US Renal Data System 2016 Annual Data Report: Epidemiology of Kidney Disease in the United States

Dialysis Modality and Incident Atrial Fibrillation in Older Patients With ESRD

RATIONALE & OBJECTIVE

Atrial fibrillation (AF) is common in patients with kidney failure treated by maintenance dialysis. Whether the incidence of AF differs between patients receiving hemodialysis and peritoneal dialysis is uncertain.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Using the US Renal Data System, we identified older patients (≥67 years) with Medicare Parts A and B who initiated dialysis therapy (1996-2011) without a diagnosis of AF during the prior 2 years.

EXPOSURE

Dialysis modality at incident end-stage renal disease (ESRD) and maintained for at least 90 days.

OUTCOME

Patients were followed up for 36 months or less for a new diagnosis of AF.

ANALYTICAL APPROACH

Time-to-event analysis using multivariable Cox proportional hazards regression to estimate cause-specific HRs while censoring at modality switch, kidney transplantation, or death.

RESULTS

Overall, 271,722 older patients were eligible; 17,487 (6.9%) were treated with peritoneal dialysis, and 254,235 (93.1%), with hemodialysis, at the onset of ESRD. During 406,225 person-years of follow-up, 69,705 patients had AF newly diagnosed. Because the proportionality assumption was violated, we introduced an interaction term between time (first 90 days vs thereafter) and modality. The AF incidence during the first 90 days was 187/1,000 person-years on peritoneal dialysis therapy and 372/1,000 person-years on hemodialysis therapy. Patients on peritoneal dialysis therapy had an adjusted 39% (95% CI, 34%-43%) lower incidence of AF than those on hemodialysis therapy. From day 91 onward, AF incidence was ∼140/1,000 person-years with no major difference between modalities.

LIMITATIONS

Residual confounding from unobserved differences between exposure groups; ascertainment of AF from billing claims; study of first modality may not generalize to patients switching modalities; uncertain generalizability to younger patients.

CONCLUSIONS

Although patients initiating dialysis therapy using peritoneal dialysis had a lower AF incidence during the first 90 days of ESRD, there was no major difference in AF incidence thereafter. The value of interventions to reduce the early excess AF risk in patients receiving hemodialysis may warrant further study.

Black-White Difference in the Impact of Long-Term Blood Pressure From Childhood on Adult Renal Function: The Bogalusa Heart Study

BACKGROUND

To examine racial difference in the impact of long-term burden of blood pressure (BP) from childhood on adult renal function between middle-aged blacks and whites.

METHODS

The study cohort consisted of 1,646 whites and 866 blacks aged 20-51 years at follow-up who had BP measured at least 4 times since childhood, with a mean follow-up period of 25.3 years. The area under the curve (AUC) was calculated as a measure of long-term burden of BP from childhood to adulthood. Estimated glomerular filtration rate (eGFR) was calculated based on serum creatinine to assess renal function in adulthood.

RESULTS

Black vs. white adults had significantly higher values of eGFR and long-term burden of systolic BP for both males and females. In multivariable linear regression analyses, adjusting for sex, adult age, body mass index, smoking, and alcohol use, adult eGFR was significantly and negatively associated with adult systolic BP (standardized regression coefficient [β] = -0.10, P = 0.005) and diastolic BP (β = -0.11, P = 0.003) in blacks, but not in whites. The total BP AUC values were also significantly and negatively associated with adult eGFR (β = -0.10, P = 0.005 for systolic BP and β = -0.09, P = 0.013 for diastolic BP) in blacks only. Childhood BP was not significantly associated with adult eGFR in blacks and whites.

CONCLUSIONS

These findings suggest that black-white disparities in the influence of elevated BP on the development of renal dysfunction occur in middle adulthood, which underscores the importance of BP control in the black population.

Association of Serum Aluminum Levels with Mortality in Patients on Chronic Hemodialysis

Despite reported evidence on the relationship between higher serum aluminum levels and poor outcomes in patients on chronic hemodialysis (CHD), the acceptable cutoff value of serum aluminum for mortality remains unclear. A retrospective observational cohort study with 636 Taiwanese patients on CHD was conducted to investigate the impact of serum aluminum levels on mortality. The predictors were bivariate serum aluminum level (<6 and ≥6 ng/mL) and the Outcomes were all-cause and cardiovascular (CV) mortality. During the mean follow-up of 5.3 ± 2.9 years, 253 all-cause and 173 CV deaths occurred. Crude analysis showed that a serum aluminum level of ≥6 ng/mL was a significant predictor of all-cause [hazard ratio (HR), 1.80; 95% confidence interval (CI), 1.40–2.23] and CV (HR, 1.84; 95% CI, 1.36–2.50) mortality. After multivariable adjustment, the serum aluminum level of ≥6 ng/mL remained a significant predictor of all-cause mortality (HR, 1.37, 95% CI, 1.05–1.81) but became insignificant for CV mortality (HR, 1.29; 95% CI, 0.92–1.81). Therefore, our study revealed that a serum aluminum level of ≥6 ng/mL was independently associated with all-cause death in patients on CHD, suggesting that early intervention for aluminum level in patients on CHD might be beneficial even in the absence of overt aluminum toxicity.

CureGN Study Rationale, Design, and Methods: Establishing a Large Prospective Observational Study of Glomerular Disease

RATIONALE & OBJECTIVES

Glomerular diseases, including minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, and immunoglobulin A (IgA) nephropathy, share clinical presentations, yet result from multiple biological mechanisms. Challenges to identifying underlying mechanisms, biomarkers, and new therapies include the rarity of each diagnosis and slow progression, often requiring decades to measure the effectiveness of interventions to prevent end-stage kidney disease (ESKD) or death.

STUDY DESIGN

Multicenter prospective cohort study.

SETTING & PARTICIPANTS

Cure Glomerulonephropathy (CureGN) will enroll 2,400 children and adults with minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy (including IgA vasculitis) and a first diagnostic kidney biopsy within 5 years. Patients with ESKD and those with secondary causes of glomerular disease are excluded.

EXPOSURES

Clinical data, including medical history, medications, family history, and patient-reported outcomes, are obtained, along with a digital archive of kidney biopsy images and blood and urine specimens at study visits aligned with clinical care 1 to 4 times per year.

OUTCOMES

Patients are followed up for changes in estimated glomerular filtration rate, disease activity, ESKD, and death and for nonrenal complications of disease and treatment, including infection, malignancy, cardiovascular, and thromboembolic events.

ANALYTICAL APPROACH

The study design supports multiple longitudinal analyses leveraging the diverse data domains of CureGN and its ancillary program. At 2,400 patients and an average of 2 years' initial follow-up, CureGN has 80% power to detect an HR of 1.4 to 1.9 for proteinuria remission and a mean difference of 2.1 to 3.0mL/min/1.73m² in estimated glomerular filtration rate per year.

LIMITATIONS

Current follow-up can only detect large differences in ESKD and death outcomes.

CONCLUSIONS

Study infrastructure will support a broad range of scientific approaches to identify mechanistically distinct subgroups, identify accurate biomarkers of disease activity and progression, delineate disease-specific treatment targets, and inform future therapeutic trials. CureGN is expected to be among the largest prospective studies of children and adults with glomerular disease, with a broad goal to lessen disease burden and improve outcomes.

Management of Traditional Cardiovascular Risk Factors in CKD: What Are the Data?

Patients with non-dialysis-dependent chronic kidney disease (NDD-CKD) are 10 times more likely to die of cardiovascular (CV) diseases than the general population, and dialysis-dependent patients are at even higher risk. Although traditional CV risk factors are highly prevalent in individuals with CKD, these patients were often excluded from studies targeting modification of these risks. Although treatment of hypertension is beneficial in CKD, the best target blood pressure has not been established. Trial data showed that renin-angiotensin-aldosterone blockade may prevent CV events in patients with CKD. The risks of aspirin may equal the benefits in NDD-CKD samples, and there are no trials testing aspirin in dialysis-dependent patients. Lipid-lowering therapy improves CV outcomes in NDD-CKD, but not in dialysis-dependent patients. Strict glycemic control prevents CV events in nonalbuminuric individuals, but showed no benefit in those with baseline albuminuria with albumin excretion > 300mg/g, and there are no data in dialysis-dependent patients. Data for lifestyle modifications, such as weight loss, physical activity, and smoking cessation, are mostly observational and extrapolated from non-CKD samples. This comprehensive review summarizes the best existing evidence and current clinical guidelines for modification of traditional risk factors for the prevention of CV events in patients with CKD and identifies knowledge gaps.

Bioengineering Organs for Blood Detoxification

For patients with severe kidney or liver failure the best solution is currently organ transplantation. However, not all patients are eligible for transplantation and due to limited organ availability, most patients are currently treated with therapies using artificial kidney and artificial liver devices. These therapies, despite their relative success in preserving the patients' life, have important limitations since they can only replace part of the natural kidney or liver functions. As blood detoxification (and other functions) in these highly perfused organs is achieved by specialized cells, it seems relevant to review the approaches leading to bioengineered organs fulfilling most of the native organ functions. There, the culture of cells of specific phenotypes on adapted scaffolds that can be perfused takes place. In this review paper, first the functions of kidney and liver organs are briefly described. Then artificial kidney/liver devices, bioartificial kidney devices, and bioartificial liver devices are focused on, as well as biohybrid constructs obtained by decellularization and recellularization of animal organs. For all organs, a thorough overview of the literature is given and the perspectives for their application in the clinic are discussed.

