Degree and duration of hypokalemia associated with peritonitis in patients undergoing peritoneal dialysis

Risk factors of peritoneal dialysis-related peritonitis in the Japan Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS)

Background

Peritoneal dialysis (PD)-related peritonitis is a major complication of PD. Wide variations in peritonitis prevention, treatment strategies and consequences are seen between countries. These between-country differences may result from modifiable risk factors and clinical practices.

Methods

A total of 1225 Japanese PD patients were included and prospectively followed in the Peritoneal Dialysis Outcomes and Practice Patterns Study phase 1 (2014-2018) and phase 2 (2018-2022). Associations between PD-related peritonitis and various risk factors were assessed by Cox proportional hazards survival models.

Results

During follow-up (median 1.52 years), 539 peritonitis episodes were experienced by 364 patients. The country crude peritonitis rate was 0.27 episodes/patient-year. In the fully adjusted model, noticeable patient-level factors associated with experiencing any peritonitis included age {hazard ratio [HR] 1.07 per 5-year increase [95% confidence interval (CI) 1.01-1.14]}, serum albumin level [HR 0.63 per 1 g/dl higher (95% CI 0.48-0.82)] and continuous ambulatory peritoneal dialysis (PD) [HR 1.31 versus automated PD (95% CI 1.05-1.63)]. The adoption of antibiotic prophylaxis practice at the time of PD catheter insertion [HR 0.63 (95% CI 0.51-0.78)] or when having complicated dental procedures [HR 0.74 (95% CI 0.57-0.95)] or lower endoscopy [HR 0.69 (95% CI 0.54-0.89)] were associated with lower hazards of any peritonitis, while a routine facility practice of having more frequent regular medical visits was associated with a higher hazard.

Conclusion

Identification of risk factors in Japan may be useful for developing future versions of guidelines and improving clinical practices in Japan. Investigation of country-level risk factors for PD-related peritonitis is useful for developing and implementing local peritonitis prevention and treatment strategies.

The effect of body mass index on mortality, peritonitis, technique proficiency and residual renal function in peritoneal dialysis patients

BACKGROUND

The prevalence of obesity is increasing worldwide. Obesity is also increasing in the chronic kidney disease (CKD) population. There are conflicting data on complications such as mortality, peritonitis, and technique proficiency of peritoneal dialysis (PD) in underweight and obese patients according to body mass index (BMI). We aimed to present the data in our region to the literature by comparing the residual renal function (RRF), peritonitis, technique proficiency, and mortality rates of the patients we grouped according to BMI.

METHODS

The data of 404 patients who were started and followed up in our clinic between March 2005 and November 2021 were evaluated retrospectively. They were grouped as underweight, normal weight, overweight, and obese according to BMI. RRF, mortality, technique proficiency and peritonitis data of the groups were compared.

RESULTS

Of the 404 patients, 44 were underweight, 199 were normal weight, 110 were overweight, and 55 were obese. No difference was found between the groups in the technique survey and in the time to first peritonitis with Kaplan-Meier analysis (respectively; p = 0.610, p = 0.445). Multivariate Cox regression analysis showed that BMI did not affect mortality (HR 1.196 [95% CI 0.722-1.981] (p = 0.488)).

CONCLUSION

In conclusion, we report that BMI has no effect on RRF, peritonitis, technique proficiency, and mortality in patients undergoing PD, and that mortality may depend on additional factors such as mean albumin, time to first peritonitis, and loss of RRF.

Peritoneal Dialysis-Related Infections

Peritoneal dialysis (PD) represents an important treatment choice for patients with kidney failure. It allows them to dialyze outside the hospital setting, facilitating enhanced opportunities to participate in life-related activities, flexibility in schedules, time and cost savings from reduced travel to dialysis centers, and improved quality of life. Despite its numerous advantages, PD utilization has been static or diminishing in parts of the world. PD-related infection, such as peritonitis, exit-site infection, or tunnel infection, is a major concern for patients, caregivers, and health professionals-which may result in hesitation to consider this as treatment or to cease therapy when these complications take place. In this review, the definition, epidemiology, risk factors, prevention, and treatment of PD-related infection on the basis of the contemporary evidence will be described.

