Introduction to Glucose Metabolism in Peritoneal Dialysis

Managing metabolic health in patients undergoing renal replacement therapy remains a significant challenge for clinicians worldwide. Specifically, impaired fasting glucose PD patients represent a unique subset of individuals who often fly under the clinical radar compared to those with overt diabetes. Peritoneal dialysis (PD) inherently disrupts normal glucose metabolism because it involves repeated and prolonged exposure to glucose-based dialysates. This constant osmotic load provides a continuous supply of exogenous glucose, which can lead to significant metabolic disturbances over time. Furthermore, the absorption of glucose through the peritoneal membrane contributes to chronic hyperglycemia and hyperinsulinemia. Consequently, many patients who enter dialysis with normal glucose levels eventually develop prediabetes or diabetes. However, the exact impact of prediabetic states, such as impaired fasting glucose, on long-term survival has remained somewhat controversial in the nephrology community until recently. Understanding these risks is crucial for improving patient outcomes and refining cardiovascular prevention strategies in the dialysis population.

Study Methodology and Patient Stratification

A recent prospective cohort study conducted in Taiwan has provided significant clarity on this issue. Researchers followed 216 patients receiving peritoneal dialysis to evaluate how glycemic status affects mortality and cardiovascular health. To ensure precision, the study stratified patients into three distinct groups based on their baseline fasting glucose levels: normal fasting glucose, impaired fasting glucose (IFG), and diabetes mellitus (DM). Moreover, the investigators utilized sophisticated tools to analyze the underlying pathophysiology of these patients. They assessed β-cell function using the Homeostasis Model Assessment of β-cell Function (HOMA-β) and evaluated insulin resistance through both the HOMA-IR and the triglyceride-glucose (TyG) index. These metrics allowed for a deeper exploration of how metabolic dysfunction drives clinical events. The primary outcomes tracked were all-cause mortality and 3-point major adverse cardiovascular events (3P-MACE) over a median period of 41 months. By focusing on these robust endpoints, the study aimed to determine if IFG carries the same weight as diabetes in a high-risk population. Specifically, the researchers adjusted for multiple variables to ensure the independence of their findings.

Clinical Outcomes of Impaired Fasting Glucose PD Patients

The results of the study were striking and demonstrated that impaired fasting glucose is far from a benign condition in the context of dialysis. During the follow-up period, nearly 32% of the cohort passed away, with cardiovascular and infectious causes being the primary drivers of mortality. Notably, when looking at the survival curves, the researchers found that the curves for patients with IFG and DM were nearly superimposable. This observation suggests that the risk profile for those with prediabetes is remarkably similar to those who have already been diagnosed with full-blown diabetes. Specifically, in the fully adjusted models, IFG independently predicted a four-fold increase in the risk of major adverse cardiovascular events. Furthermore, the risk of all-cause mortality was more than double for patients with IFG compared to those with normal glucose. These findings highlight a critical gap in current clinical practice, where prediabetes may not be treated with the same urgency as diabetes. Therefore, clinicians must recognize that patients with IFG are in a high-risk category that requires intensive monitoring and early intervention.

The Predictive Value of the TyG Index and Insulin Resistance

A major focus of the research involved identifying the specific metabolic markers that best predict poor outcomes. The study highlighted the triglyceride-glucose (TyG) index as a particularly strong independent predictor of both mortality and 3P-MACE. Unlike traditional measures, the TyG index provides a composite view of both glucose and lipid metabolism, which are often both deranged in PD patients. Because insulin resistance (IR) is a hallmark of the metabolic syndrome associated with dialysis, measuring it accurately is vital. The researchers found that increased insulin resistance was strongly linked to worse cardiovascular health. Consequently, the TyG index could serve as a valuable and cost-effective tool in clinical settings to identify patients at the highest risk. Furthermore, the study suggested that the metabolic environment created by PD promotes a cycle of worsening IR. As patients absorb glucose from the dialysate, their bodies must produce more insulin, eventually leading to the exhaustion of metabolic pathways. This process underscores why even mild elevations in fasting glucose can signal profound underlying vascular and metabolic damage.

