Association of kidney function with mortality in patients with chronic kidney disease not yet on dialysis: a historical prospective cohort study

Estimated Impact of Achieving the Australian National Sodium Reduction Targets on Blood Pressure, Chronic Kidney Disease Burden and Healthcare Costs: A Modelling Study

Excess sodium intake raises blood pressure which increases the risk of chronic kidney disease (CKD). We aimed to estimate the impact of reduced sodium intake on future CKD burden in Australia. A multi-cohort proportional multistate lifetable model was developed to estimate the potential impact on CKD burden and health expenditure if the Australian Suggested Dietary Target (SDT) and the National Preventive Health Strategy 2021-2030 (NPHS) sodium target were achieved. Outcomes were projected to 2030 and over the lifetime of adults alive in 2019. Achieving the SDT and NPHS targets could lower population mean systolic blood pressure by 2.1 mmHg and 1.7 mmHg, respectively. Compared to normal routines, attaining the SDT and NPHS target by 2030 could prevent 59,220 (95% UI, 53,140-65,500) and 49,890 (44,377-55,569) incident CKD events, respectively, while postponing 568 (479-652) and 511 (426-590) CKD deaths, respectively. Over the lifetime, this generated 199,488 health-adjusted life years (HALYs) and AUD 644 million in CKD healthcare savings for the SDT and 170,425 HALYs and AUD 514 million for the NPHS. CKD due to hypertension and CKD due to other/unspecified causes were the principal contributors to the HALY gains. Lowering sodium consumption in Australia could deliver substantial CKD health and economic benefits.

The Impact of CKD Anaemia on Patients: Incidence, Risk Factors, and Clinical Outcomes-A Systematic Literature Review

Anaemia is a common consequence of chronic kidney disease (CKD); however, the risk factors for its development and its impact on outcomes have not been well synthesised. Therefore, we undertook a systematic review to fully characterise the risk factors associated with the presence of anaemia in patients with CKD and a contemporary synthesis of the risks of adverse outcomes in patients with CKD and anaemia. We searched MEDLINE, EMBASE, and the Cochrane Library from 2002 until 2018 for studies reporting the incidence or prevalence of anaemia and associated risk factors and/or associations between haemoglobin (Hb) or anaemia and mortality, major adverse cardiac events (MACE), hospitalisation, or CKD progression in adult patients with CKD. Extracted data were summarised as risk factors related to the incidence or prevalence of anaemia or the risk (hazard ratio (HR)) of outcome by Hb level (<10, 10-12, >12 g/dL) in patients not on dialysis and in those receiving dialysis. 191 studies met the predefined inclusion criteria. The risk factor most associated with the prevalence of anaemia was CKD stage, followed by age and sex. Mean HRs (95% CI) for all-cause mortality in patients with CKD on dialysis with Hb <10, 10-12, and >12 g/dL were 1.56 (1.43-1.71), 1.17 (1.09-1.26), and 0.91 (0.87-0.96), respectively. Similar patterns were observed for nondialysis patients and for the risks of hospitalisation, MACE, and CKD progression. This is the first known systematic review to quantify the risk of adverse clinical outcomes based on Hb level in patients with CKD. Anaemia was consistently associated with greater mortality, hospitalisation, MACE, and CKD progression in patients with CKD, and risk increased with anaemia severity. Effective treatments that not only treat the anaemia but also reduce the risk of adverse clinical outcomes are essential to help reduce the burden of anaemia and its management in CKD.

Impact of the donor-recipient gender matching on the graft survival from live donors

Background

Several factors such as recipient age, BMI, serum cratinine, and positive history of dialysis are important in predicting graft survival among kidney transplant recipients. One factor affecting the transplant outcomes is donors and recipients gender, which is usually ignored.

Methods

A total of 1113 kidney transplant recipients were studied in this retrospective cohort study. Several factors were taken into account for graft survival and outcomes such as donors and recipients gender and age in addition to common recipient factors like cratinine, eGFR, BMI, and positive history of dialysis.

Results

The most successful transplant based on donor-recipient gender was observed in male donor to male recipient, and then male donor to female recipient. In female transplant recipients, level of serum cratinine and eGFR, positive dialysis history before transplant, and low donor hemoglobin level can be considered as good prognostic factors recommended for kidney transplant survival.

Conclusions

Our results suggested gender matching for kidney transplant. Only in some exceptional conditions, male donor to female recipient kidney transplant may be successful and female donors to male recipients are not suggested, especially in aged patients with the history of dialysis.

Dietary phosphate toxicity: an emerging global health concern

Phosphate is a common ingredient in many healthy foods but, it is also present in foods containing additives and preservatives. When found in foods, phosphate is absorbed in the intestines and filtered from the blood by the kidneys. Generally, any excess is excreted in the urine. In renal pathologies, however, such as chronic kidney disease, a reduced renal ability to excrete phosphate can result in excess accumulation in the body. This accumulation can be a catalyst for widespread damage to the cellular components, bones, and cardiovascular structures. This in turn can reduce mortality. Because of an incomplete understanding of the mechanism for phosphate homeostasis, and the multiple organ systems that can modulate it, treatment strategies designed to minimize phosphate burden are limited. The Recommended Dietary Allowance (RDA) for phosphorous is around 700 mg/day for adults, but the majority of healthy adult individuals consume far more phosphate (almost double) than the RDA. Studies suggest that low-income populations are particularly at risk for dietary phosphate overload because of the higher amounts of phosphate found in inexpensive, processed foods. Education in nutrition, as well as access to inexpensive healthy food options may reduce risks for excess consumption as well as a wide-range of disorders, ranging from cardiovascular diseases to kidney diseases to tumor formation. Pre-clinical and clinical studies suggest that dietary phosphate overload has toxic and prolonged adverse health effects. Improved regulations for reporting of phosphate concentrations on food labels are necessary so that people can make more informed choices about their diets and phosphate consumption. This is especially the case given the lack of treatments available to mitigate the short and long-term effects of dietary phosphate overload-related toxicity. Phosphate toxicity is quickly becoming a global health concern. Without measures in place to reduce dietary phosphate intake, the conditions associated with phosphate toxicity will likely to cause untold damage to the wellbeing of individuals around the world.

