Comparison of Dialysis Unit and Home Blood Pressures: An Observational Cohort Study.

RATIONALE & OBJECTIVE: Prior studies of patients receiving maintenance hemodialysis have shown that, on average, blood pressure (BP) measured predialysis is higher than BP measured at home. We hypothesized that a subset of hemodialysis patients has BP that is higher when measured at home than when measured predialysis and this subgroup of patients has a higher prevalence of left ventricular hypertrophy. STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: 97 hypertensive hemodialysis patients enrolled in the Blood Pressure in Dialysis Study (BID), a randomized trial of comparing target predialysis BP ≤140/90 to 155-165/90 mm Hg. EXPOSURE: Differences between predialysis and next-day home systolic BP measured ≥6 times over 1 year. OUTCOME: Left ventricular mass index (LVMI) by cardiac magnetic resonance imaging. ANALYTICAL APPROACH: A hierarchical clustering analysis divided patients into 3 clusters based on the average and variability of differences in systolic predialysis and home BP. Clusters were compared with respect to clinical factors and LVMI. RESULTS: Mean differences between predialysis and home systolic BP were 19.1 (95% CI, 17.0 to 21.1) mm Hg for cluster 1 ("home lower"), 3.7 (95% CI, 1.6 to 5.8) mm Hg for cluster 2 ("home and predialysis similar"), and -9.7 (95% CI, -12.0 to -7.4) mm Hg for cluster 3 ("home higher"). Systolic BP declined during dialysis in clusters 1 and 2 but increased in cluster 3. Interdialytic weight gains did not differ. After adjusting for sex and treatment arm, LVMI was higher in cluster 3 than in clusters 1 and 2: differences in means of 10.6 ± 4.96 (SE) g/m2 (P = 0.04) and 12.0 ± 5.08 g/m2 (P = 0.02), respectively. LIMITATIONS: Limited statistical power. CONCLUSIONS: Nearly one-third of participants had home BPs higher than predialysis BPs. These patients had LVMI higher than those with similar or lower BPs at home, indicating that their BP may have been undertreated.

Comparison of Prescribed and Measured Dialysate Sodium: A Quality Improvement Project.

BACKGROUND: There is controversy regarding the optimal dialysate sodium concentration for hemodialysis patients. Dialysate sodium concentrations of 134 to 138 mEq/L may decrease interdialytic weight gain and improve hypertension control, whereas a higher dialysate sodium concentration may offer protection to patients with low serum sodium concentrations and hypotension. We conducted a quality improvement project to explore the hypothesis that prescribed and delivered dialysate sodium concentrations may differ significantly. STUDY DESIGN: Cross-sectional quality improvement project. SETTING & PARTICIPANTS: 333 hemodialysis treatments in 4 facilities operated by Dialysis Clinic, Inc. QUALITY IMPROVEMENT PLAN: Measure dialysate sodium to assess the relationships of prescribed and measured dialysate sodium concentrations. OUTCOMES: Magnitude of differences between prescribed and measured dialysate sodium concentrations. MEASUREMENTS: Dialysate sodium measured pre- and late dialysis. RESULTS: The least square mean of the difference between prescribed minus measured dialysate sodium concentration was -2.48 (95% CI, -2.87 to -2.10) mEq/L. Clinics with a greater number of different dialysate sodium prescriptions (clinic 1, n=8; clinic 2, n=7) and that mixed dialysate concentrates on site had greater differences between prescribed and measured dialysate sodium concentrations. Overall, 57% of measured dialysate sodium concentrations were within ±2 mEq/L of the prescribed dialysate sodium concentration. Differences were greater at higher prescribed dialysate sodium concentrations. LIMITATIONS: We only studied 4 facilities and dialysate delivery machines from 2 manufacturers. Because clinics using premixed dialysate used the same type of machine, we were unable to independently assess the impact of these factors. Pressures in dialysate delivery loops were not measured. CONCLUSIONS: There were significant differences between prescribed and measured dialysate sodium concentrations. This may have beneficial or deleterious effects on clinical outcomes, as well as confound results from studies assessing the relationships of dialysate sodium concentrations to outcomes. Additional studies are needed to identify factors that contribute to differences between prescribed and measured dialysate sodium concentrations. Quality assurance and performance improvement (QAPI) programs should include measurements of dialysate sodium.

Satisfaction with Care of Patients on Hemodialysis.

