Body mass index and causes of death in chronic kidney disease

Baseline and oxidatively damaged DNA in end-stage renal disease patients on varied hemodialysis regimens: a comet assay assessment

Global estimates exhibit that one million people have end-stage renal disease, a disease-state characterized by irreversible loss of kidney structure and function, thus necessitating renal replacement therapy. The disease-state, oxidative stress, inflammatory responses, as well as the treatment procedure can have damaging effects on the genetic material. Therefore, the present study was carried out to investigate DNA damage (basal and oxidative) using the comet assay in peripheral blood leukocytes of patients (n = 200) with stage V Chronic Kidney Disease (on dialysis and those recommended but yet to initiate dialysis) and compare it to that in controls (n = 210). Basal DNA damage was significantly elevated (1.13x, p ≤ 0.001) in patients (46.23 ± 0.58% DNA in tail) compared to controls (40.85 ± 0.61% DNA in tail). Oxidative DNA damage was also significantly (p ≤ 0.001) higher in patients (9.18 ± 0.49 vs. 2.59 ± 0.19% tail DNA) compared to controls. Twice-a-week dialysis regimen patients had significantly elevated % tail DNA and Damage Index compared to the non-dialyzed and to the once-a-week dialysis group implying dialysis- induced mechanical stress and blood-dialyzer membrane interactions as probable contributors to elevated DNA damage. The present study with a statistically significant power implies higher disease-associated as well as maintenance therapy (hemodialysis)-induced basal and oxidatively damaged DNA, which if not repaired has the potential to initiate carcinogenesis. These findings mark the need for improvement and development of interventional therapies for delaying disease progression and associated co-morbidities so as to improve life expectancy of patients with kidney disease.

Underweight status and development of end-stage kidney disease: A nationwide population-based study

BACKGROUND

Underweight status increases the risk of cardiovascular disease and mortality in the general population. However, whether underweight status is associated with an increased risk of developing end-stage kidney disease is unknown.

METHODS

A total of 9 845 420 participants aged ≥20 years who underwent health checkups were identified from the Korean National Health Insurance Service database and analysed. Individuals with underweight (body mass index [BMI] < 18.5 kg/m2 ) and obesity (BMI ≥ 25 kg/m2 ) were categorized according to the World Health Organization recommendations for Asian populations.

RESULTS

During a mean follow-up period of 9.2 ± 1.1 years, 26 406 participants were diagnosed with end-stage kidney disease. After fully adjusting for other potential predictors, the moderate to severe underweight group (<17 kg/m2 ) had a significantly higher risk of end-stage kidney disease than that of the reference (normal) weight group (adjusted hazard ratio, 1.563; 95% confidence interval, 1.337-1.828), and competing risk analysis to address the competing risk of death also showed the similar results (adjusted hazard ratio, 1.228; 95% confidence interval, 1.042-1.448). Compared with that of the reference BMI group (24-25 kg/m2 ), the adjusted hazard ratios for end-stage kidney disease increased as the BMI decreased by 1 kg/m2 . In the sensitivity analysis, sustained underweight status or progression to underweight status over two repeated health checkups, when compared with normal weight status, had a higher hazard ratio for end-stage kidney disease.

CONCLUSIONS

Underweight status is associated with an increased risk of end-stage kidney disease, and this association gradually strengthens as BMI decreases.

Management of Hypertension and Associated Cardiovascular Disease in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease is the most commonly inherited disease of the kidneys affecting an estimated 12,000,000 people in the world. Autosomal dominant polycystic kidney disease is a systemic disease, with a wide range of associated features that includes hypertension, valvular heart diseases, cerebral aneurysms, aortic aneurysms, liver cysts, abdominal hernias, diverticulosis, gross hematuria, urinary tract infections, nephrolithiasis, pancreatic cysts, and seminal vesicle cysts. The cardiovascular anomalies are somewhat different than in the general population and also chronic kidney disease population, with higher morbidity and mortality rates. This review will focus on cardiovascular diseases associated with autosomal dominant polycystic kidney disease and their management.

Elevated Crude Mortality in Obese Chronic Kidney Disease Patients with Loss of Exercise Habit: A Cohort Study of the Japanese General Population

Objective The relationship between obesity and risk of death in chronic kidney disease (CKD) patients remains controversial. In addition, no clear evidence has been accumulated regarding whether or not exercise improves mortality in CKD patients. Methods The original cohort was based on a Japanese general population of 685,889 people from 40 to 74 years old who had undergone annual specific health checkups. The number of all-cause deaths during follow-up (mean, 4.7 years) in this study was 1,490. Information on walking and exercise habits was obtained by questionnaires. The study population was divided into 4 categories by the combination of CKD and obesity [body mass index (BMI) ≥25.0 kg/m2]. Changes in the BMI and walking and exercise habits were determined by results for the first year and following year. Results Obese CKD patients with weight gain (BMI increase by more than +1.0 kg/m2/year) showed a higher crude mortality (1.32%) than those with a stable BMI (within ±1.0 kg/m2/year; 0.69%). In the obese CKD population, mortality was higher with loss of exercise habits (0.96%) than in those continuously maintaining exercise habits (0.52%). The age- and sex-adjusted hazard ratio for all-cause death was 2.23 in the group with weight gain compared to the group with stable weight (p<0.01) and 2.08 in the group with loss of exercise habits compared to those who maintained exercise habits (p<0.01). Conclusion This observational cohort study suggested that loss of exercise habits as well as weight gain of more than 1 kg/m2/year might worsen all-cause mortality in the obese CKD population.

