Time-varying effects of body mass index on mortality among hemodialysis patients: Results from a nationwide Korean registry

Metabolically Abnormal Non-Obese Phenotype Is Significantly Associated with All-Cause Mortality in Hemodialysis Patients

The association between obesity and all-cause mortality in patients undergoing kidney failure with replacement therapy (KFRT) has shown conflicting results. This study aimed to evaluate whether metabolic abnormalities (MA) increase the risk of all-cause mortality in these patients. Between 2009 and 2015, 1141 patients undergoing KFRT were recruited from the Clinical Research Center for End-Stage Renal Disease dataset. Patients were divided into four groups according to the presence of obesity and MA. Multivariate Cox proportional hazard analysis was performed to determine the association between the phenotypes and all-cause mortality. During a mean follow-up of 4.2 years, all-cause mortality was observed in 491 (43.0%) patients. Obesity had a 24% decreased risk of all-cause mortality compared with non-obesity. In contrast, the presence of MA showed a 1.53-fold increased risk of all-cause mortality. There was a significant interaction between obesity and MA (p = 0.006). In Cox proportional hazard analyses after adjustment of confounding factors, the metabolically abnormal non-obesity (MANO) phenotype showed a 1.63-fold increased risk of all-cause mortality compared with the metabolically healthy non-obesity phenotype. In subgroup analysis, the risk of all-cause mortality was higher in the MANO phenotype; this phenotype was significantly associated with a higher all-cause mortality in patients undergoing KFRT.

Obesity indices and the risk of total and cardiovascular mortality among people with diabetes: a long-term follow-up study in Taiwan

BACKGROUND

The association between obesity indicators and mortality in individuals with diabetes remains unclear, and data on cardiovascular mortality are scarce. Therefore, we investigated the associations between the five adiposity indices and both all-cause and cardiovascular mortality in patients with diabetes.

METHODS

This cohort study included 34,686 adults with diabetes who underwent a standard health-screening program between 1996 and 2017 in Taiwan. The dates and causes of death till January 2022 were retrieved from the National Death Registry. Cox proportional hazards models were used to calculate the hazard ratios (HR) and 95% confidence intervals (CI) for all-cause and cardiovascular mortality in relation to body mass index (BMI), waist circumference, waist-hip ratio (WHR), body fat percentage (BF%), and A Body Shape Index (ABSI), using the third quintile as the reference group.

RESULTS

During a median follow-up of 15 years, there were 8,324 deaths, of which 1,748 were attributed to cardiovascular disease. After adjusting for demographics, lifestyle factors and comorbidities, ABSI was associated with all-cause mortality in an exposure-response manner; the HR (95% CI) for first and fifth vs. third quintile was 0.78 (0.69-0.89) and 1.24 (1.14-1.35), respectively. A similar but weaker exposure-response relationship was found between WHR and mortality. People with a lower BMI and BF% had an increased risk of mortality (HR [95% CI] for the first vs. third quintiles, 1.33 [1.22, 1.44] and 1.42 [1.30, 1.56], respectively). No association was observed between waist circumference categories and risk of mortality. Similar results were observed for the association of BF%, waist circumference, and ABSI with cardiovascular mortality. However, no significant association was observed between BMI and cardiovascular mortality. The association between WHR and cardiovascular mortality was stronger than that between WHR and all-cause mortality.

CONCLUSIONS

ABSI demonstrated a consistent exposure-response relationship with both all-cause and cardiovascular mortality in this Asian cohort with diabetes. Our findings highlight the importance of monitoring ABSI, a surrogate index of central adiposity, in patients with diabetes.

Survival and predictors of mortality among chronic kidney disease patients on hemodialysis in Amhara region, Ethiopia, 2021

BACKGROUND

Despite the high economic and mortality burden of chronic kidney disease, studies on survival and predictors of mortality among patients on hemodialysis in Ethiopia especially in the Amhara region are scarce considering their importance to identify some modifiable risk factors for early mortality to improve the patient's prognosis. So, this study was done to fill the identified gaps. The study aimed to assess survival and predictors of mortality among end-stage renal disease patients on hemodialysis in Amhara regional state, Ethiopia, 2020/2021.

