Background: High levels of alkaline phosphatase (ALP) have been associated with increased mortality in patients with advanced chronic kidney disease (CKD). We hypothesize that elevated ALP could be partly explained by subclinical liver congestion related to left ventricular diastolic dysfunction.
Methods: Doppler echocardiography was performed in 68 patients with advanced CKD followed up for a median of 2.1 years. Time-averaged levels of ALP and γ-glutamyl transferase (GGT) were compared between patients with and without diastolic dysfunction. We also evaluated the effect of intensifying diuretic treatment on ALP levels in a small group of 16 patients with high ALP and signs of volume overload.
Results: ALP correlated significantly (p < 0.001) with GGT but not with parathyroid hormone (p = 0.09). Patients with diastolic dysfunction showed higher ALP (p = 0.01), higher GGT (p = 0.03) and lower albumin (p = 0.04). The highest values of ALP were observed in patients with diastolic dysfunction plus pulmonary hypertension (p = 0.01). Intensifying diuretic therapy in a subgroup of patients with signs of fluid overload induced a significant reduction in body weight, GGT (p < 0.001) and ALP levels (p < 0.001).
Conclusions: Elevated ALP in patients with advanced CKD could be partly explained by subclinical liver congestion related to left ventricular diastolic dysfunction, hypervolemia or both. The worse prognosis of these patients could be explained by their myocardial damage.
Keywords: Alkaline phosphatase; Chronic kidney disease; Hypervolemia; Left-ventricular dysfunction; Liver congestion.