Cohort Study and Bias Analysis of the Obesity Paradox Across Stages of Chronic Kidney Disease

OBJECTIVE

In advanced chronic kidney disease (CKD), patients with obesity often have better outcomes than patients without obesity, often called the 'obesity paradox'. Yet, in CKD, the prevalence of inflammation increases as CKD progresses. Although a potential confounder, inflammation may be left unaccounted in obesity-mortality studies. We examined the associations of body mass index (BMI) with all-cause and cause-specific mortality across CKD stages, with consideration for uncontrolled confounding due to unmeasured inflammation.

METHODS

We investigated 2,703,512 patients with BMI data between 2004 and 2006. We used Cox models to examine the associations of BMI with all-cause, cardiovascular, and cancer mortality, (ref: BMI 25-<30 kg/m2), adjusted for clinical characteristics and stratified by CKD stages. To address uncontrolled confounding, we performed bias analysis using a weighted probabilistic model of inflammation given the observed data applied to weighted Cox models.

RESULTS

The cohort included 5% females and 14% African Americans. In adjusted analyses, the associations of the BMI with all-cause and cardiovascular mortality showed a reverse J-shape, where a higher BMI (>40 kg/m2) was associated with a higher risk. Conversely, a lower mortality risk was observed with a BMI 30-<35 kg/m2 across all CKD stages and for BMI >40 kg/m2 in CKD stage 4/5. Cancer mortality analyses showed an inverse relationship. Bias analysis for uncontrolled confounding suggested that independent of inflammation, the obesity paradox was present.

CONCLUSION

We observed the presence of the obesity paradox in this study. This association was consistent in advanced CKD and in our bias analysis, suggesting that inflammation may not fully explain the observed BMI-mortality associations including in patients with CKD.

Glycated hemoglobin levels and risk of all-cause and cause-specific mortality in hemodialysis patients with diabetes

AIM

Adequate glycemic control is fundamental for improving clinical outcomes in hemodialysis patients with diabetes. However, the target for glycated hemoglobin (HbA1c) level and whether cause-specific mortality differs based on HbA1c levels remain unclear.

METHODS

A total of 24,243 HD patients with diabetes were enrolled from a multicenter, nationwide registry. We examined the association between HbA1c levels and the risk of all-cause and cause-specific mortality.

RESULTS

Compared to patients with HbA1c 6.5%-7.5%, patients with HbA_1c 8.5-9.5% and ≥9.5% were associated with a 1.26-fold (95% CI, 1.12-1.42) and 1.56-fold (95% CI, 1.37-1.77) risk for all-cause mortality. The risk of all-cause mortality did not increase in patients with HbA1c < 5.5%. In cause-specific mortality, the risk of cardiovascular deaths significantly increased from small increase of HbA1c levels. However, the risk of other causes of death increased only in patients with HbA1c > 9.5%. The slope of HR increase with increasing HbA1c levels was significantly faster for cardiovascular causes than for other causes.

CONCLUSIONS

There was a linear relationship between HbA1c levels and risk of all-cause mortality in hemodialysis patients, and the risk of cardiovascular death increased earlier and more rapidly, with increasing HbA1c levels, compared with other causes of death.

Renal Function Effect on the Association Between Body Mass Index and Mortality Risk After Acute Myocardial Infarction

Background: Body mass index (BMI) is a critical determinant of mortality after acute myocardial infarction (AMI), and higher BMI is associated with survival benefit in patients with renal impairment. However, there are no studies investigating the interactive effects of BMI and renal function on mortality risk after AMI occurrence. Methods: We enrolled 12,647 AMI patients from Korea Acute Myocardial Infarction Registry between November 2011 and December 2015. Patients were categorized based on estimated Glomerular Filtration Rate (eGFR) and BMI. The primary endpoint was all-cause mortality after AMI treatment. Results: Within each renal function category, the absolute mortality rate was decreased in patients with higher BMI. However, the adjusted hazard ratio (HR) of all-cause mortality for higher BMI was decreased as renal function worsened [adjusted HR (95% confidence interval) at BMI ≥ 25 kg/m²: 0.63 (0.41-0.99), 0.76 (0.59-0.97), and 0.84 (0.65-1.08) for patients with eGFR ≥ 90, 90-45, and <45 mL/min/1.73 m², respectively]. There was a significant interaction between BMI and renal function (P for interaction = 0.010). The protective effect of higher BMI was preserved against non-cardiac death and it was also decreased with lowering eGFR in competing risks models [adjusted HR at BMI ≥25 kg/m²: 0.38 (0.18-0.83), 0.76 (0.59-0.97), and 0.84 (0.65-1.08) for patients with eGFR ≥ 90, 90-45, and <45 mL/min/1.73 m², respectively; P for interaction = 0.03]. However, renal function did not significantly affect the association between BMI and risk of cardiac death (P for interaction = 0.20). Conclusions: The effect of BMI on the mortality risk after AMI was dependent on renal function. The association between greater BMI and survival benefit was weakened as renal function was decreased. In addition, the negative effect of renal function on the BMI - mortality association was pronounced in the non-cardiac death.

Association between Body Mass Index and Chronic Kidney Disease in Asian Populations: A Participant-level Meta-Analysis

Obesity and chronic kidney disease (CKD) are major public health problems worldwide. However, the association between body mass index (BMI) and CKD is inconclusive in Asians. In this meta-analysis, eight population-based studies, from China, India, Russia (Asian), Singapore and South Korea, provided individual-level data (n=50037). CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m². BMI was analyzed both as a continuous variable and in three categories: <25kg/m², normal; 25-29.9kg/m², overweight; and ≥30kg/m², obese. The association between BMI and CKD was evaluated in each study using multivariable logistic regression models and individual estimates were pooled using random-effect meta-analysis to obtain the pooled odds ratio (OR) and 95% confidence interval (CI). Associations were also evaluated in subgroups of age, gender, smoking, diabetes, and hypertension status. Of 50037 adults, 4258 (8.5%) had CKD. 13328 (26.6%) individuals were overweight while 4440 (8.9%) were obese. The prevalence of any CKD ranged from 3.5% to 29.1% across studies. In pooled analysis, both overweight and obesity were associated with increased odds of CKD, with pooled OR (95% CI) of 1.15 (1.03-1.29) and 1.23 (1.06-1.42), respectively. In subgroup analyses, significant associations between BMI and CKD were observed in adult males, non-smokers, and those with diabetes and arterial hypertension (all p<0.05). When evaluated as a continuous variable, BMI was not significantly associated with CKD. If confirmed in longitudinal studies, these results may have clinical implications in risk stratification and preventive measures, given that obesity and CKD are two major chronic diseases with substantial public health burden worldwide.