Progression and outcomes of non-dialysis dependent chronic kidney disease patients: A single center longitudinal follow-up study

AIM

Despite increase global prevalence of End stage renal disease (ESRD) and subsequent need for renal replacement therapy (RRT), relatively little is known about disease progression and prognosis of earlier stages of CKD. Current study was conducted to examine rate of CKD progression, predictors of ESRD and death.

METHODS

A total 621 patients with estimated glomerular filtration rate (eGFR) of 15-59ml/min/1.73m² (CKD stage 3 & 4) were selected and followed up for 10 years or until ESRD or death, whichever occurred first. Subjects who did not meet inclusion criteria were excluded (n=1474).

RESULTS

Annual cumulative decline in eGFR was 3.01±0.40 ml/min/1.73m² . Overall disease progression was observed in 60% patients while 18% died. Among patients with CKD stage 3, 21% progressed to stage 4, 10% to stage 5ND (non-dialysis) and 31% to RRT while mortality was observed in 16% patients. On the other hand, 8% patients with CKD stage 4 progressed to stage 5ND, 31% to RRT and mortality was observed in 24% cases. Patients with CVD, higher systolic blood pressure, elevated phosphate levels, heavy proteinuria, microscopic hematuria and use of diuretics were more likely to develop ESRD. Advancing age, low eGFR, low systolic blood pressure, low hemoglobin and baseline diabetes were found to be significant predictors of mortality while being female reduced risk of mortality.

CONCLUSION

Our data suggest that, in this CKD cohort, patients were more likely to develop ESRD than death. Prime importance should be given to mild forms of CKD to retard and even reverse CKD progression.

Modified Lipids and Lipoproteins in Chronic Kidney Disease: A New Class of Uremic Toxins

Chronic kidney disease (CKD) is associated with an enhanced oxidative stress and deep modifications in lipid and lipoprotein metabolism. First, many oxidized lipids accumulate in CKD and were shown to exert toxic effects on cells and tissues. These lipids are known to interfere with many cell functions and to be pro-apoptotic and pro-inflammatory, especially in the cardiovascular system. Some, like F2-isoprostanes, are directly correlated with CKD progression. Their accumulation, added to their noxious effects, rendered their nomination as uremic toxins credible. Similarly, lipoproteins are deeply altered by CKD modifications, either in their metabolism or composition. These impairments lead to impaired effects of HDL on their normal effectors and may strongly participate in accelerated atherosclerosis and failure of statins in end-stage renal disease patients. This review describes the impact of oxidized lipids and other modifications in the natural history of CKD and its complications. Moreover, this review focuses on the modifications of lipoproteins and their impact on the emergence of cardiovascular diseases in CKD as well as the appropriateness of considering them as actual mediators of uremic toxicity.

HDL Cholesterol Level Is Associated with Contrast Induced Acute Kidney Injury in Chronic Kidney Disease Patients Undergoing PCI

Chronic kidney disease (CKD) is a significant risk factor for contrast induced acute kidney injury (CI-AKI) after percutaneous coronary intervention (PCI). This study included 1592 CKD patients extracted from a prospective multicenter, all comer-based registry of patients undergoing PCI. In multivariate logistic analysis for CI-AKI development, a significant linear trend was observed between the quartiles of HDL-C (quartile 1 vs. 2: odds ratio [OR], 0.716; 95% confidence interval [CI], 0.421-1.219; quartile 1 vs. 3: OR, 0.534; 95% CI, 0.301-0.947; quartile 1 vs. 4: OR, 0.173; 95% CI, 0.079-0.377; P for trend < 0.001). HDL-C quartiles were also negatively correlated with the incidence of CI-AKI; 19.0%, 12.1%, 8.7%, and 3.7% for quartile 1(Q1) (<34 mg/dL), Q2 (34-40 mg/dL), Q3 (40-48 mg/dL), and Q4 (>48 mg/dL) respectively (P < 0.001 overall and for the trend). Multivariate Cox regression analysis for the long term mortality, the highest HDL-C quartile was associated with decreased mortality compared with the lowest HDL-C quartile (hazard ratio [HR] 0.516, 95% CI, 0.320-0.832, P = 0.007). Our study suggests more intensive strategies should be considered for preventing CI-AKI in CKD patients with low serum HDL-C level who is planned for PCI.

Elevated high-density lipoprotein cholesterol and cardiovascular mortality in maintenance hemodialysis patients

BACKGROUND

High-density lipoprotein (HDL) confers protection against atherosclerosis by several different mechanisms. Although in the general population, increasing levels of HDL are associated with reduced cardiovascular (CV) mortality, this association is not well known in patients with chronic disease states such as end-stage renal disease. We hypothesize that the association of serum HDL concentration and its ratio to total cholesterol with all-cause and CV mortality in hemodialysis patients is different from the general population.

METHODS

A 3-year (July 2004 to June 2007) cohort of 33 109 chronic hemodialysis patients was studied in the USA in the dialysis clinics where lipid profile was measured in at least 50% of all outpatients of the clinic during a given calendar quarter. Cox proportional hazard models were adjusted for demographics and case-mix variables and cubic splines were plotted.

RESULTS

Higher HDL concentrations up to 50 mg/dL were associated with better overall survival, while HDL at 60 mg/dL and above was associated with a rise in all-cause and CV mortality. All-cause and CV mortality hazard ratio was 1.28 (1.20-1.38) and 1.08 (1.01-1.16) for HDL <30 mg/dL and 1.05 (1.00-1.10) and 1.08 (1.00-1.16) for HDL ≥ 60 mg/dL, respectively (reference: HDL: 30-<60 mg/dL).

CONCLUSIONS

In contrast to the general population, low total cholesterol to HDL ratio was associated with higher mortality in hemodialysis patients. A U-shaped association between HDL cholesterol level and all-cause and CV mortality exists in hemodialysis patients with HDL between 50 and <60 mg/dL exhibiting the best survival. The underlying mechanisms responsible for these seemingly paradoxical associations await further investigation.

