Plasma vaspin levels and clinical outcome in incident peritoneal dialysis patients

BACKGROUND

Vaspin is an adipokine that regulates glucose and lipid metabolism. Plasma vaspin level is increased in chronic kidney disease but decreased in hemodialysis patients. However, plasma vaspin level in peritoneal dialysis (PD) patients, as well as its prognostic role, has not been studied.

METHODS

We recruited 146 incident PD patients. Their baseline plasma vaspin levels, body anthropometry, the profile of insulin resistance, bioimpedance spectroscopy parameters, dialysis adequacy, and nutritional indices were measured. They were followed for up to 5 years for survival analysis.

RESULTS

The average age was 58.4 ± 11.8 years; 96 patients (65.8%) were men, and 90 (61.6%) had diabetes. The median vaspin level was 0.18 ng/dL (interquartile range [IQR] 0.11 to 0.30 ng/dL). Plasma vaspin level did not have a significant correlation with adipose tissue mass or baseline insulin level. However, plasma vaspin level had a modest correlation with the change in insulin resistance, as represented by the HOMA-IR index, in non-diabetic patients (r = -0.358, p = 0.048). Although the plasma vaspin level quartile did not have a significant association with patient survival in the entire cohort, it had a significant interaction with diabetic status (p < 0.001). In nondiabetic patients, plasma vaspin level quartile was an independent predictor of patient survival after adjusting for confounding clinical factors (adjusted hazard ratio 2.038, 95% confidence interval 1.191-3.487, p = 0.009), while the result for diabetic patients was not significant.

CONCLUSIONS

Plasma vaspin level quartile had a significant association with patient survival in non-diabetic PD patients. Baseline plasma vaspin level also had a modest inverse correlation with the subsequent change in the severity of insulin resistance, but the exact biological role of vaspin deserves further studies.

Circulating and Adipose Tissue Adiponectin Level and Outcomes in Incident Peritoneal Dialysis Patients

Rationale & Objective

Cardiovascular disease is the major cause of mortality and morbidity in peritoneal dialysis (PD) patients. Adiponectin, a key adipokine, is related to obesity and insulin resistance. We determined the clinical and prognostic value of plasma adiponectin level and its adipose tissue messenger RNA (mRNA) expression in new PD patients.

Study Design

Retrospective analysis of a prospective observational study.

Setting & Participants

152 new PD patients from a single center; 6 adults undergoing abdominal surgeries without kidney disease served as controls.

Predictors

Plasma adiponectin level and its adipose tissue mRNA expression.

Outcomes

Body build and composition, patient and technique survival.

Analytical Approach

Adiponectin level and mRNA expression were grouped in quartiles for correlation analysis for body build and Cox regression for survival analysis.

Results

The median plasma adiponectin level was 31.98 μg/mL (IQR, 16.81-49.49 μg/mL), and adiponectin mRNA expression in adipose tissue was 1.65 times higher than in controls (IQR, 0.98-2.63). There was a modest but statistically significant correlation between plasma adiponectin and its adipose tissue mRNA expression (r = 0.40, P < 0.001). Plasma adiponectin level inversely correlated with body mass index, waist-hip ratio, mid-arm circumference, adipose tissue mass, plasma triglyceride (r = -0.39, -0.38, -0.41, -0.38, and -0.30, respectively; P < 0.001 for all), as well as serum insulin level (r = -0.24, P = 0.005). Similar correlations were present but less marked with adipose tissue adiponectin mRNA level. Neither plasma adiponectin level nor adipose tissue adiponectin mRNA level predicted patient or technique survival.

Limitations

Observational study, single center, single baseline measurement.

Conclusions

Plasma adiponectin level correlated with the degree of adiposity in new PD patients. However, neither plasma adiponectin level nor its adipose tissue mRNA expression was an independent prognostic indicator in kidney failure patients newly started on PD.

Predictors and prognostic significance of persistent fluid overload: A longitudinal study in Chinese peritoneal dialysis patients

BACKGROUND

Cross-sectional studies showed that fluid overload (FO) measured by bioimpedance spectroscopy (BIS) predicted adverse outcomes in patients on peritoneal dialysis (PD). We aimed to describe the longitudinal change in volume status in Chinese PD patients and determine its relation with clinical outcomes.

METHODS

We performed a single-centre, retrospective analysis of all PD patients who underwent repeated BIS from 2010 to 2015. FO was defined by relative hydration index (RHI; volume of overhydration adjusted by extracellular water >7%). Variability of volume status (VVS) was denoted by the standard deviation of all RHI. The association of time-averaged RHI and VVS on patient and technique survival was explored by a competing risk model.

RESULTS

A total of 269 patients were followed for a median of 47.1 months. Mean time-averaged RHI was 17.6 ± 10.2%. Multivariable mixed linear regression revealed that RHI was significantly associated with diabetes, time-varying systolic blood pressure, and inversely with time-varying albumin level, lean tissue index and fat tissue index (p <0.0001 for all). Time-averaged RHI independently predicted patient survival (subdistribution hazard ratio (SHR) 1.05, 95% CI 1.03-1.07, p <0.0001) and technique survival (SHR 1.04, 95% CI 1.02-1.06, p <0.0001), whereas VVS did not. The mortality risk for patients with persistent FO was consistently higher than the corresponding risk estimated from baseline FO of the same extent.

CONCLUSIONS

Persistent FO was a strong predictor of patient and technique failure. Repeated bioimpedance measurements to monitor volume status may provide additional prognostic information in PD patients.

Adipose expression of miR-130b and miR-17-5p with wasting, cardiovascular event and mortality in advanced chronic kidney disease patients

BACKGROUND

There were limited data on the association of adipose microRNA expression with body composition and adverse clinical outcomes in patients with advanced chronic kidney disease (CKD). We aimed to evaluate the association of adipose miR-130b and miR-17-5p expressions with body composition, functional state, cardiovascular outcome and mortality in incident dialysis patients.

METHODS

We performed a single-centre prospective cohort study. Patients who were planned for peritoneal dialysis were recruited. MiR-130b and miR-17-5p expressions were measured from subcutaneous and pre-peritoneal fat tissue obtained during peritoneal dialysis catheter insertion. Body composition and physical function were assessed by bioimpedance spectroscopy and Clinical Frailty Scale. Primary outcome was 2-year survival. Secondary outcomes were 2-year technique survival and major adverse cardiovascular event (MACE) rate.

RESULTS

Adipose expression of miR-130b and miR-17-5p correlated with parameters of muscle mass including intracellular water (miR-130b: r = 0.191, P = 0.02; miR-17-5p: r = 0.211, P = 0.013) and lean tissue mass (miR-130b: r = 0.180, P = 0.03; miR-17-5p: r = 0.176, P = 0.004). miR-130b expression predicted frailty significantly (P = 0.016). Adipose miR-17-5p expression predicted 2-year all-cause survival (P = 0.020) and technique survival (P = 0.036), while miR-130b expression predicted incidence of major adverse cardiovascular events (P = 0.015).

CONCLUSIONS

Adipose miR-130b and miR-17-5p expressions correlated with body composition parameters, frailty, and predicted cardiovascular events and mortality in advanced CKD patients.