METHOD

Institution-based retrospective record review was conducted in Felege Hiwot, Gonder, and Gambi hospitals from March 5 to April 5, 2021. A total of 436 medical records were selected using a simple random sampling technique. A life table was used to estimate probabilities of survival at different time intervals. Multivariable cox regression was used to identify risk factors for mortality.

RESULT

Out of the 436 patients 153 (35.1%) had died. The median survival time was 345 days with a mortality rate of 1.89 per 1000 person-days (95%CI (1.62, 2.22)). Patients live in rural residences (AHR = 1.48, 95%CI (1.04, 2.12)), patients whose cause of CKD was hypertension (AHR = 1.49, 95%CI (1.01, 2.23)) and human immune virus (AHR = 2.22, 95%CI (1.41, 3.51)), and patients who use a central venous catheter (AHR = 3.15, 95%CI (2.08, 4.77)) had increased risk of death while staying 4 h on hemodialysis (AHR = 0.43, 95%CI (0.23, 0.80)) decreases the risk of death among chronic kidney disease patients on hemodialysis.

CONCLUSIONS

The overall survival rate and median survival time of chronic kidney disease patients on hemodialysis were low in the Amhara region as compared with other developing Sub-Saharan African counties.

Time-varying association between body mass index and all-cause mortality in patients with hypertension

BACKGROUND

Relationship between BMI and all-cause mortality in patients with hypertension remains controversial. This study aimed to evaluate the time-varying association between BMI in patients with hypertension and all-cause mortality.

METHODS

This population-based cohort study included 212,394 Chinese adults with hypertension from 2007 to 2015 and was followed up until death, loss-to-follow-up, or December 31, 2018. According to the World Health Organization criteria for Asians, BMI was categorized into five groups: underweight (BMI < 18.5 kg/m²), normal weight (18.5-22.9 kg/m²), overweight (23-24.9 kg/m²), class I obesity (25-29.9 kg/m²) and class II obesity (BMI ≥ 30 kg/m²). Cox model was used to estimate the time-varying association of BMI on the risk of mortality by including the interaction term between BMI and time using restricted cubic spline.

RESULTS

Compared with normal weight, underweight and class II obesity were associated with higher mortality (Hazard ratio [HRs] at 1 and 10 years of follow-up: 1.51 [95% CI: 1.39-1.65], and 1.27 (1.15-1.41) for underweight, respectively; 1.08 (0.96-1.21), and 1.16 (1.03-1.30) for class II obesity, respectively). However, overweight and class I obesity were associated with lower mortality, although the protective effects gradually attenuated over time (HRs at 1 and 10 years of follow-up: 0.85 (0.81-0.90), and 0.96 (0.91-1.02) for overweight, respectively; 0.80 (0.76-0.84), and 1.04 (0.99-1.10) for class I obesity, respectively).

CONCLUSIONS

We found increased mortality among hypertensive patients with underweight and class II obesity while decreased mortality with overweight and class I obesity was observed during the first 5 years of follow-up. Management efforts for hypertension may target controlling body weight in a reasonable range for patients, and probably more attention should be given to underweight patients.

Assessment of the Nutritional Status of the Hemodialysis Patients by Anthropometric Measurements

Objective This study assessed the nutritional status of end-stage renal disease (ESRD) patients on maintenance hemodialysis (MHD) by utilizing bedside anthropometric measurements. Methods This prospective cross-sectional study was done from November 2020 till April 2021 on ESRD patients three times a week MHD at our centre. Anthropometric measurements including body mass index (BMI), triceps skinfold thickness (TSFT), mid-arm circumference (MAC), calf circumference (CC) and handgrip strength (HGS) were measured mid-arm muscle circumference (MAMC) was calculated, and nutritional status was determined. Results Out of 195 patients recruited in our study, 127 (65.1%) were male. The mean age was 51.2 ± 14.8 years with a minimum of 20 and a maximum of 90 years, while the mean duration of HD was 4.6 ± 4.1 years. The majority of our patients had TSFT of 60 % to 90% 93 (47.7%), indicating mild to moderate depletion of fat stores and MAMC of >90 % 128 (65.6%), indicating good protein stores. Among all anthropometric measures, BMI was strongly associated with age (<0.001), while gender and duration of MHD were associated with TSFT (p <0.001). Conclusion Anthropometric measurements are easy and inexpensive bedside methods for assessing the nutritional status of ESRD patients on MHD. Our study concluded that our MHD patients have overall good nutritional status, though our young patients have low BMI and old have obesity. Male patients have weaker HGS. With the increased number of years on MHD, malnutrition increases. Our study will help to treat physicians and nutritionists for proper nutritional planning and implementation to prevent malnutrition.