Association of hypo- and hyperkalemia with disease progression and mortality in males with chronic kidney disease: the role of race

BACKGROUND/AIMS

Abnormal serum potassium is associated with higher mortality in dialysis patients, but its impact on outcomes in predialysis chronic kidney disease (CKD) is less clear. Furthermore, blacks with normal kidney function have lower urinary potassium excretion, but it is unclear if such differences have a bearing on race-associated outcomes in CKD.

METHODS

We studied predialysis mortality and slopes of estimated glomerular filtration rate, eGFR) associated with serum potassium in 1,227 males with CKD. Mortality was examined in time-dependent Cox models, and slopes of eGFR in linear mixed effects models with adjustments for case mix and laboratory values.

RESULTS

Both hypo- and hyperkalemia were associated with mortality overall and in 933 white patients, but in 294 blacks hypokalemia was a stronger death predictor. Hypokalemia was associated with loss of kidney function independent of race: a 1 mEq/l lower potassium was associated with an adjusted difference in slopes of eGFR of -0.13 ml/min/1.73 m(2)/year (95% CI: -0.20 to -0.07), p < 0.001.

CONCLUSION

Hypo- and hyperkalemia are associated with higher mortality in CKD patients. Blacks appear to better tolerate higher potassium than whites. Hypokalemia is associated with faster CKD progression independent of race. Hyperkalemia management may warrant race-specific consideration, and hypokalemia correction may slow CKD progression.

Salutary effects of hemodialysis on low-density lipoprotein proinflammatory and high-density lipoprotein anti-inflammatory properties in patient with end-stage renal disease

End-stage renal disease (ESRD) causes oxidative stress, inflammation, low-density lipoprotein (LDL) oxidation, high-density lipoprotein (HDL) deficiency and accelerated atherosclerosis. Uptake of oxidized LDL by macrophages results in foam cell and plaque formation. HDL mitigates atherosclerosis via reverse cholesterol transport and inhibition of LDL oxidation. ESRD heightens LDL inflammatory activity and suppresses HDL anti-inflammatory activity. The effect of hemodialysis on the LDL and HDL inflammatory properties is unknown. By removing the potential pro-oxidant/proinflammatory uremic toxins, dialysis may attenuate LDL inflammatory and HDL anti-inflammatory properties. Conversely, exposure to dialyzer membrane and tubing and influx of impurities from dialysate can intensify LDL and HDL inflammatory activities. This study examined the effect of hemodialysis on LDL and HDL inflammatory activities. Plasma samples were obtained from 12 normal control and 26 ESRD patients before and after hemodialysis with (16 patients) or without (10 patients) heparinization. HDL and LDL were isolated and tested for monocyte chemotactic activity in cultured endothelial cells. ESRD patients had increased LDL chemotactic activity, reduced HDL anti-inflammatory activity, paraoxonase and glutathione peroxidase levels, and elevated plasma IL-6 before dialysis. Hemodialysis partially improved LDL inflammatory and HDL anti-inflammatory activities and enhanced patients' HDL ability to suppress their LDL inflammatory activity. The salutary effect on LDL inflammatory activity was significantly greater in patients dialyzed with than those without heparin. ESRD heightens LDL inflammatory and impairs HDL anti-inflammatory activities. Hemodialysis partially improves LDL and HDL inflammatory activities. The salutary effects of hemodialysis are in part mediated by heparin, which is known to possess lipolytic and antioxidant properties.

Risk factors associated with disease progression and mortality in chronic kidney disease of uncertain etiology: a cohort study in Medawachchiya, Sri Lanka

BACKGROUND

The alarming rise in the prevalence of chronic kidney disease of uncertain etiology (CKDu) among the low socioeconomic farming community in the North Central Province of Sri Lanka has been recognized as an emerging public health issue in the country.

METHODS

This study sought to determine the possible factors associated with the progression and mortality of CKDu. The study utilized a single-center cohort registered in 2003 and followed up until 2009 in a regional clinic in the endemic region, and used a Cox proportional hazards model.

RESULTS

We repeatedly found an association between disease progression and hypertension. Men were at higher risk of CKDu than women. A significant proportion of the patients in this cohort were underweight, which emphasized the need for future studies on the nutritional status of these patients.

CONCLUSIONS

Compared with findings in western countries and other regions of Asia, we identified hypertension as a major risk factor for progression of CKDu in this cohort.

Association of echocardiographic abnormalities with mortality in men with non-dialysis-dependent chronic kidney disease

BACKGROUND

The interrelationship of left ventricular hypertrophy (LVH) with ejection fraction (EF) and their impact on mortality in non-dialysis-dependent chronic kidney disease (NDD-CKD) is unclear.

METHODS

We examined the associations of EF and LVH with all-cause mortality in a historic cohort of 650 male US veterans with moderate-to-advanced NDD-CKD. EF and LVH were examined both separately and after categorizing patients according to their concomitant EF and presence/absence of LVH. Associations with mortality were examined in Cox models with adjustments for demographics, blood pressure, comorbidities, smoking status, medication use and biochemical characteristics.

RESULTS

EF <30 and 30-50% were associated with higher all-cause mortality compared to EF >50% even after multivariable adjustments [multivariable adjusted hazard ratio, 95% confidence interval (CI): 2.83 (1.86-4.30) and 1.38 (1.06-1.78), P < 0.001 for linear trend]. LVH in itself was not associated with mortality [multivariable adjusted hazard ratio, 95% CI: 0.83 (0.66-1.05), P = 0.12], but the presence of LVH combined with an EF <50% was associated with the highest mortality [multivariable adjusted hazard ratios, 95% CI in patients with EF >50% + LVH, EF ≤ 50%-LVH and EF ≤ 50% + LVH, compared to EF >50%-LVH: 0.84 (0.63-1.13), 1.36 (1.00-1.83) and 1.62 (1.07-2.46)].

