Biomarker and clinical data–based predictor tool (MAUXI) for ultrafiltration failure and cardiovascular outcome in peritoneal dialysis patients: a retrospective and longitudinal study
Prediction of peritoneal dialysis (PD) endurance and technique failure (ultrafiltration failure (UFF)-cardiovascular disease) are still unravelled. Previous machine learning (ML) techniques had been tested with moderate accuracy within a time span of 5–7 years. Ultrafiltration and cardiovascular events take place within the first 29–60 months of PD treatment, giving importance to accurate predictions to implement prophylactic interventions. WHAT THIS STUDY ADDS Our study demonstrates that mesothelial-to-mesenchymal transition biomarkers and clinical data under ML models (MAUXI software) can predict endurance and different PD technique failures, opening new avenues to individual treatments. HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY MAUXI software implies novel interpretability of complex models based on artificial intelligence in the cardiorenal field. Paving the way to accurate predictions in PD technique will lead to an unprecedented development of prophylactic interventions related to the neurological, cardiovascular and UFF events. This will make possible the reduction of the cost burden of the European budget on PD withdrawal. 

Peritoneal dialysis (PD) is a home care, cost-effective kidney replacement therapy for removal of excess water, electrolytes and toxic metabolic products from the body. PD is based on infusing a sterile hyperosmotic solution into the peritoneal cavity. During PD, there is an ultrafiltration (UF) process based on hydrostatic pressure (convection) and oncotic pressure (diffusion) between the blood and the PD solution (PDS) through the peritoneal membrane (PM). Together with haemodialysis (HD), PD is a life-saving treatment for chronic kidney disease (CKD) and end-stage renal disease (ESRD). UF failure (UFF) occurs when patients experience long-term ultrafiltration rate (UFR) of less than 400 mL water removal in a 4-hour dwell (UFR4H) using a dextrose solution. The 6-year UFF incidence ranges from 30% to 60%, where around 54% will be transferring to HD or dying on cardiovascular disease (CVD) in concomitance with UFF. The structure of the PM is composed of a single layer of mesothelial cells (MCs) that lines a compact zone of connective tissue containing few fibroblasts, mast cells, macrophages and vessels. The PM is a semipermeable membrane, which is responsible for the UFR and UFF. During PD, mesothelial genes are silenced to allow induction of mesenchymal signatures. This process is known as mesothelial-to-mesenchymal transition (MMT), with prototypical epithelioid and non-epithelioid morphologies representing early and advanced MMT. Advanced MMT is associated with deregulated secreted MMT biomarkers and mass transfer coefficient (MTC) of creatinine ≥11 mL/min. Machine learning (ML) is a branch of artificial intelligence (AI) with learning capability of data-driven experiences, avoiding theory-driven priors and factor-balanced hypotheses. Despite limitations, ML and deep learning algorithms are being used in CKD, ESRD and PD, among others. Soluble surrogate effluent biomarkers are researched for the non-invasive validation of the PM function, but guidelines are still scarce—being this the rationale for this study. Therefore, we propose a novel prediction software as a medical device, MAUXI, based on ML and MMT-associated biomarkers with robust accuracy to determine PD endurance and technique failure. 