Good Patient and Technique Survival in Elderly Patients on Continuous Ambulatory Peritoneal Dialysis

The aging population has significant implications for the community. The increasing number of elderly end-stage renal disease (ESRD) patients presses the renal team to find an appropriate management plan. We used a retrospective analysis to study the effectiveness of continuous ambulatory peritoneal dialysis (CAPD) in elderly ESRD patients. Of the 328 CAPD patients recruited for the study, 121 were in the elderly group (≥ 65 years of age), and 207 were in the control group (under 65 years of age). Median age in the elderly group was 71 years, and in the control group, 51 years. The elderly group had a higher prevalence (54.5%) of diabetes mellitus. The 2-year and 5-year rates of patient survival were 89.3% and 54.8% respectively in the elderly group and 92.2% and 62.9% in the control group ( p = 0.19). The 2-year and 5-year rates of technique survival were 84.0% and 45.7% respectively in the elderly group and 80.9% and 49.1% in the control group ( p = 0.75). The probability of a 12-month peritonitis-free period was 76.6% in the elderly group and 76.5% in the control group ( p = 0.75).

One hundred elderly patients (82.6% of the group) performed their CAPD exchanges by themselves. We observed no significant difference in clinical outcome—including patient survival, technique survival, and peritonitis-free period—between the elderly self-care CAPD and the elderly assisted CAPD groups.

In elderly ESRD patients, CAPD is an effective dialysis modality. A slightly longer training time is to be expected for elderly patients. Self-care CAPD for elderly patients who are capable of performing their own exchanges provides them with an independent home life.

Longitudinal Changes of NF-κB Downstream Mediators and Peritoneal Transport Characteristics in Incident Peritoneal Dialysis Patients

The role of intra-peritoneal mediators in the regulation peritoneal transport is not completely understood. We investigate the relation between longitudinal changes in dialysis effluent level of nuclear factor kappa-B (NF-κB) downstream mediators and the change in peritoneal transport over 1 year. We studied 46 incident PD patients. Their peritoneal transport characteristics were determined after starting PD and then one year later. Concomitant dialysis effluent levels of interleukin-6 (IL-6), cyclo-oxygenase-2 (COX-2) and hepatocyte growth factor (HGF) are determined. There were significant correlations between baseline and one-year dialysis effluent IL-6 and COX-2 levels with the corresponding dialysate-to-plasma creatinine level at 4 hours (D/P4) and mass transfer area coefficient of creatinine (MTAC). After one year, patients who had peritonitis had higher dialysis effluent IL-6 (26.6 ± 17.4 vs 15.1 ± 12.3 pg/ml, p = 0.037) and COX-2 levels (4.97 ± 6.25 vs 1.60 ± 1.53 ng/ml, p = 0.007) than those without peritonitis, and the number of peritonitis episode significantly correlated with the IL-6 and COX-2 levels after one year. In contrast, dialysis effluent HGF level did not correlate with peritoneal transport. There was no difference in any mediator level between patients receiving conventional and low glucose degradation product solutions. Dialysis effluent IL-6 and COX-2 levels correlate with the concomitant D/P4 and MTAC of creatinine. IL-6 and COX-2 may contribute to the short-term regulation of peritoneal transport.

A Risk Analysis of Continuous Ambulatory Peritoneal Dialysis-Related Peritonitis

Objective

We studied the clinical characteristics that influence the risk of dialysis-related peritonitis complication in incident Chinese patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

Methods

A single center, retrospective, observational cohort study was carried out to examine the risk factors of developing a first episode of dialysis-related peritonitis.

Results

Between 1995 and 2004, 246 incident CAPD patients were recruited for analysis. During the study period of 897.1 patient-years, 85 initial episodes of peritonitis were recorded. The median peritonitis-free time for diabetic subjects was significantly worse than for nondiabetic subjects (49.0 ± 10.5 vs 82.3 ± 12.6 months, p = 0.0019). The difference was due mainly to a higher likelihood of developing peritonitis with gram-negative organisms in patients with diabetes mellitus ( p = 0.038). Low serum albumin concentration was also associated with worse peritonitis-free survival. There was a nonsignificant trend toward an increased risk for peritonitis in the group of patients with cerebrovascular disease. According to multivariate Cox proportional hazards model for the analysis of time to first peritonitis episode, the two independent risk factors were presence of diabetes mellitus and initial serum albumin concentration. In particular, diabetes mellitus was associated with a hazard ratio of 1.50 and a 95% confidence interval of 1.05 – 2.40 ( p = 0.030) to develop an initial peritonitis. Lower serum albumin level at the start of CAPD was a significant predictor of peritonitis, with hazard ratio of 1.67 for every decrease of 10 g/L, and 95% confidence interval 1.08 – 2.60 ( p = 0.021).

Conclusions

Our results confirm the susceptibility of diabetic CAPD and hypoalbuminemic patients to peritonitis, and highlight the role of further studies in reducing this complication.

Peritoneal Albumin Excretion is a Strong Predictor of Cardiovascular Events in Peritoneal Dialysis Patients: A Prospective Cohort Study

Background

Microalbuminuria is a marker of systemic endothelial dysfunction. We hypothesize that peritoneal albumin excretion in peritoneal dialysis (PD) patients, which is conceptually analogous to microalbuminuria in nonuremic patients, can predict cardiovascular disease in new PD patients.

Method

We studied peritoneal albumin excretion in 43 new PD patients. They were then followed prospectively for the development of cardiovascular events. All-cause mortality and duration of hospitalization for cardiovascular diseases were also recorded.

Result

The average duration of follow-up was 26.5 ± 17.6 months. During the follow-up period, 15 patients developed cardiovascular events. Event-free survival at 36 months was 81.4% and 53.6% for low (<300 mg/L) and high (≥300 mg/L) peritoneal albumin excretion groups respectively (log rank test, p = 0.042). By Cox regression analysis, the only independent factors for event-free survival were diabetic status and peritoneal albumin excretion rate. For every 100 mg/L increase in peritoneal albumin excretion, the adjusted hazard ratio of developing a cardiovascular event was 1.83 [95% confidence interval (CI) 1.11 – 3.02, p = 0.018]. Actuarial patient survival at 36 months was 85.7% and 59.1% for low and high peritoneal albumin excretion groups respectively (log rank test, p = 0.10). After adjusting for the duration of follow-up for individual patients, the average duration of hospitalization was 9.1 ± 16.2 and 21.7 ± 25.7 days per year of follow-up for low and high peritoneal albumin excretion groups respectively (Mann–Whitney U test, p = 0.012).

Conclusion

Although the sample size of our present study is small and does not have adequate statistical power, we conclude that peritoneal albumin excretion may be an important predictor of cardiovascular disease. Further studies are needed to examine the role of dialysate albumin excretion as a means of cardiovascular risk stratification in PD patients.

The Impact of Social Support on the Survival of Chinese Peritoneal Dialysis Patients

Background

Social support is an independent risk factor for mortality among new hemodialysis patients. We evaluated the effect of social support on the outcome of Chinese peritoneal dialysis (PD) patients.

Methods

We studied 167 prevalent PD patients. They completed the Medical Outcomes Study Social Support Survey, Chinese Version (MOS-SSS-C) questionnaire. Patients were followed for 1 year. Outcome measures included change in nutritional status, hospitalization, and technique and actuarial patient survival.

Results

Actuarial survival was 57.1%, 72.7%, 85.3%, and 88.6% for MOS-SSS-C total score quartiles I, II, III, and IV, respectively (log rank test, p = 0.037). Technique survival was 57.1%, 81.9%, 91.9%, and 91.4% (log rank test, p = 0.0044). By multivariate analysis with the Cox proportional hazard model to adjust for confounders, every 1 point increase in MOS-SSS-C total score was associated with a 0.6% [95% confidence interval (CI) 0.2% – 0.9%, p = 0.003] reduction in the risk of death and a 0.5% (95%CI 0.1% – 1.0%, p = 0.037) reduction in the risk of technique failure. The MOS-SSS-C score had no significant effect on change in nutritional or dialysis adequacy indices, hospitalization, or number of peritonitis episodes in 1 year.

