We all are drowning in e-mail. Today I got one from Akhtar Ashfaq, Senior Vice President, Clinical R&D, and Medical Affairs Renal Division at OPKO Pharmaceuticals.
The e-mail promises that new research shows that using calcifediol to correct PTH slows the progression of chronic kidney disease. Big if true. It is not true, and this publication actually lays bare how cynical some pharma-sponsored publishing can be.
The Tweet (actually in this case a Tweetorial)
Hours after writing this I was thinking about the tweet and it hit me. If the data OPKO used to see that the drop in PTH was associated with decreased progression of CKD was from the pivotal trial they used for approval then it was a randomized, placebo-controlled, trial and that OPKO had the data that would actually answer the question. So I pulled up the methods of the manuscript to see where the data came from.
Yep, they were randomized, placebo controlled trials. The two trials were combined and published in this manuscript (Sprague, S Am J Nephrol 2016).
And the authors looked at the most important question regarding the treatment of secondary hyperparathyroidism in CKD, “Does it slow the loss of GFR?”
No. Despite a powerful effect on PTH, there was no signal that use of calcifediol made a bit difference in the loss of eGFR.
Now this study only had patients on placebo controlled medications for 26 weeks, so perhaps there was not enough time to see a difference. But this is not the only attempt to use vitamin D to preserve kidney function. The large (1300 people randomized) and long (5 years) VITAL Study included an analysis of CKD progression and found no effect on eGFR or albuminuria. (H/T Gunnar Henrik Heine)
And last year Yeung, et al did a meta analysis of vitamin D therapy in CKD and likewise found no effect on all-cause mortality (relative risk [RR], 1.04; 95% CI: 0.84, 1.24), cardiovascular death (RR, 0.73; 95% CI: 0.31, 1.71), or fractures (RR, 0.68; 95% CI: 0.37, 1.23).