Treatment options for managing obesity in chronic kidney disease

PURPOSE OF REVIEW

Obesity is a risk factor for the development and progression of chronic kidney disease (CKD). In this review, we provide a comprehensive overview of various management options (lifestyle intervention, medications, and bariatric surgery) to address obesity in those with CKD.

RECENT FINDINGS

Few clinical trials have examined the benefits of lifestyle modifications in those with preexisting CKD and suggest potential renal and cardiovascular benefits in this population. Yet, superiority of different dietary regimen to facilitate weight loss in CKD is unclear. Although medications could offer short-term benefits and assist weight loss, their safety and long-term benefits warrant further studies in this high-risk population. Observational studies report that bariatric procedures are associated with lower risk of end stage kidney disease. Clinicians should also recognize the higher risk of acute kidney injury, nephrolithiasis, and other complications noted with bariatric surgical procedures.

SUMMARY

Lifestyle modifications and some weight loss medications may be recommended for facilitating weight loss in CKD. Referral to bariatric centers should be considered among morbidly obese adults with CKD.

Positive and Negative Aspects of Sodium Intake in Dialysis and Non-Dialysis CKD Patients

Sodium intake theoretically has dual effects on both non-dialysis chronic kidney disease (CKD) patients and dialysis patients. One negatively affects mortality by increasing proteinuria and blood pressure. The other positively affects mortality by ameliorating nutritional status through appetite induced by salt intake and the amount of food itself, which is proportional to the amount of salt under the same salty taste. Sodium restriction with enough water intake easily causes hyponatremia in CKD and dialysis patients. Moreover, the balance of these dual effects in dialysis patients is likely different from their balance in non-dialysis CKD patients because dialysis patients lose kidney function. Sodium intake is strongly related to water intake via the thirst center. Therefore, sodium intake is strongly related to extracellular fluid volume, blood pressure, appetite, nutritional status, and mortality. To decrease mortality in both non-dialysis and dialysis CKD patients, sodium restriction is an essential and important factor that can be changed by the patients themselves. However, under sodium restriction, it is important to maintain the balance of negative and positive effects from sodium intake not only in dialysis and non-dialysis CKD patients but also in the general population.

Effectiveness of Chinese herbal medicine combined with Western medicine on deferring dialysis initiation for nondialysis chronic kidney disease stage 5 patients: a multicenter prospective nonrandomized controlled study

Background

In clinical practice, Chinese herbal medicine (CHM) purportedly has beneficial therapeutic effects for chronic kidney disease (CKD), which include delaying disease progression and dialysis initiation. However, there is a lack of high-quality evidence-based results to support this. Therefore, this study aimed to evaluate the efficacy of CHM combined with Western medicine in the treatment of stage 5 CKD.

Methods

This was a prospective nonrandomized controlled study. Stage 5 CKD (nondialysis) patients were recruited form 29 AAA class hospitals across China from July 2014 to April 2019. According to doctors' advice and the patients' wishes, patients were assigned to the CHM group (Western medicine + CHM) and the non-CHM group (Western medicine). Patient demographic data, primary disease, blood pressure, Chinese and Western medical drugs, clinical test results, and time of dialysis initiation were collected during follow-up.

Results

A total of 908 patients were recruited in this study, and 814 patients were finally included for further analysis, including 747 patients in the CHM group and 67 patients in the non-CHM group. 482 patients in the CHM group and 52 patients in the non-CHM group initiated dialysis. The median time of initiating dialysis was 9 (7.90, 10.10) and 3 (0.98,5.02) months in the CHM group and non-CHM group, respectively. The multivariate Cox regression analysis showed that patients in the CHM group had a significantly lower risk of dialysis [adjusted hazard ratio (aHR): 0.38; 95% confidence interval (CI): 0.28, 0.53] compared to those in the non-CHM group. After 1:2 matching, the outcomes of 160 patients were analyzed. The multivariate Cox regression analysis showed that patients in the CHM group had a significantly lower risk of dialysis (aHR: 0.32; 95% CI: 0.21, 0.48) compared to patients in the non-CHM group. Also, the Kaplan-Meier analysis demonstrated that the cumulative incidence of dialysis in the CHM group was significantly lower than that in the non-CHM group (log-rank test, P<0.001) before and after matching.

Conclusions

This study suggest that the combination of CHM and Western medicine could effectively reduce the incidence of dialysis and delay the time of dialysis initiation in stage 5 CKD patients.

Impact of lower body mass index on risk of all-cause mortality and infection-related death in Japanese chronic kidney disease patients

Background

Several studies have reported that lower body mass index (BMI) is associated with high mortality in patients with chronic kidney disease (CKD). Rate of infection-related death in CKD patients is increasing. However, the relationship between BMI and infection-related death is unclear.

Methods

Overall, 2648 CKD outpatients (estimated glomerular filtration rate < 60 mL/min and/or presenting with proteinuria) under the care of nephrologists were prospectively followed for 5 years. Patients were stratified by quartile of BMI levels. Data on all-cause mortality before progression to end-stage kidney disease (ESKD) and the cause of death were collected.