Conclusion

The degree of social support is an important predictor of actuarial and technique survival in Chinese PD patients. Measures to enhance social support may represent an easily achievable means of improving the clinical outcome of PD patients.

Cefazolin plus Ceftazidime versus Imipenem / Cilastatin Monotherapy for Treatment of Capd Peritonitis — a Randomized Controlled Trial

Background

Peritonitis is a serious complication of peritoneal dialysis (PD). We studied the efficacy of imipenem / cilastatin monotherapy in the treatment of PD-related peritonitis.

Methods

We performed an open-label, randomized control study comparing imipenem / cilastatin monotherapy (treatment group) versus cefazolin plus ceftazidime (control group) in the treatment of PD peritonitis. The result was further compared to a historic group treated with cefazolin plus netilmycin. Outcome measures were primary response rate at day 10 and complete cure rate.

Results

We enrolled 51 patients in the treatment group, 51 in the control group, and identified 96 in the historic group. The primary response rate to the assigned antibiotics was 49.0%, 51.0%, and 49.0% for the treatment, control, and historic groups, respectively ( p = 0.97). The primary response rate allowing for change in antibiotic was 82.4%, 90.2%, and 82.3%, respectively, for the three groups ( p = 0.41). The complete cure rate was 72.5%, 80.4%, and 82.3%, respectively ( p = 0.60). Tenckhoff catheter removal was needed in 6 cases in the treatment group, 6 cases in the control group, and 13 cases in the historic group ( p = 0.90).

Conclusions

We concluded that monotherapy of imipenem / cilastatin has similar efficacy compared to the two standard regimens of cefazolin plus ceftazidime or netilmycin in the treatment of PD peritonitis.

Unexplained Exudative Pleural Effusion in Chronic Peritoneal Dialysis Patients

Background

Although the clinico-pathological entity of uremic pleuritis has long been recognized, its clinical significance remains poorly defined.

Methods

We retrospectively studied 82 chronic peritoneal dialysis (PD) patients that had pleural effusion. The pattern of diagnosis and clinical outcome were reviewed.

Results

10 patients had overt fluid overload and thoracocentesis was not performed, 23 had other specific diagnoses, 15 had transudative effusion due to fluid overload, 12 had unexplained transudative effusion, and 22 patients had unexplained exudative effusion. The 3-year actuarial survival was 40.9% and 83.3% for patients with unexplained exudative and transudative effusion respectively ( p = 0.012); technique survival was 74.2% and 90.9% respectively ( p = 0.006). For patients with unexplained exudative effusion, 11 patients had their PD regimen intensified: they had a higher 3-year actuarial survival than those with their dialysis regimen unchanged (100.0% vs 52.6%, p = 0.04).

Conclusion

Unexplained exudative pleural effusion is not uncommon in chronic PD patients. These patients have a high mortality; an intensive dialysis regimen may be considered.

The efficacy of managing fluid overload in chronic peritoneal dialysis patients by a structured nurse-led intervention protocol

Background

Extracellular volume overload is a common problem in peritoneal dialysis (PD) patients and is associated with excessive mortality. We determine the effectiveness of treating PD patients with extracellular volume overload by a structured nurse-led intervention program.

Methods

The hydration status of PD patients was screened by bioimpedance spectroscopy (BIS). Fluid overload was defined as overhydration volume ≥ 2 L. Patients were classified into Symptomatic and Asymptomatic Groups and were managed by a structured nurse-led intervention protocol that focused on education and motivation. Hypertonic cycles were given for short term symptom relief for the Symptomatic group. Patients were followed for 12 weeks for the change in volume status, blood pressure, knowledge and adherence as determined by standard questionnaires.

Results

We recruited 103 patients (53 Symptomatic, 50 Asymptomatic Group. There was a significant reduction in overhydration volume 4 weeks after intervention, which was sustained by week 12; the overall reduction in overhydration volume was 0.96 ± 1.43 L at 4 weeks, and 1.06 ± 1.70 L at 12 weeks (p < 0.001 for both). The improvement was significant for both Symptomatic and Asymptomatic Groups. There was a concomitant reduction in systolic blood pressure in the Asymptomatic (146.9 ± 20.7 to 136.9 ± 19.5 mmHg, p = 0.037) but not Symptomatic group. The scores of knowledge, adherence to dietary control and advices on daily habit at week 4 were all significantly increased, and the improvement was sustained at week 12.

Conclusions

The structured nurse-led intervention protocol has a lasting benefit on the volume status of PD patients with extracellular volume overload. BIS screening allows prompt identification of volume overload in asymptomatic patients, and facilitates a focused effort on this high risk group.

Relationship between Plasma Endocan Level and Clinical Outcome of Chinese Peritoneal Dialysis Patients

BACKGROUND

Endocan is associated with endothelial dysfunction. In peritoneal dialysis (PD) patients, cardiovascular disease is a common cause of mortality. We examined the relationship between serum endocan level and clinical outcome of PD patients.

METHODS

We recruited 193 new PD patients (118 males, mean age 58.8 ± 11.6 years). Serum endocan levels were determined and stratified into tertile 1 (lowest) to 3 (highest). Nutritional status, arterial pulse wave velocity (PWV) and serum C-reactive protein (CRP) levels were measured. The patients were followed for at least 4 years for clinical outcomes.

RESULTS

For the whole cohort, patients with higher serum endocan levels had lower serum albumin and subjective global assessment score, higher carotid-femoral PWV, and higher serum CRP. For patients with suboptimal blood pressure (BP) control, cardiovascular event-free survival was 95.0, 95.5, and 78.5% for tertiles 1, 2, and 3 at 60 months respectively (p = 0.019). Multivariate Cox regression analysis showed that serum endocan level was an independent predictor of cardiovascular event-free survival. No association with cardiovascular event-free survival was found for patients with adequate BP control (95.0, 92.3, and 100% for tertile 1, 2, and 3 at 60 months, respectively, p = 0.6).

CONCLUSIONS

Higher serum endocan level is associated with unfavourable nutritional, arterial and inflammatory conditions in PD patients. In patients with suboptimal BP control, higher serum endocan is also associated with worse cardiovascular outcome.

Urinary mitochondrial DNA level is an indicator of intra-renal mitochondrial depletion and renal scarring in diabetic nephropathy

Background

Mitochondrial dysfunction plays an important role in the pathogenesis and progression of diabetic nephropathy (DN). We study the relation between urinary and intra-renal mitochondrial deoxyribonucleic acid (mtDNA) levels and renal dysfunction in DN.

Methods

We recruited 92 patients with biopsy-proven DN. Urinary sediment, urinary supernatant and intra-renal mtDNA levels were measured and compared with baseline renal biopsy, kidney scarring and renal function decline in the subsequent 24 months.

Results

mtDNA could be detected in all urine supernatant, urine sediment and renal biopsy specimens. There was a modest but statistically significant inverse correlation between urinary supernatant and intra-renal mtDNA levels (r = -0.453, P = 0.012). Urinary supernatant mtDNA level had modest but statistically significant correlations, inversely with estimated glomerular filtration rate (r = -0.214, P = 0.04), and positively with interstitial fibrosis (r = 0.300, P = 0.005). Intra-renal mtDNA had significant inverse correlation with interstitial fibrosis (r = -0.537, P = 0.003). However, there was no significant relation between renal function decline and urinary supernatant, urinary sediment or intra-renal mtDNA levels.

