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Biomedical subjects

Catherine Stehman-Breen

Publications and source records attributed to Catherine Stehman-Breen.

At least 19 recordsLinked to original sources

Association of kidney function with incident hip fracture in older adults.

Kidney dysfunction is associated with bone loss, and patients with ESRD have an increased risk for hip fracture. However, the association of mild to moderate kidney disease with hip fracture has not been studied previously. The association of kidney function with incident hip fracture was examined among participants in the Cardiovascular Health Study, a community-based cohort of older individuals. The primary measure of kidney function was serum cystatin C, a measure that does not depend on lean mass. Hip fractures were identified using International Classification of Diseases, Ninth Revision codes for hospitalizations. A total of 4699 individuals had cystatin C measured in 1992 to 1993 and did not have a hip fracture before cystatin C measurement. The association of kidney function with hip fracture was analyzed with Cox proportional hazards models. Analyses were conducted separately for men and women. After a mean follow-up of 7.1 yr, 195 incident hip fractures occurred in women and 79 occurred in men. Higher cystatin C levels were associated with a higher risk for fracture in women (hazard ratio [HR] 1.26; 95% confidence interval [CI] 1.14 to 1.38 per SD) and in men (HR 1.27; 95% CI 1.11 to 1.46). After multivariable adjustment, higher cystatin C levels were significantly associated with hip fracture in women (HR 1.16; 95% CI 1.01, 1.33) but not in men (HR 1.14; 95% CI 0.86 to 1.52), although the magnitude of the association was similar. Kidney dysfunction, as assessed by cystatin C, is associated with an increased risk for hip fracture. Further studies are needed to evaluate potential mediators of this relationship and to assess whether interventions can decrease this risk.

Aged↗

Cystatin C and prognosis for cardiovascular and kidney outcomes in elderly persons without chronic kidney disease.

BACKGROUND: Cystatin C is an alternative measure of kidney function that may have prognostic importance among elderly persons who do not meet standard criteria for chronic kidney disease (estimated glomerular filtration rate [GFR] > or =60 mL/min per 1.73 m2). OBJECTIVE: To evaluate cystatin C as a prognostic biomarker for death, cardiovascular disease, and incident chronic kidney disease among elderly persons without chronic kidney disease. DESIGN: Cohort study. SETTING: The Cardiovascular Health Study, a population-based cohort recruited from 4 communities in the United States. PARTICIPANTS: 4663 elderly persons. MEASUREMENTS: Measures of kidney function were creatinine-based estimated GFR by using the Modification of Diet in Renal Disease equation and cystatin C concentration. Outcomes were death, cardiovascular death, noncardiovascular death, heart failure, stroke, myocardial infarction, and incident chronic kidney disease during follow-up (median, 9.3 years). RESULTS: At baseline, 78% of participants did not have chronic kidney disease (estimated GFR > or =60 mL/min per 1.73 m2) and mean cystatin C concentration, creatinine concentration, and estimated GFR were 1.0 mg/L, 79.6 micromol/L (0.9 mg/dL), and 83 mL/min per 1.73 m2, respectively. Cystatin C concentrations (per SD, 0.18 mg/L) had strong associations with death (hazard ratio, 1.33 [95% CI, 1.25 to 1.40]), cardiovascular death (hazard ratio, 1.42 [CI, 1.30 to 1.54]), noncardiovascular death (hazard ratio, 1.26 [CI, 1.17 to 1.36]), incident heart failure (hazard ratio, 1.28 [CI, 1.17 to 1.40]), stroke (hazard ratio, 1.22 [CI, 1.08 to 1.38]), and myocardial infarction (hazard ratio, 1.20 [CI, 1.06 to 1.36]) among these participants. Serum creatinine concentrations had much weaker associations with each outcome and only predicted cardiovascular death. Participants without chronic kidney disease who had elevated cystatin C concentrations (> or =1.0 mg/L) had a 4-fold risk for progressing to chronic kidney disease after 4 years of follow-up compared with those with cystatin C concentrations less than 1.0 mg/L. LIMITATIONS: Because this study did not directly measure GFR or albuminuria, the extent to which cystatin C may be influenced by nonrenal factors was not determined and participants with albuminuria might have been misclassified as having no kidney disease. CONCLUSIONS: Among elderly persons without chronic kidney disease, cystatin C is a prognostic biomarker of risk for death, cardiovascular disease, and chronic kidney disease. In this setting, cystatin C seems to identify a "preclinical" state of kidney dysfunction that is not detected with serum creatinine or estimated GFR.