Results

The median follow-up time was 3.9 years (interquartile range, 1.7–5.0); 114 patients died and 308 started renal replacement therapy. The leading causes of death were as follows; cardiovascular (41%), infection-related (21%), and malignancy-related (18%). Advanced age and lower BMI were the significant risk factors for all-cause mortality before progression to ESKD. Advanced age was statistically associated with respective causes of death, while lower BMI was associated with infection-related death only. CKD stage had no significant impact on all-cause or individual mortality.

Conclusions

Low BMI was associated with significant risk of all-cause mortality and infection-related death, which may indicate the novel clinical target to improve CKD outcomes.

Association of Body Mass Index and Outcome in Acutely Ill Patients With Chronic Kidney Disease Requiring Intensive Care Therapy

OBJECTIVE

An association of body mass index (BMI) and outcome, the "obesity paradox," has been described in patients with chronic kidney disease (CKD) and end-stage renal disease. We sought to assess whether a potential beneficial effect of a high body mass is also seen in CKD patients with critical illness.

METHODS

In a retrospective analysis of a prospectively collected database of 123,416 patients from 107 Austrian intensive care units (ICUs) in whom BMI was available, the association of 6 groups of BMI and hospital mortality was assessed in 12,206 patients with CKD 3-5 by univariate and multivariate logistic regression analyses.

RESULTS

Patients with CKD were sicker, had a longer ICU stay, and had a higher ICU and hospital mortality than those without. The association of BMI and outcome in CKD patients indicated a U-shaped curve with the highest mortality in patients with BMI <20 and ≥40, and the lowest with a BMI between ≥25 and <40. This relationship was also significant in a multivariate analysis adjusted for severity of illness assessed by Simplified Acute Physiology Score III score, age, gender, admission diagnosis, and pre-existing comorbidities. It was not found in patients with CKD 5 on renal replacement therapy, in patients below 60 years of age, and those with diabetes mellitus requiring insulin treatment.

CONCLUSIONS

BMI is associated with better outcomes in CKD 3-5 patients who have acquired acute intermittent diseases and are admitted to an ICU, but not those requiring renal replacement therapy. This higher tolerance to acute disease processes may in part explain the "obesity paradox" observed in CKD patients.

BMI and its association with death and the initiation of renal replacement therapy (RRT) in a cohort of patients with chronic kidney disease (CKD)

BACKGROUND

A survival advantage associated with obesity has often been described in dialysis patients. The association of higher body mass index (BMI) with mortality and renal replacement therapy (RRT) in preterminal chronic kidney disease (CKD) patients has not been established.

METHODS

Subjects were patients with pre-terminal CKD who were recruited to the CKD.QLD registry. BMI at time of consent was grouped as normal (BMI 18.5-24.9 kg/m2), overweight (BMI 25-29.9 kg/m2), mild obesity (BMI 30-34.9 kg/m2) and moderate obesity+ (BMI ≥ 35 kg/m2) as defined by WHO criteria. The associations of BMI categories with mortality and starting RRT were analysed.

RESULTS

The cohort consisted of 3344 CKD patients, of whom 1777 were males (53.1%). The percentages who had normal BMI, or were overweight, mildly obese and moderately obese+ were 18.9, 29.9, 25.1 and 26.1%, respectively. Using people with normal BMI as the reference group, and after adjusting for age, socio-economic status, CKD stage, primary renal diagnoses, comorbidities including cancer, diabetes, peripheral vascular disease (PVD), chronic lung disease, coronary artery disease (CAD), and all other cardiovascular disease (CVD), the hazard ratios (HRs, 95% CI) of males for death without RRT were 0.65 (0.45-0.92, p = 0.016), 0.60 (0.40-0.90, p = 0.013), and 0.77 (0.50-1.19, p = 0.239) for the overweight, mildly obese and moderately obese+. With the same adjustments the hazard ratios for death without RRT in females were 0.96 (0.62-1.50, p = 0.864), 0.94 (0.59-1.49, p = 0.792) and 0.96 (0.60-1.53, p = 0.865) respectively. In males, with normal BMI as the reference group, the adjusted HRs of starting RRT were 1.15 (0.71-1.86, p = 0.579), 0.99 (0.59-1.66, p = 0.970), and 0.95 (0.56-1.61, p = 0.858) for the overweight, mildly obese and moderately obese+ groups, respectively, and in females they were 0.88 (0.44-1.76, p = 0.727), 0.94 (0.47-1.88, p = 0.862) and 0.65 (0.33-1.29, p = 0.219) respectively.

CONCLUSIONS

More than 80% of these CKD patients were overweight or obese. Higher BMI seemed to be a significant "protective" factor against death without RRT in males but there was not a significant relationship in females. Higher BMI was not a risk factor for predicting RRT in either male or female patients with CKD.

Association of high body mass index with development of interstitial fibrosis in patients with IgA nephropathy

Background

The worldwide prevalence of obesity is increasing. Obesity is associated with a variety of chronic diseases, including chronic kidney disease. Several studies suggested that body mass index (BMI) could be an independent risk factor for progression of IgA nephropathy (IgAN). However, whether high BMI is associated with progression of IgAN remains uncertain.

Methods

This retrospective study included patients with biopsy proven IgAN from 2006 to 2017 in Sichuan Provincial People’s Hospital. BMI was categorized according to the WHO Asian guideline: underweight (< 18.5 kg/m²), normal weight (18.5-25 kg/m²), overweight (25-28 kg/m²) and obese (≥28 kg/m²). The main outcome was development of end-stage renal disease (ESRD) or a decline in eGFR by at least 30%. The association of BMI and IgAN progression was determined by propensity-score-matched cohort analysis.