Urine inositol pentakisphosphate 2-kinase and changes in kidney structure in early diabetic kidney disease in type 1 diabetes

We examined the association of urine inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IPP2K) with the presence and progression of diabetic kidney disease (DKD) lesions. Urine IPP2K was measured at baseline by quantitative liquid chromatography-mass spectrometry in 215 participants from the Renin-Angiotensin System Study who had type 1 diabetes and were normoalbuminuric and normotensive with normal or increased glomerular filtration rate (GFR). Urine IPP2K was detectable in 166 participants. Participants with IPP2K below the limit of quantification (LOQ) were assigned concentrations of LOQ/√2. All concentrations were then standardized to urine creatinine (Cr) concentration. Kidney morphometric data were available from biopsies at baseline and after 5 yr. Relationships of IPP2K/Cr with morphometric variables were assessed by linear regression after adjustment for age, sex, diabetes duration, hemoglobin A_1c, mean arterial pressure, treatment assignment, and, for longitudinal analyses, baseline structure. Baseline mean age was 29.7 yr, mean diabetes duration 11.2 yr, median albumin excretion rate 5.0 μg/min, and mean iohexol GFR 129 ml·min^-1·1.73m^-2. Higher IPP2K/Cr was associated with higher baseline peripheral glomerular total filtration surface density [Sv(PGBM/glom), tertile 3 vs. tertile 1 β = 0.527, P = 0.011] and with greater preservation of Sv(PGBM/glom) after 5 yr ( tertile 3 vs. tertile 1 β = 0.317, P = 0.013). Smaller increases in mesangial fractional volume ( tertile 3 vs. tertile 1 β = -0.578, P = 0.018) were observed after 5 yr in men with higher urine IPP2K/Cr concentrations. Higher urine IPP2K/Cr is associated with less severe kidney lesions at baseline and with preservation of kidney structure over 5 yr in individuals with type 1 diabetes and no clinical evidence of DKD at baseline.

Effects of parathyroidectomy on blood bone markers and heart rate variability in patients with stage 5 chronic kidney disease

PURPOSE

Decreased heart rate variability (HRV) is closely related to abnormal cardiac autonomic nervous function, especially sympathetic hyperactivity, which intensifies the risk of cardiovascular events and sudden death. HRV parameters are lower in chronic kidney disease (CKD) and parathyroidectomy (PTX) can improve these abnormalities in severe secondary hyperparathyroidism (SHPT) patients. However, few studies have evaluated correlations between circulating bone markers and HRV in CKD patients.

METHODS

We conducted a cross-sectional study including 134 stage 5 CKD patients with 100 controls and a prospective study of 29 PTX patients with follow-up. Circulating bone biomarkers included: (1) intact parathyroid hormone (iPTH) as bone remodeling regulator; (2) bone-specific alkaline phosphatase (BAP), representing bone formation; (3) tartrate-resistant acid phosphatase 5b (TRACP-5b), indicating bone resorption; and (4) bone-derived hormone, fibroblast growth factor 23 (FGF23).

RESULTS

Stage 5 CKD patients had higher circulating iPTH, BAP, TRACP-5b, and FGF23 than controls and these bone markers were significantly elevated in SHPT patients. Baseline iPTH, BAP, and lnFGF23 were independently associated with HRV in CKD patients. After PTX with a follow-up (median interval: 6.7 months), high blood iPTH, BAP, TRACP-5b, FGF23, and attenuated HRV were ameliorated. Furthermore, improved HRV indices were associated with reduced iPTH, BAP, TRACP-5b, and FGF23.

CONCLUSIONS

Circulating bone markers are correlated with HRV in CKD 5 patients and PTX can improve decreased HRV, which are associated with corrected bone markers in severe SHPT patients. Thus, we propose that PTH increases sympathetic tone and both high circulating PTH levels and sympathetic hyperactivity increase bone turnover, and that the products of bone turnover influence HRV.

Modeling the impact of obesity on the lifetime risk of chronic kidney disease in the United States using updated estimates of GFR progression from the CRIC study

Rationale & objective

As the prevalence of obesity continues to rise in the United States, it is important to understand its impact on the lifetime risk of chronic kidney disease (CKD).

Study design

The CKD Health Policy Model was used to simulate the lifetime risk of CKD for those with and without obesity at baseline. Model structure was updated for glomerular filtration rate (GFR) decline to incorporate new longitudinal data from the Chronic Renal Insufficiency Cohort (CRIC) study.

Setting and population

The updated model was populated with a nationally representative cohort from National Health and Nutrition Examination Survey (NHANES).

Outcomes

Lifetime risk of CKD, highest stage and any stage.

Model, perspective, & timeframe

Simulation model following up individuals from current age through death or age 90 years.

Results

Lifetime risk of any CKD stage was 32.5% (95% CI 28.6%–36.3%) for persons with normal weight, 37.6% (95% CI 33.5%–41.7%) for persons who were overweight, and 41.0% (95% CI 36.7%–45.3%) for persons with obesity at baseline. The difference between persons with normal weight and persons with obesity at baseline was statistically significant (p<0.01). Lifetime risk of CKD stages 4 and 5 was higher for persons with obesity at baseline (Stage 4: 2.1%, 95% CI 0.9%–3.3%; stage 5: 0.6%, 95% CI 0.0%–1.1%), but the differences were not statistically significant (stage 4: p = 0.08; stage 5: p = 0.23).

Limitations

Due to limited data, our simulation model estimates are based on assumptions about the causal pathways from obesity to CKD, diabetes, and hypertension.

Conclusions

The results of this study indicate that obesity may have a large impact on the lifetime risk of CKD. This is important information for policymakers seeking to set priorities and targets for CKD prevention and treatment.

Early Mortality Among Peritoneal Dialysis and Hemodialysis Patients Who Transitioned With an Optimal Outpatient Start

Introduction

Lower early mortality observed in peritoneal dialysis (PD) compared with hemodialysis (HD) may be due to differential pre–end-stage renal disease (ESRD) care and the stable setting of transition to dialysis where PD starts are more frequently outpatient rather than during an unscheduled hospitalization. To account for these circumstances, we compared early mortality among a matched cohort of PD and HD patients who had optimal and outpatient starts.

Methods

Retrospective cohort study performed among patients with chronic kidney disease (CKD) who transitioned to ESRD from 1 January 2002 to 31 March 2015 with an optimal start in an outpatient setting. Optimal start defined as (i) HD with an arteriovenous graft or fistula or (ii) PD. Propensity score modeling factoring age, race, sex, comorbidities, estimated glomerular filtration rate (eGFR) level, and change in eGFR before ESRD was used to create a matched cohort of HD and PD. All-cause mortality was compared at 6 months, 1 year, and 2 years posttransition to ESRD.

Results

Among 2094 patients (1398 HD and 696 PD) who had optimal outpatient transition to ESRD, 541 HD patients were propensity score–matched to 541 PD patients (caliper distance <0.001). All-cause mortality odds ratios (OR) in PD compared with HD were 0.79 (0.39–1.63), 0.73 (0.43–1.23), and 0.88 (0.62–1.26) for 6 months, 1 year, and 2 years, respectively. Time-varying analysis accounting for modality switch (19% PD, 1.9% HD) demonstrated a mortality hazard ratio of 0.94 (0.70–1.24)

Conclusion

Among an optimal start CKD cohort that transitioned to ESRD on an outpatient basis, we found no evidence of differences in early mortality between PD and HD.

Sex Disparities in Risk of Mortality Among Children With ESRD

RATIONALE & OBJECTIVE

In the general population, girls have lower mortality risk compared with boys. However, few studies have focused on sex differences in survival and in access to kidney transplantation among children with end-stage kidney disease.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Children aged 2 to 19 years registered in the US Renal Data System who started renal replacement therapy (RRT) between 1995 and 2011.

PREDICTOR

Study participant sex.

OUTCOME

Time to death and time to kidney transplantation.

ANALYTICAL APPROACH

We used adjusted Cox models to examine the association between sex and all-cause mortality. We used Fine-Gray models to examine the association between sex and kidney transplantation accounting for the competing risk for death.

RESULTS

We included 14,024 children, of whom 1,880 died during a median 7.1 years of follow-up. In adjusted analyses, the HR for death was higher for girls (HR, 1.36; 95% CI, 1.25-1.50) than boys. When we further adjusted our survival models for transplantation as a time-dependent covariate, the hazard rate of death in girls was partially attenuated but remained statistically significantly higher than that for boys (HR, 1.28; 95% CI, 1.17-1.41). Girls were also less likely to receive a kidney transplant than boys (adjusted subdistribution HR, 0.91; 95% CI, 0.88-0.95) in analyses treating death as a competing risk.

LIMITATIONS

Lack of data for disease course before the onset of RRT and observational study data.

CONCLUSIONS

The mortality rate was substantially higher for girls than for boys treated with RRT. Access to transplantation was lower for girls than boys, but differences in transplantation access accounted for only a small proportion of the survival differences by sex.

Home hemodialysis treatment and outcomes: retrospective analysis of the Knowledge to Improve Home Dialysis Network in Europe (KIHDNEy) cohort

Background

Utilization of home hemodialysis (HHD) is low in Europe. The Knowledge to Improve Home Dialysis Network in Europe (KIHDNEy) is a multi-center study of HHD patients who have used a transportable hemodialysis machine that employs a low volume of lactate-buffered, ultrapure dialysate per session. In this retrospective cohort analysis, we describe patient factors, HHD prescription factors, and biochemistry and medication use during the first 6 months of HHD and rates of clinical outcomes thereafter.

Methods

Using a standardized digital form, we recorded data from 7 centers in 4 Western European countries. We retained patients who completed ≥6 months of HHD. We summarized patient and HHD prescription factors with descriptive statistics and used mixed modeling to assess trends in biochemistry and medication use. We also estimated long-term rates of kidney transplant and death.