Pathogenic spectrum and risk factors of peritoneal dialysis-associated peritonitis: a single-center retrospective study

The present study aimed to explore the pathogenic spectrum and risk factors of peritoneal dialysis-associated peritonitis (Peritoneal dialysis associated peritonitis, PDAP) in Yongzhou, Hunan, China. The clinical and epidemiological data on regular peritoneal dialysis (Peritoneal dialysis, PD) between January 2016 and December 2020 in Yongzhou were collected for retrospective analysis. The related factors of peritonitis were evaluated by single-factor analysis, while risk factors of refractory PDAP were evaluated by multivariate logistic regression analysis.172/331 172 (51.9%) patients developed peritonitis. The risk factors of PDAP in PD patients included high C-reactive protein (C-reactive protein, CRP), low albumin(Albumin, ALB), low hemoglobin (Hemoglobin, Hb), low educational level (junior high school or lower), preference of spicy food, irregular diet, low annual household income, unfavorable fluid exchange conditions, unstable employment (including working as a farmer), and unfavorable humidity conditions (P < 0.05). 63/172 (36.6%) PDAP patients were intractable cases with a pathogenic bacteria positive rate of 74.60% in the peritoneal dialysate cultures, and 109/172 patients were non-intractable cases with a pathogenic bacteria positive rate of 53.21%. Gram-positive bacteria (G+) were detected in most of the dialysate cultures, with Staphylococcus epidermidis (S. epidermidis) as the most common type, while Escherichia coli (E. coli) was the most common Gram-negative bacteria (G-). Gram-positive bacteria were sensitive to vancomycin and linezolid, while G- bacteria were sensitive to imipenem and amikacin. Lifestyle, educational level, and environmental factors are the major contributors to PDAP in PD patients. Fungal and multi-bacterial infections are the major causes of death; PD is stopped for such patients.

Association between reduced left ventricular ejection fraction and peritoneal dialysis related peritonitis: a single center retrospective cohort study in Japan

We present a single-center retrospective analysis of 228 Japanese patients with peritoneal dialysis, in which we examined whether reduced left ventricular ejection fraction (LVEF) is a risk factor for peritonitis development. Time-dependent multivariable-adjusted Cox proportional hazards models revealed that reduced LVEF (LVEF < 50% vs. preserved LVEF ≥ 50%, hazard ratio (HR) 2.10; 95% confidence interval (CI) 1.16-3.82) was associated with peritonitis. Qualitatively, similar associations with reduced LVEF (< 50%) were observed for enteric peritonitis (adjusted HR 7.68; 95% CI 2.51-23.5) but not for non-enteric peritonitis (adjusted HR 1.15; 95% CI 0.54-2.44). Reduced LVEF is associated with a significantly higher risk of subsequent peritonitis, particularly enteric peritonitis. These results indicate that patients with reduced LVEF may be at risk of enteric peritonitis from bowel sources caused by intestinal involvement due to cardiac dysfunction.

Rescue plan for CAPD peritonitis: Using ultrasonography as a guide on when to remove the catheter

INTRODUCTION

Ultrasound has been found to facilitate early identification of peritonitis in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

METHODS

A retrospective analysis was carried out to evaluate the effectiveness of ultrasonography-guided removal of the Tenckhoff catheter in reducing complications like a shift to hemodialysis or death in CAPD patients.

RESULTS

The "peritonitis rescue plan" supported timely decision-making for the removal of the infected catheter and resulted in a lower peritonitis episode per patient per month ratio (from 1:36 to 1:122) in 2021, a lower death rate (from 19% to 6.6%) and lower incidences of shifts to hemodialysis (from 2%-9% to 0%) as compared to that before the implementation of the plan in 2019.

CONCLUSION

The implementation of the "peritonitis rescue plan" and the removal of the infected catheter within 3 days of peritonitis being detected was successful in improving the standard of care for patients undergoing CAPD.