Results

Four hundred eighty one patients with IgAN were finally enrolled in this study. The mean age was 37 ± 11 years and 40.3% were men. There was no significant difference in clinical and pathological characteristics among the four-group patients categorized by BMI. After matching with propensity scores, no significant correlation between BMI and renal outcomes was seen. However, compared with the reference group (18.5≦BMI≦25 kg/m²), being overweight (odd ratio [OR], 2.28; 95%CI: 1.06–4.88; P = 0.034) and obese (OR, 3.43; 95%CI: 1.06–11.04; P = 0.039) was associated with a high risk of interstitial fibrosis. In the cross figure demonstrating the association of BMI subgroup and interstitial fibrosis on renal outcomes, ORs of interstitial fibrosis groups were higher than those of no interstitial fibrosis. Compared with other BMI subgroups, patients with 18.5-25 kg/m² had lowest ORs.

Conclusions

High BMI and interstitial fibrosis were associated with progression of IgAN. Interstitial fibrosis appears to be common in IgAN patients with elevated BMI.

Body Mass Index, waist circumference, and health-related quality of life in adults with chronic kidney disease

PURPOSE

Obesity is linked to poor health-related quality of life (HRQOL) in the general population, but its role in chronic kidney disease (CKD) is uncertain.

METHODS

We conducted a cross-sectional study that investigated 1880 participants from the KoreaN cohort study for Outcome in patients With CKD (KNOW-CKD) who underwent complete baseline laboratory tests, health questionnaires, and HRQOL. HRQOL was assessed by physical component summary (PCS) and mental component summary (MCS) of the SF-36 questionnaire. We used multivariable linear regression models to examine the relationship between Body Mass Index (BMI) and sex-specific waist circumference (WC) with HRQOL.

RESULTS

Adults with higher BMI and greater WC showed lower PCS. After adjusting for age, sex, socioeconomic state, comorbidities, and laboratory findings, we found that WC, but not BMI, was associated with PCS. Greater WC quintiles were associated with lower PCS [WC-4th quintile (β, - 2.63, 95% CI - 5.19 to - 0.06) and WC-5th quintile (β, - 3.71, 95% CI - 6.28 to - 1.15)]. The association between WC and PCS was more pronounced in older adults, woman, patients with diabetes, cardiovascular disease, or lower eGFR. The relationship between BMI and WC with MCS was not significant.

CONCLUSIONS

In adults with CKD, WC is a better indicator of poor physical HRQOL than BMI. The association between WC and physical HRQOL is modified by age, sex, eGFR, and comorbidities such as diabetes and cardiovascular disease.

Truncal Adiposity Influences High-Density Lipoprotein Cholesterol Levels and Cardiovascular Events in Hemodialysis Patients

OBJECTIVE

Adiposity influences lipid metabolism and atherosclerotic cardiovascular disease (CVD) in the general population. The aim of the present study was to assess the association between fat mass (FM) and lipid metabolism and CVD events among patients on hemodialysis (HD).

METHODS

This prospective observational study examined 240 patients on prevalent HD. Blood samples were obtained before dialysis at baseline to measure lipids, high-sensitivity C-reactive protein (hs-CRP), interleukin-6, and adiponectin. Lipids and hs-CRP were measured every 3 months for 12 months. FM was estimated by dual energy x-ray absorptiometric scan at baseline and 12 months later. Patients were then prospectively followed up for 36 months after the 1-year measurement period, and composite CVD events were estimated.

RESULTS

Truncal FM was positively correlated with body mass index, hs-CRP, interleukin-6, total cholesterol, low-density lipoprotein-C, triglyceride, and negatively correlated with high-density lipoprotein (HDL)-C and adiponectin at baseline. HDL-C levels were repeatedly decreased, and triglyceride and non-HDL-C were serially increased in the patient group with truncal FM > 7,000 g at both baseline and 12 months (large truncal FM group) compared with the other groups. Cox proportional hazards models adjusted for confounders showed composite CVD events occurred significantly in patients with large truncal FM and continuous low HDL-C levels.

CONCLUSIONS

Truncal adiposity influences lipid metabolism in patients on HD, and the prevalence of CVD events may be increased in those patients with high fat and lipid abnormalities, especially continuously low HDL-C levels.

Obesity Paradox in Advanced Kidney Disease: From Bedside to the Bench

While obesity is associated with a variety of complications including diabetes, hypertension, cardiovascular disease and premature death, observational studies have also found that obesity and increasing body mass index (BMI) can be linked with improved survival in certain patient populations, including those with conditions marked by protein-energy wasting and dysmetabolism that ultimately lead to cachexia. The latter observations have been reported in various clinical settings including end-stage renal disease (ESRD) and have been described as the "obesity paradox" or "reverse epidemiology", engendering controversy. While some have attributed the obesity paradox to residual confounding in an effort to "debunk" these observations, recent experimental discoveries provide biologically plausible mechanisms in which higher BMI can be linked to longevity in certain groups of patients. In addition, sophisticated epidemiologic methods that extensively adjusted for confounding have found that the obesity paradox remains robust in ESRD. Furthermore, novel hypotheses suggest that weight loss and cachexia can be linked to adverse outcomes including cardiomyopathy, arrhythmias, sudden death and poor outcomes. Therefore, the survival benefit observed in obese ESRD patients can at least partly be derived from mechanisms that protect against inefficient energy utilization, cachexia and protein-energy wasting. Given that in ESRD patients, treatment of traditional risk factors has failed to alter outcomes, detailed translational studies of the obesity paradox may help identify innovative pathways that can be targeted to improve survival. We have reviewed recent clinical evidence detailing the association of BMI with outcomes in patients with chronic kidney disease, including ESRD, and discuss potential mechanisms underlying the obesity paradox with potential for clinical applicability.

Projecting the Burden of Chronic Kidney Disease in a Developed Country and Its Implications on Public Health

BACKGROUND

Chronic Kidney Disease (CKD) is a major public health problem worldwide. There is limited literature on a model to project the number of people with CKD. This study projects the number of residents with CKD in Singapore by 2035 using a Markov model.