Results

We identified 129 HHD patients; 104 (81%) were followed for ≥6 months. Mean age was 49 years and 66% were male. Over 70% of patients were prescribed 6 sessions per week, and the mean treatment duration was 15.0 h per week. Median HHD training duration was 2.5 weeks. Mean standard Kt/V_urea was nearly 2.7 at months 3 and 6. Pre-dialysis biochemistry was generally stable. Between baseline and month 6, mean serum bicarbonate increased from 23.1 to 24.1 mmol/L (P = 0.01), mean serum albumin increased from 36.8 to 37.8 g/L (P = 0.03), mean serum C-reactive protein increased from 7.3 to 12.4 mg/L (P = 0.05), and mean serum potassium decreased from 4.80 to 4.59 mmol/L (P = 0.01). Regarding medication use, the mean number of antihypertensive medications fell from 1.46 agents per day at HHD initiation to 1.01 agents per day at 6 months (P < 0.001), but phosphate binder use and erythropoiesis-stimulating agent dose were stable. Long-term rates of kidney transplant and death were 15.3 and 5.4 events per 100 patient-years, respectively.

Conclusions

Intensive HHD with low-flow dialysate delivers adequate urea clearance and good biochemical outcomes in Western European patients. Intensive HHD coincided with a large decrease in antihypertensive medication use. With relatively rapid training, HHD should be considered in more patients.

Prevalence, socio-demographic characteristics, and comorbid health conditions in pre-dialysis chronic kidney disease: results from the Manitoba chronic kidney disease cohort

Background

Chronic Kidney Disease (CKD) is common and its prevalence has increased steadily over several decades. Monitoring of rates and severity of CKD across populations is critical for policy development and resource planning. Administrative health data alone has insufficient sensitivity for this purpose, therefore utilizing population level laboratory data and novel methodology is required for population-based surveillance. The aims of this study include a) develop the Manitoba CKD Cohort, b) estimate CKD prevalence, c) identify individuals at high risk of progression to kidney failure and d) determine rates of comorbid health conditions.

Methods

Administrative health and laboratory data from April 1996 to March 2012 were linked from the data repository at the Manitoba Centre for Health Policy. Prevalence was estimated using three methods: a) all CKD cases in administrative and laboratory databases; b) all CKD cases captured only through the laboratory data; c) and the capture-recapture method. Patients were stratified by risk by estimated Glomerular Filtration Rate (eGFR) and albuminuria based on Kidney Disease Improving Global Outcomes (KDIGO) criteria. For comorbid health conditions, the counts were modelled using a Generalized Linear Model (GLM).

Results

The Manitoba CKD Cohort consisted of 55,876 people with CKD. Of these, 18,342 were identified using administrative health data, 27,393 with laboratory data, and 10,141 people were identified in both databases. The CKD prevalence was 5.6% using the standard definition, 10.6% using only people captured by the laboratory data and 10.6% using the capture-recapture method. Of the identified cases, 46% were at high risk of progression to end-stage kidney disease (ESKD), 41% were at low risk and 13% were not classified, due to unavailable laboratory data. High risk cases had a higher burden of comorbid conditions.

Conclusion

This study reports a novel methodology for population based CKD surveillance utilizing a combination of administrative health and laboratory data. High rates of CKD at risk of progression to ESKD have been identified with this approach. Given the high rates of comorbidity and associated healthcare costs, these data can be used to develop a targeted and comprehensive public health surveillance strategy that encompass a range of interrelated chronic diseases.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1058-3) contains supplementary material, which is available to authorized users.

Validation of a Novel Modified Aptamer-Based Array Proteomic Platform in Patients with End-Stage Renal Disease

End stage renal disease (ESRD) is characterized by complex metabolic abnormalities, yet the clinical relevance of specific biomarkers remains unclear. The development of multiplex diagnostic platforms is creating opportunities to develop novel diagnostic and therapeutic approaches. SOMAscan is an innovative multiplex proteomic platform which can measure >1300 proteins. In the present study, we performed SOMAscan analysis of plasma samples and validated the measurements by comparison with selected biomarkers. We compared concentrations of SOMAscan-measured prostate specific antigen (PSA) between males and females, and validated SOMAscan concentrations of fibroblast growth factor 23 (FGF23), FGF receptor 1 (FGFR1), and FGFR4 using Enzyme-Linked immunosorbent assay (ELISA). The median (25th and 75th percentile) SOMAscan PSA level in males and females was 4304.7 (1815.4 to 7259.5) and 547.8 (521.8 to 993.4) relative fluorescence units (p = 0.002), respectively, suggesting biological plausibility. Pearson correlation between SOMAscan and ELISA was high for FGF23 (R = 0.95, p < 0.001) and FGFR4 (R = 0.69, p < 0.001), indicating significant positive correlation, while a weak correlation was found for FGFR1 (R = 0.13, p = 0.16). In conclusion, there is a good to near-perfect correlation between SOMAscan and standard immunoassays for FGF23 and FGFR4, but not for FGFR1. This technology may be useful to simultaneously measure a large number of plasma proteins in ESRD, and identify clinically important prognostic markers to predict outcomes.

Association of Continuation of Statin Therapy Initiated Before Transition to Chronic Dialysis Therapy With Mortality After Dialysis Initiation

IMPORTANCE

De novo statin therapy in patients receiving chronic dialysis has failed to demonstrate cardiovascular (CV) protection in randomized clinical trials and thus is not recommended by current guidelines. However, current guidelines recommend the continuation of statin therapy if initiated before transition to dialysis.

OBJECTIVE

To investigate whether the continuation of statins from advanced chronic kidney disease into the dialysis therapy period is associated with improved survival.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of US veterans transitioning to dialysis between October 1, 2007, and March 30, 2014. Participants were 14 298 US veterans who were receiving statins during the 12-month period before transition to dialysis and survived the first year of dialysis. Data analysis was conducted between August 2, 2017, and June 28, 2018.

EXPOSURES

Patients were characterized as statin continuers (n = 11 936) if statin therapy was continued for at least 6 months during the first year after dialysis initiation and as statin discontinuers (n = 2362) if therapy with statins was stopped or no statin therapy was received in the year posttransition.

MAIN OUTCOMES AND MEASURES

Associations of statin continuation with 12-month all-cause mortality and CV mortality after 1 year of dialysis initiation were examined using Cox proportional hazards regression models adjusted for demographics and comorbidities.

RESULTS

The mean (SD) age of the cohort was 71 (10) years; the cohort was 96.7% (n = 13 828) male and 21.3% (n = 3043) African American, and 74.6% (n = 10 627) had diabetes. The 12-month all-cause mortality and CV mortality rates after 1 year of transition to dialysis were lower in statin continuers: deaths per 100 person-years were 21.9 (95% CI, 20.9-22.8) and 8.1 (95% CI, 7.5-8.6) in statin continuers vs 30.3 (95% CI, 27.8-32.8) and 9.8 (95% CI, 8.3-11.2) in statin discontinuers. Moreover, lower all-cause mortality and CV mortality risks with statin continuation persisted in adjusted analyses, with hazard ratios of 0.72 (95% CI, 0.66-0.79) and 0.82 (95% CI, 0.69-0.96), respectively. Associations were similar across subgroups, including age, race, and diabetes status.

CONCLUSIONS AND RELEVANCE

In this study, the continuation of statin therapy after transition to dialysis was associated with reduced all-cause mortality and CV mortality. The study findings suggest that future studies are needed to examine potential CV benefits of continuing statin therapy after dialysis initiation.

Risk factors of chronic kidney diseases in Chinese adults with type 2 diabetes

In this study we conducted a cross sectional study to comprehensively evaluated the risk factors of chronic kidney disease (CKD) in a large sample of Chinese adults under primary care for type 2 diabetes mellitus (T2DM). We investigated the risk factors associated with the prevalence of CKD in adults with T2DM, who were enrolled in the Risk Factor Assessment and Management Programme for Patients with Diabetes Mellitus (RAMP-DM) of Hong Kong from July 2014 to June 2017. We collected the individual data of 31,574 subjects, with mean age of 63.0 (±10.8) years and mean DM duration of 7.4 (±6.4) years. Of them 9,386 (29.7%) had CKD and 7,452 (23.6%) had micro- or macro-albuminuria. After adjustment for multiple demographic and lifestyle confounders, we identified several modifiable risk factors associated with higher rate of CKD: obesity (OR = 1.54), current smoking (OR = 1.33), higher systolic blood pressure (OR = 1.01), dyslipidemia (OR = 1.32 and 0.61 for triglycerides (TG) and high-density lipoprotein cholesterol (HDL-C)), hyperglycemia (OR = 1.11 for HbA1c), diabetic retinopathy (OR = 1.36 and 2.60 for non-sight and sight threatening retinopathy), and stroke (OR = 1.43). The risk factors of lower dialytic blood pressure and coronary heart disease were identified only in men, whereas peripheral arterial disease only in women. In conclusion, several modifiable and gender specific risk factors were significantly associated with higher prevalence of CKD in Chinese adults with T2DM. The high-risk populations identified in this study shall receive regular screening for renal functions to achieve better patient management in primary care settings.

Cognitive Impairment in Non-Dialysis-Dependent CKD and the Transition to Dialysis: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

BACKGROUND

Advanced chronic kidney disease is associated with elevated risk for cognitive impairment. However, it is not known whether and how cognitive impairment is associated with planning and preparation for end-stage renal disease.

STUDY DESIGN

Retrospective observational study.

SETTING & PARTICIPANTS

630 adults participating in the CRIC (Chronic Renal Insufficiency Cohort) Study who had cognitive assessments in late-stage CKD, defined as estimated glome-rular filtration rate ≤ 20mL/min/1.73m2, and subsequently initiated maintenance dialysis therapy.