Patients and data registry Our study was built on the biobank of the Hospital Universitario La Paz (Madrid, Spain), comprising a total of 921 patients initiating PD from 1979 to the present times . Thus, we generated a platform with electronic medical records of each patient. This biobank benefits from semi-annual peritoneal equilibration tests (PETs), CVD and peritonitis events and a collection of longitudinal effluents, plasm and sera of every single patient. The PET study was performed following the method of Twardowski. Importantly, definitions of the four outcomes were set up by medical doctors of our team and stayed in line with the current body of research on major cardiac events. The first PD outcome to predict (primary endpoint) was endurance as the remaining time for a given patient until PD technique failure due to CVD or UFF. Endurance (in remaining months in PD). As secondary endpoints, other specific PD outcomes ‘to predict’ (categorical variables) in the models of this study were defined as: Exit: transfer to HD, exitus (known as exitus letalis or death). Cause of PD end: UFF, CVD. Technical failure: ictus (brain haemorrhage), ischaemic cardiac congestion (ICC), vascular events (amputations and peripheral artery disease, among others), MMT, peritonitis-induced MMT (MMT-peritonitis). Thus, we provide the description of the outcomes to predict in each ML model in the , as well as the details of the external positive and negative datasets to validate algorithms. Patient involvement Patients could not participate in the study (see ). Sample preservation and cell culture For all the duration of PD, patients were extracted regularly every 6 months effluent, serum and plasm, which were frozen at −80°C until their analysis. Six dwells of effluents (0–240 min) were measured routinely for 188 variables, including anthropometrics and peritoneal transport as seen in PETs. Phenotypic information of MCs was recycled from a database from other previous studies, in which isolation and culture of MCs from human effluents was performed, as previously described. Biomarker selection and multiplex ELISA To predict PD failure and endurance in our PD population, we selected 13 biomarker proteins related to the MMT that were specifically produced and secreted by MCs, as provided in our previously reported microarrays. Selected biomarkers were: matrix metalloproteinase-2 (MMP-2), tenascin-C (TN-C), interleukin-11 (IL-11), plasminogen activator inhibitor-1 (PAI-1), periostin (PSTN), vascular endothelial growth factor A (VEGF-A), collagen-13 (COL-13), cadherin-13 (CDH-13), thrombospondin-1 (TSP-1), bone morphogenetic protein-7 (BMP-7), IL-6, fibroblast activation protein (FAP) and IL-33. All biomarkers have been associated with MMT or epithelial-mesenchymal transition (EMT) processes, including in malignancies and on contact with PDS, though different pathways—being BMP-7 the prototypical counteractor. Proteins found in diabetes and glucose imbalances are VEGF-A, TSP-1, PSTN and CDH-13. In cardiotoxic status related to hypertrophy, cardiomyopathy, infarction, coronary diseases or neurological disorders, all proteins have been found to be involved. Merely TSP-1, CDH-13, PAI-1, BMP-7 and TN-C in certain levels or isoforms can act as cardioprotective. Multiplex ELISA Quantibody (RayBio Human QuantiBody, RayBiotech Inc., Peterborough, UK) arrays were suitable for the simultaneous quantification of soluble proteins in effluents, sera and plasm with the guarantee of no cross-reaction and exclusion of homologues and orthologues . The assay was performed following the protocol given in the manufacturer’s instructions with the longest recommended incubation times and a dilution factor of 1:2 for serum and 1:1 for effluents. Additionally, we compared protein detection ranges of effluents and sera of former studies and other protein kits. Data preprocessing We digitalised and used <70 000 clinical observations, with available effluents and 166 variables, to train models. We removed variables with >45% of missingness and implemented one-hot encoding to binarise categorical variables to proceed with imputation . Further, we added biomarker values of the sera and the dialysate-serum ratio or dialysate-plasm ratio (D/P) and performed a second miceRanger run without compromising important variables. We concluded independently with 16 subdatasets for each the train (Hospital Universitario La Paz, Madrid, Spain) and for the validation datasets (Hospital Universitario La Princesa, Madrid, Spain). Statistical analysis In the present study, we used RStudio 2022.02.2+485 ‘Prairie Trillium’ Release (2022-04-19) and Python 3.9 for Windows. The modules used for each software are showcased in . For the canonical statistical analysis, retrieve . Clinical feature selection Linear correlation We calculated the Pearson correlation of all variables with RStudio to demonstrate linear dependencies among the collected variables and PD outcomes. Mutual information Correlation measures often miss dependency between features when dealing with non-linear relationships. Normalised mutual information feature selection (NMIFS) is powered to demonstrate relationships between features and response targets, as it is more sensitive to linear and non-linear relationships. To accomplish the explanation of most of the variability of the outcomes to predict (PD cause end, exit, failure, endurance), the NMIFS approach was conducted among the 162 remaining preprocessed variables. Mutual information (MI) or Shannon’s entropy is deﬁned as the decrease in uncertainty (or informational gain). MI quantiﬁes the amount of information shared by two random variables and is a non-linear dimensionality reduction to spare computational cost . The normalised MI (NMI) takes real values within the range [0, 1] like the correlation coefﬁcient. Each target to predict required the following number of variables: 30 (endurance), 38 (PD cause end), 36 (exit), 34 (failure). Advanced machine learning (ML) analysis for model selection A representative dataset is important to ensure generalisability. However, AI algorithms do not necessarily require data that mirrors specific distributions of other countries or studies. Instead, AI models need diverse and high-quality data to learn effectively (retrieve ). Ranking of machine learning (ML) regressors for numerical outcomes To allocate models without overfitting and memory learning (see ), regressors were ranked by similarity of distribution to the original values, performance of mean absolute error (MAE), mean squared error (MSE) and root MSE (RMSE). The outcome variable was deleted as input for model training and validation to avoid data leakage. Ranking of machine learning classifiers for categorical outcomes In statistical inference, the limitations of the information-theoretic performance are commonly expressed in reference to statistical divergence between the underlying statistical models. We avoided indomitable data dimension growth, by which computation of the decision-making statistics and attendant performance limits (divergence metrics) underpin complexity and instability. So, we used the following metrics of robustness to rank classifiers: Kullback–Leibler (KL) divergence, precision, recall, F1 score, MI and similarity of classifications to the original values. Additionally, we deleted outcome variables as model inputs in the training and validation phase to avoid data leakage. Sequentially, we selected models with the best recall, precision and receiver operating characteristic curve under the area (ROC-AUC). We computed for the majority of the metrics the macro-, micro- and weighted averages since all subclasses were imbalanced. Nonetheless, medical publications—even with class imbalances—normally consider direct metrics or the macro-average. Further, we scored classifiers by precision, recall and the confusion matrix (see ). Training and validation of machine learning algorithms Model development was split into four common steps and classified on the abovementioned metrics: a transformation and centering of the datasets; a prior training with the ‘La Paz’ dataset and a selection of the best raw algorithms by metrics of robustness and a final optimisation of (hyper-)parameters; and a last verification of correct predictions with ‘unseen’ datasets by using the external positive and negative validation datasets (see ). SHapley Additive exPlanations (SHAP) The goal with SHapley Additive exPlanations (SHAP) is to explain the individual feature attribution of a model by computing the contribution of each to the prediction when the feature is present or absent. The methodology is based on SHapley values from coalitional game theory. SHAP values determine how the members of a group should receive individual payoffs according to their marginal contributions (see ). MAUXI: building the automatised calculator with embedded machine learning algorithms Creation of a local server and a web-host was made using the Bulma interface template. To that extent, we created a Python server, in which a dashboard (‘get’) was included. Further, we included four different ‘post’ scripts to receive the patient data, inputted by any medical professional. The post inbox was connected indirectly with the pretrained algorithm for each target (see ). The output referred to the numerical and categorical variables. 