Aged↗

Darbepoetin alfa for the treatment of anemia in pediatric patients with chronic kidney disease.

Darbepoetin alfa, an erythropoiesis-stimulating glycoprotein, has proved efficacious in the treatment of anemia of chronic kidney disease (CKD) in adult subjects. However, little information is available from pediatric populations. We conducted an open-label, non-inferiority, 28-week study comparing the efficacy of darbepoetin alfa with that of recombinant human erythropoietin (rHuEpo) in pediatric subjects with CKD. Subjects, aged 1-18, who were receiving stable rHuEpo treatment (n=124) were randomized (1:2) to either continue receiving rHuEpo or convert to darbepoetin alfa, with doses titrated to achieve and maintain hemoglobin (Hb) levels between 10.0 and 12.5 g/dl. Darbepoetin alfa was considered to be non-inferior to rHuEpo if the lower limit of the two-sided 95% confidence interval (CI) for the difference in the mean change in Hb between the two treatment groups was above -1.0 g/dl. The adjusted mean change in Hb between the baseline and the evaluation period for the rHuEpo and darbepoetin alfa groups was -0.16 g/dl and 0.15 g/dl, respectively, with a difference of 0.31 g/dl (95% CI: -0.45, 1.07) between the means. These results, and the comparable safety profiles, demonstrate that darbepoetin alfa is non-inferior to rHuEpo in the treatment of anemia in pediatric patients with CKD.

Anemia↗

Kidney function predicts the rate of bone loss in older individuals: the Cardiovascular Health Study.

BACKGROUND: Results of cross-sectional analyses of the association of kidney function with bone mineral density (BMD) have been conflicting. We examined the association of cystatin-C, a new marker of kidney function that is unrelated to lean mass, with initial and follow-up BMD, in an ancillary study of the Cardiovascular Health Study, a population-based cohort of individuals > or = 65 years old. METHODS: Two years after measurement of cystatin-C and other covariates, the first BMD was measured in Pittsburgh, Pennsylvania and Davis, California, by using dual energy x-ray absorptiometry. Follow-up BMD was measured in Pittsburgh 4 years later. Associations of cystatin-C with initial BMD and the change in BMD (%/y) at the hip were examined with linear regression. Analyses were conducted separately for men and women. RESULTS: In 1519 participants who had cystatin-C and initial BMD assessed, 614 had follow-up BMD. The percent annual change in BMD at the total hip by cystatin-C quartiles was -0.24, -0.13, -0.40, and -0.66%/y (first to fourth quartile) in women and -0.02, -0.30, -0.18, and -0.94%/y in men. After adjusting for potential confounders, cystatin-C was marginally associated with initial BMD in men but not women. Cystatin-C was associated with bone loss in men; after adjustment for weight loss, cystatin-C was not associated with bone loss in women. CONCLUSION: Kidney dysfunction, as assessed by cystatin-C, is associated with a more rapid loss of BMD at the hip, especially in men. Further studies are needed to confirm these findings and to determine whether this loss leads to an elevated risk of fracture.

Absorptiometry, Photon↗

Observational research databases in renal disease.

Observational, patient-oriented research is a term that describes clinical or community-based studies in that they do not involve an experiment or intervention. Observational research studies can be designed and implemented by a primary data collection or using previously collected patient data. The latter is less expensive, although it has some distinct limitations. Many research databases are readily available and can be used to answer important questions that are relevant to kidney disease. This review summarizes the types of research analyses that can be conducted using existing databases, the types of research databases available, and a general approach for addressing a proposed research question using existing data.

Biomedical Research↗

Kidney function as a predictor of noncardiovascular mortality.

