) compared to the stable TIBC group. Hence, low baseline serum TIBC is associated with iron deficiency, PEW, inflammation, poor QoL and mortality, and its decline over time is independently associated with increased death risk.

Burnt-out diabetes: impact of chronic kidney disease progression on the natural course of diabetes mellitus.

Many individuals with diabetic nephropathy, the leading cause of chronic kidney disease (CKD) in the United States, progress to stage 5 of CKD and undergo maintenance dialysis treatment. Recent data indicate that in up to one third of diabetic dialysis patients with a presumptive diagnosis of diabetic nephropathy, glycemic control improves spontaneously with the progression of CKD, loss of residual renal function, and the initiation of dialysis therapy, leading to normal-to-low hemoglobin A1c (<6%) and glucose levels, requiring cessation of insulin or other anti-diabetic medications. Potential contributors to this so-called "burnt-out diabetes" include decreased renal and hepatic insulin clearance, a decline in renal gluconeogenesis, deficient catecholamine release, diminished food intake (because of anorexia or diabetic gastroparesis), protein-energy wasting (with resultant loss of weight and body fat), and the hypoglycemic effects of dialysis treatment. Although the concept of "burnt-out diabetes" appears in sharp contradistinction to the natural history of diabetes mellitus, studying this condition and its potential causes and consequences, including the role of genetic factors, may lead to a better understanding of the pathophysiology of metabolic syndrome and diabetes mellitus in the CKD population and in many other individuals with chronic disease states associated with wasting syndrome that can confound the natural history of diabetes.

Association of Malnutrition-Inflammation Score with quality of life and mortality in hemodialysis patients: a 5-year prospective cohort study.

BACKGROUND: The Malnutrition-Inflammation Score (MIS), an inexpensive and easy-to-assess score of 0 to 30 to examine protein-energy wasting (PEW) and inflammation, includes 7 components of the Subjective Global Assessment, body mass index, and serum albumin and transferrin concentrations. We hypothesized that MIS risk stratification of hemodialysis (HD) patients in predicting outcomes is better than its components or laboratory markers of inflammation. STUDY DESIGN: 5-Year cohort study. SETTING & PARTICIPANTS: We examined 809 stable HD outpatients and followed them for up to 5 years (October 2001 to December 2006). PREDICTORS: MIS and other nutritional and inflammatory markers. OUTCOMES & MEASUREMENTS: Prospective all-cause mortality, health-related quality of life using the 36-Item Short Form Health Survey (SF-36), and tests of body composition. RESULTS: The MIS correlated with logarithm of serum interleukin 6 level (r = +0.26; P < 0.001), logarithm of C-reactive protein level (r = +0.16; P < 0.001), and several measures of nutritional status. Patients with a higher MIS had lower SF-36 scores. After multivariate adjustment for case-mix and other measures of PEW, HD patients in the second (3 to 4), third (5 to 7), and fourth (>or=8) quartiles of MIS had worse survival rates than those in the first (0 to 2) quartile (P < 0.001). Each 2-unit increase in MIS was associated with a 2-fold greater death risk, ie, adjusted death hazard ratio of 2.03 (95% confidence interval, 1.76 to 2.33; P < 0.001). Cubic spline survival models confirmed linear trends. Adding MIS to the constellation of age, sex, race/ethnicity, and vintage significantly improved the area under the receiver operating characteristic curve developed for predicting mortality (0.71 versus 0.67; P < 0.001). LIMITATIONS: Selection bias and unknown confounders. CONCLUSIONS: In HD patients, the MIS is associated with inflammation, nutritional status, quality of life, and 5-year prospective mortality. The mortality predictability of the MIS appears equal to serum interleukin 6 and somewhat greater than C-reactive protein levels. Controlled trials are warranted to examine whether interventions to improve the MIS can also improve clinical outcomes in HD patients.

Impact of kidney bone disease and its management on survival of patients on dialysis.

Despite the enormous cardiovascular disease epidemic and poor survival among individuals with chronic kidney disease (CKD), traditional risk factors such as hypercholesterolemia, hypertension, and obesity appear not as relevant as was previously thought, nor would their management improve survival in patients with CKD who are undergoing dialysis. On the contrary, kidney disease wasting (KDW) (also known as the malnutrition-inflammation complex), renal anemia, and kidney bone disease (KBD) appear to be the 3 most important nontraditional risk factors associated with cardiovascular disease in CKD. KBD-associated hyperparathyroidism may contribute to worsening refractory anemia and KDW/inflammation. The main cause of secondary hyperparathyroidism is active vitamin D deficiency. Hence, treatment of patients with KBD with vitamin D analogs, especially those with lesser effects on calcium and phosphorus such as paricalcitol, may be the most promising option for improving CKD outcomes. By conducting survival analyses in a 2-year (7/2001 to 6/2003) cohort of 58,058 patients on hemodialysis, we recently found that associations between high serum parathyroid hormone and increased death risk were masked by the demographic and clinical characteristics of patients, and that alkaline phosphatase had an incremental association with mortality. Administration of paricalcitol was associated with improved survival in time-varying models. We now present additional subgroup analyses that show that administration of any dose of paricalcitol, when compared with no paricalcitol, is associated with better likelihood of survival in virtually all subgroups of patients on hemodialysis. Because these associations may be secondary to bias by indication, randomized clinical trials are necessary to verify the findings of this and similar observational studies.

K/DOQI gets to the heart of managing dyslipidemias in patients with CKD.

There is a wealth of data in the general population regarding interventions to reduce cardiovascular risk. Unfortunately, most of these studies exclude patients with chronic kidney disease. As a result, the lack of CKD specific data has resulted in a lack of attention and intervention. With the epidemic levels of cardiovascular disease in patients on dialysis, the NKF has established these K/DOQI guidelines in an effort to get to the "heart" of dyslipidemias and ultimately to assist the health care team in their effort to improve CKD patient outcomes. In addition, the National Kidney Foundation currently has draft K/DOQI Clinical Practice Guidelines for Cardiovascular Disease in the public review process. These new guidelines will elaborate on areas not covered in the dyslipidemia guidelines.