Clinical and genetic characteristics of Korean autosomal dominant polycystic kidney disease patients

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease. It is characterized by cyst growth in the kidneys, resulting in kidney enlargement and end-stage kidney disease. The polycystic kidney disease 1 (PKD1) and PKD2 have been identified as genes related to ADPKD and their significance in the molecular pathology of the disease has been studied. A disease-modifying drug has been approved; therefore, it has become important to identify patients at a high risk of kidney disease progression. Genetic tests, image analysis methods, and clinical factors for kidney disease progression prediction have been established. This review describes genetic and clinical characteristics, and discusses ongoing studies in Korean ADPKD patients.

How important is dietary management in chronic kidney disease progression? A role for low protein diets

High dietary protein intake may lead to increased intraglomerular pressure and glomerular hyperfiltration, which in the long-term can lead to de novo or aggravating preexisting chronic kidney disease (CKD). Hence, a low protein diet (LPD, 0.6 to 0.8 g/kg/day) is recommended for the management of CKD. There are evidences that dietary protein restriction mitigate progression of CKD and retard the initiation of dialysis or facilitate incremental dialysis. LPD is also helpful to control metabolic derangements in CKD such as metabolic acidosis and hyperphosphatemia. Recently, a growing body of evidence has emerged on the benefits of plant-dominant low-protein diet (PLADO), which composed of > 50% plant-based sources. PLADO is considered to be helpful for relieving uremic burden and metabolic complications in CKD compared to animal protein dominant consumption. It may also lead to favorable alterations in the gut microbiome, which can modulate uremic toxin generation along with reducing cardiovascular risk. Alleviation of constipation in PLADO may minimize the risk of hyperkalemia. A balanced and individualized dietary approach for good adherence to LPD utilizing various plant-based sources as patients' preference should be elaborated for the optimal care in CKD. Periodic nutritional assessment under supervision of trained dietitians should be warranted to avoid protein-energy wasting.

Clinical significance of central systolic blood pressure in LV diastolic dysfunction and CV mortality

Background and aims

Cardiovascular (CV) disease is the major cause of death in patients with end-stage kidney disease (ESKD). Left ventricular (LV) diastolic dysfunction reflects LV pressure overload and is common in patients with ESKD. Recently, there have been studies on the usefulness of central blood pressure (BP); however, the relationship between central BP and LV diastolic dysfunction is not clear in dialysis patients with preserved systolic function. The purpose of this study was to investigate the clinical implication of central BP on LV diastolic dysfunction and CV mortality in the ESKD patients with preserved LV systolic function.

Methods

This prospective observational cohort study investigated the effect of LV diastolic dysfunction on CV mortality in the ESKD patients with preserved systolic function using echocardiography. Vascular calcification was evaluated using the abdominal aortic calcification score, and aortic stiffness was determined by measuring pulse wave velocity (PWV). The predictors of CV mortality were analyzed using Cox proportional hazard analysis.

Results

The subjects were comprised of 61 patients, with an average age of 54 years, 20 males (32.8%), and 25 diabetics (41.0%). There were 39 patients on hemodialysis and 22 patients receiving peritoneal dialysis treatment. During the mean follow-up period of 79.3 months, 16 patients (26.2%) died, and 7 patients (11.4%) died of CV events. The central systolic BP and diabetes were independent risk factors for LV diastolic dysfunction. In addition, patients with LV diastolic dysfunction had an increased CV mortality. When left atrial volume index and PWV were adjusted, the E/E’ ratio was found to be a predictor of CV mortality.

