Progression of autosomal dominant kidney disease: measurement of the stage transitions of chronic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a progressive genetic disorder characterized by the development of numerous kidney cysts that result in kidney failure. Little is known regarding the key patient characteristics and utilization of healthcare resources for ADPKD patients along the continuum of disease progression. This observational study was designed to describe the characteristics of ADPKD patients and compare them with those of patients with other chronic kidney diseases. METHODS: This retrospective cohort study involved patients with a claim for ADPKD or PKD unspecified from 1/1/2000-2/28/2013 and ≥6 months of previous continuous enrollment (baseline) within a large database of administrative claims in the USA. A random sample of chronic kidney disease (CKD) patients served as comparators. For a subset of ADPKD patients who had only a diagnosis code of unspecified PKD, abstraction of medical records was undertaken to estimate the proportion of patients who had medical chart-confirmed ADPKD. In patients with linked electronic laboratory data, the estimated glomerular filtration rate was calculated via serum creatinine values to determine CKD stage at baseline and during follow-up. Proportions of patients transitioning to another stage and the mean age at transition were calculated. RESULTS: ADPKD patients were, in general, younger and had fewer physician visits, but had more specific comorbidities at observation start compared with CKD patients. ADPKD patients had a longer time in the milder stages and longer duration before recorded transition to a more severe stage compared with CKD patients. Patients with ADPKD at risk of rapid progression had a shorter time-to-end-stage renal disease than patients with CKD and ADPKD patients not at risk, but stage duration was similar between ADPKD patients at risk and those not at risk. CONCLUSIONS: These results suggest that distribution of patients by age at transition to next stage may be useful for identification of ADPKD patients at risk of rapid progression. The results also suggest that medical claims with diagnosis codes for "unspecified PKD", in absence of a diagnosis code for autosomal recessive polycystic kidney disease, may be a good proxy for ADPKD.

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

INTRODUCTION: Hyperphosphatemia (serum phosphorus >5.5 mg/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. METHODS: 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. RESULTS: 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. CONCLUSION: Increasing phosphate binder adherence and improving phosphorus control were associated with increased cost savings in total Medicare costs and inpatient costs.

Reasons for phosphate binder discontinuation vary by binder type.

OBJECTIVE: Nonadherence to phosphate binder regimen is common among end-stage renal disease patients and contributes to elevated phosphorus levels. Pill burden, side effects, complex regimens, and cost all contribute to nonadherence. We retrospectively analyzed reasons for discontinuation in hemodialysis patients receiving treatment at a large U.S. dialysis organization to better understand the drivers of nonadherence for particular phosphate binders. DESIGN AND SETTING: Patient electronic medical records were reviewed to identify phosphate binder prescriptions and reasons for discontinuation. Reasons for discontinuation were categorized and the percentage of patients on each type of phosphate binder was calculated within categories. SUBJECTS: Medicare patients of age ≥18 years, receiving in-center hemodialysis treatment between July 1, 2009, and June 30, 2011, were included in the analysis. RESULTS: We classified 30,933 patient records with a stated reason for phosphate binder discontinuation for this study. Of these records, 50.1% cited that the patient discontinued the phosphate binder but contained no additional information; "lab results" were cited for 27.4% of the reasons for discontinuation and "patient-reported side effects" for 10.8%. Although patients on lanthanum carbonate accounted for 14% of the total number reasons for discontinuation assessed, they comprised 40% of the "patient-reported side effects" category and were similarly overrepresented in 4 of the 5 subcategories. CONCLUSIONS: The high percentage of patient-reported side effects resulting in discontinuation identifies an unmet need for improved phosphate binders. A disproportionate percentage of patients prescribed lanthanum carbonate reported side effects, however further work is needed to identify the relative tolerability of phosphate binders and potential explanations.

Serum phosphorus levels and pill burden are inversely associated with adherence in patients on hemodialysis.

