Predicting one-year mortality in peritoneal dialysis patients: an analysis of the China Peritoneal Dialysis Registry

Development and validation of a prediction model for all-cause mortality in maintenance dialysis patients: a multicenter retrospective cohort study

BACKGROUND

The mortality risk varies considerably among individual dialysis patients. This study aimed to develop a user-friendly predictive model for predicting all-cause mortality among dialysis patients.

METHODS

Retrospective data regarding dialysis patients were obtained from two hospitals. Patients in training cohort (N = 1421) were recruited from the Fifth Affiliated Hospital of Sun Yat-sen University, and patients in external validation cohort (N = 429) were recruited from the First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine. The follow-up endpoint event was all-cause death. Variables were selected by LASSO-Cox regression, and the model was constructed by Cox regression, which was presented in the form of nomogram and web-based tool. The discrimination and accuracy of the prediction model were assessed using C-indexes and calibration curves, while the clinical value was assessed by decision curve analysis (DCA).

RESULTS

The best predictors of 1-, 3-, and 5-year all-cause mortality contained nine independent factors, including age, body mass index (BMI), diabetes mellitus (DM), cardiovascular disease (CVD), cancer, urine volume, hemoglobin (HGB), albumin (ALB), and pleural effusion (PE). The 1-, 3-, and 5-year C-indexes in the training set (0.840, 0.866, and 0.846, respectively) and validation set (0.746, 0.783, and 0.741, respectively) were consistent with comparable performance. According to the calibration curve, the nomogram predicted survival accurately matched the actual survival rate. The DCA showed the nomogram got more clinical net benefit in both the training and validation sets.

CONCLUSIONS

The effective and convenient nomogram may help clinicians quantify the risk of mortality in maintenance dialysis patients.

Immune-metabolic marker of albumin-to-fibrinogen ratio based prognostic nomogram for patients following peritoneal dialysis

Background

The nutritional status and coagulation function of peritoneal dialysis (PD) patients are closely associated with their prognosis. This study aims to investigate the prognostic value of the albumin-to-fibrinogen ratio (AFR) on mortality in PD patients and to establish a prognostic prediction model based on AFR.

Methods

We retrospectively collected data from 148 PD patients treated at our hospital between Oct. 2011 and Dec. 2021. Using the "survminer" package in R, we determined the optimal cutoff value for AFR and divided the patients into low-AFR and high-AFR groups. The primary endpoint of this study was overall survival (OS). Univariate and multivariate Cox analyses were used to assess the impact of AFR and other factors on prognosis, and a corresponding prognostic prediction model was constructed using a nomogram, which was evaluated through ROC curves, the c-index, and calibration plots.

Results

The optimal cutoff value for AFR was 9.06. In the entire cohort, 30 patients (20.2%) were classified into the low-AFR group. Compared to the high-AFR group, patients in the low-AFR group were older, had lower total urine output over 24 h, higher blood urea nitrogen, higher total protein and urinary microalbumin levels, and longer remission times (p < 0.05). They also had a poorer OS (HR: 1.824, 95%CI: 1.282-2.594, p < 0.05). Multivariate Cox analysis indicated that AFR was an independent prognostic factor for OS (HR: 1.824, 95% CI: 1.282-2.594, p < 0.05). A prognostic prediction model based on AFR, age, and cause of ESRD was successfully validated for predicting OS in PD patients.

Conclusion

AFR represents a potential prognostic biomarker for PD patients. The prognostic prediction model based on AFR can provide accurate OS predictions for PD patients, aiding clinicians in making better-informed decisions.

Peritoneal Dialysis Care in Mainland China: Nationwide Survey

BACKGROUND

Peritoneal dialysis (PD) care in mainland China has been progressing in the past 10 years.

OBJECTIVE

To complement information from the dialysis registry, a large-scale nationwide survey was conducted to investigate the current infrastructure and management of PD care at hospitals of different tiers.

METHODS

A web-based multiple-choice questionnaire was distributed through the National Center for Nephrology Medical Quality Management and Control to PD centers of secondary and tertiary hospitals in October 2020. The 2-part survey collected the information of PD centers and the clinical management of patients on PD. A total of 788 effective surveys from 746 hospitals were voluntarily returned, and data were extracted and analyzed.

