Dose of hemodialysis and survival: a marginal structural model analysis

Clinical Outcomes in Patients on Hemodialysis with Congestive Heart Failure

Introduction

Congestive heart failure (CHF) is one of the common complications in patients with end-stage kidney disease. In the general population, CHF increases the risk of the death. However, there is no well-designed relevant study in the Chinese hemodialysis (HD) population addressing the risks associated with CHF. The aim of this study was to explore the impact of CHF on clinical outcomes in HD patients.

Methods

Data from a prospective cohort study, the China Dialysis Outcomes and Practice Patterns Study (DOPPS) 5 (2012-2015), were analyzed. Demographic data, comorbidities, lab data, and death records were extracted. CHF was defined by the diagnosis records upon study inclusion. Our primary outcome was all-cause and cardiovascular (CV) mortality; secondary outcomes were all-cause and cause-specific hospitalization risk. Associations between CHF and outcomes were evaluated using Cox regression models. Stepwise multivariate logistic regression was used to identify the related risk factors, and subgroup analyses were carried out.

Results

Of 1,411 patients without missing CHF history information, 24.1% (340) had CHF diagnosis at enrollment. The overall mortality rates were 21.8% versus 12.0% (p < 0.001) in patients with and without CHF during follow-up, respectively. CHF was associated with higher all-cause mortality (adjusted HR: 1.72, 95% confidence interval [CI]: 1.17-2.53, p = 0.006), and the association with CV death was of similar magnitude (HR: 1.60, 95% CI: 0.91-2.81, p = 0.105). CHF patients had more episodes of hospitalization due to heart failure (HR: 2.93, 95% CI: 1.49-5.76, p < 0.01). However, compared with patients without CHF, the all-cause hospitalization risk was not much higher in CHF patients (HR: 1.09, 95% CI: 0.90-1.33, p = 0.39). Subgroup analysis found that the effect of CHF on all-cause mortality was stronger for male patients, patients with residual renal function, the elderly (≥60 years of age), patients with arteriovenous fistulae vascular accesses, nondiabetic patients, low-flux dialyzer users, and inadequately dialyzed patients (standardized Kt/V <2).

Conclusion

In HD patients, CHF was found to be associated with a higher risk of all-cause mortality and cause-specific hospitalization risk. Further research is needed to identify opportunities to improve care for HD patients combined with CHF.

MOONLIGHT study: the design of a comparative study of the effectiveness of belimumab in patients with a history of lupus nephritis from the post-Marketed effectiveness of belimumab cOhOrt and JapaN Lupus NatIonwide reGistry (LUNA) coHorT

Introduction

Lupus nephritis (LN) is more prevalent in patients with SLE of Asian ethnicity than in Caucasian patients. Belimumab became available in Japan in 2017 to treat patients with SLE, including those with LN. In the BLISS-LN trial (NCT01639339), belimumab showed a favourable effect on renal outcomes when combined with standard therapy (ST) starting at the induction treatment phase for active LN, but real-world effectiveness of belimumab in LN has not been extensively studied. Here we describe the protocol for the MOONLIGHT (post-Marketed effectiveness of belimumab cOhOrt and JapaN Lupus NatIonwide ReGistry (LUNA) coHorT) study, which will use data from a Japan postmarketing surveillance study and the Lupus Registry of Nationwide Institutions (LUNA) to evaluate the real-world effectiveness of belimumab plus ST versus ST alone in patients with a history of active LN who are not in the induction phase.

Methods and analysis

This multicentre, retrospective, observational study (GSK Study 214710) will enrol adults with SLE and a history of active LN, holding ≥3 years of complete follow-up data from the initiation of belimumab (no continuous treatment required). Data for patients with belimumab plus ST treatment (postmarketing registry data, belimumab cohort) will be compared with those for patients with ST only treatment (LUNA data, comparison cohort). Patients who discontinue/initiate belimumab after the start of the follow-up may be included in the comparison/belimumab cohort, respectively. The primary endpoint will be the occurrence of renal flares, for which belimumab’s effectiveness will be estimated using a marginal structural model to consider time-dependent treatment and confounding factors. Secondary endpoints will include change in corticosteroid dose, renal disease activity, extrarenal disease activity, disease severity/activity biomarkers, LN class changes, end-stage kidney disease events and hospitalisations.