BACKGROUND: Phosphate binders (PBs) account for about one half of the daily pill burden for US hemodialysis (HD) patients, which may reduce adherence. Adherence can be estimated by the medication possession ratio (MPR), which is defined as the proportion of time a patient had sufficient medication to have taken it as prescribed. Gaps of time between prescription fills lower the patient's MPR. We assessed the association of PB pill burden and adherence (MPR) with phosphorus goal attainment. METHODS: Using pharmacy management program data, HD patients on PB monotherapy were tracked from first PB fill during 1 January 2007-30 June 2011 for 1 year, or until PB change or censoring. Data were assessed with generalized linear models. RESULTS: We analyzed 8616 patients. Higher pill burden was associated with lower adherence. Lower adherence tended to be associated with higher mean phosphorus levels and lower percentage of patients with serum phosphorus ≤5.5 mg/dL (P < 0.001). The association between adherence and these clinical outcomes was most pronounced in the lowest and highest pill burden strata (<3, >3-6, >12-15, >15). CONCLUSIONS: Adherence, as measured by the MPR, was negatively related to higher pill burden and phosphorus levels and positively related to patients in the phosphorus target range. Within pill burden strata, phosphorus increased and patients in the target range generally decreased with decreasing adherence, suggesting that patients prescribed fewer PB pills are less likely to have treatment gaps, and may be more likely to achieve phosphorus targets.

Racial differences in clinical use of cinacalcet in a large population of hemodialysis patients.

BACKGROUND/AIMS: African-Americans with end-stage renal disease receiving dialysis have more severe secondary hyperparathyroidism than Whites. We aimed to assess racial differences in clinical use of cinacalcet. METHODS: This retrospective cohort study used data from DaVita, Inc., for 45,589 prevalent hemodialysis patients, August 2004, linked to Centers for Medicare & Medicaid Services data, with follow-up through July 2007. Patients with Medicare as primary payer, intravenous vitamin D use, or weighted mean parathyroid hormone (PTH) level >150 pg/ml at baseline (August 1-October 31, 2004) were included. Cox proportional hazard modeling was used to evaluate race and other demographic and clinical characteristics as predictors of cinacalcet initiation, titration, and discontinuation. RESULTS: Of 16,897 included patients, 7,674 (45.4%) were African-American and 9,223 (54.6%) were white; 53.2% of cinacalcet users were African-American. Cinacalcet was prescribed for 47.7% of African-Americans and 34.5% of Whites, and for a greater percentage of African-Americans at higher doses at each PTH strata. After covariate adjustment, African-Americans were more likely than Whites to receive cinacalcet prescriptions (hazard ratio 1.17, p < 0.001). The direction and magnitude of this effect appeared to vary by age, baseline PTH, and calcium, and by elemental calcium use. African-Americans were less likely than Whites to have prescriptions discontinued and slightly more likely to undergo uptitration (hazard ratio 1.09, 95% confidence interval 0.995-1.188), but this relationship lacked statistical significance. CONCLUSION: Cinacalcet is prescribed more commonly and at higher initial doses for African-Americans than for Whites to manage secondary hyperparathyroidism.

Trends in hip fracture rates in US hemodialysis patients, 1993-2010.

BACKGROUND: Changes in mineral and bone disorder treatment patterns and demographic changes in the dialysis population may have influenced hip fracture rates in US dialysis patients in 1993-2010. STUDY DESIGN: Retrospective follow-up study analyzing trends over time in hospitalized hip fracture rates. SETTING & PARTICIPANTS: Using Medicare data, we created 2 point-prevalent study cohorts for each study year. Hemodialysis cohorts included patients with Medicare as primary payer receiving hemodialysis in the United States on January 1 of each year; non-end-stage renal disease (ESRD) cohorts included Medicare beneficiaries 66 years or older on January 1 of each year. FACTORS: Age, sex, race, primary cause of ESRD, dual Medicare/Medicaid enrollment status, comorbid conditions. OUTCOMES: Hip fracture rates. MEASUREMENTS: Unadjusted hip fracture rates measured using number of events per 1,000 person-years in each year, then adjusted for patient characteristics. Poisson models estimated strata-specific event rates. RESULTS: The observed number of first hospitalized hip fracture events and the adjusted hip fracture rate increased steadily from 1993 (831 events; 11.9/1,000 person-years), peaked in 2004 (3,256 events; 21.9/1,000 person-years), and decreased through 2010 (2,912 events; 16.6/1,000 person-years). The trend for the subset of hemodialysis patients 66 years or older was similar to the trend for the full hemodialysis cohort; however, it differed markedly in magnitude and pattern from the non-ESRD Medicare cohort, for which rates were substantially lower and slowly decreasing since 1996. LIMITATIONS: Unable to provide causal explanations for observed changes; hip fractures identified through inpatient episodes; results do not describe hemodialysis patients without Medicare Parts A and B; laboratory values unavailable in the Medicare data set. CONCLUSIONS: Temporal trends in hip fracture rates among Medicare hemodialysis patients differ markedly from the steadily decreasing trend in non-ESRD Medicare beneficiaries, showing a relatively rapid increase until 2004 and relatively rapid decrease thereafter. Further research is needed to define associated factors.