RESULTS

The effective survey data covered 101,537 patients on PD, with 95% (96,460/101,537) in the tertiary hospitals. The median number of patients per PD center was 60 (IQR 21-152); this number was 32 (IQR 8-65) and 70 (IQR 27-192) for secondary and tertiary hospitals, respectively. There was a discrepancy in the availability of designated physical areas for different functions of PD care between the secondary and tertiary hospitals. The proportion of tertiary hospitals with PD training (P=.01), storage (P=.09), and procedure area (P<.001) was higher compared to secondary hospitals. PD catheter placement was performed in 96% (608/631) of the PD centers in tertiary hospitals, which was significantly higher compared to 86% (99/115) in secondary hospitals (P<.001). Automated PD was available in 55% (347/631) of the tertiary hospitals, which was significantly higher than that in secondary hospitals (37/115, 32%) according to the survey (P<.001). The most commonly performed PD module was continuous ambulatory peritoneal dialysis (772/788, 98%), followed by intermittent peritoneal dialysis (543/788, 69%). The overall reported nocturnal intermittent peritoneal dialysis was 31% (244/788); it was 28% (220/788) for continuous cycling peritoneal dialysis and 15% (118/788) for tidal peritoneal dialysis. Comparisons between the secondary and tertiary hospitals revealed no significant differences in prophylactic antibiotic use for PD catheter placement and therapeutic use for peritonitis. The first peritoneal equilibrium test was conducted in 58% (454/788) of patients at 4-6 weeks after initiation of PD, and 91% (718/788) reported at least one peritoneal equilibrium test per year. Overall, 79% (570/722) and 65% (469/722) of PD centers performed assessment for dialysis adequacy and residual kidney function, respectively; and 87% (685/788) of patients on PD were followed every 1 to 3 months for laboratory and auxiliary examinations.

CONCLUSIONS

This national survey reflects the current status and disparities of PD center management in mainland China. The study results suggest that the PD care needs to be more conveniently accessible in secondary hospitals, and quality management and staff training in secondary hospitals are still in high demand.

Research hotspots and emerging trends of automated peritoneal dialysis: A bibliometric analysis from 2000 to 2020

BACKGROUND

The implementation of automated peritoneal dialysis (APD) has considerably increased in many countries. We conducted a bibliometric analysis to evaluate the accumulating studies on APD in the last two decades quantitatively and qualitatively.

METHODS

Publications regarding APD research between 2000 and 2020 were retrieved from the Web of Science Core Collection database by using the index term "automated peritoneal dialysis." CiteSpace, VOSviewer, and an online platform were employed to analyze the number of publications and the collaboration relationships between countries, institutions, authors, and co-cited journals. Cluster analysis and burst keywords detection were performed on co-cited references and keywords, respectively.

RESULTS

We obtained a record of 545 publications related to APD in total. The United States was the country that contributes most, and Baxter Healthcare Corporation was the leading institution. Peritoneal Dialysis International was the most active journals in this field. Claudio Ranco was the most productive author, and Simon J Davies ranked the first in the cited authors. Co-cited reference cluster analysis and high frequency keywords showed that survival, ultrafiltration and peritonitis are continuous hot topics. While remote monitoring (RM) and telemedicine may be APD research frontiers according to burst keywords detection.

CONCLUSION

This bibliometric study provides comprehensive overview on the publications of APD over the past two decades. These findings help to identify the hotspots and explore new directions for future research. RM has become an emerging trend in APD field.

Kt/V reach rate is associated with clinical outcome in incident peritoneal dialysis patients

Background

The urea clearance index (Kt/V) is an important index for predicting the clinical outcome of peritoneal dialysis (PD) patients, but it changes with time depending on the clinical condition. This study aimed to investigate the association between the Kt/V reach rate (defined as the percentage of Kt/V measurements that reached ≥ 1.70) and clinical outcome in incident PD patients.

Methods

In this retrospective cohort study, 210 patients were enrolled from the First Affiliated Hospital of Zhengzhou University from 1 January 2013 to 31 October 2019. The target Kt/V reach rate in the first year was applied as the predictor variable. Kaplan-Meier survival curves were drawn to evaluate differences in prognosis. The association between Kt/V reach rate and the composite clinical outcome (death or transfer to hemodialysis) was tested by Cox regression analysis.

Results

The dialysis adequacy group (Kt/V reach rate 3/3 times) and the dialysis intermittent adequacy group (1/3 or 2/3 times) had significantly better clinical outcomes than the dialysis inadequacy group (0/3 times). There was no difference in clinical outcome between the lower-rate group (reach rate 1/3 times) and the higher-rate group (2/3 times). Compared with the dialysis inadequacy group, the dialysis intermittent adequacy group and dialysis adequacy group had significantly lower risks of the composite outcome (HR 0.487, 95% CI 0.244–0.971, p = 0.041; HR 0.150, 95% CI 0.043–0.520, p = 0.003) in the fully adjusted analysis.

