Impact of renal function on the prognostic value of mineral metabolism in patients with chronic ischaemic heart disease patients with chronic ischaemic heart disease.

BACKGROUND: Parathormone (PTH) is a component of the Mineral Metabolism (MM) system that has been shown recently to add prognostic value in pts. with stable coronary artery disease (SCAD) and average renal function. However, the influence of renal function on the prognostic role of PTH in pts. with SCAD has not been shown yet.

PURPOSE: To assess the influence of estimated glomerular filtration rate (eGFR) on the prognostic role of PTH and other MM markers in pts. with SCAD.

METHODS: We analyzed the prognostic value of MM markers (PTH, klotho, phosphate, calcidiol [25-hydroxyvitamin D], and fibroblast growth factor-23 [FGF23]) in 964 pts. with SCAD and eGFR<60ml/min/1.73 m2 (LGFR) vs pts. with eGFR≥60ml/min/1.73 m2 (HGFR) included in five hospitals of Madrid. The main outcome was the combination of death with ischemic events (any acute coronary syndrome, ischemic stroke or transient ischemic attack). eGFR was calculated by the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI).

RESULTS: Age was 60.0 (52.0-72.0) years, 76.2% of patients were men, and eGFR was 80.4 (65.3-93.1) ml/min/1,73 m2 . Median follow-up was 5.39 (2.81-6.92) years. There were 790 pts. with HGFR and 174 with LGFR. In HGFR pts., predictors of ischemic events or death were plasma levels of calcidiol [HR=0.023 (0.94-0.99) p=0.023], FGF23 [HR=1.00 (1.00-1.003) p=0.036], non-HDL cholesterol [HR=1.01 (1.00-1.01) p=0.026] and high sensitivity troponin I [HR=5.12 (1.67-15.59) p=0.004], along with age [HR=1.03 (1.01-1.05) p=0.01], treatment with statins [HR=0.36 (0.19-0.68) p=0.002], nitrates [HR=1.13 (1.07-2.79) p=0.027], dihydropyridines [HR=1.71 (1.05-2.77) p=0.032], verapamil [HR=5.71 (1.35-24.1) p=0.018], and proton-pump inhibitors [HR=2.23 (1.36-3.68) p= 0.002]. In the LGFR subgroup, predictors of death or ischemic events were PTH plasma levels, [HR=1.01 (1.00-1.01) p=0.005], eGFR [HR=0.96 (0.94-0.99) p=0.004], age [HR=1.06 (1.02-1.10) p=0.003], caucasian race [HR=0.04 (0.004-0.380) p=0.005], and treatment with insulin [HR=2.6 (1.20-5.63) p=0.015].

CONCLUSIONS: In pts. with SCAD, PTH is an independent predictor of poor outcomes only in those with eGFR<60ml/min/1.73 m2 , while in pts. with eGFR≥60ml/min/1.73 m2 calcidiol and FGF23 become the only components of MM that may predict prognosis. Then, renal function influences the predictive power of MM markers in pts. with SCAD.