Evaluating real-world use of cinacalcet and biochemical response to therapy in US hemodialysis patients.

BACKGROUND/AIMS: Data describing real-world use and effectiveness of cinacalcet are limited. We aimed to characterize predictors of treatment and changes in secondary hyperparathyroidism (SHPT) biochemistry after cinacalcet initiation. METHODS: We studied 25,250 in-center hemodialysis patients from a large dialysis provider, alive through November 2004, with no prior cinacalcet prescription. Patients were followed until initiation of cinacalcet, censoring, death, or July 31, 2007. Initiators were further followed for dose titration and discontinuation. Predictors of these events were evaluated using Cox proportional hazards modeling. Biochemical parameters and other SHPT medication use were compared between baseline, pre-initiation, and post-initiation time points. RESULTS: Over an average of 1.25 years of follow-up, 30% of patients initiated cinacalcet therapy. Between baseline and initiation (mean of 386 days), parathyroid hormone (PTH) and phosphorus levels increased 78 and 7%, respectively, in these patients. After adjustment, cinacalcet initiation was associated with higher SHPT severity, younger age, African-American race, higher phosphorus levels, and more comorbidity. Within 1 month of initiation, median PTH was reduced by 15-30% and phosphorus by 3-5%. Reductions were sustained or increased over 12 months, depending on initiating PTH level and whether dose up-titration occurred. Discontinuation was common, although many patients reinitiated. CONCLUSIONS: A substantial proportion of patients experienced SHPT progression and initiated cinacalcet treatment. Reductions in biochemistry varied by disease severity and whether doses were titrated.

Lifestyle-related factors, obesity, and incident microalbuminuria: the CARDIA (Coronary Artery Risk Development in Young Adults) study.

BACKGROUND: Modifiable lifestyle-related factors are associated with risk of coronary heart disease and may also influence kidney disease risk. STUDY DESIGN: Community-based prospective cohort study. SETTING & PARTICIPANTS: 2,354 African American and white participants aged 28-40 years without baseline microalbuminuria or estimated glomerular filtration rate <60 mL/min/1.73 m² recruited from 4 US centers: Birmingham, AL; Chicago, IL; Minneapolis, MN; and Oakland, CA. FACTORS: Current smoking, physical activity, fast food habits, obesity, and diet quality, which was based on 8 fundamental components of the Dietary Approaches to Stop Hypertension (DASH) diet, including increased intake of fruits, vegetables, low-fat dairy products, whole grains, and nuts and legumes and reduced intake of sodium, sugar-sweetened beverages, and red and processed meats. OUTCOMES & MEASUREMENTS: Spot urine albumin-creatinine ratios were obtained at baseline (1995-1996) and three 5-year follow-up examinations (5, 10, and 15 years' follow-up). Incident microalbuminuria was defined as the presence of age- and sex-adjusted albumin-creatinine ratio ≥25 mg/g at 2 or more of the successive follow-up examinations. RESULTS: During the 15-year follow-up, 77 (3.3%) individuals developed incident microalbuminuria. After multivariable adjustment, poor diet quality (OR, 2.0; 95% CI, 1.1-3.4) and obesity (OR, 1.9; 95% CI, 1.1-3.3) were associated significantly with microalbuminuria; current smoking (OR, 1.6; 95% CI, 0.9-2.8) was associated with microalbuminuria, although the CI crossed 1.0. Neither low physical activity (OR, 1.0; 95% CI, 0.5-1.8) nor fast food consumption (OR, 1.2; 95% CI, 0.7-2.3) was associated with microalbuminuria. Compared with individuals with no unhealthy lifestyle-related factors (poor diet quality, current smoking, and obesity), adjusted odds of incident microalbuminuria were 131%, 273%, and 634% higher for the presence of 1 (OR, 2.3; 95% CI, 1.3-4.3), 2 (OR, 3.7; 95% CI, 1.8-7.7), and 3 (OR, 7.3; 95% CI, 2.1-26.1) unhealthy lifestyle-related factors. LIMITATIONS: Self-reported dietary history and physical activity, low number of outcomes. CONCLUSIONS: Consuming an unhealthy diet and obesity are associated with incident microalbuminuria.