Conclusions

mtDNA is readily detectable in urinary supernatant and kidney tissue, and their levels correlate with renal function and scarring in DN. Further studies are needed to determine the accuracy of urinary supernatant mtDNA level as a prognostic indicator of DN, as well as its role in other kidney diseases.

Urinary miRNA profile for the diagnosis of IgA nephropathy

Background

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Urinary micro-RNA (miRNA) level is increasingly reported to as non-invasive markers of various kidney diseases. We aim to identify urinary miRNA targets for the diagnosis of IgAN.

Methods

In the development cohort, we performed complete miRNA profiling of urinary sediment in 22 patients with IgAN and 11 healthy controls (CTL). Potential miRNA targets were quantified by a separate validation cohort of 33 IgAN patients and 9 healthy controls.

Results

In the development cohort, we identified 39 miRNA targets that have significantly different expression between IgAN and CTL (14 up-regulated, and 25 down-regulated). Among the 8 miRNA targets chosen for validation study, urinary miR-204, miR-431 and miR-555 remained significantly reduced, and urinary miR-150 level was significantly increased in the IgAN as compared to CTL. The area-under-curve of the receiver operating characteristic (ROC) curve for urinary mi-204 level for the diagnosis of IgAN was 0.976, and the diagnostic performance of combining additional miRNA targets was not further improved. At the cut-off 1.70 unit, the sensitivity and specificity of urinary miR-204 was 100 and 55.5%, respectively, for diagnosing IgAN.

Conclusions

Urinary miR-150, miR-204, miR-431 and miR-555 levels are significantly different between IgAN and healthy controls; urinary miR-204 level alone has the best diagnostic accuracy.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1267-4) contains supplementary material, which is available to authorized users.

Urinary mitochondrial DNA level as a biomarker of tissue injury in non-diabetic chronic kidney diseases

Background

Urinary mitochondrial DNA (mtDNA) fragment level has been proposed as a biomarker of chronic kidney disease (CKD). In this study, we determine the relation between urinary mtDNA level and rate of renal function deterioration in non-diabetic CKD.

Methods

We recruited 102 non-diabetic CKD patients (43 with kidney biopsy that showed non-specific nephrosclerosis). Urinary mtDNA level was measured and compared to baseline clinical and pathological parameters. The patients were followed 48.3 ± 31.8 months for renal events (need of dialysis or over 30% reduction in estimated glomerular filtration rate [eGFR]).

Results

The median urinary mtDNA level was 1519.42 (inter-quartile range 511.81–3073.03) million copy/mmol creatinine. There were significant correlations between urinary mtDNA level and baseline eGFR (r = 0.429, p < 0.001), proteinuria (r = 0.368, p < 0.001), severity of glomerulosclerosis (r = − 0.537, p < 0.001), and tubulointerstitial fibrosis (r = − 0.374, p = 0.014). The overall rate of eGFR decline was − 2.18 ± 5.94 ml/min/1.73m² per year. There was no significant correlation between the rate of eGFR decline and urinary mtDNA level. By univariate analysis, urinary mtDNA level predicts dialysis-free survival, but the result became insignificant after adjusting for clinical and histological confounding factors.

Conclusion

Urinary mtDNA levels have no significant association with the rate of renal function decline in non-diabetic CKD, although the levels correlate with baseline renal function, proteinuria, and the severity of histological damage. Urinary mtDNA level may be a surrogate marker of permanent renal damage in non-diabetic CKD.

Peritoneal protein clearance predicts mortality in peritoneal dialysis patients

BACKGROUND

Peritoneal protein clearance has been suggested to be a marker of peritoneal inflammation and systemic endothelial dysfunction.

METHODS

We enrolled 711 consecutive incident PD patients. Baseline peritoneal protein clearance and other clinical information were reviewed. All patients were followed for at least 1 year for all-cause and cardiovascular mortality.

RESULTS

The average PD effluent protein loss was 6.41 ± 2.16 g/day; peritoneal protein clearance was 97.15 ± 41.55 mL/day. The average duration of follow-up was 50.8 ± 36.2 months. Multivariate linear regression analysis showed that serum albumin, C-reactive protein, and mass transfer area coefficients of creatinine were independently associated with peritoneal protein clearance. By multivariate Cox regression analysis, age, Charlson comorbidity score, volume of overhydration and peritoneal protein clearance were independent predictors of all-cause mortality. Every 10 mL/day increase in peritoneal protein clearance confers 10.4% increase in risk of all-cause mortality (95% confidence interval 2.6-18.7%, p = 0.008). Peritoneal protein clearance was also associated with cardiovascular mortality by univariate analysis, but the association became insignificant after adjusting for confounding factors Cox regression analysis.

CONCLUSIONS

Baseline peritoneal protein clearance is an independent predictor of all-cause mortality in incident PD patients. Routine measurement of peritoneal protein clearance may facilitate patient risk stratification.

Causes of nephrotic syndrome and nephrotic-range proteinuria are different in adult Chinese patients: A single centre study over 33 years

AIM

The reported causes of nephrotic syndrome (NS) varies between different countries. Less is known about the causes of nephrotic-range proteinuria (NPU). We aimed to evaluate the underlying causes of NS and NPU.

METHODS

This was a single-centre, retrospective study of adult patients who underwent renal biopsy between 1983 and 2015 in a tertiary referral hospital in Hong Kong. We determined the distribution of histopathological diagnoses with regard to the age subgroups and time periods.

RESULTS

Among 7456 patients who underwent renal biopsy, 982 and 838 patients had NS and NPU, respectively. The most common diagnosis in NS was minimal change disease (MCD) (33.3%), followed by membranous nephropathy (MN) (23.6%) and lupus nephritis (LN) (12.8%); whereas the most common diagnosis in NPU was LN (27.4%), followed by immunoglobulin A nephropathy (IgAN) (21.4%) and diabetic nephropathy (DN) (9.3%). In the NS group, MCD was the most common diagnosis in young adults while MN was the leading cause in the elderly. On the other hand, LN was the most common pathology in the NPU group until the age of 60. Over the past three decades, there was a trend of decrease in the proportion of IgAN in both NS and NPU group, while a combined pathology of hypertensive nephrosclerosis and diabetic nephropathy (HTNS and DN) increased significantly.

CONCLUSIONS

The causes of NS and NPU in Chinese adults were different and may represent two distinct pathological identities. The spectrum of renal histopathology among these two groups changed significantly over time.

Asymptomatic fluid overload predicts survival and cardiovascular event in incident Chinese peritoneal dialysis patients

Background

Fluid overload is common among asymptomatic peritoneal dialysis (PD) patients. We aim to determine the prevalence and prognostic significance of fluid overload, as measured by bioimpedance spectroscopy, in asymptomatic incident PD patients.

Methods

We performed a single-center study on 311 incident PD patients. Volume status was represented by the volume of overhydration (OH), OH/extracellular water (ECW) ratio, ECW/total body water (TBW) ratio, and ECW to intracellular water (ICW) ratio (E:I ratio). Patient survival, technique survival and cardiovascular event-free survival were determined.