PREDICTOR

Predialysis cognitive impairment, defined as a score on the Modified Mini-Mental State Examination lower than previously derived age-based threshold scores. Covariates included age, race/ethnicity, educational attainment, comorbid conditions, and health literacy.

OUTCOMES

Peritoneal dialysis (PD) as first dialysis modality, preemptive permanent access placement, venous catheter avoidance at dialysis therapy initiation, and preemptive wait-listing for a kidney transplant.

MEASUREMENTS

Multivariable-adjusted logistic regression.

RESULTS

Predialysis cognitive impairment was present in 117 (19%) participants. PD was the first dialysis modality among 16% of participants (n=100), 75% had preemptive access placed (n=473), 45% avoided using a venous catheter at dialysis therapy initiation (n=279), and 20% were preemptively wait-listed (n=126). Predialysis cognitive impairment was independently associated with 78% lower odds of PD as the first dialysis modality (adjusted OR [aOR], 0.22; 95% CI, 0.06-0.74; P=0.02) and 42% lower odds of venous catheter avoidance at dialysis therapy initiation (aOR, 0.58; 95% CI, 0.34-0.98; P=0.04). Predialysis cognitive impairment was not independently associated with preemptive permanent access placement or wait-listing.

LIMITATIONS

Potential unmeasured confounders; single measure of cognitive function.

CONCLUSIONS

Predialysis cognitive impairment is associated with a lower likelihood of PD as a first dialysis modality and of venous catheter avoidance at dialysis therapy initiation. Future studies may consider addressing cognitive function when testing strategies to improve patient transitions to dialysis therapy.

The directional and non-directional associations of periodontitis with chronic kidney disease: A systematic review and meta-analysis of observational studies

This systematic review aimed to assess the current evidence on the directional and non-directional associations of periodontitis with chronic kidney disease (CKD). Electronic search for observational studies on the association of periodontitis with CKD was performed in MEDLINE, EMBASE, PubMed, Open GREY and Cochrane library up to June 5, 2017. Two reviewers conducted study selection, data collection and assessment of methodological quality using the original and modified Newcastle-Ottawa Scale. Cohort, case-control and cross-sectional studies were included, which clearly defined periodontitis and CKD or reported acceptable clinical parameters of these 2 diseases in adults. Meta-analysis was employed to estimate the pooled odds ratio on the non-directional association and the incidence rate ratio (IRR) for the directional association. Among 2530 potential eligible articles, 47 were finally included. Most of them investigated a non-directional association of periodontitis with CKD, including 7 case-control studies and 38 cross-sectional studies; 24 studies had statistical analysis on the non-directional association and 75% of them reported significant results, which were supported further by the meta-analysis (random: odds ratio = 2.12, P < .001; χ2  = 25.74, I2  = 88.3%). None of the studies focused on the directional association of CKD (as the exposure) with periodontitis (as the outcome), whereas 2 retrospective cohort studies explored a directional association of periodontitis (as the exposure) with CKD (as the outcome) (random: IRR=2.10, P > .05; fixed: IRR=1.76, P < .05; χ2  = 4.65, I2  = 78.3%). Overall, the high heterogeneity of studies limits the significance of these results. There is substantial evidence on the non-directional association of periodontitis with CKD, while there are limited studies on the directional association. Well-designed prospective studies with longer follow-ups in representative communities are needed to clarify the directional association and enhance the quality of the evidence on this topic.

Development and content validity of a hemodialysis symptom patient-reported outcome measure

PURPOSE

To describe the process and preliminary qualitative development of a new symptom-based patient-reported outcome measure (PROM) intended to assess hemodialysis treatment-related physical symptoms.

METHODS

Experienced interviewers conducted concept elicitation and cognitive debriefing interviews with individuals receiving in-center hemodialysis in the United States. Concept elicitation interviews involved eliciting spontaneous reports of symptom experiences and probing to further explore and confirm concepts. We used patient-reported concepts to generate a preliminary symptom PROM. We conducted 3 rounds of cognitive debriefing interviews to evaluate symptom relevance, item interpretability, and draft item structure. We iteratively refined the measure based on cognitive interview findings.

RESULTS

Forty-two adults receiving in-center hemodialysis participated in the concept elicitation interviews. A total of 12 symptoms were reported by > 10% of interviewees. We developed a 13-item initial draft instrument for testing in 3 rounds of cognitive interviews with an additional 52 hemodialysis patients. Participant responses and feedback during cognitive interviews led to changes in symptom descriptions, division of the single item "nausea/vomiting" into 2 distinct items, removal of daily activity interference items, addition of instructions, and clarification about the recall period, among other changes.

CONCLUSIONS

Symptom Monitoring on Renal Replacement Therapy-Hemodialysis (SMaRRT-HD™) is a 14-item PROM intended for use in hemodialysis patents. SMaRRT-HD™ uses a single treatment recall period and a 5-point Likert scale to assess symptom severity. Qualitative interview data provide evidence of its content validity. SMaRRT-HD™ is undergoing additional testing to assess measurement properties and inform measure scoring.

Association of the kidney allocation system with dialysis exposure before deceased donor kidney transplantation by preemptive wait-listing status

BACKGROUND

It is unknown whether the new kidney transplant allocation system (KAS) has attenuated the advantages of preemptive wait-listing as a strategy to minimize pretransplant dialysis exposure.

METHODS

We performed a retrospective study of adult US deceased donor kidney transplant (DDKT) recipients between December 4, 2011-December 3, 2014 (pre-KAS) and December 4, 2014-December 3, 2017 (post-KAS). We estimated pretransplant dialysis durations by preemptive listing status in the pre- and post-KAS periods using multivariable gamma regression models.

RESULTS

Among 65 385 DDKT recipients, preemptively listed recipients (21%, n = 13 696) were more likely to be white (59% vs 34%, P < 0.001) and have private insurance (64% vs 30%, P < 0.001). In the pre- and post-KAS periods, average adjusted pretransplant dialysis durations for preemptively listed recipients were <2 years in all racial groups. Compared to recipients who were listed after starting dialysis, preemptively listed recipients experienced 3.85 (95% Confidence Interval [CI] 3.71-3.99) and 4.53 (95% CI 4.32-4.74) fewer average years of pretransplant dialysis in the pre- and post-KAS periods, respectively (P < 0.001 for all comparisons).

CONCLUSIONS

Preemptively wait-listed DDKT recipients continue to experience substantially fewer years of pretransplant dialysis than recipients listed after dialysis onset. Efforts are needed to improve both socioeconomic and racial disparities in preemptive wait-listing.

Clinical epidemiology of infectious disease among patients with chronic kidney disease

Infectious disease is recognized as an important complication among patients with end-stage renal disease, contributing to excess morbidity and health care costs. However, recent epidemiological studies have revealed that even mild to moderate stages of chronic kidney disease (CKD) substantially increase risk of infection. Regarding underlying mechanisms, evidence suggests various aspects of altered immune response in patients with CKD including impaired function of T cells, B cells and neutrophil. Multiple conditions surrounding CKD, such as older age, diabetes, and cardiovascular disease are important contributors in the increased susceptibility to infection in this population. In addition, several mechanisms impairing immune function have been hypothesized including accumulated uremic toxins, increased oxidative stress, endothelial dysfunction, low-grade inflammation, and mineral and bone disorders. In terms of prevention strategies, influenza and pneumococcal vaccines are most feasible and important. Nevertheless, the extent of vaccine utilization in CKD has not been well documented. In addition, antibody response to vaccination may be reduced in CKD patients, and thus a vaccine delivery strategy (e.g., dose and frequency) may need to be optimized among patients with CKD. Through this review, we demonstrate that infection is a major but underrecognized complication of CKD. As CKD is recognized as a serious public health issue, dedicated research is needed to better characterize the burden of infectious disease associated with CKD, understand the pathophysiology of infection in patients with CKD, and develop effective strategies to prevent infection and its sequela in this high risk population.

Dialysis Patients Undergoing Total Knee Arthroplasty Have Significantly Increased Odds of Perioperative Adverse Events Independent of Demographic and Comorbidity Factors

BACKGROUND

The prevalence of dialysis-dependent patients is growing, and an increasing number of these patients are being considered for total knee arthroplasty (TKA). Studies assessing the preoperative risk associated with TKA in this population are limited to institutional cohorts with small sample sizes or national inpatient databases that lack follow-up data.

METHODS

The 2006-2015 National Surgical Quality Improvement Program databases were queried for adult patients undergoing elective TKA. Differences in 30-day any/severe/minor adverse event, need for reoperation, readmission, and mortality were compared for dialysis-dependent and nondialysis TKA patients using risk-adjusted logistic regression. To account for the smaller number of dialysis patients and variations in study populations, coarsened exact matching was used. The proportion of adverse events that occurred before vs after discharge was also assessed.

RESULTS

In total, 250 dialysis-dependent patients and 163,560 nondialysis patients met inclusion criteria. After controlling for patient demographics (age, sex, body mass index, functional status) and overall health (American Society of Anesthesiologists class), matched analysis revealed dialysis-dependent patients to be significantly more likely to experience any adverse event (odds ratio = 2.01; 95% confidence interval [CI], 1.34-3.02; P = .001), severe adverse event (odds ratio = 2.49; 95% CI, 1.61-3.84; P < .001), reoperation (odds ratio = 2.38; 95% CI, 1.19-4.75; P = .014), readmission (odds ratio = 2.32; 95% CI, 1.47-3.66; P = .001), and mortality (odds ratio = 6.71; 95% CI, 2.99-22.50; P = .002). The majority of adverse outcomes occurred postdischarge.