Our study was built on the biobank of the Hospital Universitario La Paz (Madrid, Spain), comprising a total of 921 patients initiating PD from 1979 to the present times . Thus, we generated a platform with electronic medical records of each patient. This biobank benefits from semi-annual peritoneal equilibration tests (PETs), CVD and peritonitis events and a collection of longitudinal effluents, plasm and sera of every single patient. The PET study was performed following the method of Twardowski. Importantly, definitions of the four outcomes were set up by medical doctors of our team and stayed in line with the current body of research on major cardiac events. The first PD outcome to predict (primary endpoint) was endurance as the remaining time for a given patient until PD technique failure due to CVD or UFF. Endurance (in remaining months in PD). As secondary endpoints, other specific PD outcomes ‘to predict’ (categorical variables) in the models of this study were defined as: Exit: transfer to HD, exitus (known as exitus letalis or death). Cause of PD end: UFF, CVD. Technical failure: ictus (brain haemorrhage), ischaemic cardiac congestion (ICC), vascular events (amputations and peripheral artery disease, among others), MMT, peritonitis-induced MMT (MMT-peritonitis). Thus, we provide the description of the outcomes to predict in each ML model in the , as well as the details of the external positive and negative datasets to validate algorithms. 

Patients could not participate in the study (see ). 

For all the duration of PD, patients were extracted regularly every 6 months effluent, serum and plasm, which were frozen at −80°C until their analysis. Six dwells of effluents (0–240 min) were measured routinely for 188 variables, including anthropometrics and peritoneal transport as seen in PETs. Phenotypic information of MCs was recycled from a database from other previous studies, in which isolation and culture of MCs from human effluents was performed, as previously described. 