Conclusion

Higher Kt/V reach rates are associated with a better prognosis in incident PD patients.

Serum albumin at 1 year after peritoneal dialysis predicts long-term outcomes on continuous ambulatory peritoneal dialysis

Background

Hypoalbuminemia at baseline is a powerful predictor of long-term outcomes in peritoneal dialysis patients. However, the levels of serum albumin are dynamically changed during PD. The present study investigated whether the improvement of hypoalbuminemia during PD can affect the patients’ outcomes.

Methods

436 consecutive incidents continuous ambulatory peritoneal dialysis patients were involved in this study. Demographic, hematologic, biochemical, and dialysis-related data at baseline as well as 1 year after PD were collected. All patients were followed for at least 1 year for mortality.

Results

Among the 436 patients, the mean age was 48.44 ± 14.98 years, with 58.26% males and 18.12% prevalence of diabetes. The mean follow-up time was 48.25 ± 24.05 months. During the follow-up period, a total of 68 patients died. Serum albumin was 34.35 ± 5.65 g/L at baseline, which increased to 37.39 ± 5.05 g/L at 1 year after PD. Multivariate linear regression analysis showed that sex, age, BMI, diabetic nephropathy, as well as albumin at baseline were independently associated with albumin at 1 year. Every 1 year of age rise would result in a 3.9% increase in the risk of mortality (HR = 1.039, 95%CI 1.016–1.061, p = 0.001). Every 1 g/L increase in albumin at 1 year after PD confers an 8.7% decrease in the risk of mortality (HR = 0.913, 95%CI 0.856–0.973, p = 0.005).

Conclusion

The level of serum albumin was increased in the first year of PD. Serum albumin after 1 year of PD predicted mortality in peritoneal dialysis.

Peritoneal transport status and first episode of peritonitis: a large cohort study

BACKGROUND

Peritonitis is one of the most serious complications of peritoneal dialysis (PD). This study aimed to explore the relationship between peritoneal transport status and the first episode of peritonitis, as well as the prognosis of patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

METHOD

A retrospective cohort study was conducted, analyzing data of CAPD patients from 1st January 2009, to 31st December 2017. Baseline data within 3 months after PD catheter placement was recorded. Cox multivariate regression analysis was performed to determine the risk factors for the first episode of peritonitis, technique failure and overall mortality.

RESULTS

A total of 591 patients were included in our analysis, with a mean follow-up visit of 49 months (range: 27-75months). There were 174 (29.4%) patients who had experienced at least one episode of peritonitis. Multivariate Cox regression analysis revealed that a higher peritoneal transport status (high and high-average) (HR 1.872, 95%CI 1.349-2.599, p = 0.006) and hypoalbuminemia (HR 0.932,95% CI 0.896, 0.969, p = 0.004) were independent risk factors for the occurrence of the first episode of peritonitis. In addition, factors including gender (male) (HR 1.409, 95%CI 1.103, 1.800, p = 0.010), low serum albumin (HR 0.965, 95%CI 0.938, 0.993, p = 0.015) and the place of residence (rural) (HR 1.324, 95%CI 1.037, 1.691, p = 0.024) were independent predictors of technique failure. Furthermore, low serum albumin levels (HR 0.938, 95%CI 0.895, 0.984, p = 0.008) and age (>65years) (HR 1.059, 95%CI 1.042, 1.076, p < 0.001) were significantly associated with the risk of overall mortality of PD patients.

CONCLUSIONS

Baseline hypoalbuminemia and a higher peritoneal transport status are risk factors for the first episode of peritonitis. Factors including male gender, hypoalbuminemia, and residing in rural areas are associated with technique failure, while hypoalbuminemia and age (>65years) are predictors of the overall mortality in PD patients. Nevertheless, the peritoneal transport status does not predict technique failure or overall mortality of PD patients.

Development and validation of a novel score to predict dialysis inadequacy in continuous ambulatory peritoneal dialysis patients

Objective

Adequate dialysis is of great importance for continuous ambulatory peritoneal dialysis (CAPD) patients. This study aimed to develop and validate an easily applicable quantitative dialysis adequacy risk scoring system in CAPD patients based on laboratory parameters from a single blood draw.