CONCLUSION

Independent of patient demographics and overall health (American Society of Anesthesiologists), patients undergoing dialysis before TKA are significantly more likely to experience 30-day adverse outcomes than matched nondialysis cohorts. Preoperative evaluation of bone health status and management of medical treatment are warranted in this fragile population. Cautious surgical planning, patient counseling, and heightened surveillance are necessitated throughout their perioperative period and postoperative recovery plans may need to be different from nondialysis counterparts. Furthermore, hospitals and physicians must take these increased risks into account when working on bundle payment reimbursement strategies and resource allocation.

LEVEL OF EVIDENCE

3.

A Comparative Study of Carvedilol Versus Metoprolol Initiation and 1-Year Mortality Among Individuals Receiving Maintenance Hemodialysis

BACKGROUND

Carvedilol and metoprolol are the β-blockers most commonly prescribed to US hemodialysis patients, accounting for ∼80% of β-blocker prescriptions. Despite well-established pharmacologic and pharmacokinetic differences between the 2 medications, little is known about their relative safety and efficacy in the hemodialysis population.

STUDY DESIGN

A retrospective cohort study using a new-user design.

SETTING & PARTICIPANTS

Medicare-enrolled hemodialysis patients treated at a large US dialysis organization who initiated carvedilol or metoprolol therapy from January 1, 2007, through December 30, 2012.

PREDICTOR

Carvedilol versus metoprolol initiation.

OUTCOMES

All-cause mortality, cardiovascular mortality, and intradialytic hypotension (systolic blood pressure decrease ≥ 20mmHg during hemodialysis plus intradialytic saline solution administration) during a 1-year follow-up period.

MEASUREMENTS

Survival models were used to estimate HRs and 95% CIs in mortality analyses. Poisson regression was used to estimate incidence rate ratios (IRRs) and 95% CIs in intradialytic hypotension analyses. Inverse probability of treatment weighting was used to adjust for several demographic, clinical, laboratory, and dialysis treatment covariates in all analyses.

RESULTS

27,064 individuals receiving maintenance hemodialysis were included: 9,558 (35.3%) carvedilol initiators and 17,506 (64.7%) metoprolol initiators. Carvedilol (vs metoprolol) initiation was associated with greater all-cause (adjusted HR, 1.08; 95% CI, 1.02-1.16) and cardiovascular mortality (adjusted HR, 1.18; 95% CI, 1.08-1.29). In subgroup analyses, similar associations were observed among patients with hypertension, atrial fibrillation, heart failure, and a recent myocardial infarction, the main cardiovascular indications for β-blocker therapy. During follow-up, carvedilol (vs metoprolol) initiators had a higher rate of intradialytic hypotension (adjusted IRR, 1.10; 95% CI, 1.09-1.11).

LIMITATIONS

Residual confounding may exist.

CONCLUSIONS

Relative to metoprolol initiation, carvedilol initiation was associated with higher 1-year all-cause and cardiovascular mortality. One potential mechanism for these findings may be the increased occurrence of intradialytic hypotension after carvedilol (vs metoprolol) initiation.

Development and Validation of Prediction Scores for Early Mortality at Transition to Dialysis

OBJECTIVE

To develop and validate a risk prediction model that would help individualize treatment and improve the shared decision-making process between clinicians and patients.

PATIENTS AND METHODS

We developed a risk prediction tool for mortality during the first year of dialysis based on pre-end-stage renal disease characteristics in a cohort of 35,878 US veterans with incident end-stage renal disease who transitioned to dialysis treatment between October 1, 2007, and March 31, 2014 and then externally validated this tool among 4284 patients in the Kaiser Permanente Southern California (KPSC) health care system who transitioned to dialysis treatment between January 1, 2007, and September 30, 2015.

RESULTS

To ensure model goodness of fit, 2 separate models were selected for patients whose last estimated glomerular filtration rate (eGFR) before dialysis initiation was less than 15 mL/min per 1.73 m² or 15 mL/min per 1.73 m² or higher. Model discrimination in the internal validation cohort of veterans resulted in C statistics of 0.71 (95% CI, 0.70-0.72) and 0.66 (95% CI, 0.65-0.67) among patients with eGFR lower than 15 mL/min per 1.73 m² and 15 mL/min per 1.73 m² or higher, respectively. In the KPSC external validation cohort, the developed risk score exhibited C statistics of 0.77 (95% CI, 0.74-0.79) in men and 0.74 (95% CI, 0.71-0.76) in women with eGFR lower than 15 mL/min per 1.73 m² and 0.71 (95% CI, 0.67-0.74) in men and 0.67 (95% CI, 0.62-0.72) in women with eGFR of 15 mL/min per 1.73 m² or higher.

CONCLUSION

A new risk prediction tool for mortality during the first year after transition to dialysis (available at www.DialysisScore.com) was developed in the large national Veterans Affairs cohort and validated with good performance in the racially, ethnically, and gender diverse KPSC cohort. This risk prediction tool will help identify high-risk populations and guide management strategies at the transition to dialysis.

The impact of chronic kidney disease on lower extremity bypass outcomes in patients with critical limb ischemia

OBJECTIVE

Patient selection for open lower extremity revascularization in patients with chronic kidney disease (CKD) remains a clinical challenge. This study investigates the impact of CKD on early graft failure, postoperative complications, and mortality in patients undergoing lower extremity bypass for critical limb ischemia.

METHODS

The National Surgical Quality Improvement Program database was queried for all patients with critical limb ischemia from 2012 to 2015 who underwent lower extremity bypass using the targeted vascular set. The glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration Study equation. CKD categories were determined from the National Kidney Foundation Kidney Disease Outcomes Quality Initiative staging criteria. Patients were classified into three groups: CKD stages 3 or lower (mild to moderate CKD), CKD stages 4 or 5 (severe CKD), and on hemodialysis (HD). Multiple variable analysis was used to examine graft failure, mortality, and postoperative complications.

RESULTS

The Surgical Quality Improvement Program database identified 6978 patients who underwent infrainguinal lower extremity arterial bypass during the study period. There were 6101 patients (87.4%) with mild to moderate CKD, 327 (4.7%) with severe CKD, and 550 (7.9%) on HD. Patients with severe CKD and on HD were more likely to have revascularization for tissue loss (54.9% vs 68.8% and 74.7%; P < .01). Patients with severe CKD and those on HD had higher rates of early graft failure, postoperative myocardial infarction, and rates of reoperation. Multiple variable analysis confirmed these results showing that HD was associated with postoperative myocardial infarction, readmission, and increased mortality. It also demonstrated that severe CKD was associated with graft failure (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.12-2.50; P = .01), postoperative myocardial infarction (OR, 2.16; 95% CI, 1.35-3.45; P < .01), and readmission (OR, 1.38; 95% CI, 1.06-1.80; P = .02). Other factors associated with graft failure include functional status (OR, 1.39; 95% CI, 1.08-1.80; P = .01), African American race (OR, 1.72; 95% CI, 1.39-2.13; P < .01), and distal bypass (OR, 1.33; 95% CI, 1.09-1.61; P < .01).

CONCLUSIONS

CKD is a significant predictor of perioperative morbidity after lower extremity bypass. Patients with severe CKD have worse postoperative outcomes without increased mortality. Those on HD have worse survival and postoperative outcomes.

Risk of ESRD and Mortality in Kidney and Bladder Stone Formers

RATIONALE & OBJECTIVES

Kidney stones have been associated with increased risk for end-stage renal disease (ESRD). However, it is unclear whether there is also an increased risk for mortality and if these risks are uniform across clinically distinct categories of stone formers.

STUDY DESIGN

Historical matched-cohort study.

SETTING & PARTICIPANTS

Stone formers in Olmsted County, MN, between 1984 and 2012 identified using International Classification of Diseases, Ninth Revision codes. Age- and sex-matched individuals who had no codes for stones were the comparison group.

PREDICTOR

Stone formers were placed into 5 mutually exclusive categories after review of medical charts: incident symptomatic kidney, recurrent symptomatic kidney, asymptomatic kidney, bladder only, and miscoded (no stone).

OUTCOMES

ESRD, mortality, cardiovascular mortality, and cancer mortality.

ANALYTICAL APPROACH

Cox proportional hazards models with adjustment for baseline comorbid conditions.

RESULTS

Overall, 65 of 6,984 (0.93%) stone formers and 102 of 28,044 (0.36%) non-stone formers developed ESRD over a mean follow-up of 12.0 years. After adjusting for baseline hypertension, diabetes mellitus, dyslipidemia, gout, obesity, and chronic kidney disease, risk for ESRD was higher in recurrent symptomatic kidney (HR, 2.34; 95% CI, 1.08-5.07), asymptomatic kidney (HR, 3.94; 95% CI, 1.65-9.43), and miscoded (HR, 6.18; 95% CI, 2.25-16.93) stone formers, but not in incident symptomatic kidney or bladder stone formers. The adjusted risk for all-cause mortality was higher in asymptomatic kidney (HR, 1.40; 95% CI, 1.18-1.67) and bladder (HR, 1.37; 95% CI, 1.12-1.69) stone formers. Chart review of asymptomatic and miscoded stone formers suggested increased risk for adverse outcomes related to diagnoses including urinary tract infection, cancer, and musculoskeletal or gastrointestinal pain.

CONCLUSIONS

The higher risk for ESRD in recurrent symptomatic compared with incident symptomatic kidney stone formers suggests that stone events are associated with kidney injury. The clinical indication for imaging in asymptomatic stone formers, the correct diagnosis in miscoded stone formers, and the cause of a bladder outlet obstruction in bladder stone formers may explain the higher risk for ESRD or death in these groups.