To predict PD failure and endurance in our PD population, we selected 13 biomarker proteins related to the MMT that were specifically produced and secreted by MCs, as provided in our previously reported microarrays. Selected biomarkers were: matrix metalloproteinase-2 (MMP-2), tenascin-C (TN-C), interleukin-11 (IL-11), plasminogen activator inhibitor-1 (PAI-1), periostin (PSTN), vascular endothelial growth factor A (VEGF-A), collagen-13 (COL-13), cadherin-13 (CDH-13), thrombospondin-1 (TSP-1), bone morphogenetic protein-7 (BMP-7), IL-6, fibroblast activation protein (FAP) and IL-33. All biomarkers have been associated with MMT or epithelial-mesenchymal transition (EMT) processes, including in malignancies and on contact with PDS, though different pathways—being BMP-7 the prototypical counteractor. Proteins found in diabetes and glucose imbalances are VEGF-A, TSP-1, PSTN and CDH-13. In cardiotoxic status related to hypertrophy, cardiomyopathy, infarction, coronary diseases or neurological disorders, all proteins have been found to be involved. Merely TSP-1, CDH-13, PAI-1, BMP-7 and TN-C in certain levels or isoforms can act as cardioprotective. Multiplex ELISA Quantibody (RayBio Human QuantiBody, RayBiotech Inc., Peterborough, UK) arrays were suitable for the simultaneous quantification of soluble proteins in effluents, sera and plasm with the guarantee of no cross-reaction and exclusion of homologues and orthologues . The assay was performed following the protocol given in the manufacturer’s instructions with the longest recommended incubation times and a dilution factor of 1:2 for serum and 1:1 for effluents. Additionally, we compared protein detection ranges of effluents and sera of former studies and other protein kits. 

We digitalised and used <70 000 clinical observations, with available effluents and 166 variables, to train models. We removed variables with >45% of missingness and implemented one-hot encoding to binarise categorical variables to proceed with imputation . Further, we added biomarker values of the sera and the dialysate-serum ratio or dialysate-plasm ratio (D/P) and performed a second miceRanger run without compromising important variables. We concluded independently with 16 subdatasets for each the train (Hospital Universitario La Paz, Madrid, Spain) and for the validation datasets (Hospital Universitario La Princesa, Madrid, Spain). 

In the present study, we used RStudio 2022.02.2+485 ‘Prairie Trillium’ Release (2022-04-19) and Python 3.9 for Windows. The modules used for each software are showcased in . For the canonical statistical analysis, retrieve . 

Linear correlation We calculated the Pearson correlation of all variables with RStudio to demonstrate linear dependencies among the collected variables and PD outcomes. Mutual information Correlation measures often miss dependency between features when dealing with non-linear relationships. Normalised mutual information feature selection (NMIFS) is powered to demonstrate relationships between features and response targets, as it is more sensitive to linear and non-linear relationships. To accomplish the explanation of most of the variability of the outcomes to predict (PD cause end, exit, failure, endurance), the NMIFS approach was conducted among the 162 remaining preprocessed variables. Mutual information (MI) or Shannon’s entropy is deﬁned as the decrease in uncertainty (or informational gain). MI quantiﬁes the amount of information shared by two random variables and is a non-linear dimensionality reduction to spare computational cost . The normalised MI (NMI) takes real values within the range [0, 1] like the correlation coefﬁcient. Each target to predict required the following number of variables: 30 (endurance), 38 (PD cause end), 36 (exit), 34 (failure). 

We calculated the Pearson correlation of all variables with RStudio to demonstrate linear dependencies among the collected variables and PD outcomes. 

Correlation measures often miss dependency between features when dealing with non-linear relationships. Normalised mutual information feature selection (NMIFS) is powered to demonstrate relationships between features and response targets, as it is more sensitive to linear and non-linear relationships. To accomplish the explanation of most of the variability of the outcomes to predict (PD cause end, exit, failure, endurance), the NMIFS approach was conducted among the 162 remaining preprocessed variables. Mutual information (MI) or Shannon’s entropy is deﬁned as the decrease in uncertainty (or informational gain). MI quantiﬁes the amount of information shared by two random variables and is a non-linear dimensionality reduction to spare computational cost . The normalised MI (NMI) takes real values within the range [0, 1] like the correlation coefﬁcient. Each target to predict required the following number of variables: 30 (endurance), 38 (PD cause end), 36 (exit), 34 (failure). 