BACKGROUND AND OBJECTIVES: Little is known about patients receiving dialysis who respond to satisfaction and experience of care surveys and those who do not respond, nor is much known about the corollaries of satisfaction. This study examined factors predicting response to Dialysis Clinic, Inc. (DCI)'s patient satisfaction survey and factors associated with higher satisfaction among responders. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENT: A total of 10,628 patients receiving in-center hemodialysis care at 201 DCI facilities between January 1, 2011, and December 31, 2011, aged ≥18 years, treated during the survey administration window, and at the facility for ≥3 months before survey administration. Primary outcome was response to at least one of the nine survey questions; secondary outcome was overall satisfaction with care. RESULTS: Response rate was 77.3%. In adjusted logistic regression (odds ratios with 95% confidence intervals), race other than black (white race, 1.23 [1.10 to 1.37]), missed treatments (1.16 [1.02 to 1.32]) or shortened treatments (≥5 treatments, 1.40 [1.22 to 1.60]), more hospital days (>3 days in the last 3 months, 1.89 [1.66 to 2.15]), and lower serum albumin (albumin level <3.5 g/dl, 1.4 [1.28 to 1.73]) all independently predicted nonresponse. In adjusted linear regression, the following were more satisfied with care: older patients (age ≥63 years, 1.84 [1.78 to 1.90]; age <63 years, 1.91 [1.86 to 1.97]; P<0.001), white patients (1.76 [1.71 to 1.81]) versus black patients (1.93 [1.88 to 1.99]) or those of other race (1.93 [1.83 to 2.03]) (P<0.001), patients with shorter duration of dialysis (≤2.5 years, 1.79 [1.73 to 1.84]; >2.5 years, 1.96 [1.91 to 2.02]; P<0.001), patients who had missed one or fewer treatments (1.83 [1.78 to 1.88]) versus those who had missed more than one treatment (1.92 [1.85 to 1.98]; P=0.002) and those who had shortened treatment (for one treatment or less, 1.84 [1.77 to 1.90]; for two to four treatments, 1.87 [1.81 to 1.93]; for five or more treatments, 1.92 [1.87 to 1.98]; P=0.004). CONCLUSIONS: Survey results represent healthier and more adherent patients on hemodialysis. Shorter survey administration windows were associated with higher response rates. Older, white patients with shorter dialysis vintage were more satisfied.

Genetics of kidney disease and related cardiometabolic phenotypes in Zuni Indians: the Zuni Kidney Project.

The objective of this study is to identify genetic factors associated with chronic kidney disease (CKD) and related cardiometabolic phenotypes among participants of the Genetics of Kidney Disease in Zuni Indians study. The study was conducted as a community-based participatory research project in the Zuni Indians, a small endogamous tribe in rural New Mexico. We recruited 998 members from 28 extended multigenerational families, ascertained through probands with CKD who had at least one sibling with CKD. We used the Illumina Infinium Human1M-Duo version 3.0 BeadChips to type 1.1 million single nucleotide polymorphisms (SNPs). Prevalence estimates for CKD, hyperuricemia, diabetes, and hypertension were 24%, 30%, 17% and 34%, respectively. We found a significant (p < 1.58 × 10(-7)) association for a SNP in a novel gene for serum creatinine (PTPLAD2). We replicated significant associations for genes with serum uric acid (SLC2A9), triglyceride levels (APOA1, BUD13, ZNF259), and total cholesterol (PVRL2). We found novel suggestive associations (p < 1.58 × 10(-6)) for SNPs in genes with systolic (OLFML2B), and diastolic blood pressure (NFIA). We identified a series of genes associated with CKD and related cardiometabolic phenotypes among Zuni Indians, a population with a high prevalence of kidney disease. Illuminating genetic variations that modulate the risk for these disorders may ultimately provide a basis for novel preventive strategies and therapeutic interventions.

Heritability of measures of kidney disease among Zuni Indians: the Zuni Kidney Project.

