Serum inorganic phosphate is independently associated with left ventricular myocardial mass index in patients with chronic kidney disease stages 1–4

Background . Driven by multiple factors, heart failure is a leading cause of mortality among patients with chronic kidney disease (CKD). The impact of hyperphosphatemia, a hallmark of CKD, on myocardial remodelling has not been investigated. Objective . To assess the association between serum Pi levels and left ventricular mass index (LVMI) in a population of patients with CKD stages 1–4. Design and methods . Thе cross-sectional cohort study included 1,213 patients with CKD (48 % male, mean age 48 ± 16 years, mean estimated glomerular filtration rate (eGFR) 58 (36; 82) ml/min/1,73 m2 ). We evaluated clinical and demographic parameters, echocardiographic measures, serum Pi levels and parameters of its renal excretion, renal electrolyte excretion, proteinuria, and eGFR. The association between serum Pi and LVMI was analysed using adjusted linear and logistic regression models combined with a pseudo-randomisation approach — 1:1 propensity score matching (PSM) and inverse probability of treatment weighting (IPTW). Results . Patients with left ventricular hypertrophy (LVH, n = 571) had higher Pi levels compared to those without LVH (1,31 [1,12–1,43] vs 1,19 [1,09–1,31] mmol/L; p < 0,0001). Multivariable regression analysis showed that Pi was independently associated with LVMI (B = 13,67 ± 3,31; p < 0,0001; adjusted R² = 0,37), independently of other clinical indices. In IPTW and 1 : 1 PSM regression models, the estimated increase of LVMI at serum Pi levels > 1,37 mmol/L ranged from 5,7 to 11,3 g/m². Conclusion . In CKD patients, serum inorganic phosphate concentration can be an independent factor for left ventricular remodelling and represents a potential target for therapeutic interventions to improve cardiovascular outcomes.