Nomogram to predict feeding intolerance in critically ill children

Feed intolerance (FI) is significantly associated with poor prognosis in critically ill patients. This study aimed to understand the characteristics of children with FI and identify the factors predicting FI in critically ill children. This retrospective cohort study was conducted between January 2017 and June 2022 in the Pediatric Intensive Care Unit of a specialized children's hospital. Eighteen factors, including age, body mass index for age z-score (BAZ) < -2, paediatric index of mortality (PIM)3 score, Glasgow coma scale score, mechanical ventilation (MV), enteral nutrition delay, vasoactive drugs, sedatives, sepsis, heart disease, neurological disease, hypokalemia, arterial PH < 7.35, arterial partial pressure of oxygen (PaO2), blood glucose, hemoglobin, total protein, and albumin, were retrieved to predict FI. The outcome was FI during PICU stay. During the study period, a total of 854 children were included, of which 215 children developed FI. Six predictors of FI were selected: PIM3 score, MV, sepsis, hypokalemia, albumin, and PaO2. Multivariate logistic regression analysis showed that higher PIM3 score, MV, sepsis, hypokalemia, and lower PaO2 were independent risk factors for FI, whereas higher albumin was an independent protective factor for FI. The C-index of the predictive nomogram of 0.943 was confirmed at internal validation to be 0.940, indicating a good predictive value of the model. Decision curve analysis shows good clinical applicability of the nomogram in predicting FI.    Conclusion: The nomogram was verified to have a good prediction performance based on discrimination, calibration, and clinical decision analysis. What is Known: • Research has demonstrated that gastrointestinal (GI) dysfunction is not only a fundamental element of Multiple Organ Dysfunction Syndrome (MODS), but also the initiator of MODS. • Previous study has demonstrated a significant association between FI and poor prognosis in critically ill patients. What is New: • We excluded patients with primary gastrointestinal tract disease from our study, and we observed an incidence of FI of 25.2% in the Pediatric Intensive Care Unit (PICU). • Our study revealed that PIM3 score, MV, sepsis, hypokalemia, albumin, and PaO2 are significant predictors of FI.

Comparison of clinical outcomes between culture-negative and positive peritonitis in patients undergoing maintenance peritoneal dialysis: a prospective cohort study

BACKGROUND

Culture-negative peritonitis is a serious complication in patients undergoing maintenance peritoneal dialysis (PD) and occurs in up to 40% of all peritonitis episodes. Despite its high incidence, data regarding treatment response and prognosis remain poorly defined. This study compared the clinical outcomes of patients with culture-negative and positive peritonitis.

METHOD

This prospective cohort study was conducted between 2021 and 2022. Patients treated with maintenance PD who developed PD-associated peritonitis were included and received standard treatment. The primary endpoint was the primary response (resolution of peritonitis 10 days after the initiation of treatment).

RESULTS

Of the 81 patients who developed PD-associated peritonitis during the study, 35 and 46 had culture-negative and culture-positive peritonitis, respectively. Overall, 52 (64.2%) patients achieved the primary response: 24 (68.6%) in the culture-negative group and 28 (60.9%) in the culture-positive group (p = 0.630). There were no significant differences between the two groups in the incidence of complete cure (complete resolution of peritonitis without the need for Tenckhoff catheter removal or salvage antibiotic therapy or peritonitis within 120 days after treatment) (culture-negative vs. culture-positive group, 57.1% vs. 45.7%), refractory peritonitis (28.6% vs. 41.3%), relapse peritonitis (8.6% vs. 2.2%), repeat peritonitis (11.4% vs. 10.9%), salvage antibiotics (40.0% vs. 50.0%), permanent hemodialysis transfer (11.4% vs. 10.9%), Tenckhoff catheter removal (25.7% vs. 41.3%), or mortality (2.9% vs. 2.2%) (all p > 0.05).

CONCLUSION

This study offers valuable insights into the clinical outcomes of culture-negative peritonitis versus culture-positive peritonitis. However, caution must be exercised in interpreting these findings due to the limitations of the small sample size.

CLINICAL TRIAL REGISTRATION

The study was retrospectively registered in the Thai Clinical Trials Registry (TCTR20221130006).

Dietary Potassium and Clinical Outcomes among Patients on Peritoneal Dialysis

BACKGROUND

The association between dietary potassium and clinical prognosis is unclear in patients with chronic kidney disease (CKD). Here, we explored the association between dietary potassium intake and all-cause and cardiovascular (CV) mortality in peritoneal dialysis (PD) patients.

METHODS

Here, we present a retrospective analysis of a prospective study. Patients that began incident PD in our center between 1 October 2002 and 31 August 2014 were screened. We recorded all demographic and clinical data at baseline. Repeated measurements were recorded at regular intervals to calculate time-averaged values. Spline regression analysis and Cox proportional regression models were used to evaluate the relationship between dietary potassium and mortality.

