Is chronic alkali therapy in orthotopic ileal neobladders necessary? A prospective controlled study

Prevalence of metabolic acidosis in ileal diversions more than one year after radical cystectomy and associated secondary metabolic effects

INTRODUCTION AND OBJECTIVE

Metabolic acidosis (MA) is a well-known complication in patients with ileal urinary diversions. It is common in the early postoperative stages and decreases over time. Our objective is to investigate the prevalence of MA after more than one year of follow-up, identify the associated risk factors, and analyze its secondary metabolic consequences.

MATERIALS AND METHODS

We conducted an observational study between January 2018 and September 2022 following the STROBE guidelines. MA was defined as a serum bicarbonate level ​​<22mEq/L. Finally, we analyzed 133 patients with a mean follow-up of 55.24 ± 42.36 months.

RESULTS

MA was observed in 16 (12%) patients. Patients with and without MA were comparable in age, sex, and follow-up time. The group with MA presented a higher rate of anemia (68,75% vs 19,65%, p < 0.001) and renal failure (100% vs 45,29%, p < 0.001), statistically significant higher levels of serum creatinine, chloride, potassium, parathyroid hormone, and phosphorus but lower serum values ​​of hemoglobin, renal glomerular filtration rate, total cholesterol, vitamin D, calcium, and albumin (all p < 0.05). Renal glomerular filtration rate was the only independent risk factor related to the development of MA (OR 0.914; 95% CI 0.878-0.95; p < 0.0001), proving a close correlation with venous bicarbonate values ​​(r = 0.387, p < 0.001).

CONCLUSIONS

MA is a little prevalent disorder in ileal urinary diversions more than one year after radical cystectomy is performed but it has secondary consequences on hematologic, renal, protein, lipid, and bone metabolism. We recommend to a close follow-up in patients with renal failure for early diagnosis and treatment.

Metabolic acidosis after ileal urinary diversion and radical cystectomy. Do we know as much as we think we do? A systematic review

Urine contact with the mucosa of the urinary diversion (UD) after radical cystectomy (RC) produces different ion exchanges that favor the development of metabolic acidosis (MA). This phenomenon is a frequent cause of hospital readmission and short/long-term complications. We performed a systematic review of MA in RCs with ileal UD, analyzing its prevalence, diagnosis, risk factors and treatment. We systematically searched Pubmed® and Cochrane Library for original articles published before May 2022 according to PRISMA guidelines. A total of 421 articles were identified. We selected 25 studies that met the inclusion criteria involving 5811 patients. Obtaining precise data on the prevalence of MA is difficult, largely due to the heterogeneity of the diagnostic criteria used given the diversity of studies analyzed. Development of MA is multifactorial. In the early period, MA is more prevalent in patients with UD with longer ileal segments, better urinary continence, and impaired renal function. Age and diabetes are risk factors associated with MA in later periods. MA is the most common cause of second or more hospital readmissions. Prophylaxis with oral bicarbonate for three months in patients at risk could improve these results. Although MA after ileal UD is a well-known condition, this review highlights the need to implement homogeneous criteria for the diagnosis, follow-up, and treatment, in addition to protocolizing prevention/prophylaxis strategies in patients at risk.

[Metabolic acidosis in neobladder patients : Risk factors and treatment options]

BACKGROUND

In cystectomy patients who underwent neobladder creation, the intestinal mucosa of the neobladder is in constant contact with urine, which may result in chronic metabolic acidosis (CMA) due to specific absorption capabilities of the intestinal mucosa. Despite being a prevalent comorbidity, the risk factors for CMA and its diagnostic parameters are poorly understood.

OBJECTIVES

This review examines the risk factors associated with the development of CMA and their prevalence in patients with a neobladder.

MATERIALS AND METHODS

We conducted a systematic literature search using the PubMed database to detect studies about the topics CMA and neobladder that were published between 2000 and 2020. The prevalence and risk factors for CMA in neobladder patients were assessed by reviewing 23 studies.

RESULTS

Acidosis is most prevalent during the first year after surgery (25-70%). Risk factors are renal failure, high continence, old age and diabetes mellitus.

CONCLUSIONS

The prevalence of CMA is at its highest during the early postoperative period for neobladder patients, so for this time period, weekly diagnostic investigations are recommended according to the German S3-guidelines for the "Früherkennung, Diagnose, Therapie und Nachsorge des Harnblasenkarzinomsent für Neoblasepatienten". Blood gas tests should not only be used to analyze the pH value but also to detect and counteract acid-base imbalance issues in time. The recommended normalization of serum bicarbonate levels with oral bicarbonate follows patient-specific therapy strategies.