Serum bicarbonate is an independent determinant of protein catabolic rate in chronic hemodialysis

Serum bicarbonate is an independent determinant of protein catabolic rate in chronic hemodialysis. Recent biochemical studies suggest that metabolic acidosis induces an increase in protein catabolic rate. Therefore, we retrospectively examined the relationship between serum total CO2, normalized protein catabolic rate (NPCR), midweek BUN, KT/V, and serum albumin in 70 chronic hemodialysis patients over a period of 4-6 months (total of 270 determinations). Multiple regression analysis indicated an independent and inverse association of tCO2 with NPCR (p < 0.0001). Subsequent analysis of the data indicated a nonlinear relationship between serum CO2 and NPCR. Indeed, the slope of the regression abruptly increased from -0.015 +/- 0.005 to -0.108 +/- 0.032 when analyzed for serum CO2 < or = 15 mEq/l. We conclude that metabolic acidosis may modulate protein kinetics in patients receiving maintenance hemodialysis. Moreover, this relationship appears to be exaggerated at moderate to severe reductions in tCO2. Thus, this analysis suggests that decreases in tCO2 have a detrimental effect on protein catabolism in stable patients maintained on chronic hemodialysis.