Impact of hemodialysis catheter dysfunction on dialysis and other medical services: an observational cohort study.

Practice guidelines define hemodialysis catheter dysfunction as blood flow rate (BFR) <300 mL/min. We conducted a study using data from DaVita and the United States Renal Data System to evaluate the impact of catheter dysfunction on dialysis and other medical services. Patients were included if they had ≥8 consecutive weeks of catheter dialysis between 8/2004 and 12/2006. Actual BFR <300 mL/min despite planned BFR ≥300 mL/min was used to define catheter dysfunction during each dialysis session. Among 9,707 patients, the average age was 62,53% were female, and 40% were black. The median duration of catheter dialysis was 190 days, and the cohort accounted for 1,075,701 catheter dialysis sessions. There were 70,361 sessions with catheter dysfunction, and 6,33 1 (65.2%) patients had at least one session with catheter dysfunction. In multivariate repeated measures analysis, catheter dysfunction was associated with increased odds of missing a dialysis session due to access problems (Odds ratio [OR] 2.50; P < 0.001), having an access-related procedure (OR 2.10; P < 0.001), and being hospitalized (OR 1.10; P = 0.001). Catheter dysfunction defined according to NKF vascular access guidelines results in disruptions of dialysis treatment and increased use of other medical services.

Racial differences in the incidence of chronic kidney disease.

BACKGROUND AND OBJECTIVES: The incidence of ESRD is higher in African Americans than in whites, despite reports of a similar or lower prevalence of CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This study compared the incidence of CKD among young African-American and white adults over 20 years of follow-up in the community-based Coronary Artery Risk Development in Young Adults study. Participants included 4119 adults, 18-30 years of age, with an estimated GFR (eGFR) ≥60 ml/min per 1.73 m(2) at baseline. Incident CKD was defined as an eGFR <60 ml/min per 1.73 m(2) and a ≥25% decline in eGFR at study visits conducted 10, 15, and 20 years after baseline. RESULTS: At baseline, the mean age of African Americans and whites was 24 and 26 years, respectively (P<0.001), and 56% and 53% of participants, respectively, were women (P=0.06). There were 43 incident cases of CKD during follow-up, 29 (1.4%) among African Americans and 14 (0.7%) among whites (P=0.02). The age- and sex-adjusted hazard ratio (HR) for incident CKD comparing African Americans to whites was 2.56 (95% confidence interval [95% CI], 1.35-5.05). After further adjustment for body mass index, systolic BP, fasting plasma glucose, and HDL cholesterol, the HR was 2.51 (95% CI, 1.25-5.05). After multivariable adjustment including albuminuria at year 10, the HR for CKD at year 15 or 20 was 1.12 (95% CI, 0.52-2.41). CONCLUSIONS: In this study, the 20-year CKD incidence was higher among African Americans than whites, a difference that is explained in part by albuminuria.

Association of family history of ESRD, prevalent albuminuria, and reduced GFR with incident ESRD.

BACKGROUND: The contribution of albuminuria to the increased risk of incident end-stage renal disease (ESRD) in individuals with a family history of ESRD has not been well studied. STUDY DESIGN: Prospective cohort study. STUDY SETTING & PARTICIPANTS: We analyzed data for family history of ESRD collected from 19,409 participants of the Renal REGARDS (Reasons for Geographic and Racial Differences in Stroke) cohort study. PREDICTOR: Family history of ESRD was ascertained by asking "Has anyone in your immediate family ever been told that he or she had kidney failure? This would be someone who is on or had been on dialysis or someone who had a kidney transplant." STUDY OUTCOMES: Incidence rate for ESRD. MEASUREMENTS: Morning urine albumin-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR). Incident cases of ESRD were identified through the US Renal Data System. RESULTS: A family history of ESRD was reported by 11.1% of participants. Mean eGFRs for those with and without a family history of ESRD were 87.5 ± 22.2 (SD) and 86.5 ± 19.3 mL/min/1.73 m(2), respectively (P = 0.05) and the respective geometric mean ACRs were 12.2 and 9.7 mg/g (P < 0.001). ESRD incidence rates for those with and without a family history of ESRD were 244.3 and 106.1/100,000 person-years, respectively. After adjusting for age, sex, and race, the ESRD HR for those with versus those without a family history of ESRD was 2.13 (95% CI, 1.18-3.83). Adjustment for comorbid conditions and socioeconomic status attenuated this association (HR, 1.82; 95% CI, 1.00-3.28), and further adjustment for baseline eGFR and ACR completely attenuated the association between family history of ESRD and incident ESRD (HR, 1.12; 95% CI, 0.69-1.80). LIMITATIONS: The report of a family history of ESRD was not validated. CONCLUSION: Family history of ESRD is common in older Americans and the increased risk of ESRD associated with a family history reflects lower GFR, higher albuminuria, and comorbid conditions.