Chronic kidney disease is associated with a higher risk for cardiovascular mortality, as well as all-cause mortality. Whether chronic kidney disease is a predictor of noncardiovascular mortality is less clear. To further explore the latter, the association of kidney function with total noncardiovascular mortality and cause-specific mortality was assessed in the Cardiovascular Health Study, a community-based cohort of older individuals. Kidney disease was assessed using cystatin C and estimated GFR in 4637 participants in 1992 to 1993. Participants were followed until June 30, 2001. Deaths were adjudicated as cardiovascular or noncardiovascular disease by committee, and an underlying cause of death was assigned. The associations of kidney function with total noncardiovascular mortality and cause-specific mortality were analyzed by proportional hazards regression. Noncardiovascular mortality rates increased with higher cystatin C quartiles (16.8, 17.1, 21.6, and 50.0 per 1000 person-years). The association of cystatin C with noncardiovascular mortality persisted after adjustment for demographic factors; the presence of diabetes, C-reactive protein, hemoglobin, and prevalent cardiovascular disease; and measures of atherosclerosis (hazard ratio 1.69; 95% confidence interval 1.33 to 2.15, for the fourth quartile versus the first quartile). Results for estimated GFR were similar. The risk for noncardiac deaths attributed to pulmonary disease, infection, cancer, and other causes was similarly associated with cystatin C levels. Kidney function predicts noncardiovascular mortality from multiple causes in the elderly. Further research is needed to understand the mechanisms and evaluate interventions to reduce the high mortality rate in chronic kidney disease.

Age Factors↗

Cystatin C and the risk of death and cardiovascular events among elderly persons.

BACKGROUND: Cystatin C is a serum measure of renal function that appears to be independent of age, sex, and lean muscle mass. We compared creatinine and cystatin C levels as predictors of mortality from cardiovascular causes and from all causes in the Cardiovascular Health Study, a cohort study of elderly persons living in the community. METHODS: Creatinine and cystatin C were measured in serum samples collected from 4637 participants at the study visit in 1992 or 1993; follow-up continued until June 30, 2001. For each measure, the study population was divided into quintiles, with the fifth quintile subdivided into thirds (designated 5a, 5b, and 5c). RESULTS: Higher cystatin C levels were directly associated, in a dose-response manner, with a higher risk of death from all causes. As compared with the first quintile, the hazard ratios (and 95 percent confidence intervals) for death were as follows: second quintile, 1.08 (0.86 to 1.35); third quintile, 1.23 (1.00 to 1.53); fourth quintile, 1.34 (1.09 to 1.66); quintile 5a, 1.77 (1.34 to 2.26); 5b, 2.18 (1.72 to 2.78); and 5c, 2.58 (2.03 to 3.27). In contrast, the association of creatinine categories with mortality from all causes appeared to be J-shaped. As compared with the two lowest quintiles combined (cystatin C level, < or =0.99 mg per liter), the highest quintile of cystatin C (> or =1.29 mg per liter) was associated with a significantly elevated risk of death from cardiovascular causes (hazard ratio, 2.27 [1.73 to 2.97]), myocardial infarction (hazard ratio, 1.48 [1.08 to 2.02]), and stroke (hazard ratio, 1.47 [ 1.09 to 1.96]) after multivariate adjustment. The fifth quintile of creatinine, as compared with the first quintile, was not independently associated with any of these three outcomes. CONCLUSIONS: Cystatin C, a serum measure of renal function, is a stronger predictor of the risk of death and cardiovascular events in elderly persons than is creatinine.

Aged↗

Cardiovascular mortality risk in chronic kidney disease: comparison of traditional and novel risk factors.