Value-based evaluation of dialysis versus conservative care in older patients with advanced chronic kidney disease: a cohort study

BACKGROUND

Conservative care is argued to be a reasonable treatment alternative for dialysis in older patients with advanced chronic kidney disease (CKD). However, comparisons are scarce and generally focus on survival only. Comparative data on more patient-relevant outcomes are needed to truly foster shared decision-making on an individual level, and cost comparison is needed to assess value of care.

METHODS

We conducted a retrospective observational single-center cohort study in 366 patients aged ≥70 years with advanced CKD, who chose dialysis (n = 240) or conservative care (n = 126) after careful counselling by a multidisciplinary team in a non-academic teaching hospital in The Netherlands. Using a value-based health care approach (value = outcomes/cost): survival, health-related quality of life-cross-sectionally assessed with the Kidney Disease Quality of Life Short Form™-treatment burden, and treatment costs were evaluated.

RESULTS

The overall survival benefit of patients on a dialysis pathway compared with patients on conservative care diminished or lost significance in patients aged ≥80 years or with severe comorbidity. There were no differences between patients managed conservatively and dialysis patients on physical and mental health summary scores (all P > 0.1). Patients on conservative care had 352.7 hospital free days per year versus 282.7 in patients on a dialysis pathway, calculated from treatment decision (adjusted incidence rate ratio: 1.15, 95% confidence interval: 1.09 to 1.21, P <  0.001). Annual treatment costs were lower in patients on conservative care (adjusted cost ratio: 0.43, 95% confidence interval: 0.28 to 0.67, P <  0.001).

CONCLUSIONS

In this study, conservative care is shown to be a viable treatment option in older patients with advanced CKD, particularly in the oldest old and those with severe comorbidity. By achieving similar outcomes at lower treatment burden and treatment costs, value was generated for older patients choosing conservative care and society.

Patient-Centered Approach for Hypertension Management in End-Stage Kidney Disease: Art or Science?

Hypertension is present in most patients with end-stage kidney disease initiating dialysis and management of hypertension is a routine but challenging task in everyday dialysis care. End-stage kidney disease patients are uniquely heterogeneous individuals with significant variations in demographic characteristics, functional capacity, and presence of concomitant comorbid conditions and their severity. Therefore, these patients require personalized approaches in addressing not only hypertension but related illnesses, while also accounting for overall prognosis and projected longevity. There are only limited clinical trial data to guide individualized blood pressure management and current guidelines are based predominantly on observational evidence and expert opinions. Inthis review, we reflect on the shortcomings of peridialytic blood pressure recordings and discuss an important paradigm shift toward using out-of-dialysis blood pressure for evaluating hypertension control and for making treatment decisions. In addition, we provide our personal view on blood pressure goals and summarize nonpharmacologic and pharmacologic treatment options for individualized management of hypertension in end-stage kidney disease.

Characterizing Approaches to Dialysis Decision Making with Older Adults: A Qualitative Study of Nephrologists

BACKGROUND AND OBJECTIVES

Despite guidelines recommending shared decision making, nephrologists vary significantly in their approaches to discussing conservative management for kidney replacement therapy with older patients. Many older patients do not perceive dialysis initiation as a choice or receive sufficient information about conservative management for reasons incompletely understood. We examined how nephrologists' perceptions of key outcomes and successful versus failed treatment discussions shape their approach and characterized different models of decision making, patient engagement, and conservative management discussion.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our qualitative study used semistructured interviews with a sample of purposively sampled nephrologists. Interviews were conducted from June 2016 to May 2017 and continued until thematic saturation. Data were analyzed using typological and thematic analyses.

RESULTS

Among 35 nephrologists from 18 practices, 20% were women, 66% had at least 10 years of nephrology experience, and 80% were from academic medical centers. Four distinct approaches to decision making emerged: paternalist, informative (patient led), interpretive (navigator), and institutionalist. Five themes characterized differences between these approaches, including patient autonomy, engagement and deliberation (disclosing all options, presenting options neutrally, eliciting patient values, and offering explicit treatment recommendation), influence of institutional norms, importance of clinical outcomes (e.g., survival and dialysis initiation), and physician role (educating patients, making decisions, pursuing active therapies, and managing symptoms). Paternalists and institutionalists viewed initiation of dialysis as a measure of success, whereas interpretive and informative nephrologists focused on patient engagement, quality of life, and aligning patient values with treatment. In this sample, only one third of providers presented conservative management to patients, all of whom followed either informative or interpretive approaches. The interpretive model best achieved shared decision making.

CONCLUSIONS

Differences in nephrologists' perceptions of their role, patient autonomy, and successful versus unsuccessful encounters contribute to variation in decision making for patients with kidney disease.

Assessment of Atrial Fibrillation and Ventricular Arrhythmia Risk After Transplant in Patients With End-Stage Renal Disease by P-wave/QT Interval Dispersion, T-Wave Peak-End Interval, and T-Wave Peak-End/QT Interval Ratio

OBJECTIVES

The association between end-stage renal disease with atrial fibrillation and ventricular arrhythmias is well documented. The aim of this study was to investigate whether kidney transplant has any effect on P-wave dispersion, a predictor of atrial fibrillation and corrected QT interval dispersion, T-wave peak-end interval, and T-wave peak-end/corrected QT ratio, which are predictors of ventricular arrhythmias in patients with end-stage renal disease.

MATERIALS AND METHODS

In a retrospective study, 234 patients (125 kidney transplant and 109 healthy control patients) were examined. P-wave dispersion, corrected QT dispersion, T-wave peak-end interval, and T-wave peak-end/corrected QT ratio values before and 3, 6, and 12 months after transplant were calculated and compared in transplant recipients. Baseline values of the control group were compared with 12-month values of kidney transplant patients.

RESULTS

We observed a statistically significant decline in P-wave dispersion, corrected QT dispersion, T-wave peak-end interval, and T-wave peak-end/corrected QT ratio values among the pretransplant and 3-, 6-, and 12-month posttransplant measurements (P < .001 for all comparisons). However, the values of these measurements in the transplant group at 12 months were significantly higher than baseline values of the control group (P < .001 for all comparisons).

CONCLUSIONS

P-wave dispersion, corrected QT dispersion, T-wave peak-end interval, and T-wave peak-end/corrected QT ratio were shown to be attenuated after transplant, although they remained higher than baseline measurements in healthy individuals. These results indirectly offer that there may be a reduction in risk of atrial fibrillation and ventricular arrhythmias after transplant.

Hands hygiene and the use of gloves by nursing team in hemodialysis service

ABSTRACT Objective: to analyze the adhesion of the nursing team to the practice of hands hygiene (HH) and the use of latex gloves in a hemodialysis service. Method: this is a descriptive-exploratory study with a quantitative approach, performed between August and October 2016 in a hemodialysis service in the countryside of São Paulo State, Brazil, where the nursing team adhered to HH and the use of gloves. All ethical aspects have been contemplated. Results: there were 1090 opportunities for HH, with the adhesion rate being only 16.6%. Regarding the use of gloves, of the 510 opportunities observed, there was correct use in 45%, reuse in 25% and absence of latex gloves in 29% of the time. Conclusion: the rate of HH and adherence to gloves is far from ideal, contributing to the increased risk of infection for both the user and the professional.

The complex effects of adipokines in the patients with kidney disease

Kidney diseases are categorized as the highest prevalent ones with worldwide noticeable incidence. They cause accelerated cardiovascular diseases and noticeable mortalities. Adipose tissue and its messengers, adipokines, are reported to have the highest relationship with end-stage renal diseases or chronic kidney diseases. Over recent years, with shifting of scientists’ mindset from a simple overview of adipose tissue as a fat store to the complex paradigm of this issue as a multipotential secretory organ, the importance of studies on this tissue has emerged.

Organ Donation Attitudes Among Individuals With Stage 5 Chronic Kidney Disease

Background

The need for transplantable organs drastically outweighs the supply. Misconceptions are a barrier to increasing the rate of donor registration. Individuals with stage 5 chronic kidney disease (CKD) may incorrectly believe they are unable to be donors; however, their attitudes have not been studied. This study aims to explore beliefs of individuals with stage 5 CKD about their ability to donate and test the validity of an organ donation scale.

Methods

We examined the psychometric properties of a new 25-item organ donation scale among 554 patients with stage 5 CKD at 12 dialysis units in southeast Michigan. Patients completed surveys during dialysis treatment with assistance from a program coordinator or social worker.

Results

Two subscales with good psychometric properties were identified: general benefits (α = 0.86) and general barriers (α = 0.80). For both subscales, more positive attitudes were associated with higher intent to sign up on the donor registry, suggesting validity of the scale.

Conclusions

Patients who were older than 60 years, white, or of higher education status reported more positive attitudes. Misconceptions about the ability of patients with stage 5 CKD to donate are common and highlight a need for education about donor eligibility. Individuals with stage 5 CKD may be able to donate organs and tissues.

Impact of intradialytic blood pressure changes on cardiovascular outcomes is independent of the volume status of maintenance hemodialysis patients

Intradialytic systolic blood pressure (SBP) changes are related to the volume status; however, whether SBP change impacts on adverse outcomes depends on the volume status remains uncertain. We retrospectively investigated the relationship among intradialytic changes in SBP, cardiovascular outcomes, and volume status in maintenance hemodialysis patients. We determined SBP changes (ΔSBP) as postdialysis SBP minus predialysis SBP and volume status as the ratio of extracellular water to total body water (ECW/TBW) using bioelectrical impedance analysis. There were 82 (60.3%) with ΔSBP -20 to 10 mm Hg, 21 (15.4%) with ΔSBP ≤ -20 mm Hg, and 33 (24.3%) with ΔSBP ≥ 10 mm Hg, and they were followed up for a median of 34 months. Cardiovascular events more frequently occurred in the patients with ΔSBP ≤ -20 mm Hg and ≥ 10 mm Hg (hazard ratio: 2.3 and 3.0; P = .062 and .006); these associations persisted even after adjusting for postdialysis ECW/TBW (P = .056 and .028). Moreover, ΔSBP ≥ 10 mm Hg was associated with increased cardiovascular mortalities independent of postdialysis ECW/TBW (P = .043). There was an independent association of volume status between considerable SBP decrease or increase during hemodialysis and adverse cardiovascular outcomes. Besides appropriate volume control, other factors related to BP changes during hemodialysis must be investigated.