CONCLUSIONS

Low EF is associated with higher mortality in patients with NDD-CKD. In the presence of a low EF, LVH is also associated with higher mortality. Clinical trials are needed to determine if interventions targeting patients with low EF and LVH can lower mortality in NDD-CKD.

Animal models for the atherosclerosis research: a review

Atherosclerosis is a leading cause of death worldwide, and its mechanisms are still unclear. However, various animal models have significantly advanced our understanding of the mechanisms involved in atherosclerosis and have allowed the evaluation of therapeutic options. The aim of this paper is to review those animal models (i.e., rabbits, mice, rats, guinea pigs, hamsters, avian, carnivores, swine, and, non-human primates) that have been used to study atherosclerosis. Though there is no single perfect animal model that completely replicates the stages of human atherosclerosis, cholesterol feeding and mechanical endothelial injury are two common features shared by most models of atherosclerosis. Further, with the development of genetically modified animals, these models are significantly broadening our understanding of the pathogenesis of atherosclerosis.

The obesity paradox and mortality associated with surrogates of body size and muscle mass in patients receiving hemodialysis

OBJECTIVE

To determine whether dry weight gain accompanied by an increase in muscle mass is associated with a survival benefit in patients receiving maintenance hemodialysis (HD).

PATIENTS AND METHODS

In a nationally representative 5-year cohort of 121,762 patients receiving HD 3 times weekly from July 1, 2001, through June 30, 2006, we examined whether body mass index (BMI) (calculated using 3-month averaged post-HD dry weight) and 3-month averaged serum creatinine levels (a likely surrogate of muscle mass) and their changes over time were predictive of mortality risk.

RESULTS

In the cohort, higher BMI (up to 45) and higher serum creatinine concentration were incrementally and independently associated with greater survival, even after extensive multivariate adjustment for available surrogates of nutritional status and inflammation. Dry weight loss or gain over time exhibited a graded association with higher rates of mortality or survival, respectively, as did changes in serum creatinine level over time. Among the 50,831 patients who survived the first 6 months and who had available data for changes in weight and creatinine level, those who lost weight but had an increased serum creatinine level had a greater survival rate than those who gained weight but had a decreased creatinine level. These associations appeared consistent across different demographic groups of patients receiving HD.

CONCLUSION

In patients receiving long-term HD, larger body size with more muscle mass appears associated with a higher survival rate. A discordant muscle gain with weight loss over time may confer more survival benefit than weight gain while losing muscle. Controlled trials of muscle-gaining interventions in patients receiving HD are warranted.

Outcomes associated with phosphorus binders in men with non-dialysis-dependent CKD

BACKGROUND

Phosphorus binders are used to treat hyperphosphatemia in maintenance dialysis patients, in whom the use of these medications has been associated with lower mortality in some observational studies. It is not clear whether similar benefits can be seen in patients with non-dialysis-dependent chronic kidney disease (CKD).

STUDY DESIGN

Historical cohort.

SETTING & PARTICIPANTS

1,188 men with moderate and advanced non-dialysis-dependent CKD at a single medical center.

PREDICTOR

Administration of any phosphorus binder.

OUTCOMES & MEASUREMENTS

We examined associations of any phosphorus-binder administration with all-cause mortality and the slopes of estimated glomerular filtration rate using time-varying Cox models and mixed-effects models. Associations also were examined in intention-to-treat analyses and in 133 patient-pairs matched according to propensity scores.

RESULTS

344 patients were treated with a phosphorus binder; 658 patients died (mortality rate, 141 deaths/1,000 patient-years; 95% CI, 131-153) during a median follow-up of 3.1 years. Treatment with phosphorus binders was associated with significantly lower mortality (adjusted HR, 0.61; 95% CI, 0.45-0.81; P < 0.001). Results were similar when exposure was modeled in intention-to-treat analyses and examining propensity-matched patients. Phosphorus-binder use was not associated with significant changes in kidney function loss.

LIMITATIONS

Results may not apply to all patients with non-dialysis-dependent CKD.

CONCLUSIONS

Administration of phosphorus binders is associated with lower mortality in men with moderate and advanced non-dialysis-dependent CKD. Clinical trials are needed to determine the risks and benefits of phosphorus-binder use in this patient population.

HDL metabolism and activity in chronic kidney disease

Chronic kidney disease (CKD) is associated with development of atherosclerosis and premature death from cardiovascular disease. The predisposition of patients with CKD to atherosclerosis is driven by inflammation, oxidative stress and dyslipidemia, all of which are common features of this condition. Markers of dyslipidemia in patients with advanced CKD are impaired clearance and heightened oxidation of apolipoprotein-B-containing lipoproteins and their atherogenic remnants, and a reduction of the plasma concentration, antioxidant, and anti-inflammatory properties of high-density lipoprotein (HDL). Studies in animal models of CKD indicate that the disease promotes lipid accumulation in the artery wall and kidney, leading to atherosclerosis, glomerulosclerosis and tubulointerstitial injury. These effects seem to be mediated by an increased cellular influx of lipids, elevated cellular production and reduced cellular catabolism of fatty acids, and impaired antioxidant, anti-inflammatory and reverse lipid transport properties of HDL. Available pharmacological therapies have been largely ineffective in ameliorating oxidative stress, inflammation, HDL deficiency and/or dysfunction, and the associated atherosclerosis and cardiovascular disease in patients with end-stage renal disease. This Review aims to provide an overview of the mechanisms and consequences of CKD-induced HDL deficiency and dysfunction.

Outcome predictability of serum alkaline phosphatase in men with pre-dialysis CKD

BACKGROUND

Serum alkaline phosphatase (ALP) increases in patients with chronic kidney disease (CKD) and high-turnover bone disease. ALP may represent an adjunct marker of high bone turnover devoid of drawbacks of serum parathyroid hormone (PTH), and it may also be associated with cardiovascular calcification in CKD. Higher ALP has been recently associated with increased mortality and coronary calcification in dialysis patients. In pre-dialysis CKD patients, this association is not clear.