CONTEXT: Elderly persons with chronic kidney disease have substantial risk for cardiovascular mortality, but the relative importance of traditional and novel risk factors is unknown. OBJECTIVE: To compare traditional and novel risk factors as predictors of cardiovascular mortality. DESIGN, SETTING, AND PATIENTS: A total of 5808 community-dwelling persons aged 65 years or older living in 4 communities in the United States participated in the Cardiovascular Health Study cohort. Participants were initially recruited from 1989 to June 1990; an additional 687 black participants were recruited in 1992-1993. The average length of follow-up in this longitudinal study was 8.6 years. MAIN OUTCOME MEASURES: Cardiovascular mortality among those with and without chronic kidney disease. Chronic kidney disease was defined as an estimated glomerular filtration rate of less than 60 mL/min per 1.73 m2. RESULTS: Among the participants, 1249 (22%) had chronic kidney disease at baseline. The cardiovascular mortality risk rate was 32 deaths/1000 person-years among those with chronic kidney disease vs 16/1000 person-years among those without it. In multivariate analyses, diabetes, systolic hypertension, smoking, low physical activity, nonuse of alcohol, and left ventricular hypertrophy were predictors of cardiovascular mortality in persons with chronic kidney disease (all P values <.05). Among the novel risk factors, only log C-reactive protein (P = .05) and log interleukin 6 (P<.001) were associated with the outcome as linear predictors. Traditional risk factors were associated with the largest absolute increases in risks for cardiovascular deaths among persons with chronic kidney disease: for left ventricular hypertrophy, there were 25 deaths per 1000 person-years; current smoking, 20 per 1000 person-years; physical inactivity, 15 per 1000 person-years; systolic hypertension, 14 per 1000 person-years; diabetes, 14 per 1000 person-years; and nonuse of alcohol, 11 per 1000 person-years vs 5 deaths per 1000 person-years for those with increased C-reactive protein and 5 per 1000 person-years for those with increased interleukin 6 levels. A receiver operating characteristic analysis found that traditional risk factors had an area under the curve of 0.73 (95% confidence interval, 0.70-0.77) among those with chronic kidney disease. Adding novel risk factors only increased the area under the curve to 0.74 (95% confidence interval, 0.71-0.78; P for difference = .15). CONCLUSIONS: Traditional cardiovascular risk factors had larger associations with cardiovascular mortality than novel risk factors in elderly persons with chronic kidney disease. Future research should investigate whether aggressive lifestyle intervention in patients with chronic kidney disease can reduce their substantial cardiovascular risk.

Aged↗

Rationale--Trial to Reduce Cardiovascular Events with Aranesp Therapy (TREAT): evolving the management of cardiovascular risk in patients with chronic kidney disease.

BACKGROUND: Patients with chronic kidney disease (CKD) have a high burden of mortality and cardiovascular morbidity. Additional strategies to modulate cardiovascular risk in this population are needed. Data suggest that anemia is a potent and potentially modifiable risk factor for cardiovascular disease in patients with CKD, but these data remain unsubstantiated by any randomized controlled trial (RCT). Furthermore, the clinical practice guidelines for anemia management in patients with CKD are based on limited data. The need for new RCTs to address critical knowledge deficits, particularly with regard to the impact of anemia therapy on cardiovascular disease and survival, is recognized within the guidelines and independent comprehensive reviews of the existing published trial data. STUDY DESIGN: The Trial to Reduce Cardiovascular Events with Aranesp (Amgen Inc, Thousand Oaks, Calif) (darbepoetin alfa) Therapy (TREAT) is a 4000-patient, multicenter, double-blind RCT, designed to determine the impact of anemia therapy with darbepoetin alfa on mortality and nonfatal cardiovascular events in patients with CKD and type 2 diabetes mellitus. Subjects will be randomized in a 1:1 manner to either darbepoetin alfa therapy to a target hemoglobin (Hb) of 13 g/dL or control, consisting of placebo for Hb > or =9 g/dL or darbepoetin alfa for Hb <9 g/dL until Hb is again Hb > or =9 g/dL. TREAT is event-driven and has a composite primary end point comprising time to mortality and nonfatal cardiovascular events, including myocardial infarction, myocardial ischemia, stroke, and heart failure. TREAT will provide data that are critical to evolution of the management of cardiovascular risk in this high-risk population.

Anemia↗

Cystatin-C and inflammatory markers in the ambulatory elderly.