BACKGROUND: The long-term goal of the GKDZI (Genetics of Kidney Disease in Zuni Indians) Study is to identify genes, environmental factors, and genetic-environmental interactions that modulate susceptibility to renal disease and intermediate phenotypes. STUDY DESIGN: A community-based participatory research approach was used to recruit family members of individuals with kidney disease. SETTING & PARTICIPANTS: The study was conducted in the Zuni Indians, a small endogamous tribe located in rural New Mexico. We recruited members of extended families, ascertained through a proband with kidney disease and at least 1 sibling with kidney disease. 821 participants were recruited, comprising 7,702 relative pairs. PREDICTOR OUTCOMES & MEASUREMENTS: Urine albumin-creatinine ratio (UACR) and hematuria were determined in 3 urine samples and expressed as a true ratio. Glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease (MDRD) Study equation modified for American Indians. Probands were considered to have kidney disease if UACR was >or=0.2 in 2 or more of 3 spot urine samples or estimated GFR was decreased according to the CRIC (Chronic Renal Insufficiency Cohort) Study criteria. RESULTS: Kidney disease was identified in 192 participants (23.4%). There were significant heritabilities for estimated GFR, UACR, serum creatinine, serum urea nitrogen, and uric acid and a variety of phenotypes related to obesity, diabetes, and cardiovascular disease. There were significant genetic correlations of some kidney-related phenotypes with these other phenotypes. LIMITATIONS: Limitations include absence of renal biopsy, possible misclassification bias, lack of direct GFR measurements, and failure to include all possible environmental interactions. CONCLUSIONS: Many phenotypes related to kidney disease showed significant heritabilities in Zuni Indians, and there were significant genetic correlations with phenotypes related to obesity, diabetes, and cardiovascular disease. The study design serves as a paradigm for the conduct of research in relatively isolated, endogamous, underserved populations.

The burden of chronic kidney disease among the Zuni Indians: the Zuni Kidney Project.

The Zuni Indians of New Mexico are experiencing an epidemic of chronic kidney disease (CKD). The Zuni Pueblo created the Zuni Kidney Project (ZKP) to decrease the burden of CKD in the community. The aim of this study was to estimate the prevalence of CKD among Zuni Indians using National Kidney Foundation Kidney Disease Outcomes Quality Initiative criteria. The ZKP conducted a population-based, cross-sectional survey to estimate the prevalence of CKD and related risk factors among Zuni Indians aged > or =20 yr (n = 1113). GFR was estimated using equations based on serum creatinine, and urine albumin:creatinine ratio was calculated in a single spot urine sample. ESRD counts were obtained from health care providers. The age- and sex-adjusted prevalence of CKD among the Zuni Indians was >2.5-fold higher than that among the US composite population. The estimated prevalence of CKD stages 1 and 2 combined was three- to four-fold higher than that of CKD stages 3 and 4 combined. This ratio was significantly higher than that in the US composite population (1.4-fold). The prevalence of CKD stage 5 was eight-fold higher among the Zuni Indians than among the composite US population. The Zuni Indians have an expanded pool of CKD that contributes to the high burden of ESRD. The high prevalence of CKD stages 1 and 2 provides a unique opportunity to develop innovative treatment programs to reduce the burden of CKD in Zuni Pueblo.

Kidney disease among the Zuni Indians: the Zuni Kidney Project.

BACKGROUND: There is an epidemic of kidney disease among the Zuni Indians. In collaboration with health care providers and research institutions, the Zuni Pueblo established the Zuni Kidney Project to reduce the burden of kidney disease. METHODS: The Zuni Kidney Project conducted a population-based, cross-sectional survey to estimate the prevalence of albuminuria, hematuria, and related risk factors. Neighborhood household clusters served as the sampling frame. Participants completed a questionnaire, donated blood and urine samples, and had blood pressure, height, and weight measured. This survey provided the foundation for ongoing studies to identify genetic and environmental risk factors for disease susceptibility and progression. RESULTS: Age and gender distributions among survey participants were similar to those in the eligible Zuni population. Prevalence of incipient albuminuria (IA) (0.03< or = urine albumin:creatinine ratio, UACR <0.3) and overt albuminuria (OA) (UACR < 0.3) were higher among diabetics [IA 34.3% (28.3, 40.4%); OA 18.6% (13.7, 23.6%)] than nondiabetics [IA 11.1% (9.3, 12.8%); OA 1.7% (1.0, 2.5%)]. Nondiabetics comprised 58.6% (52.2, 65.0%) and 30.9% (19.9, 41.9%) of participants with IA and OA, respectively. The prevalence of hematuria was higher among diabetics [> or = trace 47.0% (40.7, 53.4); > or =50 red blood cell/microL 25.8% (20.3, 31.4%)] than nondiabetics [> or = trace 31.1% (28.5, 33.7%); > or =50 red blood cell/microL 16.6% (14.5, 18.7%)]. Hypertension was associated with albuminuria among diabetic and nondiabetic participants. Hypercholesterolemia was associated with albuminuria among nondiabetic participants. Diabetes and alcohol use were associated with hematuria. CONCLUSION: The high prevalences of albuminuria among nondiabetics and of hematuria among diabetics and nondiabetics are consistent with high rates of nondiabetic kidney disease among Zuni Indians with and without diabetes.