Results

The median period of follow up was 27.3 months. Fluid overload was present in 272 patients (87.5%) when defined as OH volume over 1.1L. All hydration parameters significantly correlated with Charlson Comorbidity Index, and inversely with total Kt/V, and serum albumin. Multivariate cause-specific Cox analysis showed that volume status independently predicted patient survival; every 0.1 unit increase in E:I ratio was associated with 24.5% increase in all-cause mortality (adjusted cause-specific hazard ratio [ACSHR] 1.245, p = 0.002). Hydration status was also an independent predictor of cardiovascular event-free survival after excluding hospital admission for congestive heart failure; each 0.1 unit increase in E:I ratio was associated with 18.7% decrease in cardiovascular event-free survival (ACSHR 1.187, p = 0.011). In contrast, hydration parameters were not associated with technique survival.

Conclusions

Fluid overload is common in asymptomatic incident PD patients and is a strong predictor of patient survival and cardiovascular event. The impact of bioimpedance spectroscopy-guided fluid management on the outcome of PD patients deserves further study.

Depression and Physical Frailty Have Additive Effect on the Nutritional Status and Clinical Outcome of Chinese Peritoneal Dialysis

BACKGROUND/AIMS

Frailty and depression both contribute to malnutrition and adverse clinical outcome of peritoneal dialysis (PD) patients. However, their interaction is incompletely defined.

METHODS

We studied 178 adult Chinese PD patients. Physical frailty was assessed by a validated in-house questionnaire; depressive symptoms was screened by the Geriatric Depression Scale; nutritional status was determined by subjective global assessment (SGA) and malnutrition inflammation score (MIS). All patients were followed for up to 24 months for survival and hospitalization analysis.

RESULTS

There were 111 patients (62.4%) physically frail, amongst those 48 (43.2%) had depressive symptoms. Only 1 patient had depressive symptoms without frailty. There was an additive effect of depressive symptoms and physical frailty on nutritional status. For the groups with no frailty, frail but no depressive symptoms, and frail with depressive symptoms, serum albumin decreased in a stepwise manner (35.8 ± 5.6, 34.9 ± 4.4, and 32.9 ± 5.3 g/L, respectively, p=0.025); overall SGA score was 5.75 ± 0.61, 5.41 ± 0.59, and 5.04 ± 0.77, respectively (p< 0.0001), and MIS was 5.12 ± 2.30, 7.13 ± 3.22, and 9.48 ± 3.97, respectively (p< 0.0001). At 24 months, patient survival was 86.6%, 71.4%, and 62.5% for patients with no frailty, frail but no depressive symptoms, and frail with depressive symptoms, respective (p=0.001). The median number of hospital stay was 8.04 (inter-quartile range [IQR] 0.91 - 19.42), 14.05 (IQR 3.57 - 37.27), and 26.62 (IQR 10.65 - 61.18) days per year of follow up, respectively (p< 0.0001).

CONCLUSION

Physical frailty and depressive symptoms are both common in Chinese PD patients, and they have additive adverse effect on the nutritional status and clinical outcome.

Urinary mitochondrial DNA level in non-diabetic chronic kidney diseases

BACKGROUND

Mitochondrial dysfunction plays an important role in the pathogenesis and progression of chronic kidney disease (CKD). We study the relation between urinary mitochondrial DNA (mtDNA) levels and renal dysfunction in non-diabetic CKD.

METHODS

We recruited 32 CKD patients (20 had hypertensive nephrosclerosis, 12 had IgA nephropathy). Urinary supernatant mtDNA level was measured and compared to baseline clinical and pathological parameters. The patients were followed 57.8 ± 30.5 months for renal function decline.

RESULTS

The average urinary supernatant mtDNA level was 222.0 ± 210.3 copy/μL. There was a modest but significant correlation between urinary mtDNA level and proteinuria (Spearman's r = 0.387, p = 0.035), but not any other baseline clinical or pathological parameter. Urinary mtDNA level had a significant inverse correlation with the slope of GFR decline (r = -0.402, p = 0.023). Urinary mtDNA level is a predictor of renal survival even after adjusting for baseline proteinuria with multivariate Cox analysis. In this model, every increase in urinary mtDNA by 100 copy/μL confers a 25.0% increase in risk of doubling of serum creatinine or need of dialysis (95%CI, 0.7% to 55.1%).

CONCLUSION

Mitochondrial DNA is readily detectable in the urinary supernatant of non-diabetic CKD, and its level correlates with the rate of renal function decline and predicts the risk of doubling of serum creatinine or need of dialysis. Further studies are needed to determine the value of urinary supernatant mtDNA level as a prognostic indicator of non-diabetic CKD.

Peritoneal Dialysis Catheter Revision and Replacement by Nephrologist for Peritoneal Dialysis Catheter Malfunction

BACKGROUND

Catheter malfunction is an important cause of technique failure for peritoneal dialysis (PD) patients, and is commonly managed by surgeons or intervention radiologists. We reviewed our experience in catheter revision or replacement by nephrologists.

METHOD

We reviewed the clinical outcome and complication rate of 95 consecutive patients who had PD catheter malfunction, with catheter revision or replacement by nephrologist.

RESULT

Amongst the 95 patients, 32 had catheter revision, 24 catheter replacement via the original wound, and 39 catheter replacement via a new mini-laparotomy wound. Catheter survival was 71.6% at 1 month and 48.4% at 6 months; technique survival was 88.4% at 1 month and 77.4% at 6 months. When the 3 types of procedure were analyzed separately, technique survival at 1 month was 96.8, 75.0, and 89.7%, respectively, for patients who received catheter revision, catheter replacement via the original wound, and catheter replacement via a new mini-laparotomy wound (p = 0.0002), although their catheter survival rates were not significantly different. Also, 2 patients had bleeding that required urgent surgical exploration, 2 had wound infection, and 8 had peritonitis within 4 weeks after the surgery.

CONCLUSION

PD catheter revision and replacement by nephrologist has an acceptable catheter survival and a reasonable complication rate. Given that prompt intervention is an important consideration, catheter revision and replacement by nephrologist is a suitable method for the management of catheter malfunction.

Urinary Mitochondrial DNA Level as a Biomarker of Acute Kidney Injury Severity

BACKGROUND

Mitochondrial dysfunction contributes to the pathogenesis of acute kidney injury (AKI). The urinary mitochondrial DNA (mtDNA) level was previously shown to predict renal function recovery in AKI following cardiac surgery. Herein, we determine whether urinary mtDNA is a marker of severity and predictor of recovery in AKI due to other etiologies.

METHODS

We recruited 107 AKI patients. The urinary mtDNA level was measured, the severity of AKI was quantified, and patients were followed for 90 days.

RESULTS

The urinary mtDNA level had modest but statistically significant correlations with the peak serum creatinine level (Spearman's r = -0.248, p = 0.010) and the duration of hospital stay (r = -0.217, p = 0.025). Patients who required temporary dialysis also tended to have higher urinary mtDNA levels than those without dialysis (22.6 ± 4.5 vs. 24.9 ± 5.7 cycles, p = 0.06). There was no definite relation between the urinary mtDNA level and renal function recovery.

CONCLUSION

The urinary mtDNA level is a marker of AKI severity, as reflected by its significant correlation with the peak serum creatinine level, duration of hospital stay, and probably the need for temporary dialysis. Our result suggests that urinary mtDNA has the potential to serve as a biomarker of AKI.