Patterns of Hemodialysis Catheter Dysfunction Defined According to National Kidney Foundation Guidelines As Blood Flow <300 mL/min.

Blood flow rate (BFR) <300 mL/min commonly is used to define hemodialysis catheter dysfunction and the need for interventions to prevent complications. The objective of this study was to describe patterns of unplanned BFR <300 mL/min during catheter hemodialysis using data from DaVita dialysis facilities and the United States Renal Data System. Patients were included if they received at least eight weeks of hemodialysis exclusively through a catheter between 08/04 and 12/06, and catheter hemodialysis was the first treatment modality following diagnosis of end-stage renal disease (first access), or it immediately followed at least one 30-day period of dialysis exclusively through a fistula or graft (replacement access). Actual BFR <300 mL/min despite a planned BFR ≥300 mL/min defined catheter dysfunction during each dialysis session. There were 3,364 patients, 268,363 catheter dialysis sessions, and 19,118 (7.1%) sessions with catheter dysfunction. Almost two-thirds of patients had ≥1 catheter dysfunction session, and 30% had ≥1 catheter dysfunction session per month. Patients with catheter as a replacement access had a higher rate of catheter dysfunction than those with a catheter as first access (hazard ratio: 1.13; P = 0.04). Catheter dysfunction affects almost one-third of catheter dialysis patients each month and two-thirds overall.

Albuminuria and racial disparities in the risk for ESRD.

The causes of the increased risk for ESRD among African Americans are not completely understood. Here, we examined whether higher levels of urinary albumin excretion among African Americans contributes to this disparity. We analyzed data from 27,911 participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study who had urinary albumin-to-creatinine ratio (ACR) and estimated GFR (eGFR) measured at baseline. We identified incident cases of ESRD through linkage with the United States Renal Data System. At baseline, African Americans were less likely to have an eGFR <60 ml/min per 1.73 m(2) but more likely to have an ACR ≥ 30 mg/g. The incidence rates of ESRD among African Americans and whites were 204 and 58.6 cases per 100,000 person-years, respectively. After adjustment for age and gender, African Americans had a fourfold greater risk for developing ESRD (HR 4.0; 95% CI 2.8 to 5.9) compared with whites. Additional adjustment for either eGFR or ACR reduced the risk associated with African-American race to 2.3-fold (95% CI 1.5 to 3.3) or 1.8-fold (95% CI 1.2 to 2.7), respectively. Adjustment for both ACR and eGFR reduced the race-associated risk to 1.6-fold (95% CI 1.1 to 2.4). Finally, in a model that further adjusted for both eGFR and ACR, hypertension, diabetes, family income, and educational status, African-American race associated with a nonsignificant 1.4-fold (95% CI 0.9 to 2.3) higher risk for ESRD. In conclusion, the increased prevalence of albuminuria may be an important contributor to the higher risk for ESRD experienced by African Americans.

Kidney function, albuminuria, and all-cause mortality in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study.