Hypoglycemia-Related Hospitalizations and Mortality Among Patients With Diabetes Transitioning to Dialysis

RATIONALE & OBJECTIVE

Diabetic patients with declining kidney function are at heightened risk for hypoglycemia. We sought to determine whether hypoglycemia-related hospitalizations in the interval before dialysis therapy initiation are associated with post-end-stage renal disease (ESRD) mortality among incident patients with ESRD with diabetes.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

US veterans from the national Veterans Affairs database with diabetes and chronic kidney disease transitioning to dialysis therapy from October 2007 to September 2011.

EXPOSURE

Hypoglycemia-related hospitalizations during the pre-ESRD period and antidiabetic medication regimens.

OUTCOME

The outcome of post-ESRD all-cause mortality was evaluated relative to pre-ESRD hypoglycemia. The outcome of pre-ESRD hypoglycemia-related hospitalization was evaluated relative to antidiabetic medication regimens.

ANALYTIC APPROACH

We examined whether the occurrence and frequency of pre-ESRD hypoglycemia-related hospitalizations are associated with post-ESRD mortality using Cox regression models adjusted for case-mix covariates. In a subcohort of patients prescribed 0 to 2 oral antidiabetic drugs and/or insulin, we examined the 12 most commonly prescribed antidiabetic medication regimens and risk for pre-ESRD hypoglycemia-related hospitalization using logistic regression models adjusted for case-mix covariates.

RESULTS

Among 30,156 patients who met eligibility criteria, the occurrence of pre-ESRD hypoglycemia-related hospitalization(s) was associated with higher post-ESRD mortality risk: adjusted HR (aHR), 1.25; 95% CI, 1.17-1.34 (reference group: no hypoglycemia hospitalization). Increasing frequency of hypoglycemia-related hospitalizations was independently associated with incrementally higher mortality risk: aHRs of 1.21 (95% CI, 1.12-1.30), 1.47 (95% CI, 1.19-1.82), and 2.07 (95% CI, 1.46-2.95) for 1, 2, and 3 or more hypoglycemia-related hospitalizations, respectively (reference group: no hypoglycemia hospitalization). Compared with patients who were prescribed neither oral antidiabetic drugs nor insulin, medication regimens that included sulfonylureas and/or insulin were associated with higher risk for hypoglycemia.

LIMITATIONS

Residual confounding cannot be excluded.

CONCLUSIONS

Among incident patients with ESRD with diabetes, a dose-dependent relationship between frequency of pre-ESRD hypoglycemia-related hospitalizations and post-ESRD mortality was observed. Further study of diabetic management strategies that prevent hypoglycemia as patients with chronic kidney disease transition to ESRD are warranted.

Emotional Impact of Illness and Care on Patients with Advanced Kidney Disease

BACKGROUND AND OBJECTIVES

The highly specialized and technologically focused approach to care inherent to many health systems can adversely affect patients' emotional experiences of illness, while also obscuring these effects from the clinician's view. We describe what we learned from patients with advanced kidney disease about the emotional impact of illness and care.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

As part of an ongoing study on advance care planning, we conducted semistructured interviews at the VA Puget Sound Healthcare System in Seattle, Washington, with 27 patients with advanced kidney disease between April of 2014 and May of 2016. Of these, ten (37%) were receiving center hemodialysis, five (19%) were receiving peritoneal dialysis, and 12 (44%) had an eGFR≤20 ml/min per 1.73 m2 and had not started dialysis. Interviews were audiotaped, transcribed, and analyzed inductively using grounded theory methods.

RESULTS

We here describe three emergent themes related to patients' emotional experiences of care and illness: (1) emotional impact of interactions with individual providers: when providers seemed to lack insight into the patient's experience of illness and treatment, this could engender a sense of mistrust, abandonment, isolation, and/or alienation; (2) emotional impact of encounters with the health care system: just as they could be affected emotionally by interactions with individual providers, patients could also be affected by how care was organized, which could similarly lead to feelings of mistrust, abandonment, isolation, and/or alienation; and (3) emotional impact of meaning-making: patients struggled to make sense of their illness experience, worked to apportion blame, and were often quick to blame themselves and to assume that their illness could have been prevented.

CONCLUSIONS

Interactions with individual providers and with the wider health system coupled with patients' own struggles to make meaning of their illness can take a large emotional toll. A deeper appreciation of patients' emotional experiences may offer important opportunities to improve care.

Association between Medicaid Expansion under the Affordable Care Act and Preemptive Listings for Kidney Transplantation

BACKGROUND AND OBJECTIVES

Before 2014, low-income individuals in the United States with non-dialysis-dependent CKD had fewer options to attain health insurance, limiting their opportunities to be preemptively wait-listed for kidney transplantation. We examined whether expanding Medicaid under the Affordable Care Act was associated with differences in the number of individuals who were pre-emptively wait-listed with Medicaid coverage.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the United Network of Organ Sharing database, we performed a retrospective observational study of adults (age≥18 years) listed for kidney transplantation before dialysis dependence between January 1, 2011-December 31, 2013 (pre-Medicaid expansion) and January 1, 2014-December 31, 2016 (post-Medicaid expansion). In multinomial logistic regression models, we compared trends in insurance types used for pre-emptive wait-listing in states that did and did not expand Medicaid with a difference-in-differences approach.

RESULTS

States that fully implemented Medicaid expansion on January 1, 2014 ("expansion states," n=24 and the District of Columbia) had a 59% relative increase in Medicaid-covered pre-emptive listings from the pre-expansion to postexpansion period (from 1094 to 1737 listings), compared with an 8.8% relative increase (from 330 to 359 listings) among 19 Medicaid nonexpansion states (P<0.001). From the pre- to postexpansion period, the adjusted proportion of listings with Medicaid coverage decreased by 0.3 percentage points among nonexpansion states (from 4.0% to 3.7%, P=0.09), and increased by 3.0 percentage points among expansion states (from 7.0% to 10.0%, P<0.001). Medicaid expansion was associated with absolute increases in Medicaid coverage by 1.4 percentage points among white listings, 4.0 percentage points among black listings, 5.9 percentage points among Hispanic listings, and 5.3 percentage points among other listings (P<0.001 for all comparisons).

CONCLUSIONS

Medicaid expansion was associated with an increase in the proportion of new pre-emptive listings for kidney transplantation with Medicaid coverage, with larger increases in Medicaid coverage among racial and ethnic minority listings than among white listings.

Plasma biomarkers improve prediction of diabetic kidney disease in adults with type 1 diabetes over a 12-year follow-up: CACTI study

Background

The objective of the study was to determine whether plasma biomarkers of kidney injury improve the prediction of diabetic kidney disease (DKD) in adults with type 1 diabetes (T1D) over a period of 12 years.

Methods

Participants (n = 527, 53% females) in the Coronary Artery Calcification in T1D (CACTI) Study were examined during 2002-04, at a mean (± standard deviation) age of 39.6 ± 9.0 years with 24.8 years as the median duration of diabetes. Urine albumin-to-creatinine (ACR) and estimated glomerular filtration rate (eGFR) by CKD-EPI (chronic kidney disease epidemiology collaboration) creatinine were measured at the baseline and after mean follow-up of 12.1 ± 1.5 years. Albuminuria was defined as ACR ≥30 mg/g and impaired GFR as eGFR <60 mL/min/1.73 m2. Kidney injury biomarkers (Meso Scale Diagnostics) were measured on stored baseline plasma samples. A principal component analysis (PCA) identified two components: (i) kidney injury molecule-1, calbindin, osteoactivin, trefoil factor 3 and vascular endothelial growth factor; and (ii) β-2 microglobulin, cystatin C, neutrophil gelatinase-associated lipocalin and osteopontin that were used in the multivariable regression analyses.

Results

Component 2 of the PCA was associated with increase in log modulus ACR [β ± standard error (SE): 0.16 ± 0.07, P = 0.02] and eGFR (β ± SE: -2.56 ± 0.97, P = 0.009) over a period of 12 years after adjusting for traditional risk factors (age, sex, HbA1c, low-density lipoprotein cholesterol and systolic blood pressure and baseline eGFR/baseline ACR). Only Component 2 of the PCA was associated with incident-impaired GFR (odds ratio 2.08, 95% confidence interval 1.18-3.67, P = 0.01), adjusting for traditional risk factors. The addition of Component 2 to traditional risk factors significantly improved C-statistics and net-reclassification improvement for incident-impaired GFR (ΔAUC: 0.02 ± 0.01, P = 0.049, and 29% non-events correctly reclassified, P < 0.0001).

Conclusions

Plasma kidney injury biomarkers can help predict development of DKD in T1D.

End-of-Life Care for Patients With Advanced Kidney Disease in the US Veterans Affairs Health Care System, 2000-2011

BACKGROUND

Little is known about patterns of end-of-life care for patients with advanced kidney disease not treated with maintenance dialysis.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

A sample of 14,071 patients with sustained estimated glomerular filtration rates < 15mL/min/1.73m2 treated in the US Veterans Affairs health care system who died during 2000 to 2011. Before death, 12,756 of these patients had been treated with dialysis, 503 had been discussing and/or preparing for dialysis therapy, and for 812, there had been a decision not to pursue dialysis therapy.