METHODS

A Markov model with nine mutually exclusive health states was developed according to the clinical course of CKD, based on a discrete time interval of 1 year. The model simulated the transition of cohorts across different health states from 2007 to 2035 using prevalence, incidence, mortality, disease transition, and disease detection rates.

RESULTS

From 2007 to 2035, the number of residents with CKD is projected to increase from 316,521 to 887,870 and the prevalence from 12.2% to 24.3%. Patients with CKD stages 1-2 constituted the largest proportion. The proportion of undiagnosed cases will decline from 72.1% to 56.4%, resulting from faster progression to higher CKD stages and its eventual detection.

CONCLUSION

By 2035, about one-quarter of the Singapore residents are expected to have CKD. National policies need to focus on primary disease prevention and early disease detection to avoid delayed treatment of CKD which eventually leads to end-stage renal disease.

Blood pressure parameters and morbid and mortal outcomes in nondialysis-dependent chronic kidney disease

PURPOSE OF REVIEW

Observational and interventional studies provide conflicting evidence regarding optimal blood pressure (BP) control in persons with chronic kidney disease (CKD). Recent publications provide additional information to inform therapeutic decision-making.

RECENT FINDINGS

Targeting SBP to less than 120 mmHg, versus less than 140 mmHg, decreased cardiovascular events and all-cause mortality in persons with nondiabetic CKD. A meta-analysis of trials testing blood pressure management among nondialysis-dependent CKD patients (15 924 total patients) found more intensive therapies generally reduced mortality in all subgroups. Observational studies demonstrate that low SBP is associated with higher mortality in CKD. A recent report suggests that this is because of death from cardiovascular and noncardiovascular and nonmalignant causes, whereas higher BP is associated with death from cardiovascular causes. The shape of association between BP and cardiovascular and noncardiovascular events also appears to vary depending on baseline risk factors. Furthermore, BP measurement methodology may differ importantly between observational and interventional studies.

SUMMARY

We review and summarize observational and interventional literature relating BP parameters to key clinical outcomes in persons with CKD. Apart from the inherent differences between these study designs, the disparate findings from trials and observational studies may be because of differences in patient characteristics and BP measurement techniques.

Relationship between Modified Body Mass Index and Prognosis of Renal Amyloid a Amyloidosis

Objectives:

Overhydration occurs in nephrotic syndrome related to kidney involvement of amyloid A (AA) amyloidosis, which can cause an overestimation of body mass index (BMI). Modified BMI (mBMI, albumin×BMI) may be a better marker of nutritional status; therefore, we investigated the relationship between mBMI and the prognosis of patients with renal AA amyloidosis.

Methods:

We retrospectively reviewed the data of patients with biopsy-proven renal AA amyloidosis who were followed up between January 2001 and May 2013. Data regarding baseline characteristics, etiology of amyloidosis, dialysis, and mortality were recorded. Patients were divided into two groups according to median mBMI (group 1, n=60 and group 2, n=61).

Results:

The median age and follow-up period of the cohort (M/F 37/84) were 43 (19) years and 26 (56) months, respectively. Familial Mediterranean fever (37.2%) and tuberculosis (24.8%) were the most common etiologies. The baseline serum creatinine and albumin and proteinuria levels were 1.3 (2.2) mg/dL, 2.6 (1.5) g/dL, and 5.3 (7) g/day, respectively. The mBMIs of groups 1 and 2 were significantly different [41.5 (15.6) vs. 74.2 (21.8) g.kg/m², p =< 0.001]. Group 1 patients had shorter time to dialysis (13.9±20.8 vs. 25.7±28.1 months, p=0.040) and higher mortality (50% vs. 32.7%, p=0.041), whereas the rates of dialysis inception were similar. The area under the curve for mBMI as a predictor of mortality was larger than that for serum albumin and BMI in ROC analysis.

Conclusion:

Lower mBMI has been associated with worse prognosis in renal AA amyloidosis. As an anthropometric measure of nutritional status, mBMI may be a better marker in patients with hypoalbuminemia.

High-density lipoprotein cholesterol and causes of death in chronic kidney disease

BACKGROUND

Recent data suggest a U-shaped association between high-density lipoprotein cholesterol (HDL-c) and death in chronic kidney disease (CKD). However, whether the increased mortality in patients with extreme levels is explained by specific causes of death remains unclear.

OBJECTIVES

We studied the associations between HDL-c and cause-specific deaths in CKD.

METHODS

We included 38,377 patients with estimated glomerular filtration rate 15-59 mL/min/1.73 m². We classified deaths into 3 major categories: (1) cardiovascular; (2) malignant; and (3) noncardiovascular/nonmalignant causes. We fitted Cox regression models for overall mortality and separate competing risk models for each major cause of death category to evaluate their respective associations with categories of HDL-c (≤30, 31-40, 41-50 [referent], 51-60, >60 mg/dL). Separate analyses were conducted for men and women.

RESULTS

During a median follow-up of 4.5 years, 9665 patients died. After adjusting for relevant covariates, in both sexes, HDL-c 31 to 40 mg/dL and ≤30 mg/dL were associated with higher risk of all-cause mortality, cardiovascular mortality, malignancy-related deaths, and noncardiovascular/nonmalignancy-related deaths. HDL-c >60 mg/dL was associated with lower all-cause (hazard ratio: 0.75, 95% confidence interval: 0.69, 0.81), cardiovascular, malignancy-related, and noncardiovascular/nonmalignancy-related deaths among women but not in men. Similar results were noted when HDL-c was examined as a continuous measure.

