Metabolic acidosis in patients after kidney transplantation

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Background: Metabolic acidosis (MA) is one of the most common consequences of CKD. MA is also a risk factor of CKD progression and increased mortality in these patients. Aim: The aim of this retrospective, cross-sectional study was to assess the prevalence of MA in different stages of CKD and renal replacement therapy (RRT) modalities – haemodialysis (HD) and peritoneal dialysis (PD). Additionally, the relationship between the prevalence of MA and aetiology of kidney disease was analysed. Methods: One thousand five patients in different stages of CKD, or modalities of RRT were enrolled into this single-centre cross-sectional study. Forty-one patients were ruled out because of oral bicarbonate supplementation. In the remaining 964 patients (698 CKD stages 1–5, 226 HD, 40 PD), venous blood HCO3− concentration, as well as serum Cr and urea concentrations were assessed. MA was diagnosed when blood HCO3− concentration was below 22 mmol/L. Results: The prevalence of MA increased among all stages of CKD. Patients on HD had lower prevalence of MA in comparison with CKD 5 patients with no RRT (38.5 vs. 56.0%; p = 0.02) In PD patients, the prevalence of MA was significantly lower than in HD patients (2.5 vs. 38.5%; p < 0.001). In the whole study group, there were no significant differences in the prevalence of MA between different aetiologies of CKD (glomerulonephritis 24%, hypertension 23%, diabetes 25%, and tubule-interstitial diseases 24%). Also, when only patients in stages CKD 3–5 were compared, no significant differences in the prevalence of acidosis were found (glomerulonephritis 28%, hypertension 22%, diabetes 24%, and tubule-interstitial 21%). Conclusions: (1) MA is more frequent in patients with more advanced stages of CKD. (2) RRT reduces the prevalence of MA. (3) In PD patients, MA is rare. (4) Aetiology of CKD seems not to have a significant impact on MA prevalence.

Section: Discussionsupporting

confidence: 87%

“…In a study by Skiba et al [24], a 12% prevalence of MA in kidney allograft recipients was found. This was significantly less than in an eGFR matched control group of CKD patients from their study (19% MA prevalence).…”

Section: Discussionmentioning

confidence: 91%

The Prevalence of Metabolic Acidosis in Patients with Different Stages of Chronic Kidney Disease: Single-Centre Study

Kuczera

Ciaston-Mogilska

Oślizło

et al. 2020

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“…Clase et al found blood bicarbonate concentration below 23 mmol/l in 6% of patients with CKD stage 3 and in 33% of patients with CKD stages 4 -5 [30]. Similarly, Skiba et al observed significant increase in the metabolic acidosis prevalence in patients with CKD stage 4 (44% of patients) and with CKD stage 5 (63% of patients) compared to patients with CKD stage 1 (10% of patients) [8]. It is therefore recommended that patients with stage 4 or 5 CKD should have their venous serum or venous blood bicarbonate concentrations monitored at least once a year.…”

Section: Recommendationmentioning

confidence: 94%

“…[31]. In a study performed in the Department of Nephrology, Transplantation and Internal Diseases, Medical University of Silesia in Katowice, metabolic acidosis (venous blood bicarbonate concentration below 22 mmol/l) was diagnosed in 19.6% of CKD stages 1 -5 patients [8].…”

Section: Recommendationmentioning

confidence: 99%

Diagnosis and Treatment of Metabolic Acidosis in Patients with Chronic Kidney Disease – Position Statement of the Working Group of the Polish Society of Nephrology

Adamczak

Masajtis-Zagajewska

Mazanowska

et al. 2018

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Metabolic acidosis is commonly found in patients with chronic kidney disease (CKD), and its causes are: impaired ammonia excretion, reduced tubular bicarbonate reabsorption and insufficient renal bicarbonate production in relation to the amount of acids synthesised by the body and ingested with food. As the consequence, numerous metabolic abnormalities develop, which may lead to dysfunction of several organs. In observational studies, it has been found that CKD patients with metabolic acidosis are characterised by faster progression of kidney disease towards end stage kidney failure, and by increased mortality. Results of interventional studies suggest that alkali therapy in CKD patients slows progression of kidney disease. In view of these facts, the members of “The Working Group of the Polish Society of Nephrology on Metabolic and Endocrine Abnormalities in Kidney Diseases” have prepared the following statement and guidelines for the diagnosis and treatment of metabolic acidosis in CKD patients. Measurement of bicarbonate concentration in venous plasma or venous blood to check for metabolic acidosis should be performed in all CKD patients and metabolic acidosis in these patients should be diagnosed when the venous plasma or venous blood bicarbonate concentration is lower than 22 mmol/l. In patients with metabolic acidosis and CKD, oral sodium bicarbonate administration is recommended. The goal of such a treatment is to achieve a plasma or blood bicarbonate concentration equal to or greater than 22 mmol/l.

“…The results of available studies suggest that the prevalence of MA in patients after KTx ranges from 11 to 58% [17][18][19][20][21][22]. The results of the observational study from our site suggests that MA is less common in patients after transplantation than in the CKD group with similar eGFR (12.0 vs. 19.6%) [23]. However, there was a scarcity of data regarding the influence of MA on graft function.…”

Section: Introductionmentioning

confidence: 90%

Is Metabolic Acidosis a Novel Risk Factor for a Long-Term Graft Survival in Patients after Kidney Transplantation?

Gojowy

Skiba

Bartmańska

et al. 2020

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Background: Results of both experimental and clinical studies suggest that metabolic acidosis (MA) contributes to the progression of chronic kidney disease (CKD) and mortality in CKD patients. It is unknown whether the same relationship exists in kidney transplantation (KTx) patients. The aim of this observational study was to examine this relationship between MA and both mortality and renal outcomes in patients after KTx. Methods: Four hundred eighty-six (290 male; 196 female) patients aged 48 ± 12 years, at least 1 year after KTx, were analyzed. Blood HCO3– was measured, and patients were then observed over 3 years. MA was defined as the blood HCO3– concentration <22 mmol/L. The end points of survival analysis were death and initiation of dialysis therapy. In patients who did not reach the above-mentioned end points, the difference between final (after 3 years of follow-up) and initial estimated glomerular filtration rate (eGFR) was calculated. Results: MA was initially diagnosed in 57 (12%) patients after KTx. Three-year patient survival was 89.5% in the MA group and 97.4% in the non-MA group (p = 0.001). Three-year graft survival was 73.7% for patients with MA and 93.0% for patients without MA (p < 0.001). In patients with MA who did not reach study end points, blood bicarbonate concentration at baseline correlated positively with a change in eGFR (R = 0.48, p = 0.002, n = 36). Such a correlation was not found in patients without MA (n = 388). Conclusions: (1) MA significantly increases the risk of mortality in patients after KTx. (2) The intensity of MA may be associated with progression of transplanted kidney dysfunction in KTx patients.