Aim: Increasing left ventricular mass index (LVMI) is associated with a poor prognosis in patients with chronic kidney disease (CKD). Blockade of the mineralocorticoid receptor (MR) in CKD leads to improvement in proteinuria and LV mass. However, the MR can be activated by aldosterone, cortisol and deoxycorticosterone (DOC) and their relative contribution to adverse events in CKD is unclear. We aimed to assess the correlation between mineralocorticoid excretion and LVMI in patients with CKD.
Methods: Fifty-eight patients with CKD stages 3/4 and 29 patients with essential hypertension (EH) were recruited. Patients underwent 24 h urine collection for urinary tetrahydroaldosterone (THAldo) and tetrahydrodeoxycorticosterone (THDOC) (measured using GCMS), urinary electrolytes and protein (QP). LVMI was measured using gold standard cardiac MRI scanning. Factors which correlated significantly with LVMI were entered into linear regression models.
Results: Mean age was 57.1 years, 75.9% were male, mean BMI 29.2 kg/m2, systolic blood pressure (SBP) 148 mmHg, DBP 86 mmHg and the mean number of anti-hypertensive agents was 2.4 (range 06). In CKD patients, mean eGFR was 38.5 ml/min per 1.73 m2 and median QP 0.8 g/24 h. LVMI was significantly higher in patients with EH compared with CKD (86.1 vs 81.2 g/m2 P=0.009). There were no significant differences in drug therapies, THAldo or THDOC excretion between the two groups.
In patients with CKD, significant predictors of LVMI were male gender, SBP, 24 h QP, THAldo and THDOC excretion. On multivariate linear regression analysis, the significant independent predictors were SBP, male gender and THDOC excretion. THAldo was not an independent predictor. In patients with EH, plasma aldosterone concentration was the only significant independent predictor of LVMI. No association was seen with THAldo or THDOC.
Conclusions: Using cardiac MRI to assess LVMI, we have demonstrated that the mineralocorticoid THDOC is a novel independent predictor of LVMI in patients with CKD and not subjects with essential hypertension.