CONCLUSIONS

In a non-dialysis-dependent CKD population, HDL-c ≤40 mg/dL was associated with risk of higher all-cause, cardiovascular, malignant, and noncardiovascular/nonmalignant mortality in men and women. HDL >60 mg/dL was associated with lower risk of all-cause, cardiovascular, malignant, and noncardiovascular/nonmalignant mortality in women but not in men.

Associations of dysnatremias with mortality in chronic kidney disease

Background

Hyponatremia and hypernatremia are associated with death in the general population and those with chronic kidney disease (CKD). We studied the associations between dysnatremias, all-cause mortality and causes of death in a large cohort of Stage 3 and 4 CKD patients.

Methods

We included 45 333 patients with Stage 3 and 4 CKDs followed in a large healthcare system. Associations between hyponatremia (<136 mmol/L) and hypernatremia (>145), and all-cause mortality and causes of death (cardiovascular, malignancy related and non-cardiovascular/non-malignancy related) were studied using Cox proportional hazards and competing risk models.

Results

Dysnatremias were found in 9.2% of the study population. In separate multivariable Cox proportional hazards models using baseline serum sodium levels and time-dependent repeated measures, both hyponatremia and hypernatremia were associated with all-cause mortality. In the competing risk analyses, hyponatremia was significantly associated with increased risk for various cause-specific mortality categories [cardiovascular (hazard ratio, HR 1.16, 95% confidence interval, CI: 1.04, 1.30), malignancy related (HR 1.48, 95% CI: 1.33, 1.65) and non-cardiovascular/non-malignancy deaths (HR 1.25, 95% CI: 1.13, 1.39)], while hypernatremia was significantly associated with higher non-cardiovascular/non-malignancy mortality only (HR 1.36, 95% CI: 1.08, 1.72).

Conclusions

In those with CKD, hyponatremia was associated with all-cause mortality, cardiovascular, malignancy and non-cardiovascular/non-malignancy-related deaths. Hypernatremia was associated with all-cause and non-cardiovascular/non-malignancy-related deaths. Further studies are needed to elucidate the mechanisms of differences in cause-specific death among CKD patients with hyponatremia and hypernatremia.

Chow fed UC Davis strain female Lepr fatty Zucker rats exhibit mild glucose intolerance, hypertriglyceridemia, and increased urine volume, all reduced by a Brown Norway strain chromosome 1 congenic donor region

Our objective is to identify genes that influence the development of any phenotypes of type 2 diabetes (T2D) or kidney disease in obese animals. We use the reproductively isolated UC Davis fatty Zucker strain rat model in which the defective chromosome 4 leptin receptor (Lepr^faSte/faSte) results in fatty obesity. We previously produced a congenic strain with the distal half of chromosome 1 from the Brown Norway strain (BN) on a Zucker (ZUC) background (BN.ZUC-D1Rat183–D1Rat90). Previously published studies in males showed that the BN congenic donor region protects from some phenotypes of renal dysfunction and T2D. We now expand our studies to include females and expand phenotyping to gene expression. We performed diabetes and kidney disease phenotyping in chow-fed females of the BN.ZUC-D1Rat183-D1Rat90 congenic strain to determine the specific characteristics of the UC Davis model. Fatty Lepr^faSte/faSte animals of both BN and ZUC genotype in the congenic donor region had prediabetic levels of fasting blood glucose and blood glucose 2 hours after a glucose tolerance test. We observed significant congenic strain chromosome 1 genotype effects of the BN donor region in fatty females that resulted in decreased food intake, urine volume, glucose area under the curve during glucose tolerance test, plasma triglyceride levels, and urine glucose excretion per day. In fatty females, there were significant congenic strain BN genotype effects on non-fasted plasma urea nitrogen, triglyceride, and creatinine. Congenic region genotype effects were observed by quantitative PCR of mRNA from the kidney for six genes, all located in the chromosome 1 BN donor region, with potential effects on T2D or kidney function. The results are consistent with the hypothesis that the BN genotype chromosome 1 congenic region influences traits of both type 2 diabetes and kidney function in fatty UC Davis ZUC females and that there are many positional candidate genes.

Analysis of survival for patients with chronic kidney disease primarily related to renal cancer surgery

OBJECTIVES

To evaluate predictors of long-term survival for patients with chronic kidney disease primarily due to surgery (CKD-S). Patients with CKD-S have generally good survival that approximates patients who do not have CKD even after renal cancer surgery (RCS), yet there may be heterogeneity within this cohort.

PATIENTS AND METHODS

From 1997 to 2008, 4 246 patients underwent RCS at our centre. The median (interquartile range [IQR]) follow-up was 9.4 (7.3-11.0) years. New baseline glomerular filtration rate (GFR) was defined as highest GFR between nadir and 6 weeks after RCS. We retrospectively evaluated three cohorts: no-CKD (new baseline GFR of ≥60 mL/min/1.73 m² ); CKD-S (new baseline GFR of <60 mL/min/1.73 m² but preoperative GFR of ≥60 mL/min/1.73 m² ); and CKD due to medical aetiologies who then require RCS (CKD-M/S, preoperative and new baseline GFR both <60 mL/min/1.73 m² ). Analysis focused primarily on non-renal cancer-related survival (NRCRS) for the CKD-S cohort. Kaplan-Meier analysis assessed the longitudinal impact of new baseline GFR (45-60 mL/min/1.73 m² vs <45 mL/min/1.73 m² ) and Cox regression evaluated relative impact of preoperative GFR, new baseline GFR, and relevant demographics/comorbidities.