Ethics and dissemination

This study will be conducted according to the Declaration of Helsinki and the local ethical guidelines. Findings will be submitted to peer-reviewed journals and presented at scientific meetings.

The association between dose of hemodialysis and patients mortality in a prospective cohort study

Dialysis adequacy is a known risk factor for mortality in maintenance hemodialysis (MHD) patients. However, the optimal dialysis dose remains controversial. Therefore, we aimed to explore the relationship between dialysis dose and all-cause and cardiovascular disease (CVD) mortality among MHD. We examined the associations of dialysis dose with mortality in a cohort (n = 558) of MHD patients from 31 December 2015 to 31 December 2020. Dialysis adequacy was assessed using baseline Single-pool Kt/V_urea (spKt/V), which was categorized into three groups, and the lowest dose group was used as the reference category. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression models. A total of 214 patients died (64.5% for CVD). Compared with the low-dose group, high-dose group could reduce the risk of all-cause mortality by 33% (HR = 0.67, 95% CI: 0.47–0.98). Of note, when stratification by age, high-dose group was associated with both lower all-cause (HR = 0.46, 95% CI: 0.26–0.81) and CVD mortality (HR = 0.42, 95% CI: 0.20–0.88) among patients with age below 65 years. When stratification by dialysis age, high-dose group was associated with decreased risk of CVD mortality (HR = 0.43, 95% CI: 0.20–0.91) among patients with dialysis age over 60 months. spKt/V is a simple index of hemodialysis dose used in clinical practice and a useful modifiable factor in predicting the risk of death, especially in MHD patients under 65 years old or dialysis age more than 60 months.

Using the Intelligent System to Improve the Delivered Adequacy of Dialysis by Preventing Intradialytic Complications

Acute kidney failure patients while detoxificated by hemodialysis (HD) mostly or continuously faced regular problems such as low blood pressure (hypotension), muscle cramps, nausea, or vomiting. Higher intradialytic symptom leads to low-quality HD treatment. Although more known therapeutic interventions are used to relieve the HD side effects, this study was designed to investigate how intelligent systems can make highly beneficial alterations in dialysis facilities and equipment to ease intradialytic complications and help the staff deliver high-quality treatment. A search was performed among relevant research articles based on nonpharmacological intervention methods considered to prevent adverse effects of renal replacement therapy until 2020 in the PubMed databases using the terms “intradialytic complications,” “intradialytic complication interventions,” “nonpharmacological interventions,” “intradialytic exercises,” and “adequacy calculation methods.” Studies included the prevalence of intradialytic complications, different strategies with the aim of preventing complications, the outcome of intradialytic exercises on dialysis symptoms, and dialysis dose calculation methods. The results showed the incidence of hypotension varying between 5% and 30%, fatigue, muscular cramps, and vomiting as the most common complications during dialysis, which greatly affect the outcome of HD sessions. To prevent hypotension, ultrafiltration profiling, sodium modeling, low dialysate temperature, and changing the position to Trendelenburg are some strategies. Urea reduction ratio (URR), formal urea kinetic modeling (FUKM), formal single-pool urea kinetics, and online clearance monitoring (OCM) are methods for calculating the delivered dose of dialysis in which OCM is a low-cost and accessible way to monitor regularly the quality of dialysis delivered. Integration of the chair and HD machine which is in direct contact with the patient provides an intelligent system that improves the management of the dialysis session to enhance the quality of healthcare service.