PURPOSE: Inflammatory factors are elevated in persons with severe renal dysfunction, but their association across all levels of renal function is unclear. We compared cystatin-C, a novel marker of renal function, with creatinine and estimated glomerular filtration rate (eGFR) as predictors of C-reactive protein and fibrinogen levels. METHODS: This study is a cross-sectional analysis to evaluate cystatin-C, creatinine, and eGFR as predictors of the inflammatory markers C-reactive protein and fibrinogen. Participants included 4637 ambulatory elderly patients from the Cardiovascular Health Study. Multivariate linear regression was used to determine the independent associations of each renal function measurement with the inflammatory marker outcomes. RESULTS: After adjustment for confounding factors, cystatin-C was correlated with both C-reactive protein (coefficient = 0.13; 95% confidence interval: 0.10-1.16, P <.0001) and fibrinogen levels (0.15; 0.13-0.18, P <.0001). Associations were larger than those for creatinine and C-reactive protein (0.05; 0.02-0.07, P = .003) or fibrinogen (0.07; 0.04-0.10, P <.0001). Adjusted levels of C-reactive protein increased incrementally across quintiles of cystatin-C, from a median of 2.2 mg/L in quintile 1 to 3.7 mg/L in quintile 5. In contrast, both C-reactive protein and fibrinogen had U-shaped associations with quintiles of creatinine and eGFR, because the inflammatory markers were equivalently elevated in quintiles 1 and 5. CONCLUSIONS: The finding of a significant linear association of cystatin-C and inflammation markers suggests that even small reductions in renal function may be associated with adverse pathophysiologic consequences.

Age Factors↗

Cinacalcet HCl attenuates parathyroid hyperplasia in a rat model of secondary hyperparathyroidism.

BACKGROUND: Secondary hyperparathyroidism (HPT) in chronic kidney disease (CKD) is a physiologic response to kidney failure characterized by elevated serum parathyroid hormone (PTH) levels and parathyroid gland enlargement. Calcimimetic agents acting through allosteric modification of the calcium-sensing receptor (CaR) can attenuate parathyroid hyperplasia in rats with secondary HPT. The present study explores the effects of the calcimimetic cinacalcet HCl on parathyroid hyperplasia, apoptosis, and PTH secretion in a rat model of secondary HPT. METHODS: Cinacalcet HCl was gavaged daily (1, 5, or 10 mg/kg) for 4 weeks starting 6 weeks post-5/6 nephrectomy. After dosing, hyperplasia was determined using parathyroid weight and proliferating cell nuclear antigen (PCNA) immunochemistry. Apoptosis was determined using in situ techniques. Serum PTH((1-34)) and blood chemistries were determined throughout the course of the study. RESULTS: Administration of cinacalcet HCl (5 or 10 mg/kg) significantly reduced the number of PCNA-positive cells and decreased parathyroid weight compared with vehicle-treated 5/6 nephrectomized rats. There was no difference in apoptosis from cinacalcet HCl-treated or vehicle-treated animals. Serum PTH and blood ionized calcium levels decreased in cinacalcet HCl-treated animals compared with vehicle-treated controls. CONCLUSION: The results confirm previous work demonstrating that calcimimetic agents attenuate the progression of parathyroid hyperplasia in subtotally nephrectomized rats, extending earlier observations to now include cinacalcet HCl. These results support a role for the CaR in regulating parathyroid cell proliferation. Therefore, cinacalcet HCl may represent a novel therapy for improving the management of secondary HPT.

Animals↗

Creatinine levels and cardiovascular events in women with heart disease: do small changes matter?

BACKGROUND: Small changes in creatinine levels have been incrementally associated with increased risk for heart failure morbidity, but their association with cardiovascular events has not been evaluated in persons with established coronary heart disease (CHD). METHODS: This was an observational study from the Heart and Estrogen/Progestin Replacement Study (HERS) and the HERS-II follow-up study. Participants were 2,763 postmenopausal women with CHD who were followed up for a mean of 4.1 years during HERS and an additional 2.7 years during HERS-II. We evaluated the association of worsened renal function (creatinine level increase > or = 0.3 mg/dL [> or =26.5 micromol/L]) during HERS with CHD outcomes (nonfatal myocardial infarction and CHD death) that occurred during HERS-II. RESULTS: Only 194 participants (9%) had worsened renal function during HERS, and they were characterized by a greater prevalence of diabetes, lower high-density lipoprotein cholesterol and higher triglyceride levels, and increased rate of cardiovascular events during HERS (all P < 0.01). After adjustment for only baseline creatinine levels, worsened renal function was associated with HERS-II CHD events (relative hazard [RH], 1.54; 95% confidence interval [CI], 1.04 to 2.29). After adjustment for baseline characteristics, HERS cardiovascular events, and medication use, worsened renal function was no longer associated with CHD events (RH, 1.08; 95% CI, 0.70 to 1.67). However, baseline creatinine levels from HERS were remarkably strong predictors of HERS-II events. CONCLUSION: Although baseline renal function was among the strongest predictors of CHD events during 7 years of HERS follow-up, we found no significant association of worsened renal function with cardiovascular outcomes after adjustment for cardiovascular risk factors and interim events.