A representative dataset is important to ensure generalisability. However, AI algorithms do not necessarily require data that mirrors specific distributions of other countries or studies. Instead, AI models need diverse and high-quality data to learn effectively (retrieve ). 

To allocate models without overfitting and memory learning (see ), regressors were ranked by similarity of distribution to the original values, performance of mean absolute error (MAE), mean squared error (MSE) and root MSE (RMSE). The outcome variable was deleted as input for model training and validation to avoid data leakage. Ranking of machine learning classifiers for categorical outcomes In statistical inference, the limitations of the information-theoretic performance are commonly expressed in reference to statistical divergence between the underlying statistical models. We avoided indomitable data dimension growth, by which computation of the decision-making statistics and attendant performance limits (divergence metrics) underpin complexity and instability. So, we used the following metrics of robustness to rank classifiers: Kullback–Leibler (KL) divergence, precision, recall, F1 score, MI and similarity of classifications to the original values. Additionally, we deleted outcome variables as model inputs in the training and validation phase to avoid data leakage. Sequentially, we selected models with the best recall, precision and receiver operating characteristic curve under the area (ROC-AUC). We computed for the majority of the metrics the macro-, micro- and weighted averages since all subclasses were imbalanced. Nonetheless, medical publications—even with class imbalances—normally consider direct metrics or the macro-average. Further, we scored classifiers by precision, recall and the confusion matrix (see ). 

In statistical inference, the limitations of the information-theoretic performance are commonly expressed in reference to statistical divergence between the underlying statistical models. We avoided indomitable data dimension growth, by which computation of the decision-making statistics and attendant performance limits (divergence metrics) underpin complexity and instability. So, we used the following metrics of robustness to rank classifiers: Kullback–Leibler (KL) divergence, precision, recall, F1 score, MI and similarity of classifications to the original values. Additionally, we deleted outcome variables as model inputs in the training and validation phase to avoid data leakage. Sequentially, we selected models with the best recall, precision and receiver operating characteristic curve under the area (ROC-AUC). We computed for the majority of the metrics the macro-, micro- and weighted averages since all subclasses were imbalanced. Nonetheless, medical publications—even with class imbalances—normally consider direct metrics or the macro-average. Further, we scored classifiers by precision, recall and the confusion matrix (see ). 

Model development was split into four common steps and classified on the abovementioned metrics: a transformation and centering of the datasets; a prior training with the ‘La Paz’ dataset and a selection of the best raw algorithms by metrics of robustness and a final optimisation of (hyper-)parameters; and a last verification of correct predictions with ‘unseen’ datasets by using the external positive and negative validation datasets (see ). 

The goal with SHapley Additive exPlanations (SHAP) is to explain the individual feature attribution of a model by computing the contribution of each to the prediction when the feature is present or absent. The methodology is based on SHapley values from coalitional game theory. SHAP values determine how the members of a group should receive individual payoffs according to their marginal contributions (see ). 

Creation of a local server and a web-host was made using the Bulma interface template. To that extent, we created a Python server, in which a dashboard (‘get’) was included. Further, we included four different ‘post’ scripts to receive the patient data, inputted by any medical professional. The post inbox was connected indirectly with the pretrained algorithm for each target (see ). The output referred to the numerical and categorical variables. 