METHODS

We examined the association of baseline, time-varying and time-averaged ALP with all-cause mortality and the composite of pre-dialysis mortality or end-stage renal disease in a historical prospective cohort of 1158 male veterans with pre-dialysis CKD from a single institution by using multivariable-adjusted Cox models.

RESULTS

Higher ALP was associated with increased mortality irrespective of the statistical model. Time-averaged ALP displayed a consistent linear association with mortality: a 50-U/L higher serum ALP was associated with a multivariable-adjusted death hazard ratio (95% confidence interval) of 1.17 (1.08-1.28), P < 0.001. Baseline and time-varying ALP showed non-linear associations with mortality, with serum levels above 70 U/L in all models and with lower levels in time-varying models. Associations between ALP levels and the composite outcomes were similar. However, compared to serum PTH, mortality predictability of ALP appeared more incremental.

CONCLUSIONS

Elevated ALP is associated with increased mortality in patients with pre-dialysis CKD. Low ALP appears to be associated with short-term mortality.

Outcomes associated with serum calcium level in men with non-dialysis-dependent chronic kidney disease

BACKGROUND AND OBJECTIVES

Elevated serum calcium has been associated with increased mortality in dialysis patients, but it is unclear whether the same is true in non-dialysis-dependent (NDD) chronic kidney disease (CKD). Outcomes associated with low serum calcium are also not well-characterized.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined associations of baseline, time-varying, and time-averaged serum calcium with all-cause mortality in a historic prospective cohort of 1243 men with moderate and advanced NDD CKD by using Cox models.

RESULTS

The association of serum calcium with mortality varied according to the applied statistical models. Higher baseline calcium and time-averaged calcium were associated with higher mortality (multivariable adjusted hazard ratio (95% confidence interval): 1.31 (1.13, 1.53); P < 0.001 for a baseline calcium 1 mg/dl higher). However, in time-varying analyses, lower calcium levels were associated with increased mortality.

CONCLUSIONS

Higher serum calcium is associated with increased long-term mortality (as reflected by the baseline and time-averaged models), and lower serum calcium is associated with increased short-term mortality (as reflected by the time-varying models) in patients with NDD CKD. Clinical trials are warranted to determine whether maintaining normal serum calcium can improve outcomes in these patients.

In vitro stimulation of HDL anti-inflammatory activity and inhibition of LDL pro-inflammatory activity in the plasma of patients with end-stage renal disease by an apoA-1 mimetic peptide

Features of end-stage renal disease such as oxidative stress, inflammation, hypertension, and dyslipidemia are associated with accelerated atherosclerosis and increased risk of death from cardiovascular disease. By inhibiting the formation and increasing the disposal of oxidized lipids, HDL exerts potent antioxidant and anti-inflammatory actions. Given that apolipoproteinA-1 can limit atherosclerosis, we hypothesized that an apolipoproteinA-1 mimetic peptide, 4F, may reduce the proinflammatory properties of LDL and enhance the anti-inflammatory properties of HDL in uremic plasma. To test this, plasma from each of 12 stable hemodialysis patients and age-matched control subjects was incubated with 4F or vehicle. The isolated HDL and LDL fractions were added to cultured human aortic endothelial cells to quantify monocyte chemotactic activity, thus measuring their pro- or anti-inflammatory index. The LDL from the hemodialysis patients was more pro-inflammatory and their HDL was less anti-inflammatory than those of the control subjects. Pre-incubation of the plasma from the hemodialysis patients with 4F decreased LDL pro-inflammatory activity and enhanced HDL anti-inflammatory activity. Whether 4F or other apolipoproteinA-1 mimetic peptides will have any therapeutic benefit in end-stage renal disease will have to be examined directly in clinical studies.

Outcome predictability of biomarkers of protein-energy wasting and inflammation in moderate and advanced chronic kidney disease

BACKGROUND

Markers of protein-energy wasting (PEW) and inflammation are common in chronic kidney disease (CKD) and are among the strongest predictors of mortality in dialysis patients.

OBJECTIVE

We hypothesized that markers of PEW and inflammation show similar associations in patients with non-dialysis-dependent CKD (NDD-CKD).

DESIGN

We examined the associations of serum albumin, white blood cell (WBC) count, percentage of lymphocytes in WBCs (%LYM), and a combination of all 3 with all-cause mortality and with the composite of predialysis mortality or end-stage renal disease (ESRD) by using fixed-covariate and time-dependent Cox models in 1220 men with NDD-CKD.

RESULTS

Lower albumin and %LYM and a higher WBC count were significantly associated with outcomes. In time-dependent Cox models, compared with patients in whom none of these markers indicated PEW, those in whom 1, 2, or all 3 markers indicated the presence of PEW had multivariable-adjusted hazard ratios (95% CI) for all-cause mortality of 1.7 (1.2, 2.4), 2.4 (1.7, 3.4), and 3.6 (2.5, 5.1); the P for trend was <0.001. Similar associations were present in fixed-covariate models for all-cause mortality and in fixed-covariate and time-dependent models for the composite outcome.

CONCLUSIONS

Traditional and nontraditional markers of PEW display robust, strong, and independent associations with mortality in patients with NDD-CKD. Clinical trials are warranted to examine whether PEW-improving interventions can lead to better outcomes in these patients.

Severity of hypoalbuminemia predicts response to intradialytic parenteral nutrition in hemodialysis patients

BACKGROUND

Intradialytic parenteral nutrition (IDPN) is used infrequently to correct hypoalbuminemia in maintenance hemodialysis (MHD) patients. We hypothesized that the severity of baseline hypoalbuminemia correlates with the success rate of IDPN therapy in MHD patients.

METHODS

In a prospective and contemporary cohort of 196 hypoalbuminemic MHD patients who received IDPN through Pentec Health (Boothwyn, PA), predictors of IDPN response were examined using multivariate logistic regression.