RESULTS

We followed 881 PD patients for 45.0 (21.5, 80.0) months; 467 patients died, of which 189 (40.5%) died of CV death and 93 were still on PD treatment. Compared with those who had baseline dietary potassium ≥1200 mg/d, the majority of patients with lower dietary potassium were female, older, or poorly educated. They were prone to have poorer nutritional status, CV disease, and diabetes mellitus (p < 0.05). In the unadjusted analysis, both baseline and time-averaged dietary potassium <1200 mg/d predicted higher all-cause and CV mortality (p < 0.001~0.01). After adjusting for demographic and laboratory data, the association between potassium intake and all-cause and CV mortality weakened, which even disappeared after additional adjustment for dietary fiber, protein, and energy intake.

CONCLUSIONS

Dietary potassium in PD patients was not independently associated with all-cause and CV mortality.

Hypokalemia Duration in the First Year Associated with Subsequent Peritoneal Dialysis-Associated Peritonitis: A Multicenter Retrospective Cohort Study

BACKGROUND

The association of hypokalemia (LK) with peritoneal dialysis-associated peritonitis (PDAP) risk remains uncertain. Here, we calculated LK duration in the first PD year and evaluated its association with PDAP.

METHODS

A multicenter, retrospective, incident cohort study of 1633 participants was conducted from January 2008 to October 2020 in China. The duration of LK and severe hypokalemia (SLK) was calculated as the total number of months that a patient's serum potassium (SK) level was less than 3.5 or 3.0 mEq/L during the first PD year. The study outcome was the risk of subsequent PDAP started in the second year and later. Cox proportional hazards models and competing risk models were used to assess the association.

RESULTS

The subsequent PDAP occurred in 420 (25.7%) participants during a median of 28 months of follow-up. Overall, LK duration in the first year was positively associated with a subsequent PDAP risk (per 3-month increments, adjusted HR, 1.13; 95%CI: 1.05-1.23). After categorization, patients with LK duration longer than 6 months had the highest adjusted HR of 1.53 (p = 0.005 vs. those without LK) for subsequent PDAP risk. A similar trend was also found for SLK duration. In a competing risk model, a similar trend was also observed. None of the variables, including demographic and PD characteristics, diabetes history, and several clinical measurements, significantly modified this association. The causative organisms of PDAP were similar to those previously reported.

CONCLUSIONS

PD patients with longer LK duration in the first year had a higher subsequent PDAP risk.

Low potassium disrupt intestinal barrier and result in bacterial translocation

Background

Bacterial translocation was observed in critical illness and patients with chronic diseases such as liver cirrhosis and chronic kidney disease (CKD). Hypokalemia is a common complication in these diseases. Whether low potassium diet may increase intestinal permeability and result in bacterial translocation lack of evidence. The present study was aimed to investigate the potential effects of LK on intestinal permeability.

Methods

Grade 8-week-old male Bal B/C mice were randomly placed either on a normal potassium (NK) mouse chow or a low potassium (LK) diet for 28 days. Intestinal permeability and expression of tight junction proteins were compared between the two groups.

Results

Compared with the NK group, the mice in LK group had significantly lower serum potassium level, increased levels of plasmas endotoxin and plasma d-lactate. The bacterial translocation was higher and in occurred mainly in mesenteric lymph nodes (MLN), liver and spleen. The pathologic change of small intestine was obvious with thinner villus lamina propria, shorter crypt depth and thinner intestinal wall. Slight increases in the expression of proteins and mRNA levels of both claudin-1 and claudin-2 were observed in LK group.

Conclusions

Low potassium diet could increase intestinal permeability and thereby lead to bacterial translocation, which was suspected to result from impaired intestinal epithelial barrier and biological barrier.

ISPD peritonitis guideline recommendations: 2022 update on prevention and treatment

Peritoneal dialysis (PD)-associated peritonitis is a serious complication of PD and prevention and treatment of such is important in reducing patient morbidity and mortality. The ISPD 2022 updated recommendations have revised and clarified definitions for refractory peritonitis, relapsing peritonitis, peritonitis-associated catheter removal, PD-associated haemodialysis transfer, peritonitis-associated death and peritonitis-associated hospitalisation. New peritonitis categories and outcomes including pre-PD peritonitis, enteric peritonitis, catheter-related peritonitis and medical cure are defined. The new targets recommended for overall peritonitis rate should be no more than 0.40 episodes per year at risk and the percentage of patients free of peritonitis per unit time should be targeted at >80% per year. Revised recommendations regarding management of contamination of PD systems, antibiotic prophylaxis for invasive procedures and PD training and reassessment are included. New recommendations regarding management of modifiable peritonitis risk factors like domestic pets, hypokalaemia and histamine-2 receptor antagonists are highlighted. Updated recommendations regarding empirical antibiotic selection and dosage of antibiotics and also treatment of peritonitis due to specific microorganisms are made with new recommendation regarding adjunctive oral N-acetylcysteine therapy for mitigating aminoglycoside ototoxicity. Areas for future research in prevention and treatment of PD-related peritonitis are suggested.