Dialysate bacterial endotoxin as a prognostic indicator of peritoneal dialysis related peritonitis

Peritonitis is the major complication of peritoneal dialysis (PD). The aim of our present study is to explore the prognostic value of endotoxin level in PD effluent for the prediction of treatment failure in PD-related peritonitis. We studied 325 peritonitis episodes in 223 patients. PD effluent (PDE) was collected every 5 days for endotoxin level and leukocyte count. Patients were followed for relapsing or recurrent peritonitis. We found 20 episodes (6.2%) had primary treatment failure; 41 (12.6%) developed relapsing, 19 (5.8%) had recurrent, and 22 (6.8%) had repeat episodes. Endotoxin was detectable in the PDE of 19 episodes (24.4%) caused by Gram negative organisms, 4 episodes (6.8%) of mixed bacterial growth, and none of the culture negative episodes or those by Gram positive organisms. For episodes caused by Gram negative bacteria, a detectable endotoxin level in PDE on day 5 had a sensitivity and specificity of 66.7% and 83.3%, respectively, for predicting primary treatment failure. In contrast, PDE leukocyte count > 1000 per mm3 on day 5 had a sensitivity and specificity of 88.9% and 89.1%, respectively; the addition of PDE endotoxin assay did not improve the sensitivity or specificity. We conclude that detectable endotoxin in PDE 5 days after antibiotic therapy might predict primary treatment failure in peritonitis episodes caused by Gram negative organisms. However, the sensitivity and specificity of PDE endotoxin assay was inferior to PDE leukocyte count.

Peritonitis before Peritoneal Dialysis Training: Analysis of Causative Organisms, Clinical Outcomes, Risk Factors, and Long-Term Consequences

BACKGROUND AND OBJECTIVES

Peritonitis before peritoneal dialysis (PD) training (pretraining peritonitis [PTP]) is an uncommon event. The study aim was to examine the causative organisms, clinical outcomes, risk factors, and long-term consequences of PTP.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this single-center, retrospective, observational study involving all incident patients on PD who developed PTP between 1998 and 2012, we examined the causative organisms, primary response rate, complete cure rate, risk factors, and associations of PTP with peritoneal equilibration test (PET) and patient survival. For each patient in the PTP group, the patients who underwent catheter insertion immediately before and after the index case were identified as controls.

RESULTS

Among 1252 incident patients on PD, 52 (4.2%) patients developed PTP, and 104 patients were identified as controls. The two groups were similar in age, sex distribution, comorbidities, and residual renal function, but the PTP group had significantly lower hemoglobin and serum albumin. Patients were followed up for a median of 37.5 months (interquartile range [IQR], 16.3-62.2 months). The most common causative organisms of PTP were Staphylococcus aureus (30.8%) and polymicrobial (21.2%); 25% had negative growth. The primary response and complete cure rates were 82.7% and 78.8%, respectively. In the PTP group, 7.7% of patients died, 9.6% of patients required catheter removal, and PD training was significantly delayed (median =42.0; IQR, 26.0-65.8 days versus 27.5; IQR, 23.0-35.0 days; P=0.01). Multivariate logistic regression analysis showed that serum albumin was the only predictor of PTP (adjusted odds ratio, 0.89 per 1-g/dl increase; 95% confidence interval, 0.82 to 0.97). There were no differences in PET results and dialysis adequacy (measured around 1 month after PD training). The PTP group had significantly worse patient survival (median =41.2; IQR, 21.8-60.5 months versus 55.8; IQR, 40.4-71.2 months; P=0.02). Technique failure occurred in 11.5% and 10.6% of patients in the PTP and control groups, respectively.

CONCLUSIONS

S. aureus is the most common causative organism of PTP. Nutritional interventions in patients who are hypoalbuminemic before catheter insertion deserve additional study.

Newer antibiotics for the treatment of peritoneal dialysis-related peritonitis

Peritonitis is a debilitating infectious complication of peritoneal dialysis (PD). Drug-resistant bacterial peritonitis typically has a lower response rate to antibiotics. In the past 15 years, newer antibiotics with activities against drug-resistant Gram-positive bacteria have been developed. In most circumstances, peritonitis due to methicillin-resistant staphylococci responds to vancomycin. If vancomycin cannot be used due to allergy and/or non-susceptibility, there is increasing evidence that linezolid and daptomycin are the drugs of choice. It is reasonable to start linezolid orally or intravenously, but subsequent dose reduction may be necessary in case of myelosuppression. Daptomycin can be given intravenously or intraperitoneally and has excellent anti-biofilm activity. Other treatment options for drug-resistant Gram-positive bacterial peritonitis include teicoplanin, tigecycline and quinupristin/dalfopristin. Teicoplanin is not available in some countries (e.g. the USA). Tigecycline can only be given intravenously. Quinupristin/dalfopristin is ineffective against Enterococcus faecalis and there is only low-quality evidence to support its efficacy in the treatment of peritonitis. Effective newer antibiotics against drug-resistant Gram-negative bacteria are lacking. Polymyxins can be considered, but evidence on its efficacy is limited. In this review, we will discuss the potential use of newer antibiotics in the treatment of drug-resistant bacterial peritonitis in PD patients.

Urinary mRNA levels of ELR-negative CXC chemokine ligand and extracellular matrix in diabetic nephropathy

BACKGROUND

Inflammation and fibrosis play important roles in the progression of diabetic nephropathy. We determine the urinary mRNA levels of ELR-CXC chemokine ligand and extracellular matrix in diabetic nephropathy.

METHODS

We studied 26 patients with biopsy-proven diabetic nephropathy, 15 with hypertensive nephrosclerosis and 10 healthy controls. Urinary mRNA levels of CXCL9, CXCL10, CXCL11, collagen I A1 chain, collagen IV A3 chain and fibronectin were measured. Patients were followed for 36.9 ± 7.4 months to determine the rate of glomerular filtration rate (GFR) decline.

RESULTS

Urinary mRNA levels of CXCL10 and CXCL11 are decreased, and those of collagen I A1 chain and fibronectin are increased in diabetic nephropathy. Baseline estimated GFR correlates with urinary mRNA level of CXCL9 (r = 0.583, p = 0.002) and CXCL11 (r = 0.703, p < 0.0001), respectively. The rate of GFR decline significantly correlates with urinary CXCL9 (r = -0.618, p = 0.0008) and CXCL11 mRNA levels (r = -0.726, p < 0.0001). Multivariate linear regression analysis confirms that urinary CXCL9 mRNA level is independently associated with the rate of GFR decline, while the correlation with urinary CXCL11 mRNA level has borderline significance.

CONCLUSION

Urinary CXCL9 and CXCL11 mRNA levels correlate with baseline renal function. The rate of renal function decline correlates with urinary CXCL9 mRNA level. Our results suggest that urinary CXCL9 mRNA levels may be used for risk stratification of diabetic nephropathy.

Intrarenal and Urinary Th9 and Th22 Cytokine Gene Expression in Lupus Nephritis

OBJECTIVE

We studied the urinary sediment mRNA level of Th9- and Th22-related cytokines in patients with systemic lupus erythematosus (SLE).

METHODS

We quantified urinary mRNA levels of interleukin (IL) 9, IL-10, IL-22, and their corresponding transcription factors in 73 patients with active lupus nephritis, 13 patients with hypertensive nephrosclerosis (HTN), and 25 healthy subjects.