Aged↗

The presence of frailty in elderly persons with chronic renal insufficiency.

BACKGROUND: Frailty has been defined as a tool to define individuals who lack functional reserve and are at risk for functional decline. We hypothesized that chronic renal insufficiency (CRI) would be associated with a greater prevalence of frailty and disability in the elderly. METHODS: This cross-sectional analysis used baseline data collected from the Cardiovascular Health Study, which enrolled 5,888 community-dwelling adults aged 65 years or older from 4 clinical centers in the United States. Renal insufficiency is defined as a serum creatinine level of 1.3 mg/dL or greater (> or =115 micromol/L) in women and 1.5 mg/dL or greater (> or =133 micromol/L) in men. Frailty is defined by the presence of 3 of the following abnormalities: unintentional weight loss, self-reported exhaustion, measured weakness, slow walking speed, and low physical activity. Disability is defined as any self-reported difficulty with activities of daily living. RESULTS: Among 5,808 participants with creatinine levels measured at entry, 15.9% of men (n = 394) and 7.6% of women (n = 254) had CRI. Prevalences of frailty (15% versus 6%; P < 0.001) and disability (12% versus 7%; P = 0.001) were greater in participants with CRI compared with those with normal renal function. After multivariate adjustment for comorbidity, CRI remained significantly associated with frailty (odds ratio, 1.76; 95% confidence interval, 1.28 to 2.41), but not disability (odds ratio, 1.26; 95% confidence interval, 0.94 to 1.69). CONCLUSION: Elderly persons with CRI have a high prevalence of frailty, which may signal their risk for progression to adverse health outcomes. If confirmed in other studies, identification of frailty in patients with CRI may warrant special interventions to preserve their independence, quality of life, and survival.

Activities of Daily Living↗

Osteoporosis and chronic kidney disease.

Bone disease is heterogenous and highly prevalent among those with chronic kidney disease, stage V (CKD-V) patients. Although we know much regarding the risk factors and outcomes associated with renal osteodystrophy, less is known about osteoporosis in CKD-V. Factors that predict bone loss in the CKD-V population are similar to those in the general population and include female gender, Caucasian race, older age, chronic disease, and immobility. In addition, some studies suggest that chronic acidosis and renal osteodystrophy may also increase the risk for bone loss. Little is known about associated adverse outcomes or the impact of therapeutic interventions for osteoporosis. Although we know that the risk for hip fracture is high among CKD-V patients and that fracture is associated with an increased risk for death, the role that bone loss plays is largely unknown. Current recommendations suggest that risk-factor modification is the most appropriate course of treatment for CKD-V-associated osteoporosis.

Absorptiometry, Photon↗

Inflammatory and prothrombotic markers and the progression of renal disease in elderly individuals.

Inflammatory and prothrombotic markers are elevated in individuals with mild to moderate renal disease. It was hypothesized that these markers may also be determinants of the progression of renal disease. The association of six markers-serum C-reactive protein (CRP), white blood cell (WBC) count, fibrinogen, factor VII, albumin, and hemoglobin-with subsequent elevations of creatinine and decline in estimated GFR in the Cardiovascular Health Study, a community-based cohort of elderly individuals, was analyzed. Linear regression was used to determine predictors of an annualized change in serum creatinine as the main outcome. Duration of follow-up was 7 yr for the original cohort and 4 yr for the more recently recruited black cohort. A total of 588 (12.7%) individuals had a decline in estimated GFR of at least 3 ml/min per yr per 1.73 m(2). Higher CRP (P < 0.001), WBC count (P < 0.001), fibrinogen (P < 0.001), and factor VII (P < 0.001) levels and lower albumin (P < 0.001) and hemoglobin levels (P < 0.001) were associated with a rise in creatinine, after adjusting for age. With additional adjustments for race, gender, baseline creatinine, systolic and diastolic BP, lipid levels, weight, and pack-years smoking, higher CRP, factor VII, fibrinogen, WBC count, and lower albumin and hemoglobin levels remained associated with a rise in creatinine. Similar results were found for decline in estimated GFR. The decline in GFR was greater with increasing number of inflammatory or prothrombotic markers that were above the median (below for hemoglobin and albumin). Inflammatory and prothrombotic markers are predictors for a change in kidney function in elderly individuals. Interventions that reduce inflammation might confer significant cardiovascular and renal benefits.