Survival with low- and high-flux dialysis

Background

Besides advances in haemodialysis (HD), mortality rates are still high. The effect of the different types of HD membranes on survival is still a controversial issue. The aim of this COSMOS (Current management Of Secondary hyperparathyroidism: a Multicentre Observational Study) analysis was to survey, in HD patients, the relationship between the use of conventional low- or high-flux membranes and all-cause and cardiovascular mortality.

Methods

COSMOS is a multicentre, open-cohort, 3-year prospective study, designed to evaluate mineral and bone disorders in the European HD population. The present analysis included 5138 HD patients from 20 European countries, 3502 randomly selected at baseline (68.2%), plus 1636 new patients with <1 year on HD (31.8%) recruited to replace patients who died, were transplanted, switched to peritoneal dialysis or lost to follow-up by other reasons. Cox-regression analysis with time-dependent variables, propensity score matching and the use of an instrumental variable (facility-level analysis) were used.

Results

After adjustments using three different multivariate models, patients treated with high-flux membranes showed a lower all-cause and cardiovascular mortality risks {hazard ratio (HR) = 0.76 [95% confidence interval (CI) 0.61-0.96] and HR = 0.61 (95% CI 0.42-0.87), respectively}, that remained significant after matching by propensity score for all-cause mortality (HR = 0.69, 95% CI 0.52-0.93). However, a facility-level analysis showed no association between the case-mix-adjusted facility percentage of patients dialysed with high-flux membranes and all-cause and cardiovascular mortality.

Conclusions

High-flux dialysis was associated with a lower relative risk of all-cause and cardiovascular mortality. However, dialysis facilities using these dialysis membranes to a greater extent did not show better survival.

Associations of Systolic Blood Pressure With Incident CKD G3-G5: A Cohort Study of South Korean Adults

RATIONALE & OBJECTIVE

Clinical practice guidelines recommend a target blood pressure (BP)<130/80 mm Hg to reduce cardiovascular risk. However, the optimal BP to prevent chronic kidney disease (CKD) is unknown.

STUDY DESIGN

Population-based retrospective cohort study.

SETTING & PARTICIPANTS

10.5 million adults who participated in the National Health Insurance Service National Health Checkup Program in South Korea between 2009 and 2015 and had an estimated glomerular filtration rate (GFR) ≥ 60 mL/min/1.73 m² at the beginning of follow-up.

PREDICTORS

Baseline and time-updated systolic BP (SBP) as a continuous variable and categorized as<110, 110 to 119, 120 to 129, 130 to 139, or≥140 mm Hg.

OUTCOME

Incident CKD GFR categories 3 to 5 (CKD G3-G5), defined as de novo development of estimated GFR<60 mL/min/1.73 m² for at least 2 consecutive assessments confirmed at least 90 days apart.

ANALYTICAL APPROACH

Cox proportional hazards regression for baseline BP and marginal structural analysis for time-updated BP.

RESULTS

During 49,169,311 person-years of follow-up, incident CKD G3-G5 developed in 172,423 (1.64%) individuals with a crude event rate of 3.51 (95% CI, 3.49-3.52) per 1,000 person-years. Compared to a baseline SBP of 120 to 129 mm Hg, HRs for incident CKD G3-G5 for the<110, 110 to 119, 130 to 139, and≥140 mm Hg categories were 0.84 (95% CI, 0.82-0.85), 0.92 (95% CI, 0.91-0.94), 1.11 (95% CI, 1.09-1.12), and 1.30 (95% CI, 1.28-1.31), respectively. For time-updated SBPs, corresponding HRs were 0.57 (95% CI, 0.56-0.59), 0.79 (95% CI, 0.78-0.80), 1.58 (95% CI, 1.55-1.60), and 2.49 (95% CI, 2.45-2.53), respectively. Treated as a continuous exposure, each 10-mm Hg higher SBP was associated with 35% higher risk for incident CKD G3-G5 (95% CI, 1.35-1.36).

LIMITATIONS

Use of International Classification of Diseases codes to assess comorbid condition burden; residual confounding, and potential selection bias cannot be excluded.