Conclusions

Central systolic BP and diabetes were found to be significant risk factors for LV diastolic dysfunction. LV diastolic dysfunction can independently predict CV mortality in dialysis patients with preserved LV systolic function.

Rapid Weight Change Over Time Is a Risk Factor for Adverse Outcomes in Patients With Predialysis Chronic Kidney Disease: A Prospective Cohort Study

OBJECTIVE

Both obesity and being underweight are risk factors for adverse outcomes in chronic kidney disease (CKD) patients. However, the effects of longitudinal weight changes on patients with predialysis CKD have not yet been studied. In this study, we analyzed the effects of weight change over time on the adverse outcomes in predialysis CKD population.

METHODS

Longitudinal data from a multicenter prospective cohort study (KNOW-CKD) were analyzed. In a total of 2,022 patients, the percent weight change per year were calculated using regression analysis and the study subjects were classified into five categories: group 1, ≤ -5%/year; group 2, -5< to ≤ -2.5%/year; group 3, -2.5< to <2.5%/year; group 4, 2.5≤ < 5%/year; and group 5, ≥5%/year. The incidences of end-stage renal disease (ESRD) and the composite outcome of cardiovascular disease (CVD) and death were calculated in each group and compared to group 3 as reference.

RESULTS

During a median 4.4 years of follow-up, 414 ESRD, and 188 composite of CVD and mortality events occurred. Both weight gain and loss were independent risk factors for adverse outcomes. There was a U-shaped correlation between the degree of longitudinal weight change and ESRD (hazard ratio 3.61, 2.15, 1.86 and 3.66, for group 1, 2, 4 and 5, respectively) and composite of CVD and death (hazard ratio 2.92, 2.15, 1.73 and 2.54, respectively), when compared to the reference group 3. The U-shape correlation was most prominent in the subgroup of estimated glomerular filtration rate <45 mL/min/1.73 m².

CONCLUSION

Both rapid weight gain and weight loss are associated with high risk of adverse outcomes, particularly in the advanced CKD.

Association of Body Mass Index and Waist Circumference with All-Cause Mortality in Hemodialysis Patients

In this study based on a large nationally representative sample of Korean adults, we investigated the potential associations of the body mass index (BMI) and waist circumference (WC) with mortality in patients undergoing hemodialysis. We obtained the data of 18,699 participants >20 years of age who were followed up with for 4 years and for whom BMI and WC information were available, using a nationally representative dataset from the Korean National Health Insurance System. Patients were stratified into five levels by their baseline BMI and into six levels by their WC (5-cm increments). A total of 4975 deaths occurred during a median follow-up period of 48.2 months. Participants with a higher BMI had a lower mortality rate than those with a lower BMI. In a fully adjusted Cox regression analysis, being overweight and obese was associated with a significantly lower relative risk of all-cause mortality relative to the reference group. Conversely, the mortality rate was higher among participants with a high WC than among those with a low WC. Participants with the highest WC had a higher risk of mortality, while those with the lowest WC level had a significantly lower risk of mortality. In conclusion, all-cause mortality was positively associated with WC, a measure of abdominal obesity, and inversely associated with BMI, a measure of body volume, in patients undergoing hemodialysis.

Changes in mortality hazard of the Korean long-term dialysis population: The dependencies of time and modality switch

BACKGROUND

Many studies have compared patient survival outcome between hemodialysis (HD) and peritoneal dialysis (PD); however, time-varying risks of dialysis modality have been rarely investigated. This study aimed to investigate dialysis modality switch and its association with the survival outcome in the Korean population.

METHODS

Data from the Korean Society of Nephrology were used. A total of 21,840 incident dialysis patients who started dialysis in or after 2000 were analyzed. For the survival analysis, both proportional and non-proportional hazard assumptions were applied. For the modality switch, time-varying covariate Cox regression was applied.