Aged↗

Survival following parathyroidectomy among United States dialysis patients.

BACKGROUND: Secondary hyperparathyroidism (SHPTH) is highly prevalent among persons with end-stage renal disease (ESRD). SHPTH has been linked to uremic bone disease, vascular calcification, and a higher risk of death. Parathyroidectomy (PTX) can dramatically reduce parathyroid hormone (PTH) and phosphate levels; however, the relationship between PTX and survival is not known. METHODS: We conducted an observational matched cohort study utilizing data from the United States Renal Database System (USRDS) in which 4558 patients undergoing a first PTX while on hemodialysis or peritoneal dialysis were individually matched by age, race, gender, cause of ESRD, dialysis duration, prior transplantation status, and dialysis modality to 4558 control patients who did not undergo PTX. Patients were followed from the date of PTX until they died or were lost to follow-up. RESULTS: The 30-day postoperative mortality rate following PTX was 3.1%. Long-term relative risks of death among patients undergoing PTX were estimated to be 10% to 15% lower than those of matched control patients not undergoing surgery. Survival curves between the 2 groups crossed 587 days following PTX. Median survival was 53.4 months (95% CI: 51.2-56.4) in the PTX group, and 46.8 months (95% CI: 44.7-48.9) in the control group. CONCLUSION: PTX was associated with higher short-term, and lower long-term, mortality rates among U.S. patients receiving chronic dialysis. Measures to attenuate SHPTH may play an important role in reducing mortality among patients with end-stage renal disease.

Adult↗

Pharmacokinetics of oral micronized beta-estradiol in postmenopausal women receiving maintenance hemodialysis.

BACKGROUND: Although 11% of postmenopausal women with end-stage renal disease (ESRD) are prescribed hormone replacement therapy (HRT), the appropriate use remains poorly explored. Although there remains controversy surrounding the benefits of HRT, it may be of particular interest in this population, which has a high risk of bone loss and a fourfold increase in fracture risk compared to the general population. However, the appropriate dose of estrogen for use in postmenopausal women with ESRD is not known. The objective of this study was to evaluate the steady-state pharmacokinetics of oral micronized beta-estradiol in postmenopausal women with ESRD compared with postmenopausal women with normal renal function in order to determine equivalent dosing. METHODS: Six postmenopausal women with ESRD receiving maintenance hemodialysis and 6 healthy postmenopausal controls received 14 days of micronized beta-estradiol (1.0 mg for control, 0.5 mg for ESRD). Blood, urine, and dialysate samples were obtained during a dosage interval on day 14. Estradiol, estrone, albumin, and sex-hormone binding globulin (SHBG) concentrations were determined. Free estradiol concentrations were calculated using a previously described method. RESULTS: Women with ESRD had significantly lower serum albumin (610 +/- 31 micromol/L vs. 684 +/- 83 micromol/L) and SHBG (78 +/- 17 vs. 118 +/- 13 nmol/L) than control subjects. Total clearance of estradiol was not significantly different. Due to difference in binding, free estradiol concentrations were significant higher in ESRD women (53.2 +/- 17.7 pg/mL) than control women (43.5 +/- 8.7 pg/mL), despite receiving 50% of the dose. There was no significant difference in estrone concentrations. Clearance of both estradiol and estrone in the dialysate was minimal. CONCLUSION: Women with ESRD should receive approximately 50% of the dose typically prescribed to women without ESRD.

Administration, Oral↗