Baseline characteristics of clinical cohorts Patient characteristics, biomarkers and clinical parameters are described longitudinally (n=369) in for a total of 151 independent patients, stratified by gender in . Patients were further stratified into groups with similar features (CCuts) based on the Jenks natural breaks classification method, to determine descriptive statistics and logical assumptions. Exploration of the CCuts  revealed that C3 patients with increased endurance (median 104 months) displayed a decreased time undergoing PD (median 5.10 months), whereas C0 patients enduring shorter already have spent a median of 24.9 months in PD. Long PD endurers were younger and had undergone less time in PD in other external centres (PRIORPD). The female population accounted for 33–64%, being overall 6–9% and <1% Latin-American and Black population, respectively. The diabetic status was reported to be as high as 46% for the mid-endurers C2, appearing in higher frequency the type 2. Hypertension, dyslipidaemia, smoking habits, any type of cancer and co-infection were annotated. Patients being permanently transferred to HD were >43%, whereas patients undergoing fatal events were >40%. Drop-off (UFF or PM failure) was reported at a rate of >71%. CVD events leading to death entailed 4–21%. High PD endurers displayed higher levels of biomarkers in effluents, except calcium and glucose in blood . The interslide variation in the biomaker array was [−2.20, 4.65] %, indicating assay replicability. Feature selection Missingness of datasets The missingness of the total train dataset (17.7%) and each variable (0–43%) are displayed in , as well as the missingness of the positive and the negative validation cohorts  with >50% missingness. Linear correlation We observed linearly high MTCs in UFF patients . Clinical variables related to renal function, PM functionality and ultrafiltration efficiency correlated to each other positively: residual renal function (RRF), UFR4H, generation of urea (GENERUREA) or creatinine (GENER) in effluent and urine, DWELL, ratio dialysate plasma of creatinine (D/P CREATININE) and dialysate ratio of glucose in the dwell time 240 min and 0 min (D5/D0 glucose ratio). Mutual information Overall, 30–38 variables were found to be sufficient to train and test robustly ML algorithms, by selecting the top first 20 of 162 variables, in addition to the biomarkers . Advanced ML analysis for model selection Training and validation of machine learning algorithms Conceptually, we designed a brute force regressor pipeline ( and ) of 28 algorithms, which was used to predict endurance. We discovered, based on the MAE, that Extra Tree (ET), random forest (RF) and k-nearest neighbours regressors were the most robust, including distribution similarities and overfitting . Several models were skewed to the mean of the distribution, acquiring great metrics but poor distributions (Bernoulli Naïve Bayes, etc). Further, the pipeline for categorical targets to predict (PD cause end, exit, failure) comprised 16 algorithms ( and ). The most optimal models were linear discriminant analysis (LDA), decision tree (DT) and RF. Optimisation and validation of selected algorithms Algorithms generally performed properly when comparing all robustness indices on hyperparameter optimisation . ET regressor seemed more suitable for prediction of PD endurance , since validating with the CV test, positive external and negative validation datasets entailed the lowest MAE and highest MI. For binary and multiclass variables, the LDA classifier  resembled the original distribution without overfitting and displayed the highest metrics, excluding the KL divergence, for all the categorical outcomes . Generally, it could be said that predictions were robustly drawn for PD cause end with metrics >0.72 . The other predictions were scoring >0.72 in the micro-averaged ROC-AUC (for almost all the datasets). Infinitesimal-branching classifiers (DT, RF) displayed again perfect metrics biased to the most frequent class . Negative validation showed sensitivity. Consistently, we obtained robust classifications of MMT, peritonitis-induced MMT, ICC, HD and CVD with up to 78% of correct classifications. Overfitted ML algorithms worsened metrics of robustness . This performance analytics further proved that LDA  was the most robust model for PD cause end, PD exit and PD failure. So, ET and LDA models were embedded in the MAUXI software . Metrics worsened by predicting patients with other causes of leave. All algorithms were trained with the proposed dynamic ranges in protein detection of the selected kit. Other kits detecting different levels of protein concentrations, as shown in , may interfere with correct predictions. Thus, harmonised measurements are imperative for proper AI and ML use and performance. SHapley values for model selection We chose SHAP values as our major provider for causality insights about predicting PD endurance . Variables impacting negatively on the remaining time until failure were weight, IL-11, MMP-2, age, accumulated ictus and MTCs. Opposingly, increasing values of RRF, TSP-1, IL-6, TN-C, VEGF-A, COL-13, systolic arterial tension (TASYS), PAI-1 and FAP provided patients with longer survival in PD. 

Patient characteristics, biomarkers and clinical parameters are described longitudinally (n=369) in for a total of 151 independent patients, stratified by gender in . Patients were further stratified into groups with similar features (CCuts) based on the Jenks natural breaks classification method, to determine descriptive statistics and logical assumptions. Exploration of the CCuts  revealed that C3 patients with increased endurance (median 104 months) displayed a decreased time undergoing PD (median 5.10 months), whereas C0 patients enduring shorter already have spent a median of 24.9 months in PD. Long PD endurers were younger and had undergone less time in PD in other external centres (PRIORPD). The female population accounted for 33–64%, being overall 6–9% and <1% Latin-American and Black population, respectively. The diabetic status was reported to be as high as 46% for the mid-endurers C2, appearing in higher frequency the type 2. Hypertension, dyslipidaemia, smoking habits, any type of cancer and co-infection were annotated. Patients being permanently transferred to HD were >43%, whereas patients undergoing fatal events were >40%. Drop-off (UFF or PM failure) was reported at a rate of >71%. CVD events leading to death entailed 4–21%. High PD endurers displayed higher levels of biomarkers in effluents, except calcium and glucose in blood . The interslide variation in the biomaker array was [−2.20, 4.65] %, indicating assay replicability. 