Protective Role of β-cell Function in Dialysis

In addition to insulin resistance, the study examined the role of pancreatic β-cell function in determining patient survival. The investigators found that greater β-cell function, as measured by HOMA-β, was associated with a significantly reduced risk of both mortality and cardiovascular events. Specifically, patients who maintained better insulin-secreting capacity appeared to have a buffer against the metabolic stresses of peritoneal dialysis. However, the continuous glucose load from the dialysate often leads to β-cell dysfunction over time. This loss of function means the body can no longer compensate for the high insulin resistance, leading to the superimposable risk profiles of IFG and DM patients. Therefore, preserving β-cell health should be a secondary goal of therapy. Transitioning to glucose-sparing dialysates, such as those containing icodextrin, might offer a way to reduce the glycemic burden. Furthermore, lifestyle modifications and pharmacological agents that improve insulin sensitivity may help protect β-cells from overwork. By addressing both sides of the metabolic equation—insulin sensitivity and secretion—clinicians might be able to alter the trajectory of cardiovascular disease in this population.

Strategic Implications for Peritoneal Dialysis Management

The implications of this study for nephrologists and internists are profound and suggest a need for a paradigm shift. Since IFG carries risks comparable to DM, the traditional distinction between prediabetes and diabetes may be less relevant in the PD population. Consequently, we must adopt more aggressive screening and management protocols for all patients with abnormal fasting glucose. Specifically, monitoring the TyG index could provide an early warning system for cardiovascular complications before they manifest clinically. Moreover, clinicians should consider the total glucose exposure from dialysis fluids when assessing a patient's metabolic risk. Reducing this exposure through individualized dialysis prescriptions is essential. In addition, managing traditional risk factors like hypertension and dyslipidemia remains vital, but they must be addressed alongside glucose control. Ultimately, the goal is to provide a holistic approach that recognizes the complex interplay between renal failure and metabolic health. Future research should focus on whether reversing IFG in these patients can directly lead to a reduction in cardiovascular events and improved longevity.

Frequently Asked Questions

Why is impaired fasting glucose as dangerous as diabetes in PD patients?

In patients undergoing peritoneal dialysis, the continuous absorption of glucose from the dialysate creates a state of chronic metabolic stress. This environment causes impaired fasting glucose to represent a more advanced state of metabolic failure than it might in the general population. Specifically, the study found that the cardiovascular and mortality risks are nearly identical because both groups suffer from similar levels of insulin resistance and vascular damage, leading to equivalent clinical outcomes.

What is the TyG index and how does it help in clinical assessment?

The triglyceride-glucose (TyG) index is a mathematical product of fasting triglycerides and fasting glucose levels. It is recognized as a reliable surrogate marker for insulin resistance. In this study, the TyG index was a powerful independent predictor of major adverse cardiovascular events and death. For clinicians, it offers a simple, accessible way to evaluate a patient's metabolic risk profile without the need for expensive or complex insulin assays used in research settings.

Can β-cell function be preserved in patients on peritoneal dialysis?

Preserving β-cell function is possible through strategies that reduce the systemic glucose load. Using glucose-sparing peritoneal dialysis solutions, such as icodextrin-based fluids, can significantly decrease the amount of glucose absorbed by the body. Additionally, managing obesity and using certain medications that improve insulin sensitivity may reduce the secretory demand on the pancreas. Maintaining this function is critical because it is associated with lower risks of mortality and fewer major cardiovascular events in the dialysis population.

Disclaimer: This content is for informational and educational purposes only. It does not constitute professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

Tang CC et al. Impaired fasting glucose is comparable to diabetes mellitus in predicting mortality and cardiovascular events in patients undergoing peritoneal dialysis: the role of β-cell function and insulin resistance. Ren Fail. 2026 Dec undefined. doi: 10.1080/0886022X.2026.2692758. PMID: 42402705.

Sánchez-García A et al. The Triglyceride-Glucose Index (TyG) as a marker of insulin resistance in patients with chronic kidney disease. Journal of Clinical Medicine. 2020;9(11):3544.

KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney International. 2024;105(4S):S117-S314.