Methods

A total of 634 CAPD patients from four study centers were enrolled in this study (345 and 289 patients in development and validation groups, respectively). A risk score model for inadequate dialysis was developed based on multivariate regression analysis, which was validated by the area under the receiver operator curve and calibrated by a calibration curve.

Results

Seven independent predictors for inadequate dialysis were identified in the development group (male sex, hypoalbuminemia, anemia, being overweight, hyperuricemia, estimated glomerular filtration rate <4.7 mL/min/1.73 m², and serum creatinine >800 μmol/L). A risk prediction score model was established and validated in the development and validation groups. Further analysis indicated that this model is suitable for CAPD patients with a wide range of clinical manifestations.

Conclusion

An easily applicable novel risk scoring system was established to detect inadequate dialysis in CAPD patients.

Development of a scoring tool for predicting prolonged length of hospital stay in peritoneal dialysis patients through data mining

Background

The hospital admission rate is high in patients treated with peritoneal dialysis (PD), and the length of stay (LOS) in the hospital is a key indicator of medical resource allocation. This study aimed to develop a scoring tool for predicting prolonged LOS (pLOS) in PD patients by combining machine learning and traditional logistic regression (LR).

Methods

This study was based on patient data collected using the Hospital Quality Monitoring System (HQMS) in China. Three machine learning methods, classification and regression tree (CART), random forest (RF), and gradient boosting decision tree (GBDT), were used to develop models to predict pLOS, which is longer than the average LOS, in PD patients. The model with the best prediction performance was used to identify predictive factors contributing to the outcome. A multivariate LR model based on the identified predictors was then built to derive the score assigned to each predictor. Finally, a scoring tool was developed, and it was tested by stratifying PD patients into different pLOS risk groups.

Results

A total of 22,859 PD patients were included in our study, with 25.2% having pLOS. Among the three machine learning models, the RF model achieved the best prediction performance and thus was used to identify the 10 most predictive variables for building the scoring system. The multivariate LR model based on the identified predictors showed good discrimination power with an AUROC of 0.721 in the test dataset, and its coefficients were used as a basis for scoring tool development. On the basis of the developed scoring tool, PD patients were divided into three groups: low risk (≤5), median risk [5–10], and high risk (>10). The observed pLOS proportions in the low-risk, median-risk, and high-risk groups in the test dataset were 11.4%, 29.5%, and 54.7%, respectively.

Conclusions

This study developed a scoring tool to predict pLOS in PD patients. The scoring tool can effectively discriminate patients with different pLOS risks and be easily implemented in clinical practice. The pLOS scoring tool has a great potential to help physicians allocate medical resources optimally and achieve improved clinical outcomes.

Fibrinogen/Albumin ratio: A more powerful prognostic index for patients with end-stage renal disease

BACKGROUND

Microinflammation is linked to an increased risk of death due to cardiovascular disease (CVD) in patients with end-stage renal disease (ESRD). Although the fibrinogen/albumin ratio (FAR), a novel inflammatory marker, has been shown to predict mortality in various diseases, limited evidence is available for its role in ESRD. The purpose of this study is to explore the prognostic value of the FAR in ESRD patients on peritoneal dialysis (PD).

METHODS

In this retrospective observational study, we enrolled patients with ESRD who underwent PD therapy in our hospital between 1 January 2011 and 31 December 2017. The Kaplan-Meier method and Cox proportional hazards models were used to determine the contact between the FAR level and mortality.

RESULTS

A total of 562 patients were enrolled in our research. The median FAR was 0.12, and patients were divided into two groups (low FAR group: FAR < 0.12, n = 250, and high FAR group: FAR ≥ 0.12, n = 312) according to the median FAR. Kaplan-Meier curves showed that the cumulative incidences of both all-cause mortality and CVD mortality were significantly higher in patients with FAR ≥ 0.12 (both P < .001). In multivariable analysis, the high FAR group had an important increased risk of all-cause and CVD mortality (HR: 1.80; 95% CI: 1.03-3.14, P = .038 and HR: 2.31; 95% CI: 1.17-4.59, P = .016, respectively).

CONCLUSIONS

Our results suggest that a high baseline FAR value is an independent prognostic factor in ESRD patients on PD.

Development of a risk prediction model for infection-related mortality in patients undergoing peritoneal dialysis

Background

Assessment of infection-related mortality remains inadequate in patients undergoing peritoneal dialysis. This study was performed to develop a risk model for predicting the 2-year infection-related mortality risk in patients undergoing peritoneal dialysis.