Missingness of datasets The missingness of the total train dataset (17.7%) and each variable (0–43%) are displayed in , as well as the missingness of the positive and the negative validation cohorts  with >50% missingness. Linear correlation We observed linearly high MTCs in UFF patients . Clinical variables related to renal function, PM functionality and ultrafiltration efficiency correlated to each other positively: residual renal function (RRF), UFR4H, generation of urea (GENERUREA) or creatinine (GENER) in effluent and urine, DWELL, ratio dialysate plasma of creatinine (D/P CREATININE) and dialysate ratio of glucose in the dwell time 240 min and 0 min (D5/D0 glucose ratio). Mutual information Overall, 30–38 variables were found to be sufficient to train and test robustly ML algorithms, by selecting the top first 20 of 162 variables, in addition to the biomarkers . 

The missingness of the total train dataset (17.7%) and each variable (0–43%) are displayed in , as well as the missingness of the positive and the negative validation cohorts  with >50% missingness. 

We observed linearly high MTCs in UFF patients . Clinical variables related to renal function, PM functionality and ultrafiltration efficiency correlated to each other positively: residual renal function (RRF), UFR4H, generation of urea (GENERUREA) or creatinine (GENER) in effluent and urine, DWELL, ratio dialysate plasma of creatinine (D/P CREATININE) and dialysate ratio of glucose in the dwell time 240 min and 0 min (D5/D0 glucose ratio). 

Overall, 30–38 variables were found to be sufficient to train and test robustly ML algorithms, by selecting the top first 20 of 162 variables, in addition to the biomarkers . 

 

Conceptually, we designed a brute force regressor pipeline ( and ) of 28 algorithms, which was used to predict endurance. We discovered, based on the MAE, that Extra Tree (ET), random forest (RF) and k-nearest neighbours regressors were the most robust, including distribution similarities and overfitting . Several models were skewed to the mean of the distribution, acquiring great metrics but poor distributions (Bernoulli Naïve Bayes, etc). Further, the pipeline for categorical targets to predict (PD cause end, exit, failure) comprised 16 algorithms ( and ). The most optimal models were linear discriminant analysis (LDA), decision tree (DT) and RF. Optimisation and validation of selected algorithms Algorithms generally performed properly when comparing all robustness indices on hyperparameter optimisation . ET regressor seemed more suitable for prediction of PD endurance , since validating with the CV test, positive external and negative validation datasets entailed the lowest MAE and highest MI. For binary and multiclass variables, the LDA classifier  resembled the original distribution without overfitting and displayed the highest metrics, excluding the KL divergence, for all the categorical outcomes . Generally, it could be said that predictions were robustly drawn for PD cause end with metrics >0.72 . The other predictions were scoring >0.72 in the micro-averaged ROC-AUC (for almost all the datasets). Infinitesimal-branching classifiers (DT, RF) displayed again perfect metrics biased to the most frequent class . Negative validation showed sensitivity. Consistently, we obtained robust classifications of MMT, peritonitis-induced MMT, ICC, HD and CVD with up to 78% of correct classifications. Overfitted ML algorithms worsened metrics of robustness . This performance analytics further proved that LDA  was the most robust model for PD cause end, PD exit and PD failure. So, ET and LDA models were embedded in the MAUXI software . Metrics worsened by predicting patients with other causes of leave. All algorithms were trained with the proposed dynamic ranges in protein detection of the selected kit. Other kits detecting different levels of protein concentrations, as shown in , may interfere with correct predictions. Thus, harmonised measurements are imperative for proper AI and ML use and performance. 