CONCLUSIONS

In this large national cohort study, higher SBPs were associated with higher risk for incident CKD G3-G5. These findings support evaluation of SBP-lowering strategies to reduce the development of CKD.

Impact of residual kidney function on hemodialysis adequacy and patient survival

Background

Both dialysis dose and residual kidney function (RKF) contribute to solute clearance and are associated with outcomes in hemodialysis patients. We hypothesized that the association between dialysis dose and mortality is attenuated with greater RKF.

Methods

Among 32 251 incident hemodialysis patients in a large US dialysis organization (2007-11), we examined the interaction between single-pool Kt/V (spKt/V) and renal urea clearance (rCLurea) levels in survival analyses using multivariable Cox proportional hazards regression model.

Results

The median rCLurea and mean baseline spKt/V were 3.06 [interquartile range (IQR) 1.74-4.85] mL/min/1.73 m2 and 1.32 ± 0.28, respectively. A total of 7444 (23%) patients died during the median follow-up of 1.2 years (IQR 0.5-2.2 years) with an incidence of 15.4 deaths per 100 patient-years. The Cox model with adjustment for case-mix and laboratory variables showed that rCLurea modified the association between spKt/V and mortality (Pinteraction = 0.03); lower spKt/V was associated with higher mortality among patients with low rCLurea (i.e. <3  mL/min/1.73 m2) but not among those with higher rCLurea. The adjusted mortality hazard ratios (aHRs) and 95% confidence intervals of the low (<1.2) versus high (≥1.2) spKt/V were 1.40 (1.12-1.74), 1.21 (1.10-1.33), 1.06 (0.98-1.14), and 1.00 (0.93-1.08) for patients with rCLurea of 0.0, 1.0, 3.0 and 6.0 mL/min/1.73 m2, respectively.

Conclusions

Incident hemodialysis patients with substantial RKF do not exhibit the expected better survival at higher hemodialysis doses. RKF levels should be taken into account when deciding on the dose of dialysis treatment among incident hemodialysis patients.

The Effect of Automated versus Continuous Ambulatory Peritoneal Dialysis on Mortality Risk in China

Background

There is an emerging practice pattern of automated peritoneal dialysis (APD) in China. We report on outcomes compared to continuous ambulatory peritoneal dialysis (CAPD) in a Chinese cohort.

Methods

Data were sourced from the Baxter Healthcare (China) Investment Co. Ltd Patient Support Program database, comprising an inception cohort commencing PD between 1 January 2005 and 13 August 2015. We used time-dependent cause-specific Cox proportional hazards and Fine-Gray competing risks (kidney transplantation, change to hemodialysis) models to estimate relative mortality risk between APD and CAPD. We adjusted or matched for age, gender, employment, insurance, primary renal disease, size of PD program, and year of dialysis inception. We used cluster robust regression to account for center effect.

Results

We modeled 100,351 subjects from 1,178 centers over 240,803 patient-years. Of these, 368 received APD at some time. Compared with patients on CAPD, those on APD were significantly younger, more likely to be male, employed, self-paying, and from larger programs. Overall, APD was associated with a hazard ratio (HR) for death of 0.79 (95% confidence interval [CI] 0.64 – 0.97) compared with CAPD in Cox proportional hazards models, and 0.76 (0.62 – 0.95) in Fine-Gray competing risks regression models. There was prominent effect modification by follow-up time: benefit was observed only up to 4 years follow-up, after which risk of death was similar.

Conclusion

Automated peritoneal dialysis is associated with an overall lower adjusted risk of death compared with CAPD in China. Analyses are limited by the likelihood of important selection bias arising from group imbalance, and residual confounding from unavailability of important clinical covariates such as comorbidity and Kt/V.

Number of Daily Peritoneal Dialysis Exchanges and Mortality Risk in a Chinese Population

Background

We report outcomes on ≥ 4 compared with < 4 exchanges/day in a Chinese cohort on continuous ambulatory peritoneal dialysis (CAPD).

