Author Affiliations: Division of Nephrology, Massachusetts General Hospital, Boston (Drs Thadhani and Tamez) (firstname.lastname@example.org); and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, Massachusetts (Dr Solomon).
In Reply: Dr Fourtounas and Drs Rajagopalan and Chan highlight the challenge of identifying the most accurate population for a clinical trial. The PRIMO study aimed to evaluate the effect of activated vitamin D analogs in patients otherwise receiving standard of care therapy in 11 different countries worldwide. Therefore, patients who were well treated according to standard clinical practices, which included use of RAAS inhibitors and other blood pressure agents, were enrolled. While these agents themselves may influence left ventricular hypertrophy,1,2 the conduct of a clinical trial performed on a background of less than standard-of-care therapy would have been unethical, and a positive result from such a trial would have been difficult to interpret. Although paricalcitol did not have an effect on LVMI in patients receiving state-of-the-art care, there was a suggested benefit in other parameters, including cardiovascular hospitalizations, levels of brain natriuretic peptide, and left atrial volume index.
Thadhani R, Tamez H, Solomon SD. Vitamin D Therapy and Cardiac Function in Chronic Kidney Disease—Reply. JAMA. 2012;307(21):2253. doi:10.1001/jama.2012.4176