RESULTS

Of 196 hypoalbuminemic MHD patients, 134 had severe hypoalbuminemia, defined as a baseline serum albumin level of less than 3.0 g/dL. The average period of IDPN therapy was 5.8 +/- 2.4 months, S.D. The baseline level of serum albumin was lower in MHD patients who responded to IDPN (2.68 +/- 0.47 g/dL, S.D.). A multivariate logistic regression analysis adjusted the associations for age, gender, diabetes, and IDPN time. The presence of severe hypoalbuminemia (serum albumin, <3.0 g/dL) at baseline was associated with a 2.5 times higher chance of responding to IDPN (95% confidence interval, 1.3 to 4.9; P = .006). The same severe hypoalbuminemia was associated with a 3.5 times increased likelihood of serum albumin correction by at least 0.5 g/dL (95% confidence interval, 1.8 to 6.8; P < .001).

CONCLUSIONS

Improvement of hypoalbuminemia occurs in most hypoalbuminemic MHD patients who receive IDPN therapy. The likelihood and magnitude of the response to IDPN are associated with the severity of baseline hypoalbuminemia. These associations need to be verified in controlled trials.

Outcomes associated with race in males with nondialysis-dependent chronic kidney disease

BACKGROUND AND OBJECTIVES

Blacks are over-represented among dialysis patients, but they have better survival rates than whites. It is unclear if the over-representation of blacks on dialysis is due to faster loss of kidney function or greater survival (or both) in predialysis stages of chronic kidney disease (CKD).

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

We compared predialysis mortality, incidence of end stage renal disease (ESRD), and slopes of estimated GFR (eGFR) in 298 black versus 945 white male patients with moderate and advanced nondialysis-dependent CKD (NDD-CKD) from a single medical center. Mortality and ESRD incidence were compared in parametric survival models, and slopes of eGFR were assessed in mixed-effects models.

RESULTS

Blacks had lower crude mortality and higher crude ESRD incidence. The lower mortality in blacks was explained by differences in case mix, especially a lower prevalence of cardiovascular disease, and the higher incidence of ESRD was explained by differences in case mix and baseline kidney function. The slopes of eGFR were similar in blacks and whites.

CONCLUSIONS

Lower mortality in black versus white patients is also observed in NDD-CKD and can be accounted for by differences in clinical characteristics. Higher mortality of black patients in earlier stages of CKD may result in the selection of a subgroup with fewer comorbidities and better survival in later stages of CKD. The higher crude ESRD rate in blacks appears to result from lower mortality in late stages of CKD, not faster progression of CKD.

Impaired antioxidant activity of high-density lipoprotein in chronic kidney disease

Chronic kidney disease (CKD) is associated with accelerated atherosclerosis and increased mortality from cardiovascular disease. CKD results in oxidative stress, inflammation, and high-density lipoprotein (HDL) deficiency, which work in concert to promote atherosclerosis. Normal HDL confers protection against atherosclerosis by inhibiting the oxidation of lipids and lipoproteins and by retrieving surplus cholesterol and phospholipids from lipid-laden cells in the artery wall for disposal in the liver (reverse cholesterol transport). The plasma level of oxidized low-density lipoprotein (LDL) is increased, plasma HDL-cholesterol is reduced, and HDL maturation is impaired in CKD. This study was designed to examine the antioxidant properties of HDL in patients with CKD. In all, 32 stable hemodialysis-dependent patients and 13 age-matched controls were studied. HDL was isolated and used for determination of in vitro antioxidant activity. In addition, the plasma level of key components of HDL, namely paraoxonase (PON), glutathione peroxidase (GPX), platelet activating factor acetylhydrolase (PAF-AH), lecithin cholesterol acyltransferase (LCAT), and apolipoprotein A-I (ApoA-I), were measured. The end-stage renal disease (ESRD) patients exhibited significant reductions of HDL-cholesterol, ApoA-I (-41%), GPX (-50%), and LCAT (-60%) concentrations, and a decrease in PON (-30%) and GPX (-50%) activities. These results were accompanied by a marked reduction of antioxidant activity of HDL (-127%), which was unaffected by the hemodialysis procedure. Thus, in addition to diminished plasma HDL concentration, the composition and antioxidant activity of HDL are altered in CKD; these events can contribute to a heightened risk of atherosclerosis.

Why is protein-energy wasting associated with mortality in chronic kidney disease?

Observational studies in chronic kidney disease (CKD) populations consistently have shown the strong mortality-predictability of such markers of protein-energy wasting (PEW) as hypoalbuminemia, low serum cholesterol levels, low body mass index, and reduced dietary protein intake. Even though the PEW-mortality association data traditionally are reported mostly in maintenance dialysis patients, emerging studies extend the existence of these associations to predialysis stages of CKD. Paradoxic risk factor patterns (reverse epidemiology) for both obesity and cholesterol recently have been reported in predialysis CKD, underscoring the overwhelming impact of PEW, a short-term killer, on reversing the long-term effect of conventional cardiovascular risk factors. Multiple pathophysiologic mechanisms have been suggested to explain the link between PEW and mortality in CKD, including derangements in muscle, adipose tissue, and the gastrointestinal, hematopoietic, and immune systems; complications related to deficiencies of multiple micronutrients; and the maladaptive activation of the inflammatory cascade. In addition to well-described pathophysiologic mechanisms involved in the higher mortality seen with PEW, we also discuss the potential role of novel factors such as circulating actin, gelsolin, and proinflammatory high-density lipoprotein. Whether PEW is causally related to adverse outcomes in CKD needs to be verified in randomized controlled trials of nutritional interventions. The initiation of major clinical trials targeting nutritional interventions with the goal of improving survival in CKD offer the promise of extending the survival of this vulnerable patient population.

Association of markers of iron stores with outcomes in patients with nondialysis-dependent chronic kidney disease

BACKGROUND AND OBJECTIVES

Assessments of iron stores by serum iron saturation ratio (ISAT) and ferritin are used to direct anemia therapy in chronic kidney disease (CKD) and are associated with clinical outcomes in patients on dialysis. The association of ISAT and ferritin with outcomes in patients with nondialysis-dependent CKD (NDD-CKD) has not been studied.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

All-cause mortality and progression of CKD [slopes of estimated GFR (eGFR)] were examined in 453 men with NDD-CKD. Mortality and the composite of mortality and ESRD were studied in Cox models. Slopes of eGFR were examined in mixed-effects models.