Methods

Data were sourced from the Baxter (China) Investment Co. Ltd Patient Support Program database, comprising an inception cohort commencing CAPD between 1 January 2005 and 13 August 2015. We used cause-specific Cox proportional hazards and Fine-Gray competing risks (kidney transplantation, change to hemodialysis) models to estimate mortality risk on ≥ 4 compared with < 4 exchanges/day. We matched or adjusted for age, gender, employment, insurance, primary renal disease, size of CAPD program, year of dialysis inception, and treatment center.

Results

We modeled 100,022 subjects from 1,177 centers over 239,876 patient-years. Of these subjects, 43,185 received < 4 exchanges/day and 56,837 ≥ 4 exchanges/day. The proportion of patients on < 4 exchanges/day varied widely between centers. Those on < 4 exchanges/day were significantly older, more often female, of unknown employment, and from rural China. In the various models, ≥ 4 exchanges/day was associated with a significantly lower risk of death by 30% – 35% compared with < 4 exchanges/day. This beneficial effect was greatest in younger and rural patients.

Conclusions

In this Chinese CAPD cohort, ≥ 4 exchanges/day was associated with significantly lower mortality risk than < 4 exchanges/day. Analyses are limited by residual confounding from unavailability of important prognostic covariates (e.g., comorbidity, socioeconomic factors) and data on residual renal function, peritoneal clearance, and transport status with which to judge the clinical appropriateness of CAPD prescription. Nonetheless, our study indicates this area as a high priority for further detailed study.

Association of Dose and Frequency on the Survival of Patients on Maintenance of Hemodialysis in China: A Kaplan-Meier and Cox-Proportional Hazard Model Analysis

Background

Dialysis frequency and dose are controversial prognostic factors of hemodialysis morbidity and mortality. The aim of this study was to find out the effect of frequency and dosage of dialysis on mortality and survival in a group of Chinese hemodialysis patients.

Material/Methods

In total, 183 patients seen from February 2008 to January 2018, who were on maintenance hemodialysis for at least 3 months, were included in the study cohort. An anonymized database of age, gender, diabetic status, comorbidities, date of initiation of dialysis, hematological characters, biochemical variables, and status of survived or died was established from DICOM (Digital Imaging and Communications in Medicine) files of patients. Kaplan-Meier and Cox-proportional hazard model was used for calculation of survival over time at 95% confidence level.

Results

Overall, the 10-year survival rate was 27%. Kaplan-Meier analysis showed patient survival as 94% at one-year, 59% at 5-years, and 27% at 10-years. Hemoglobin, serum albumin, calcium, potassium, phosphorous, calcium-phosphorous-products, and hemodialysis frequency and the dose had a significant effect on survival. Cox regression proportional hazard model showed that patients with serum albumin level of >4 g/dL were better associated with survival. Patients who underwent twice-weekly hemodialysis had 4.26 times less chance of survival as compared to patients with thrice-weekly hemodialysis. A higher dialysis dose of >1.2 spKt/V offered better survival as compared to a lower dose of <1.2 spKt/V.

Conclusions

Hypoalbuminemia, hemodialysis time, and hemodialysis frequency were significantly associated with mortality.

The Obesity Paradox in Kidney Disease: How to Reconcile it with Obesity Management

Obesity, a risk factor for de novo chronic kidney disease (CKD), confers survival advantages in advanced CKD. This so-called obesity paradox is the archetype of the reverse epidemiology of cardiovascular risks, in addition to the lipid, blood pressure, adiponectin, homocysteine, and uric acid paradoxes. These paradoxical phenomena are in sharp contradistinction to the known epidemiology of cardiovascular risks in the general population. In addition to advanced CKD, the obesity paradox has also been observed in heart failure, chronic obstructive lung disease, liver cirrhosis, and metastatic cancer, as well as in the elderly. These are populations in whom protein-energy wasting and inflammation are strong predictors of early death. Both larger muscle mass and higher body fat provide longevity in these patients, whereas thinner body habitus and weight loss are associated with higher mortality. Muscle mass appears to be superior to body fat in conferring an even greater survival. The obesity paradox may be the result of a time discrepancy between competing risk factors, i.e., overnutrition as the long-term killer versus undernutrition as the short-term killer. Hemodynamic stability of obesity, lipoprotein defense against circulating endotoxins, protective cytokine profiles, toxin sequestration of fat mass, and antioxidation of muscle may play important roles. Despite claims that obesity paradox is a statistical fallacy and a result of residual confounding, the consistency of data and other causality clues suggest a high biologic plausibility. Examining the causes and consequences of the obesity paradox may help discover important pathophysiologic mechanisms leading to improved outcomes in patients with CKD.