RESULTS

There was no detectable IL-9 mRNA in all samples. Patients with proliferative lupus nephritis had significantly lower urinary IL-22 mRNA levels than those with nonproliferative nephritis (2.2 ± 5.4 vs 8.6 ± 20.0 copies, p = 0.019), and urinary IL-22 mRNA level inversely correlated with the histological activity index (r = -0.427, p < 0.0001). In contrast, patients with lupus nephritis had significantly higher urinary IL-10 mRNA levels than patients with HTN (7.8 ± 18.5 vs 1.9 ± 4.0 copies, p = 0.012), and urinary IL-10 mRNA levels correlated with its intrarenal mRNA levels (r = 0.337, p = 0.004) and SLE disease activity index (r = 0.277, p = 0.018). Urinary IL-10 mRNA level was significantly lower among patients who achieved complete remission than those with partial remission or no response (4.1 ± 6.5 vs 14.1 ± 28.0 copies, p = 0.036).

CONCLUSION

Urinary IL-22 mRNA level is decreased in patients with SLE with proliferative nephritis, while urinary IL-10 mRNA levels correlates with its intrarenal mRNA level and disease activity. Urinary IL-10 mRNA levels may also predict treatment response. These results suggest that urinary mRNA levels of IL-10 and IL-22 might be used as biomarkers for assessing disease activity and risk stratification in lupus nephritis.

Circulating bacterial-derived DNA fragment level is a strong predictor of cardiovascular disease in peritoneal dialysis patients

BACKGROUND

Circulating bacterial DNA fragment is related to systemic inflammatory state in peritoneal dialysis (PD) patients. We hypothesize that plasma bacterial DNA level predicts cardiovascular events in new PD patients.

METHODS

We measured plasma bacterial DNA level in 191 new PD patients, who were then followed for at least a year for the development of cardiovascular event, hospitalization, and patient survival.

RESULTS

The average age was 59.3 ± 11.8 years; plasma bacterial DNA level 34.9 ± 1.5 cycles; average follow up 23.2 ± 9.7 months. At 24 months, the event-free survival was 86.1%, 69.8%, 55.4% and 30.8% for plasma bacterial DNA level quartiles I, II, III and IV, respectively (p < 0.0001). After adjusting for confounders, plasma bacterial DNA level, baseline residual renal function and malnutrition-inflammation score were independent predictors of composite cardiovascular end-point; each doubling in plasma bacterial DNA level confers a 26.9% (95% confidence interval, 13.0 - 42.5%) excess in risk. Plasma bacterial DNA also correlated with the number of hospital admission (r = -0.379, p < 0.0001) and duration of hospitalization for cardiovascular reasons (r = -0.386, p < 0.0001). Plasma bacterial DNA level did not correlate with baseline arterial pulse wave velocity (PWV), but with the change in carotid-radial PWV in one year (r = -0.238, p = 0.005).

CONCLUSIONS

Circulating bacterial DNA fragment level is a strong predictor of cardiovascular event, need of hospitalization, as well as the progressive change in arterial stiffness in new PD patients.

Functional and histological improvement after everolimus rescue of chronic allograft dysfunction in renal transplant recipients

Background

We tested the strategy of mTOR inhibitors with calcineurin inhibitor minimization in renal transplant recipients with known chronic allograft dysfunction.

Methods

In this open-label, single-arm study, renal transplant patients were recruited after biopsy-confirmed chronic allograft dysfunction in the absence of acute rejection episode within 2 months, with proteinuria <0.8 g/day, and serum creatinine <220 μmol/L or estimated glomerular filtration rate >40 mL/min/1.73 m². They were converted to everolimus (aiming for trough everolimus level 3–8 ng/mL) with cyclosporine minimization, to assess the effect on renal function, rate of glomerular filtration rate decline, and longitudinal transplant biopsy at 12 months.

Results

Seventeen Chinese patients (median transplant duration, 4.2 years) were recruited; no patients discontinued study medication. The mean slope of the glomerular filtration rate over time was −4.31±6.65 mL/min/1.73 m² per year in the year before everolimus, as compared with 1.29±5.84 mL/min/1.73 m² per year in the 12 months of everolimus therapy, a difference of 5.61 mL/min/1.73 m² per year (95% confidence interval [CI], 0.40–10.8) favoring everolimus therapy (P=0.036). Serial renal biopsy histology showed significant decrease of tubular atrophy (15.7%±11.3% versus 7.1%±7.3%, P=0.005) and interstitial fibrosis (14.8%±11.5% versus 7.2%±8.2%, P=0.013). Intrarenal expression of TGF-β1 mRNA showed a nonsignificant decrease after everolimus treatment.

Conclusion

In renal transplant recipients with biopsy-confirmed chronic allograft dysfunction, we found a significant beneficial effect of everolimus rescue therapy and calcineurin inhibitor minimization strategy on the improvement of glomerular filtration rate decline rate. In secondary analysis, everolimus was shown to slow down the disease progression by reducing the tubular atrophy and interstitial fibrosis scoring.

Relationship between HSP70-2 A+1267G Polymorphism and Cardiovascular Events of Chinese Peritoneal Dialysis Patients

BACKGROUND

Heat shock proteins (HSPs) are expressed by cells in response to various environmental stresses. A single-nucleotide polymorphism A+1267G of the HSPA1B gene affects the expression of HSP70-2, with the A allele being protective against inflammatory conditions. We investigated the relation between the HSP A+1267G polymorphism and the clinical outcomes of Chinese peritoneal dialysis (PD) patients.

METHODS

We studied 347 new PD cases (181 males, age 56.6 ± 13.7 years). Genotyping was done by standard methods. Patients were followed for 40.5 ± 20.7 months for survival analysis.

RESULTS

For the entire cohort, there was no difference in the 5-year survival between genotype groups. However, there was a significant interaction between HSP polymorphism and diabetic status on the cardiovascular event-free survival. In patients without pre-existing diabetes, 5-year cardiovascular event-free survival of the GG/AG genotype group was significantly better than that of the AA genotype group (57.2 vs. 32.1%, p = 0.011).

CONCLUSION

The G allele of the HSP70-2 A+1267G polymorphism confers survival advantages in non-diabetic PD patients. The role of HSP in the pathogenesis of cardiovascular disease in renal failure patients needs further investigation.

Long-term outcome of biopsy-proven minimal change nephropathy in Chinese adults

BACKGROUND

Minimal change nephropathy is a common cause of primary nephrotic syndrome in adults. However, there are few studies of its clinical course, response to treatment, and long-term outcome.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

340 consecutive adult patients with nephrotic syndrome and biopsy-proven minimal change nephropathy treated in a university hospital from 1984 until 2004.

FACTORS

Treatment response groups: primary steroid resistance, frequent relapse (≥4 relapses within 1 year), infrequent relapse (≥1 relapse but not frequent relapse), and no relapse (reference group); disease pattern.

OUTCOME

Medical problems after diagnosis; patient survival; renal survival.

RESULTS

Median time to remission was 10 (IQR, 8-12) weeks; 179 (52.6%) had no relapse, 42 (12.4%) had infrequent relapses, 86 (25.3%) were frequent relapsers or steroid dependent, and 33 (9.7%) had primary steroid resistance. After a median follow-up of 174.7 (IQR, 119.7-235.0) months, 32 patients developed end-stage renal disease and 62 died (25 after progression to end-stage renal disease). Cox regression analysis showed that age and treatment response groups were the independent predictors of patient survival. Compared to the no-relapse group, the infrequent-relapse group had significantly better patient survival (adjusted HR, 0.19; 95% CI, 0.08-0.44; P<0.001), whereas the primary-steroid-resistance group had significantly worse patient survival (adjusted HR, 5.87; 95% CI, 1.83-18.85; P<0.001). Renal survival was excellent except in the primary-steroid-resistance group.

