Clinical Utility of Potassium-Sparing Diuretics to Maintain Normal Serum Potassium in Peritoneal Dialysis Patients

Complications of Peritoneal Dialysis Part II: Nonmechanical Complications

Peritoneal dialysis (PD) is a form of KRT that offers flexibility and autonomy to patients with ESKD. It is associated with lower costs compared with hemodialysis in many countries. Unlike mechanical complications that typical arise early in the course of treatment, noninfectious, nonmechanical complications often present late in patients who are established on PD. In this review, we first discuss abnormal-appearing drained dialysate, including hemoperitoneum, chyloperitoneum, and noninfectious cloudy dialysate. The underlying cause is frequently unrelated to PD. We then discuss encapsulating peritoneal sclerosis, a rare complication of PD. Finally, we review metabolic changes associated with PD and methods to mitigate its effects.

Peritoneal dialysis adequacy: a paradigm shift

For the past 30 years, nephrologists have focused on a single minimal threshold of Kt/V_urea to determine the adequacy of peritoneal dialysis (PD). To date, there is no evidence that shows Kt/V_urea to be a good surrogate measure of uremic symptom control or nutritional state in patients on PD. Volume of distribution (V_urea) generally is considered equivalent to total body water (TBW). Yet, accurate determination of TBW is difficult. The most recent International Society for Peritoneal Dialysis practice recommendations on prescribing high-quality PD emphasized incorporation of multiple measures rather than the single value of Kt/V_urea. These measures include shared decision-making between the patient and the care team and assessment of health-related quality of life, burden of uremic symptoms, presence of residual kidney function, volume status, and biochemical measures including serum potassium and bicarbonate levels. In some cases, PD prescriptions can be tailored to the patient priorities and goals of care, such as in frail and pediatric patients. Overall, there has been a paradigm shift in providing high-quality care to PD patients. Instead of focusing on small solute clearance in the form of Kt/V_urea, nephrologists are encouraged to use a more comprehensive assessment of the patient as a whole.

Role of Potassium-Sparing Diuretics in the Management of Hypokalemia in Peritoneal Dialysis

BACKGROUND

Patients with kidney disease are at a higher risk of experiencing potassium imbalance. The kidney plays an important role in maintaining potassium homeostasis. A common dyskalemia that peritoneal dialysis (PD) patients experience is hypokalemia.

AREAS OF UNCERTAINTY

Potassium-sparing diuretics such as spironolactone causes increased amounts of sodium and water to be excreted, while potassium is retained. Owing to its potassium-sparing effects, it may correct hypokalemia that PD patients experience. The proper usage of potassium-sparing diuretics in PD patients and data on the efficacy and safety are being explored.

DATA SOURCES

Four relevant trials were identified. One randomized double-blind placebo-controlled cross-over study (n = 20), one interventional study without the control group (n = 20), one retrospective single-center chart review (n = 53), and one cross-sectional review (n = 75) trial. The randomized controlled trial did not note a statistically significant change in K levels (P > 0.05); the other 3 trials observed an increase in potassium levels in the potassium-sparing diuretics groups, but trials contained small participants and inadequate statistic rigor.

THERAPEUTIC OPINIONS

The role of potassium-sparing diuretics use for hypokalemia management in PD patients remains unclear.

Prescribing high-quality peritoneal dialysis: Moving beyond urea clearance

Urea removal in peritoneal dialysis (PD) has been a primary measure of dialysis adequacy, but its utility remains limited due to its poor correlation with the clearance of other important uraemic retention solutes and the low certainty of evidence relating peritoneal urea clearance and survival of individuals doing PD. Indeed, clearances of other uraemic solutes, electrolyte imbalances, hypoalbuminaemia and nutritional status, may provide a more holistic measure of dialysis adequacy when evaluating individuals on PD in addition to focusing on person-centred outcomes. Here, we review the history of the urea and creatinine-centric approach to dialysis adequacy and explore the potential importance of other uraemic retention solutes, electrolyte disturbances, phosphorus control, peritoneal protein losses and hypoalbuminaemia, as well as nutritional management to promote a broader multidimensional concept of clearance for PD.

Review on Preclinical and Clinical Evidence of Food (Beverages, Fruits and Vegetables) and Drug Interactions: Mechanism and Safety

Background:

The therapeutic potency and efficacy of drugs can be affected by a patient’s dietary habit. The food composition and their nutritional value interact with drugs that lead to alteration of the therapeutic response of drugs in patients.