Test of the recommended dialysis dose on one-year mortality of nondiabetic maintenance hemodialysis patients; observations from a single dialysis unit

BACKGROUND

The optimal delivered dialysis dose has been of a great interest for the last three decades, though a clear cut point has not been reached yet. We aimed to evaluate the relationship between one-year mortality and the delivered dialysis dose, which was recommended by Kidney Disease Outcomes Quality Initiative (KDOQI), in our maintenance hemodialysis (MHD) patients.

METHODS

This was a single center, prospective observational study with one year of follow-up. Patients with extremes of age, BMI, residual renal function, diabetes mellitus, severe infection malignancy, and recent hospitalization within the last three months were excluded. Demographic, anthropometric, laboratory, and outcome data (mortality as the primary) were prospectively collected. Patients were classified into two groups according to baseline spKt/V levels; group 1 (n = 20): spKt/V ≤ 1.4, group 2 (n = 60): spKt/V > 1.4.

RESULTS

Median (IQR) age and hemodialysis vintage of all patients (M/F: 41/39) were 49.5 (29) years and 60 (94) months, respectively. Both groups had similar characteristics, with the exception of significantly higher BMI (24 vs. 21.7, p = 0.012), serum creatinine and uric acids, and lower spKt/V (1.30 vs. 1.71, p < 0.001) in group 1. Overall death occurred in seven (8.75%) patients (5 from group 1 and 2 from group 2). Patients in group 1 had significantly higher one-year mortality rate and shorter survival time (25% vs. 3.3%, p = 0.003 and 43.9 vs. 47.3 weeks, p = 0.003, respectively).

CONCLUSIONS

Higher spKt/V (>1.4) was associated with a lower one-year mortality in this small cohort of patients.

Examining the robustness of the obesity paradox in maintenance hemodialysis patients: a marginal structural model analysis

BACKGROUND

The inverse association between body mass index (BMI) and mortality observed in patients treated with maintenance hemodialysis (MHD), also known as the obesity paradox, may be a result of residual confounding. Marginal structural model (MSM) analysis, a technique that accounts for time-varying confounders, may be more appropriate to investigate this association. We hypothesize that after applying MSM, the inverse association between BMI and mortality in MHD patients is attenuated.

METHODS

We examined the associations between BMI and all-cause mortality among 123 624 adult MHD patients treated during 2001-6. We examined baseline and time-varying BMI using Cox proportional hazards models and MSM while considering baseline and time-varying covariates, including demographics, comorbidities and markers of malnutrition and inflammation.

RESULTS

The patients included 45% women and 32% African Americans with a mean age of 61(SD 15) years. In all models, BMI showed a linear incremental inverse association with mortality. Compared with the reference (BMI 25 to <27.5 kg/m(2)), a BMI of <18 kg/m(2) was associated with a 3.2-fold higher death risk [hazard ratio (HR) 3.17 (95% CI 3.05-3.29)], and mortality risks declined with increasing BMI with the greatest survival advantage of 31% lower risk [HR 0.69 (95% CI 0.64-0.75)] observed with a BMI of 40 to <45 kg/m(2).

CONCLUSIONS

The linear inverse relationship between BMI and mortality is robust across models including MSM analyses that more completely account for time-varying confounders and biases.