Magnesium and FGF-23 are independent predictors of pulse pressure in pre-dialysis diabetic chronic kidney disease patients

BACKGROUND The aim of our study was to evaluate the relevance of magnesium and FGF-23 in terms of cardiovascular disease in a population of type 2 diabetic patients with nephropathy. METHODS In a cross-sectional study, we included 80 type 2 diabetic patients with chronic kidney disease (CKD) stages 2, 3 and 4. We analysed mineral metabolism, inflammation, oxidative stress and insulin resistance. Our population was divided into two groups according to their pulse pressure (PP) as follows: G-1 with PP < 50 mmHg (n = 34) and G-2 with PP ≥ 50 mmHg (n = 46). RESULTS We found that G-2 patients showed lower calcium (P = 0.004), eGFR (P = 0.001), magnesium (P = 0.0001), osteocalcin (P = 0.0001) and 25(OH)D3 (P = 0.001), and higher iPTH (P = 0.001), FGF-23 (P = 0.0001), malonaldehyde (P = 0.0001), interleukin 6 (P = 0.001) and HOMA-IR (P = 0.033). No differences were found between the two groups regarding age, duration of disease, haemoglobin, HgA1c and phosphorus. In a multivariate analysis, we found that FGF-23 and magnesium independently influenced the PP [OR = 1.239 (1.001-2.082), P = 0.039 and OR = 0.550 (0.305-0.727), P = 0.016, respectively]. CONCLUSIONS In our diabetic population with early stages of CKD, FGF-23 as well as lower magnesium levels were significantly and independently associated with higher PP levels, an established marker of cardiovascular morbidity and mortality.