Algorithms generally performed properly when comparing all robustness indices on hyperparameter optimisation . ET regressor seemed more suitable for prediction of PD endurance , since validating with the CV test, positive external and negative validation datasets entailed the lowest MAE and highest MI. For binary and multiclass variables, the LDA classifier  resembled the original distribution without overfitting and displayed the highest metrics, excluding the KL divergence, for all the categorical outcomes . Generally, it could be said that predictions were robustly drawn for PD cause end with metrics >0.72 . The other predictions were scoring >0.72 in the micro-averaged ROC-AUC (for almost all the datasets). Infinitesimal-branching classifiers (DT, RF) displayed again perfect metrics biased to the most frequent class . Negative validation showed sensitivity. Consistently, we obtained robust classifications of MMT, peritonitis-induced MMT, ICC, HD and CVD with up to 78% of correct classifications. Overfitted ML algorithms worsened metrics of robustness . This performance analytics further proved that LDA  was the most robust model for PD cause end, PD exit and PD failure. So, ET and LDA models were embedded in the MAUXI software . Metrics worsened by predicting patients with other causes of leave. All algorithms were trained with the proposed dynamic ranges in protein detection of the selected kit. Other kits detecting different levels of protein concentrations, as shown in , may interfere with correct predictions. Thus, harmonised measurements are imperative for proper AI and ML use and performance. 

We chose SHAP values as our major provider for causality insights about predicting PD endurance . Variables impacting negatively on the remaining time until failure were weight, IL-11, MMP-2, age, accumulated ictus and MTCs. Opposingly, increasing values of RRF, TSP-1, IL-6, TN-C, VEGF-A, COL-13, systolic arterial tension (TASYS), PAI-1 and FAP provided patients with longer survival in PD. 

For the first time, we show that MMT-associated biomarkers are relevant for prediction of PD drop-out: MMP-2, TN-C, IL-11, PAI-1, PSTN, VEGF-A, COL-13, CDH-13, TSP-1, BMP-7, IL-6, FAP and IL-33. Interestingly, immunoassays have different detection ranges, and robust predictions are tied to those. All biomarkers had proper NMIFS and SHAP values, indicating that MMT processes may have a causal relationship with the development of CVD-UFF in PD. We confirmed that small longitudinal PD datasets, attribute shrinkage and gold-standard algorithms (ET, LDA) with overfitting testing and class imbalances predict PD endurance and technique failure. We acknowledge that our study has several constraints. Our train and validation datasets possessed a preponderance of white males with class imbalances of PD technique failure. Most patients with PD dropoff due to CVD were only registered with missing samples and/or reports. We note that this study comprised merely a small cohort, limiting the prediction power. Nevertheless, we expanded common knowledge that MTC, UFR4H, RRF and electrolyte sieving, among others, are indeed predictors of PD endurance and can even be cardioprotective. External validations verified predictions only for MMT-UFF-CVD patients, preventing vague risk scores with a time resolution of 5–7 years. MAUXI predictions, requiring only effluents, avoid patient invasiveness and time burden. We divided PD outcomes into four categories (cohort selection) based on the observed historical registry of the entire dataset of patients since the first registry in the training dataset (1979). There were no other outcomes in the hospitals with whom we collaborated in the European Union. In our study, only real-world patients were integrated. We included as well patients who left PD for a transplant, failing shortly afterwards and returning to PD until failure due to MMT or CVD. Further, we did not include any outcome related to final transplant, or any failure not related to MMT (catheter, abdominal perforations, surgery, etc.). ET—as an ensemble method building multiple DTs with random splits—effectively handles repeated measures (time series data) by modelling complex relationships and robustness against noise. By correctly formatting temporal data (natural logarithm, identification of longitudinal samples), ET captured patterns across time points. LDA was adapted to include temporal features, indirectly accounting for repeated measures, using feature engineering. Despite LDA’s limitations compared with ET, it was effective for this dataset due to the prevalence of linear dependencies. The study highlights the importance of aligning models with specific data structures to enhance medical predictions. MAUXI software intends to provide more predictability of the PD technique failure, avoiding unprecedented neurological, cardiovascular and UFF consequences. Further studies should unravel molecular mechanisms of these MMT biomarkers in PD. 

In conclusion, the MAUXI medical device can help healthcare professionals to predict robustly PD patient fate, increasing the current knowledge in the field of prophylactic interventions. 

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