Methods

The study cohort comprised 606 patients who started and continued peritoneal dialysis for 90 at least days and was drawn from the Fukuoka Peritoneal Dialysis Database Registry Study in Japan. The patients were registered from 1 January 2006 to 31 December 2016 and followed up until 31 December 2017. To generate a prediction rule, the score for each variable was weighted by the regression coefficients calculated using a Cox proportional hazard model adjusted by risk factors for infection-related mortality, including patient characteristics, comorbidities, and laboratory data.

Results

During the follow-up period (median, 2.2 years), 138 patients died; 58 of them of infectious disease. The final model for infection-related mortality comprises six factors: age, sex, serum albumin, serum creatinine, total cholesterol, and weekly renal Kt/V. The incidence of infection-related mortality increased linearly with increasing total risk score (P for trend <0.001). Furthermore, the prediction model showed adequate discrimination (c-statistic = 0.79 [0.72–0.86]) and calibration (Hosmer–Lemeshow test, P = 0.47).

Conclusion

In this study, we developed a new model using clinical measures for predicting infection-related mortality in patients undergoing peritoneal dialysis.

Membrane transport status does not predict peritonitis risk in patients on peritoneal dialysis

AIM

The aim of this study is to determine whether peritoneal membrane transport status (MTS) is associated with peritonitis or poor peritoneal dialysis-related outcomes.

METHODS

This retrospective cohort study analysed data of incident adult patients on peritoneal dialysis in Western Sydney between 1 October 2003 and 31 December 2012. Only patients who underwent peritoneal equilibration and adequacy tests within 6 months of commencement were included. Kaplan-Meier survival curves for time until first peritonitis and time until composite endpoint of peritonitis, death or technique failure, censored for transplant, were constructed.

RESULTS

About 397 patients, mean age 58.8(+/-2SD29) years, body mass index (BMI) 26.6(+/-5) kg/m² and serum albumin 35.4(+/-5) g/L were included. About 59.2% had high/high-average peritoneal MTS; 45.8% were past and current smokers; 51.9% developed at least one episode of peritonitis; 7.6% changed to haemodialysis; 6.3% underwent transplantation; 8.8% died; and 25.4% remained free of the aforementioned events over a mean follow-up period of 22.5 months (range 0-115 months). Peritoneal MTS was not associated with time to first peritonitis (p = 0.67) or composite endpoint of peritonitis, death or technique failure (p = 0.12). Smoking and hypoalbuminaemia independently predicted time to first peritonitis. Past and current smokers had a hazard ratio of 1.38 (95% CI 1.03-1.86) for shorter time to first peritonitis, significant after adjustment for serum albumin (p = 0.033). Serum albumin <32 g/L had a hazard ratio of 1.74 (95% CI 1.13-2.67) for shorter time to first peritonitis, significant after adjusting for smoking (p = 0.012).

CONCLUSION

Smoking and hypoalbuminaemia, but not MTS, were associated with shorter time to first peritonitis and composite endpoint of peritonitis, death and technique failure.

Prediction models for the mortality risk in chronic dialysis patients: a systematic review and independent external validation study

OBJECTIVE

In medicine, many more prediction models have been developed than are implemented or used in clinical practice. These models cannot be recommended for clinical use before external validity is established. Though various models to predict mortality in dialysis patients have been published, very few have been validated and none are used in routine clinical practice. The aim of the current study was to identify existing models for predicting mortality in dialysis patients through a review and subsequently to externally validate these models in the same large independent patient cohort, in order to assess and compare their predictive capacities.

METHODS

A systematic review was performed following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. To account for missing data, multiple imputation was performed. The original prediction formulae were extracted from selected studies. The probability of death per model was calculated for each individual within the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD). The predictive performance of the models was assessed based on their discrimination and calibration.

RESULTS

In total, 16 articles were included in the systematic review. External validation was performed in 1,943 dialysis patients from NECOSAD for a total of seven models. The models performed moderately to well in terms of discrimination, with C-statistics ranging from 0.710 (interquartile range 0.708-0.711) to 0.752 (interquartile range 0.750-0.753) for a time frame of 1 year. According to the calibration, most models overestimated the probability of death.

CONCLUSION

Overall, the performance of the models was poorer in the external validation than in the original population, affirming the importance of external validation. Floege et al's models showed the highest predictive performance. The present study is a step forward in the use of a prediction model as a useful tool for nephrologists, using evidence-based medicine that combines individual clinical expertise, patients' choices, and the best available external evidence.