Serum total LDH activity and LDH-2 isozyme in nephrotic syndrome.

Background/aims: Proteinuria, hypoproteinaemia, hypoalbuminaemia and oedema are major characteristics of nephrotic syndrome. Aims of this study were to detect serum total LDH activity and its isozymes in nephrotic syndrome.

Methods: In a cross-sectional study, clinical parameters were compared in three cohorts, namely kidney patients with or without nephrotic syndrome and hypoalbuminaemic controls (NEPHR, NON-NEPHR, CONTR, respectively).

Results: Serum total LDH activity in the NEPHR group was increased compared with the NON-NEPHR and CONTR groups (p < 0.001) and correlated with serum total protein (r = -0.549, p < 0.001), serum albumin (r = -0.596, p < 0.001), proteinuria (r = 0.456, p < 0.001) and serum total cholesterol (r = 0.523, p < 0.001). LDH isozyme pattern was analysed in three subgroups of the patients. Serum LDH-2 activity was higher in the NEPHR subgroup compared with the NON-NEPHR and CONTR subgroups (p < 0.001). Serum LDH-2 activity correlated with serum total protein (r = -0.665, p < 0.001), serum albumin (r = -0.615, p < 0.001), proteinuria (r = 0.694, p < 0.001), and serum total cholesterol (r = 0.723, p < 0.001). Linear regression analysis revealed that serum total protein proved to be an independent predictor of serum total LDH activity, while serum total protein and proteinuria were predictors of LDH-2.

Conclusions: These findings suggest that serum total LDH activity might be a marker of the activity of the nephrotic syndrome.