Characteristics Analysis, Clinical Outcome and Risk Factors for Fungal Peritonitis in Peritoneal Dialysis Patients: A 10-Year Case-Control Study

Background: Fungal peritonitis (FP) is a rare but severe complication that can appear in patients receiving peritoneal dialysis (PD). This study aimed to investigate the incidence rate and clinical characteristics of FP, evaluate clinical outcomes between FP and bacterial peritonitis (BP) patients on PD, and especially estimate the risk factors for FP outbreak.

Methods: All episodes of FP diagnosed in our hospital from January 1, 2011, to December 31, 2020, were reviewed in this single-center study. FP cases were analyzed and compared with patients diagnosed with BP in a 1:6 ratio matching for case-control study. Patient information, including clinical information, biochemical analysis, and outcomes, was recorded. Univariate and multivariate logistic regression model were used to analyze the risk factors for FP.

Results: A total of 15 FP episodes were observed in 15 PD patients, with an FP rate of 0.0071 episodes per patient-year. Seventeen strains of fungi were isolated and identified. Candida was the most common pathogen (15 strains, 88.2%), followed by Aspergillus fumigatus (2 strains, 11.8%). Between the groups, FP group showed a higher rate of HD transfer and catheter removal, and a lower rate of PD resumption in the short-term outcome (all P < 0.01), while no significant difference in the mortality was noted during the whole study period. The multivariate logistic regression analysis showed that longer PD duration (odds ratio [OR] 1.042, 95% confidence interval [CI] 1.012–1.073, P < 0.01), higher serum potassium (OR 3.373, 95% CI 1.068–10.649, P < 0.05), elevated estimated glomerular filtration rate (eGFR) (OR 1.845, 95% CI 1.151–2.955, P < 0.05), reduced serum albumin level (OR 0.820, 95% CI 0.695–0.968, P < 0.05) and peritoneal effluent polymorphonuclear (PMN) count (OR 0.940, 95%CI 0.900–0.981, P < 0.01) were significantly increased the risk for FP.

Conclusion: These results suggested that FP leads to higher rate of catheter removal and HD transfer, and a lower rate of PD resumption than BP, and that additional attention should be paid to hypoalbuminemia, increased serum potassium, long PD duration, and low peritoneal effluent PMN in PD patients.

Serum potassium, albumin and vitamin B12 as potential oxidative stress markers of fungal peritonitis

BACKGROUND

Biomarkers of oxidative stress (OS) have been poorly explored in fungal peritonitis (FP). Potassium is a regulator of pro-oxidants and antioxidants. Albumin and vitamin B₁₂ (B₁₂) are vital antioxidant agents in the circulatory system. This study aimed to investigate the antioxidative role of serum potassium, albumin and B₁₂ in FP.

METHODS

Serum levels of potassium, albumin and B₁₂ were retrospectively analyzed in 21 patients with a confirmed diagnosis of FP, 105 bacterial peritonitis (BP) patients and 210 patients receiving peritoneal dialysis without peritonitis.

RESULTS

Serum levels of potassium, albumin and B₁₂ were lower in FP patients than in BP patients. Serum potassium concentration was statistically related to albumin concentration in peritonitis patients. Univariate and multivariate binary logistic regression analysis suggested that serum level of potassium and albumin were independent risk factors of FP when compared with BP. Lower potassium and B₁₂ levels were independently associated with higher rates of technique failure in peritonitis.

CONCLUSION

These findings suggest lower serum potassium, albumin and B₁₂ as potential oxidative stress markers of FP and raise the hypothesis that an increased level of OS could contribute to FP.KEY MESSAGESFP remains a serious complication of peritoneal dialysis (PD), with higher morbidity (1-23.8%) and mortality (2-25%), and oxidative stress plays a role in it.Our study suggested serum potassium, albumin and vitamin B₁₂ as potential oxidative stress markers of fungal peritonitis.