Objective:

This present review is an attempt to illustrate clinical reports of food-drug interaction. Further, it also highlights specific interaction mechanism(s) and the safety thereof.

Methods:

Through the search engine “Scopus”; literature on recent advances in food and drug interactions includes almost all therapeutic categories such as antimicrobials, antiviral, antifungal, antihistamines, anticoagulants, non-steroidal anti-inflammatory drugs, and drugs acting on the central nervous system and cardiovascular system.

Results:

Preclinical and clinical studies that have been conducted by various researchers affirm significant drug-food interactions across the various therapeutic categories of drugs. Preclinical studies have documented the effects of food, milk products, alcohols, fruit and vegetables on the drug absorption, metabolizing enzymes and drug transporters. The clinical studies on fruits/vegetables and drugs interactions report significant alteration in therapeutic response.

Conclusion:

Based on the preclinical and clinical reports, it can be concluded that the interaction of food with drug(s) significantly alters their therapeutic potential. The inputs from clinical practitioners to elucidate potential risk of food-drug interaction need to be intensified in order to prevent adverse clinical consequences.

Prevalence and Management of Hypokalemia in Peritoneal Dialysis Patients in Qatar

Introduction

Hypokalemia is common in patients undergoing peritoneal dialysis (PD). It is associated with increased cardiovascular and all-cause mortality. Treatment usually includes oral potassium supplements, which are poorly tolerated. Our aim was to evaluate the prevalence of hypokalemia in PD patients in Qatar and to improve treatment measures.

Methods

All PD patients in Qatar with persistent hypokalemia and on potassium supplement were included. We performed a root cause analysis, and a management pathway was created. We collected data before (Period 1) and after (Period 2) implementation of the new pathway.

Results

A total of 143 patients with a mean age of 54 years (range 21–82 years) were included in the study. Initial results of Period 1 showed hypokalemia in 48 patients (34%); of these, 14 (29%) had hypomagnesemia. Hypokalemia resolved in 10 of the patients after correction of their hypomagnesemia. The remaining 4 patients continued to require potassium supplementation despite correction of their hypomagnesemia. We started spironolactone (25 mg daily) in 13 of the hypokalemia patients. After 3 months, their mean serum potassium level improved from 3.2 ± 0.3 mmol/L to 3.9 ± 0.4 mmol/L (p < 0.001), and the prevalence of patients with persistent hypokalemia decreased from 36% to 21% (statistically significant with p= 0.006). No episodes of hypotension or hyperkalemia were observed. Only 1 patient developed mild gynecomastia without discontinuation of the medications.

Conclusion

Our study showed that hypokalemia is a prevalent problem in PD patients in Qatar. Hypomagnesemia is a significant contributing factor to hypokalemia in PD and correcting it leads to improvement of hypokalemia. Addition of spironolactone is safe and effective in treating hypokalemia. Implementing a holistic pathway led to a significant improvement in hypokalemia prevalence in PD patients.

Spironolactone is effective in treating hypokalemia among peritoneal dialysis patients

BACKGROUND

Hypokalemia is common in peritoneal dialysis (PD) patients and is associated with increased cardiovascular and all-cause mortality. The management approach for such patients routinely includes spironolactone at our centre. We undertook this study to assess the efficacy of spironolactone for the treatment of hypokalemia in PD patients.

METHODS

Retrospective chart review of PD patients at a single centre. Serum potassium was compared prior to initiation of spironolactone and two months afterwards. Indication for spironolactone and changes in blood pressure (BP), weight, and serum creatinine were also recorded.

RESULTS

The chart review identified 53 patients who fit our selection criteria. The mean age was 64 +/- 15 years and the majority was treated with continuous cyclic peritoneal dialysis. Serum potassium rose from 3.7 +/- 0.5 to 4.2 +/- 0.5 mmol/L (P<0.0001) after 2 months with a mean dose of spironolactone of 28.5+/-15.2 mg (median dose 25 mg). A significant reduction in systolic BP was observed from 150+/- 18 to 137 +/-24 (P = 0.002); a non- significant reduction in diastolic BP was also observed. The rise in potassium was constant in the range of 0.4 to 0.5 mmol/L regardless of whether spironolactone was initiated for hypokalemia, diuresis, or as an antihypertensive. There was no change in serum creatinine or body weight two months after introduction of spironolactone.

CONCLUSIONS

Spironolactone is safe and effective in treating hypokalemia in PD patients. It is also an effective antihypertensive agent and merits further study in the PD population.