RESULTS

Lower ISAT was associated with higher mortality; adjusted hazard ratio [95% confidence interval (CI)] with ISAT of <12%, 13 to 17%, and >23% versus 18 to 23%; 1.40 (0.99 to 1.98), 1.20 (0.82 to 1.76), and 0.97 (0.67 to 1.41), P = 0.025 for trend. ISAT was also associated with steeper slopes of eGFR (one log-unit higher ISAT associated with a slope of -0.89 ml/min/1.73 m(2) /yr (95% CI: -1.75, -0.02, P = 0.044). Serum ferritin level showed no significant association with outcomes overall, but a trend for higher mortality was observed in patients with a serum ferritin level >250 ng/ml.

CONCLUSIONS

Higher ISAT is associated with lower mortality and with more progressive CKD. Clinical trials are needed to examine if correction of low iron levels can improve mortality without affecting kidney function in NDD-CKD.

Association of serum bicarbonate levels with mortality in patients with non-dialysis-dependent CKD

BACKGROUND

Metabolic acidosis, usually manifested by low serum bicarbonate level, is common in chronic kidney disease (CKD) and appears to be associated with higher mortality in dialysis patients. It is not known whether a similar association is present in patients with non-dialysis-dependent CKD (NDD-CKD).

METHODS

We used multivariable-adjusted Cox models to examine the association between baseline and time-variable serum bicarbonate (measured as total CO2) with the outcomes of all-cause mortality and the composite of pre-dialysis mortality or end-stage renal disease in 1240 male patients with moderate and advanced NDD-CKD.

RESULTS

Serum bicarbonate showed a significant U-shaped association with all-cause mortality, with the highest mortality rate observed in patients with baseline serum bicarbonate levels <22 mmol/L [multivariable-adjusted hazard ratio (95% confidence interval) for patients with serum bicarbonate <22 mmol/L versus > or =22 mmol/L: 1.33 (1.05-1.69), P = 0.02] and the lowest mortality observed in patients with baseline serum bicarbonate of 26-29 mmol/L. The associations between lower serum bicarbonate level and mortality were more accentuated in subgroups of patients with better nutritional status and lower inflammation.

CONCLUSIONS

Both lower and higher serum bicarbonates are associated with increased all-cause mortality in patients with moderate and advanced NDD-CKD. Clinical trials are needed to determine if therapeutic interventions aimed at optimizing serum bicarbonate can result in improved outcomes in this population.

Secondary hyperparathyroidism is associated with higher mortality in men with moderate to severe chronic kidney disease

Secondary hyperparathyroidism is associated with mortality in patients undergoing maintenance dialysis treatment. We studied 515 male US veterans with chronic kidney disease, who were not yet on dialysis, to see what outcomes were associated with secondary hyperparathyroidism in this population. Relationships between intact parathyroid hormone levels and all-cause mortality along with the composite of mortality or incidence of dialysis were measured in unadjusted and adjusted Cox models for case-mix and laboratory variables. Elevated parathyroid hormone levels above the upper limit compared to the lower limit of the normal range were significantly associated with mortality after adjustments. Higher intact parathyroid hormone levels in the upper limit of normal were significantly associated with higher mortality overall and showed similar trends in subgroups of patients with stage 3 and stage 4-5 chronic kidney disease and with higher and lower serum calcium and phosphorus levels. Similar associations were found with the composite outcome of mortality or dialysis. Our study shows that secondary hyperparathyroidism is independently associated with higher mortality in patients with chronic kidney disease but not yet on dialysis.

Reverse epidemiology in patients with chronic kidney disease who are not yet on dialysis

Many traditional risk factors show a seemingly paradoxical, inverse association with mortality in patients on dialysis. In spite of their larger numbers, patients with chronic kidney disease (CKD) who are not yet on dialysis are less well studied. Preliminary studies indicate that "reverse epidemiology" is also present in patients with CKD who are not yet on dialysis. Studying patients with CKD offers hope to further our understanding of this phenomenon.

Racial and survival paradoxes in chronic kidney disease

Most of the 20 million people in the US with chronic kidney disease (CKD) die before commencing dialysis. One of every five dialysis patients dies each year in the US. Although cardiovascular disease is the most common cause of death among patients with CKD, conventional cardiovascular risk factors such as hypercholesterolemia, hypertension and obesity are paradoxically associated with better survival in hemodialysis populations. Emerging data indicate the existence of this 'reverse epidemiology' in earlier stages of CKD. There are also paradoxical relationships between outcomes and race and ethnicity. For example, the survival rate of African American dialysis patients seems to be superior to that of whites on dialysis. Paradoxes-within-paradoxes have been detected among Hispanic and Asian American CKD patients. These survival paradoxes might evolve and change over the natural course of CKD progression as a result of the time differentials of competing risk factors and the overwhelming impact of malnutrition, inflammation and wasting. Reversal of the reverse epidemiology as a result of successful kidney transplantation underscores the role of nutritional status and kidney function in engendering these paradoxes. The observation of paradoxes and their reversal might lead to the formulation of new paradigms and management strategies to improve the survival of patients with CKD. Such movement away from the use of targets set on the basis of data gathered in general populations (e.g. the Framingham cohort) would be a major paradigm shift in clinical medicine and public health.