BACKGROUND: Chronic kidney disease and albuminuria are associated with increased risk of all-cause mortality. STUDY DESIGN: Prospective observational cohort study. SETTING & PARTICIPANTS: 17,393 participants (mean age, 64.3 ± 9.6 years) in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study. PREDICTOR: Estimated glomerular filtration rate (eGFR), urinary albumin-creatinine ratio (ACR). OUTCOME: All-cause mortality (710 deaths); median duration of follow-up, 3.6 years. MEASUREMENTS & ANALYSIS: Categories of eGFR (90 to <120, 60 to <90, 45 to <60, 30 to <45, and 15 to <30 mL/min/1.73 m(2)) and urinary ACR (<10 mg/g or normal, 10 to <30 mg/g or high normal, 30 to 300 mg/g or high, and >300 mg/g or very high). Cox proportional hazards models were adjusted for demographic factors, cardiovascular covariates, and hemoglobin level. RESULTS: The background all-cause mortality rate for participants with normal ACR, eGFR of 90 to <120 mL/min/1.73 m(2), and no coronary heart disease was 4.3 deaths/1,000 person-years. Higher ACR was associated with an increased multivariable-adjusted HR for all-cause mortality within each eGFR category. Decreased eGFR was associated with a higher adjusted HR for all-cause mortality for participants with high-normal (P = 0.01) and high (P < 0.001) ACRs, but not those with normal or very high ACRs. LIMITATIONS: Only 1 laboratory assessment for serum creatinine and ACR was available. CONCLUSIONS: Increased albuminuria was an independent risk factor for all-cause mortality. Decreased eGFR was associated with increased mortality risk in those with high-normal and high ACRs. The mortality rate was low in the normal-ACR group and increased in the very-high-ACR group, but did not vary with eGFR in these groups.

Associations of dietary fat with albuminuria and kidney dysfunction.

BACKGROUND: Diet represents a potentially important target for intervention in nephropathy, yet data on this topic are scarce. OBJECTIVES: The objective was to investigate associations between dietary fats and early kidney disease. DESIGN: We examined cross-sectional associations between dietary fats and the presence of high albuminuria (an established independent predictor of kidney function decline, cardiovascular disease, and mortality) or estimated glomerular filtration rate (eGFR) <60 mL ⋅ min(-1) ⋅ 1.73 m(-2) at baseline in 19,256 participants of the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study, an ongoing cohort study in US adults aged ≥45 y at time of enrollment. We used logistic regression to assess associations between quintiles of total fat and subtypes of dietary fat (saturated, monounsaturated, polyunsaturated, and trans fat) and presence of high albuminuria or eGFR <60 mL ⋅ min(-1) ⋅ 1.73 m(-2). RESULTS: After multivariable adjustment, only saturated fat intake was significantly associated with high albuminuria [for quintile 5 compared with quintile 1, odds ratio (OR): 1.33; 95% CI: 1.07, 1.66; P for trend = 0.04]. No significant associations between any type of fat and eGFR <60 mL · min(-1) · 1.73 m(-2) were observed. ORs between the highest quintile of saturated fat and eGFR <60 mL · min(-1) · 1.73 m(-2) varied by race with a borderline significant interaction term (ORs: 1.24 in whites compared with 0.74 in blacks; P for interaction = 0.05) in multivariable-adjusted models, but no other associations were significantly modified by race or diabetes status. CONCLUSION: Higher saturated fat intake is significantly associated with the presence of high albuminuria, but neither total nor other subtypes of dietary fat are associated with high albuminuria or eGFR <60 mL · min(-1) · 1.73 m(-2).

Hemoglobin concentration and cognitive impairment in the renal REasons for Geographic And Racial Differences in Stroke (REGARDS) Study.

BACKGROUND: There is growing interest in determining the degree of anemia, which is clinically significant. The goal of this study was to determine the association between hemoglobin concentration and cognitive impairment in a large sample of U.S. adults. METHODS: We used cross-sectional data from 19,701 adults participating in the REasons for Geographic And Racial Differences in Stroke study. Cognitive impairment was defined as a score of 4 or less on the six-item screener. Hemoglobin was analyzed in 1 g/dL increments relative to the World Health Organization (WHO) threshold (<13 g/dL for men and <12 g/dL for women). RESULTS: The mean hemoglobin concentration was 13.7 ± 1.5 g/dL. The prevalence of cognitive impairment increased from 4.3% among individuals with a hemoglobin >3 g/dL above the WHO threshold to 16.8% for those with a hemoglobin ≥2 g/dL below the WHO threshold. After adjustment for demographics, chronic health conditions, health status, and inflammation, the association between reduced hemoglobin and cognitive impairment was attenuated and no longer significant, including among those with hemoglobin ≥2 g/dL below the WHO threshold (odds ratio 1.39, 95% confidence interval = 0.94-2.04). A test for linear trend was of borderline significance (p value = .06). For 94% of the sample within 2 g/dL of the WHO threshold, there was no relationship between hemoglobin concentration and the odds of cognitive impairment. The associations did not differ by sex and race. CONCLUSIONS: Within a large sample of community-dwelling adults, there was no significant association between hemoglobin concentration and cognitive impairment after multivariable adjustment.