RESULTS

During the median follow-up of 8 years, PD group showed increased adjusted hazard ratio (HR) of 1.248 (95% CI 1.071-1.454, p = 0.004) for mortality. Interaction of PD status with female sex was significant with an HR of 1.080 (95% CI 1.000-1.165, p = 0.050). Dialysis modality switch was associated with increased HR of 1.094 (95% CI 1.015-1.180, p = 0.019), albeit switch from PD to HD did not show significant HR until 6 years. Interestingly, time-varying risk analysis showed a decreased HR of PD after 10 years in the non-switcher group, which was consistent in patients with high traditional risk factors (with diabetes, elderly).

CONCLUSIONS

PD was associated with increased HR of mortality in the first 8 years, then it was associated with decreased HR of mortality after 10 years. Dialysis modality switch was associated with increased mortality risk, but switch from PD to HD within 6 years did not show significant hazard of mortality.

The Impact of Comorbidity Burden on The Association between Vascular Access Type and Clinical Outcomes among Elderly Patients Undergoing Hemodialysis

The optimal vascular access type for elderly hemodialysis patients is controversial. We evaluated the impact of comorbidity burden on the association between vascular access type and mortality risk among 23,100 hemodialysis patients aged ≥65 years from the Korean Society of Nephrology End-Stage Renal Disease registry data. Subjects were stratified into tertiles according to the simplified Charlson comorbidity index (sCCI), and the survival and hospitalization rates were compared with respect to vascular access type: arteriovenous fistula (AVF), arteriovenous graft (AVG), and central venous catheter (CVC). Among all tertiles of sCCI, CVC use showed highest risk of mortality than AVF use. In the lowest to middle tertile, no difference was observed in survival rates between the use of AVF and AVG. However, in the highest tertile, AVG use showed higher risk of mortality than AVF use. When subjects were classified according to a combination of sCCI tertile and access type (AVF vs. AVG), patients with the highest CCI with AVG showed 1.75-folded increased risk of mortality than those with the lowest sCCI with AVF. Hospitalization rates due to access malfunction were highest in patients with CVC in all sCCI tertiles. In the highest tertile, patients with AVG showed increased rates of hospitalization compared to those with AVF due to access malfunction. However, hospitalization rates due to access infection were highest in patients with AVG in all tertiles. The use of AVF may be of benefit and switching to AVF should be considered in elderly hemodialysis patients with a high burden of comorbidity.

The association of dialysis adequacy, body mass index, and mortality among hemodialysis patients

Background

Although hemodialysis (HD) adequacy, single-pool Kt/V_urea (spKt/V), is inversely correlated with body size, each is known to affect patient survival in the same direction. Therefore, we sought to examine the relationship between HD adequacy and mortality according to body mass index (BMI) in HD patients and explore a combination effect of BMI and HD adequacy on mortality risk.

Methods

We retrospectively reviewed patient data from the Korean Society of Nephrology registry, a nationwide database of medical records of HD patients, from January 2001 to June 2017. We included patients ≥18 years old who were receiving maintenance HD. Patients were categorized into three groups according to baseline BMI (< 20 (low), 20 to < 23 (normal), and ≥ 23 (high) kg/m²). Baseline spKt/V was divided into six categories.

Results

Among 18,242 patients on HD, the median follow-up duration was 5.2 (IQR, 1.9–8.9) years. Cox regression analysis showed that, compared to the reference (spKt/V 1.2–1.4), lower and higher baseline spKt/V were associated with greater and lower risks for all-cause mortality, respectively. However, among patients with high BMI (n = 5588), the association between higher spKt/V and lower all-cause mortality was attenuated in all adjusted models (P_interaction < 0.001). Compared to patients with normal BMI and spKt/V within the target range (1.2–1.4), those with low BMI had a higher risk for all-cause mortality at all spKt/V levels. However, the gap in mortality risk became narrower for higher values of spKt/V. Compared to patients with normal BMI and spKt/V in the target range, those with high BMI and spKt/V < 1.2 were not at increased risk for mortality despite low dialysis adequacy.

Conclusions

The association between spKt/V and mortality in HD patients may be modified by BMI.