Chronic kidney disease (CKD) in the elderly -- a geriatrician's perspective

Chronic kidney disease (CKD) is becoming increasingly prevalent among many different populations all over the world, including the US and Europe. Its multitude of complications with devastating outcomes leads to a significantly higher risk for cardio-vascular and all-cause mortality in an individual. However, it is clear now that early detection of CKD might not only delay some of the complications but also prevent them. Therefore, various important public health organizations all over the world have turned their focus and attention to CKD and its risk factors, early detection and early intervention. Nevertheless, the general goals in preventing the increase in CKD and its complications are far from being completely achieved. Why is this so? What is the magnitude and complexity of the problem? How is it affecting the population - are there differences in its affection by age, gender or frail elderly versus the robust? Are we modifying the risk factors appropriately and aggressively? Are there subtle differences in managing the risk factors in those on dialysis versus the non-dialysis CKD patients? Is it important to treat anaemia of CKD aggressively, will it make a difference in the disease progression, its complications or to quality of life? What do these unfortunate individuals commonly succumb to? What do we advise patients who refuse dialysis or those who desire dialysis or transplant? Are there useful non-dialytic treatment recommendations for those who refuse dialysis? What is the role of the physicians caring for the elderly with CKD? When should the primary care givers refer a CKD patient to a nephrologist? The key to eventually controlling incident and prevalent CKD and improve quality of life of affected individuals, lies in not only knowing these and many other vital aspects, but also in applying such knowledge compulsively in day-to-day practice by each and every one us. As CKD is increasingly a disease of the elderly with men being affected more, this review details fairly comprehensively the vital aspects of CKD, especially from a primary care geriatrician's practical standpoint.

Risk factor paradox in wasting diseases

PURPOSE OF REVIEW

Emerging data indicate that conventional cardiovascular risk factors (e.g. hypercholesterolemia and obesity) are paradoxically associated with better survival in distinct populations with wasting. We identify these populations and review survival paradoxes and common pathophysiologic mechanisms.

RECENT FINDINGS

A 'reverse epidemiology' of cardiovascular risk is observed in chronic kidney disease, chronic heart failure, chronic obstructive lung disease, cancer, AIDS and rheumatoid arthritis, and in the elderly. These populations apparently have slowly progressive to full-blown wasting and significantly greater short-term mortality than the general population. The survival paradoxes may result from the time differential between the two competing risk factors [i.e. over-nutrition (long-term killer but short-term protective) versus undernutrition (short-term killer)]. Hemodynamic stability of obesity, protective adipokine profile, endotoxin-lipoprotein interaction, toxin sequestration of fat, antioxidation of muscle, reverse causation, and survival selection may also contribute.

SUMMARY

The seemingly counterintuitive risk factor paradox is the hallmark of chronic disease states or conditions associated with wasting disease at the population level. Studying similarities among these populations may help reveal common pathophysiologic mechanisms of wasting disease, leading to a major shift in clinical medicine and public health beyond the conventional Framingham paradigm and to novel therapeutic approaches related to wasting and short-term mortality.

Paradoxical association between body mass index and mortality in men with CKD not yet on dialysis

BACKGROUND

Low body mass index (BMI) is associated with greater mortality in patients on dialysis therapy. This relationship is less well characterized in patients with chronic kidney disease (CKD) who are not yet on dialysis therapy.

STUDY DESIGN

Historic prospective cohort.

SETTING & PARTICIPANTS

521 male US veterans with CKD (age, 68.8 +/- 10.4 years; 21.3% black; estimated glomerular filtration rate, 37.5 +/- 16.8 mL/min/1.73 m(2) [0.62 +/- 0.28 mL/s/1.73 m(2)]) at a single medical center.

PREDICTOR

BMI.

OUTCOMES & MEASUREMENTS

Associations with all-cause mortality were explored in fixed-covariate and time-dependent Cox models and sequentially adjusted for demographic characteristics (age and race), case-mix (comorbidity index, smoking, blood pressure, estimated glomerular filtration rate, and medication use), and surrogates of malnutrition and inflammation (serum albumin, cholesterol, and bicarbonate levels; white blood cell count; percentage of lymphocytes; and hemoglobin level).

RESULTS

Patients were followed up for up to 5.5 years, and the mortality rate was 128.3 deaths/1,000 patient-years (95% confidence interval [CI], 110.5 to 149.0). Higher BMI was associated with lower mortality in the fixed-covariate Cox models, including the fully adjusted model (adjusted hazard ratios for mortality in the group with BMI in 10th to 50th, 50th to 90th, and >90th versus <10th percentiles, 0.75 [95% CI, 0.46 to 1.22], 0.56 [95% CI, 0.33 to 0.94], and 0.39 [95% CI, 0.17 to 0.87]; P(trend) = 0.005). Associations were similar in a time-dependent Cox model (P(trend) = 0.008 in the fully adjusted model).

LIMITATIONS

Results may not be generalizable.

CONCLUSIONS

Lower BMI is associated with greater mortality in patients with CKD not yet on dialysis therapy. Adjustment for case-mix and surrogate markers of malnutrition and inflammation attenuated, but did not reverse, this relationship.

Inverse association between lipid levels and mortality in men with chronic kidney disease who are not yet on dialysis: effects of case mix and the malnutrition-inflammation-cachexia syndrome

High total cholesterol is associated with lower mortality in dialysis patients, but the relationship between lipid levels and mortality in patients who have chronic kidney disease (CKD) and are not yet on dialysis is poorly described. This study examined the association between lipid levels and all-cause and cardiovascular mortality in 986 male patients (age 67.4 +/- 10.9 yr; race 23.7% black) who had CKD and were not yet on dialysis. Associations were determined in fixed-covariate and time-dependent Cox models, before and after adjustment for components of case mix and surrogates for malnutrition-inflammation-cachexia syndrome (MICS). Lower total cholesterol quartiles were associated with higher all-cause mortality in a fixed-covariate model that was adjusted for age, race, and body mass index (hazard ratio [95% confidence interval] for cholesterol <153, 153 to 182, and 183 to 215 versus >215 mg/dl: 1.91 [1.35 to 2.69], 1.36 [0.96 to 1.92], 1.10 [0.78 to 1.57]; P < 0.001 for trend), but this association was attenuated after adjustment for case mix (P = 0.023 for trend) and abolished after additional adjustment for MICS (P = 0.14 for trend), with time-dependent Cox models showing similar results. Similar tendencies also were detected in the association between levels of LDL cholesterol with total and cardiovascular mortality and triglycerides with all-cause mortality in both fixed-covariate and time-dependent analyses. Lower lipid levels are associated with higher mortality in patients who have moderate and advanced CKD and are not yet on dialysis. This inverse association is explained in part by case-mix characteristics and the presence of surrogates for MICS.