PTH and chronic kidney disease: However, several results indicate that CKD-MBD may begin earlier in the disease process and clinically asymptomatic metabolic disturbances may precede the development of detectable abnormalities in plasma calcium, phosphorus, and parathyroid hormone (Pereira et al., 2009; Oliveira et al., 2010; Isakova et al., 2011; Sabbagh et al., 2012).