LIMITATIONS

Retrospective study.

CONCLUSIONS

A substantial proportion of adult patients with minimal change nephropathy continue to have disease flares more than 10 years after the initial presentation, and medical problems after diagnosis are common.

Clinical manifestation of macrolide antibiotic toxicity in CKD and dialysis patients

Macrolide antibiotics, erythromycin, clarithromycin and azithromycin are commonly prescribed for upper respiratory infection, and their use has recently been further linked to immunomodulatory effects. With the widespread and expanded use of macrolides, special attention should be paid to their potential adverse effects. We reported two cases of end-stage renal disease (ESRD) patients who developed hallucinations such as vivid images of worms after taking clarithromycin. Similar to previous case reports of clarithromycin neurotoxicity, the visual hallucination resolved upon cessation of clarithromycin. Furthermore, we discussed the pharmacokinetic properties and other toxicities of macrolide antibiotics in patients with chronic kidney disease and ESRD.

Urinary mRNA in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a relapsing autoimmune disease with clinical manifestations that affect multiple organ systems. Lupus nephritis is recognized as one of the most severe organ involvements in SLE and affects half of the lupus patients. Notably, lupus nephritis is characterized by intrarenal lymphocyte activation and inflammation. Since most of the cytokines exert their effects in a paracrine fashion, measuring their expression at the site of pathology should be of biological relevance. Although kidney biopsy is widely used to determine the histology and severity of lupus nephritis, this invasive procedure has its own risk and is not practical for serial monitoring. In the past decade, extraction and quantification of messenger RNA (mRNA) from urinary sediment has emerged as a robust laboratory technique. Quantification of mRNA expression in urinary sediment has been tested as a noninvasive means to assess the disease activity of SLE patients. Available published evidence, however, is limited to small-scale studies. Based on the result of these studies, a number of cytokine and transcript factor genes have been found to have potential for the differentiation between active and inactive SLE, between proliferative and membranous types of lupus nephritis, assessment of the systemic lupus activity or histological activity of kidney biopsy specimen, monitoring of treatment response in active lupus nephritis, or detection of lupus disease flare in clinically quiescent patients. Being a simple and noninvasive method, urinary mRNA level deserves further studies to validate its role in risk stratification and monitoring of therapeutic response in patients with lupus nephritis.

Predictors of residual renal function decline in patients undergoing continuous ambulatory peritoneal dialysis

BACKGROUND

Residual renal function (RRF) is an important prognostic indicator in continuous ambulatory peritoneal dialysis (CAPD) patients. We determined the predictors of RRF loss in a cohort of incident CAPD patients.

METHODS

We reviewed the record of 645 incident CAPD patients. RRF loss is represented by the slope of decline of residual glomerular filtration rate (GFR) as well as the time to anuria.

RESULTS

The average rate of residual GFR decline was -0.083 ± 0.094 mL/min/month. The rate of residual GFR decline was faster with a higher proteinuria (r = -0.506, p < 0.0001) and baseline residual GFR (r = -0.560, p < 0.0001). Multivariate analysis showed that proteinuria, baseline residual GFR, and the use of diuretics were independent predictors of residual GFR decline. Cox proportional hazard model showed that proteinuria, glucose exposure, and the number of peritonitis episodes were independent predictors of progression to anuria, while a higher baseline GFR was protective. Each 1 g/day of proteinuria is associated with a 13.2% increase in the risk of progressing to anuria, each 10 g/day higher glucose exposure is associated with a 2.5% increase in risk, while each peritonitis episode confers a 3.8% increase in risk.

CONCLUSIONS

Our study shows that factors predicting the loss of residual solute clearance and urine output are different. Proteinuria, baseline residual GFR, and the use of diuretics are independently related to the rate of RRF decline in CAPD patients, while proteinuria, glucose exposure, and the number of peritonitis episodes are independent predictors for the development of anuria. The role of anti-proteinuric therapy and measures to prevent peritonitis episodes in the preservation of RRF should be tested in future studies.

Metabolic syndrome in peritoneal dialysis patients: choice of diagnostic criteria and prognostic implications

BACKGROUND AND OBJECTIVE

In the general population, metabolic syndrome (MES) is associated with cardiovascular risk. However, the definition of MES and its prognostic implication among patients undergoing peritoneal dialysis (PD) remain controversial.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied 329 prevalent PD patients from April 2008 to April 2011 and compared four sets of diagnostic criteria: the original World Health Organization (WHO) criteria, the International Diabetes Federation (IDF) criteria, the original National Cholesterol Education Program (NCEP) criteria, and the modified NCEP criteria. Nutritional status, body composition, and arterial pulse-wave velocity were measured. Patients were followed for 31.7 ± 15.5 months.

RESULTS

Among the 329 patients, 175 (53.2%) fulfilled the WHO criteria, 177 (53.8%) the IDF criteria, 199 (60.5%) the original NCEP criteria, and 218 (66.3%) the modified NCEP criteria. The agreement among the four sets of criteria was fair to moderate (Cohen κ=0.35-0.58). Patients with MES defined by all four criteria had higher adipose tissue mass than the others, although the difference in adipose tissue mass was most pronounced with the IDF criteria (MES versus no MES, 18.2 ± 7.9 versus 10.7 ± 5.9 kg; P<0.001). Patients with MES, as defined by the IDF criteria, were hospitalized longer than those without MES (3.82 [interquartile range, 0.00-12.61] versus 1.07 [interquartile range, 0.00-6.43]) days per year of follow-up; P=0.01). Overall survival, cardiovascular survival, or technique survival did not differ between patients with and without MES, irrespective of the diagnostic criteria after adjustment for diabetic status.

CONCLUSION

In patients undergoing PD, overall survival, cardiovascular survival, and technique survival did not differ between patients with and without MES, irrespective of diabetic status and diagnostic criteria. Further studies are needed to establish a new definition or clinical scoring system for risk stratification of PD patients.

Bioimpedance spectroscopy for the detection of fluid overload in Chinese peritoneal dialysis patients

BACKGROUND

Fluid overload probably contributes to the cardiovascular risk of peritoneal dialysis (PD) patients. We studied the relationship between over-hydration as determined by bioimpedance spectroscopy and dialysis adequacy, nutritional status, and arterial stiffness in Chinese PD patients.

METHODS

We studied 122 asymptomatic prevalent PD patients: bioimpedance spectroscopy, arterial pulse wave velocity, dialysis adequacy and nutritional status were determined.

RESULTS

Of the 122 patients, 88 (72.1%) had over-hydration of ≥ 1 L, while 25 (20.5%) were ≥ 5 L. Over-hydration significantly correlated with total body water (r = 0.474, p < 0.001) and extracellular water (r = 0.755, p < 0.001). Over-hydration was more severe in male and diabetic patients, and significantly correlated with Charlson's comorbidity score, blood pressure, body mass index, body weight, peritoneal transport characteristics, and carotid-femoral pulse wave velocity. Over-hydration significantly correlated with Kt/V (r = -0.287, p = 0.016), serum albumin level (r = -0.465, p < 0.001) and malnutrition inflammation score (r = 0.410, p = 0.006), but not residual renal function.

CONCLUSION

Over-hydration is common in asymptomatic Chinese PD patients. The degree of over-hydration is particularly pronounced in patients who are inadequately dialyzed, have multiple comorbid conditions and low serum albumin levels. Over-hydration is associated with high blood pressure and arterial stiffness, and may contribute to the excessive risk of cardiovascular disease in this group of patients.