RESULTS

Of the 4 246 patients who underwent RCS, 931 had CKD-S and 1 113 had CKD-M/S, whilst 2 202 had no-CKD even after RCS. Partial/radical nephrectomy (PN/RN) was performed in 54%/46% of the patients, respectively. For CKD-S, 641 patients had a new baseline GFR of 45-60 mL/min/1.73 m² and 290 had a new baseline GFR of <45 mL/min/1.73 m² . Kaplan-Meier analysis showed significantly reduced NRCRS for patients with CKD-S with a GFR of <45 mL/min/1.73 m² compared to those with no-CKD or CKD-S with a GFR of 45-60 mL/min/1.73 m² (both P ≤ 0.004), and competing risk analysis confirmed this (P < 0.001). Age, gender, heart disease, and new baseline GFR were all associated independently with NRCRS for patients with CKD-S (all P ≤ 0.02).

CONCLUSION

Our data suggest that CKD-S is heterogeneous, and patients with a reduced new baseline GFR have compromised survival, particularly if <45 mL/min/1.73 m² . Our findings may have implications regarding choice of PN/RN in patients at risk of developing CKD-S.

Diabetes Control and the Risks of ESRD and Mortality in Patients With CKD

BACKGROUND

Diabetes is the leading cause of end-stage renal disease (ESRD) and a significant contributor to mortality in the general population. We examined the associations of hemoglobin A1c (HbA1c) levels with ESRD and death in a population with diabetes and chronic kidney disease (CKD).

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

6,165 patients with diabetes (treated with oral hypoglycemic agents and/or insulin) and CKD stages 1 to 5 at a large health care system.

PREDICTOR

HbA1c level (examined as a categorical and continuous measure).

OUTCOMES

All-cause and cause-specific mortality ascertained from the Ohio Department of Health mortality files and ESRD ascertained from the US Renal Data System.

RESULTS

During a median 2.3 years of follow-up, 957 patients died (887 pre-ESRD deaths) and 205 patients reached ESRD. In a Cox proportional hazards model, after multivariable adjustment including for kidney function, HbA1c level < 6% was associated with higher risk for death when compared with HbA1c levels of 6% to 6.9% (HR, 1.23; 95% CI, 1.01-1.50). Similarly, HbA1c level ≥ 9% was associated with higher risk for all-cause death (HR, 1.34; 95% CI, 1.06-1.69). In competing-risk models, baseline HbA1c level was not associated with ESRD. For cause-specific mortality, diabetes accounted for >12% of deaths overall and >19% of deaths among those with HbA1c levels > 9%.

LIMITATIONS

Small proportion of participants with advanced kidney disease; single-center population.

CONCLUSIONS

In this cohort of patients with CKD with diabetes, HbA1c levels < 6% and ≥9% were associated with higher risk for death. HbA1c levels were not associated with ESRD in this specific CKD population. Diabetes-related deaths increased with higher HbA1c levels.

Blood pressure parameters are associated with all-cause and cause-specific mortality in chronic kidney disease

Previous observational studies reported J or U-shaped associations between blood pressure parameters and mortality in patients with chronic kidney disease (CKD). Here we examined the associations of different blood pressure levels with various causes of death in a CKD population that included patients with eGFR 15-59 ml/min/1.73 m² with underlying hypertension receiving at least one antihypertensive agent. We obtained data on date and cause of death from State Department of Health mortality files and classified deaths into three categories: cardiovascular, malignancy-related, and non-cardiovascular/non-malignancy related. Cox models were fitted for overall mortality, and separate competing risk regression models for each major cause of death category, to evaluate their associations with various systolic and diastolic blood pressures. During a median follow-up of 3.9 years, 13,332 of 45,412 patients died. Systolic blood pressures under 100, 100-109, 110-119, and over 150 (vs. 130-139 mm Hg) were associated with higher all-cause and cardiovascular mortality. Systolic blood pressures under 100 mm Hg and 100-109 were associated with higher non-cardiovascular/non-malignancy related mortality. Diastolic blood pressures under 50 and 50-59 (vs. 70-79 mm Hg) were associated with higher all-cause and non-cardiovascular/non-malignancy-related mortality while diastolic blood pressures over 90 mm Hg was associated with higher cardiovascular but lower non-cardiovascular/non-malignancy related mortality. Thus, in a non-dialysis dependent CKD population, systolic blood pressures under 110 and over 150 mm Hg were associated with cardiovascular and non-cardiovascular/non-malignancy related deaths. However, diastolic blood pressure under 60 mm Hg was associated in contrast with all-cause mortality and non-cardiovascular/non-malignancy-related deaths.

Screening for Chronic Kidney Disease in Adult Males in Vojvodina: A Cross-sectional Study

BACKGROUND

Chronic kidney disease (CKD) is one of the most significant global health problems accompanied by numerous complicatons, with constant increase in the number of affected people. This number is much higher in early phases of disease and patients are mostly asymptomatic, so early detection of CKD is crucial. The aim was examination of the prevalence of CKD in the general population of males in Vojvodina, based on estimated glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (ACR), and exploring the determinants and awareness of CKD.

METHODS

This cross-sectional study included 3060 male examinees from the general population, over 18 years of age, whose eGFR and ACR were calculated, first morning urine specimen examined, arterial blood pressure measured and body mass index calculated. Standard biochemistry methods determined creatinine, urea, uric acid and glucose serum concentrations as well as albumin and creatinine urine levels.

RESULTS

Prevalence of CKD in the adult male population is 7.9%, highest in men over 65 years of age (46.7%), while in the other age groups it is 3.6-12.6%. The largest number of examinees with a positive CKD marker suffer from arterial hypertension (HTA) and diabetes mellitus (DM). Only 1.3% of examinees with eGFR<60 ml/min/1.73 m2 and/or ACR≥ 3 mg/mmol had been aware of positive CKD biomarkers.

CONCLUSIONS

Obtained results show the prevalence of CKD in adult males is 7.9%, HTA and DM are the most important CKD risk factors and the level of CKD awareness is extremely low (1.3%) indicating the necessity for introduction of early stage disease recognition measures, including raising CKD awareness.