Poverty and racial disparities in kidney disease: the REGARDS study.

UNLABELLED: There are pronounced disparities among black compared to white Americans for risk of end-stage renal disease. This study examines whether similar relationships exist between poverty and racial disparities in chronic kidney disease (CKD) prevalence. METHODS: We studied 22,538 participants in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort study. We defined individual poverty as family income below USD 15,000 and a neighborhood as poor if 25% or more of the households were below the federal poverty level. RESULTS: As the estimated glomerular filtration rate (GFR) declined from 50-59 to 10-19 ml/min/ 1.73 m2, the black:white odds ratio (OR) for impaired kidney function increased from 0.74 (95% CI 0.66, 0.84) to 2.96 (95% CI 1.96, 5.57). Controlling for individual income below poverty, community poverty, demographic and comorbid characteristics attenuated the black:white prevalence to an OR of 0.65 (95% CI 0.57, 0.74) among individuals with a GFR of 59-50 ml/min/1.73 m2 and an OR of 2.21 (95% CI 1.25, 3.93) among individuals with a GFR between 10 and 19 ml/min/ 1.73 m2. CONCLUSION: Household, but not community poverty, was independently associated with CKD and attenuated but did not fully account for differences in CKD prevalence between whites and blacks.

Physical and psychological burden of chronic kidney disease among older adults.

INTRODUCTION: The purpose of the study is to determine if functional status and quality of life (QoL) vary with glomerular filtration rate (GFR) among older adults. METHODS: We studied adults aged 45 years and older participating in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort study. Data included demographic and health information, serum creatinine and hemoglobin, the 4-item Center for Epidemiologic Studies Depression Scale (CES-D-4), the 4-item Cohen's Perceived Stress Scale (PSS-4), reported health status and inactivity and the Medical Outcomes Study Short Form-12 (SF-12) QoL scores. RESULTS: CKD (GFR <60 ml/min/1.73 m(2)) was present in 11.6% of the subjects. As GFR declined, the SF-12 physical component score, adjusted for other participant attributes, declined from 38.9 to 35.9 (p = 0.0001). After adjustment for other risk factors, poorer personal health scores (p < 0.0001) and decreased physical activity (p < 0.0001) were reported as GFR declined. In contrast, after adjusting for other participant characteristics, depression scores and stress scores and the mental component score of the SF-12 were not associated with kidney function. CONCLUSION: Older individuals with CKD in the US population experience an increased prevalence of impaired QoL that cannot be fully explained by other individual characteristics.

Exploration of anaemia as a progression factor in African Americans with cardiovascular disease.

BACKGROUND: Despite the higher incidence of end-stage renal disease (ESRD) among African Americans, whites in the USA have a higher prevalence of chronic kidney disease. This may be due, in part, to faster progression to ESRD among African Americans. Anaemia is associated with a risk of kidney disease progression and is more prevalent among African Americans. The purpose of this study is to determine if anaemia is associated with progression to ESRD differently according to race. METHODS: A retrospective cohort study of Cooperative Cardiovascular Project data for 87 693 Medicare beneficiaries >or=65 years old and ESRD free admitted to 4047 hospitals with acute myocardial infarction between February 1994 and June 1995 was conducted. Follow-up was collected through June 2004 for ESRD and mortality. RESULTS: Among 87 693 patients, 7.0% were African Americans and 50.1% females. African Americans had a higher prevalence of anaemia than whites (40.2% versus 26.7%, respectively; P < 0.001). Lower haematocrit was associated with higher ESRD rates after adjustment, and the association of haematocrit with ESRD did not vary according to race (P = 0.19). This association was strongest at the lowest baseline kidney function (GFR <15) with hazard ratios increasing 7-fold as haematocrit decreased from >or= 42% to <28%. CONCLUSIONS: In a nationally representative sample of patients with cardiovascular disease, anaemia was associated equally among African Americans and whites with an increased risk of ESRD.