OUTCOMES

Hospitalization and receipt of an intensive procedure during the final month of life, in-hospital death, and palliative care consultation and hospice enrollment before death.

RESULTS

Compared with decedents treated with dialysis, those for whom a decision not to pursue dialysis therapy had been made were less often hospitalized (57.3% vs 76.8%; OR, 0.40 [95% CI, 0.34-0.46]), less often the recipient of an intensive procedure (3.5% vs 24.6%; OR, 0.15 [95% CI, 0.10-0.22]), more often the recipient of a palliative care consultation (52.6% vs 21.6%; OR, 4.19 [95% CI, 3.58-4.90]), more often used hospice services (38.7% vs 18.2%; OR, 3.32 [95% CI, 2.83-3.89]), and died less frequently in a hospital (41.4% vs 57.3%; OR, 0.78 [95% CI, 0.74-0.82]). Hospitalization (55.5%; OR, 0.39 [95% CI, 0.32-0.46]), receipt of an intensive procedure (13.7%; OR, 0.60 [95% CI, 0.46-0.77]), and in-hospital death (39.0%; OR, 0.47 [95% CI, 0.39-0.56]) were also less common among decedents who had been discussing and/or preparing for dialysis therapy, but their use of palliative care and hospice services was similar.

LIMITATIONS

Findings may not be generalizable to groups not well represented in the Veterans Affairs health care system.

CONCLUSIONS

Among decedents, patients not treated with dialysis before death received less intensive patterns of end-of-life care than those treated with dialysis. Decedents for whom there had been a decision not to pursue dialysis therapy before death were more likely to receive palliative care and hospice.

Does inflammation affect outcomes in dialysis patients?

Chronic, low-grade inflammation is a common comorbid condition in chronic kidney disease (CKD), and particularly in chronic dialysis patients. In this review, we consider the question of whether inflammation affects outcomes in dialysis patients. Levels of proinflammatory cytokines, as well as C-reactive protein, are elevated in chronic dialysis patients. Multiple factors likely contribute to chronic inflammatory activation in kidney disease patients including the uremic milieu, lifestyle and epigenetic influences, infectious and thrombotic events, the dialysis process, and dysbiosis. Increased inflammatory markers in both CKD and chronic dialysis patients are associated with adverse clinical outcomes including all-cause mortality, cardiovascular events, kidney disease progression, protein energy wasting and diminished motor function, cognitive impairment, as well as other adverse consequences including CKD-mineral and bone disorder, anemia, and insulin resistance. Strategies that have been shown to reduce chronic systemic inflammation in CKD and chronic dialysis patients include both pharmacological and nonpharmacological interventions. However, despite evidence that systemic inflammatory markers can be lowered in kidney disease patients treated with various strategies, evidence that this improves clinical outcomes is largely unavailable and represents an important future research direction. Overall, there is strong observational evidence that inflammation is high in chronic dialysis patients and that this is independently associated with numerous adverse clinical outcomes. Targeting inflammation represents a potentially novel and attractive strategy if it can indeed improve adverse outcomes common in this population.

Incidence, Risk Factors, and Treatment of Achilles Tendon Rupture in Patients With End-Stage Renal Disease

BACKGROUND

Dialysis-dependent patients and kidney transplant recipients may be at increased risk for Achilles tendon rupture (ATR).

METHODS

We studied Medicare patients with end-stage renal disease (ESRD) from 1999 through 2013. Patients were categorized as waitlisted for a transplant, not waitlisted, or received a transplant. We performed multivariate negative binomial regression using demographic characteristics, comorbidities, and year of study entry to estimate adjusted incidence rate ratios (aIRRs), identify ATR risk factors, and determine treatment patterns and outcomes.

RESULTS

We identified 1091 ATRs (incidence, 3.80/10 000 person-years; 95% confidence interval [CI], 3.58-4.03). Compared with transplant recipients, nonwaitlisted patients had a lower incidence (aIRR, 0.44; 95% CI, 0.37-0.53), and waitlisted patients had a similar incidence (aIRR, 0.94; 95% CI, 0.78-1.12) of ATR. ATR incidence was higher among patients taking fluoroquinolones (aIRR, 1.65; 95% CI, 1.32-1.84) and corticosteroids (aIRR, 1.72; 95% CI, 1.44-2.05) compared with those who did not. Patients with ATR were younger, had higher mean body mass index, and had fewer comorbidities than patients without ATR. Seventeen percent of patients received operative treatment within 14 days of ATR diagnosis. The 30-day cumulative incidence of operative site infections was 6.5%.

CONCLUSION

The incidence of ATR was higher among transplant recipients and waitlisted patients compared with nonwaitlisted patients. Younger age, higher body mass index, fewer comorbidities, fluoroquinolone use, and corticosteroid use were risk factors for ATR. Patients were more likely to receive nonoperative than operative treatment for ATR. Those who underwent operative treatment had a low incidence of operative site infection.

LEVEL OF EVIDENCE

Prognostic level III, comparative study.

Serum fibrinogen predicts diabetic ESRD in patients with type 2 diabetes mellitus

AIMS

Although increased serum fibrinogen level was often observed in patients with diabetic nephropathy (DN), its association with DN severity and progression remains unclear. The aim of this study was to investigate the relationship between the serum fibrinogen levels and clinicopathological features and renal prognosis in Chinese patients with type 2 diabetes mellitus (T2DM) and DN.

METHODS

A total of 174 patients with T2DM and biopsy-proven DN were enrolled. Patients were stratified by the quartiles of serum fibrinogen levels; Q1: <3.30 g/L; Q2: between 3.30 and 4.00 g/L; Q3: between 4.00 and 4.74 g/L; Q4:≥4.74 g/L. The renal outcomes were defined by reaching end stage renal disease (ESRD). The influence of serum fibrinogen levels on renal outcomes was evaluated using Cox regression analysis.

RESULTS

The factors associated with higher level of fibrinogen (Q3 and Q4) were diabetic retinopathy, low e-GFR, high proteinuria and severe glomerular and tubulointerstitial lesions. Importantly, in adjusted analysis, higher levels of fibrinogen were independently related with a greater risk of reaching ESRD with a hazard ratio (HR) of 1.64 per standard deviation (SD) of the natural log-transformed fibrinogen concentration (95%CI, 1.22-2.20; p = 0.001). In reference to the Q1, the risk of renal failure increased by quartiles of the serum fibrinogen level: the HRs were 7.12 for the Q2 (95%CI, 2.29-22.16; p = 0.001), 5.77 for Q3 (95%CI, 1.99-16.75; p = 0.001), and 8.81 for Q4 (95%CI, 2.79-27.80; p < 0.001).

CONCLUSIONS

These findings suggested that the elevated serum levels of fibrinogen were associated with diabetic ESRD in patients with T2DM.

Urinary Plasmin(ogen) as a Prognostic Factor for Hypertension

Introduction

Plasmin and its precursor, plasminogen, are detectable in urine from patients with glomerular disease. Urinary plasmin(ogen) levels correlate with blood pressure (BP) and may contribute to renal Na⁺ retention by activating the epithelial Na⁺ channel (ENaC). In a longitudinal nested-cohort study, we asked whether urinary plasmin(ogen) levels predict subsequent increase in BP, incident hypertension, or mortality in subjects with type I diabetes, who often develop proteinuria.

Methods

The Pittsburgh Epidemiology of Diabetes Complications (EDC) study followed up type I diabetic subjects for 25 years. Urine specimens from 70 subjects with a spectrum of baseline urinary albumin levels were examined. Outcomes included increased BP after 2 years (≥1 SD over baseline systolic or diastolic BP, examined via logistic regression), 25-year incident hypertension (≥140/90 mm Hg or initiating BP-lowering medications), and all-cause or cardiovascular mortality, examined using Cox regression.

Results

Subjects experiencing a 2-year increase in BP had higher baseline urinary plasmin(ogen)/creatinine levels (uPl/Cr) than other subjects (P = 0.04); the difference in baseline urinary albumin/creatinine levels (uAlb/Cr) was similar (P = 0.07). Baseline uPl/Cr was associated with increased 25-year hypertension incidence (hazard ratio = 2.05, P = 0.001), all-cause mortality (HR = 2.05, P = 0.01) and cardiovascular mortality (HR = 3.30, P = 0.005), although not independent of uAlb/Cr.

Conclusion

This is the first long-term prospective study addressing clinical outcomes associated with increased urinary plasmin(ogen). Findings are consistent with a role for plasmin(ogen) in promoting increased BP, but also demonstrate the difficulty in distinguishing effects due to plasmin(ogen) from those of albuminuria.

Non-invasive detection of the early phase of kidney injury by photoacoustic/computed tomography imaging

The early diagnosis of kidney diseases, which can remarkably impair the quality of life and are costly, has encountered great difficulties. Therefore, the development of methods for early diagnosis has great clinical significance. In this study, we used an emerging technique of photoacoustic (PA) imaging, which has relatively high spatial resolution and good imaging depth. Two kinds of PA gold nanoparticle (GNP)-based bioprobes were developed based on their superior photo detectability, size controllability and biocompatibility. The kidney injury mouse model was developed by unilateral ureteral obstruction for 96 h and the release of obstruction model). Giving 3.5 and 5.5 nm bioprobes by tail vein injection, we found that the 5.5 nm probe could be detected in the bladder in the model group, but not in the control group. These results were confirmed by computed tomography imaging. Furthermore, the model group did not show changes in the blood biochemical indices (BUN and Scr) and histologic examination. The 5.5 nm GNPs were found to be the critical point for early diagnosis of kidney injury. This new method was faster and more sensitive and accurate for the detection of renal injury, compared with conventional methods, and can be used for the development of a PA GNP-based bioprobe for diagnosing renal injury.