American Journal of Transplantation
Association of blood bicarbonate and pH with mineral metabolism disturbance and outcome after kidney transplantation
In kidney transplant recipients (KTR), scarce evidence has associated low blood bicarbonate levels with mineral metabolic disturbance and reduced allograft survival. However, the contribution of the blood pH to these observations remains unassessed. Equally, little is known about the influence of the blood provenance (arteriovenous fistula vs peripheral vein) on the bicarbonate values. We analysed blood gas parameters in a single centre cohort of 1260 stable KTR, 3 months after transplantation. Inspection of pO2 distribution allowed the unambiguous identification of the arterial (N=914) or venous (N=346) origin of the samples. In patients with arterial blood samples, 435 (46%) had bicarbonate levels below 22 mmol/L. Among them, 196 (40%) were acidemic (blood pH < 7.38). In multivariable analysis, low arterial blood pH was associated with increased blood ionized calcium and phosphate and reduced FGF23 and calcitriol, but not with outcome. In contrast, low bicarbonate concentration predicted allograft loss independently of mGFR and other potential confounders (hazard ratio [HR] 1.70; 95% CI, 1.04 to 2.80). In KTR, reduced arterial blood bicarbonate levels predict outcome while acidemia is associated with altered mineral metabolism.
Source: American Journal of Transplantation