A new open label trial suggests that vitamin D supplementation may help patients with chronic heart failure.
Chronic heart failure is a disease characterized by the heart’s inability to sufficiently pump and maintain good blood flow for the rest of the body. The main causes of chronic heart failure are coronary artery disease, hypertension and cigarette smoking.
When you’re diagnosed with chronic heart failure, you have a significant increased risk of mortality. A common treatment for the disease is to prescribe renin-angiotensin-aldosterone system (RAAS) blockers, which effectively reduces morbidity and mortality for reasons we won’t go into detail about.
One side effect of these drugs is that they increase plasma renin activity (PRA) and plasma renin concentration (PRC). Observational studies paradoxically show that despite RAAS blockade, high PRA is related to poor survival. So the next question is, can we both use RAAS blockers and find a treatment to lower PRA?
Vitamin D deficiency has been linked to increased risk of mortality in heart failure. Some small experimental studies show that vitamin D may be able to lower PRA, which may explain some of the reason why vitamin D sufficiency has been associated with better survival.
Here in this study, Dr Nicolas F Schroten and colleagues of the University of Groningen in the Netherlands wanted to know, if we supplement patients with chronic heart failure with vitamin D in a well-designed and controlled study, can we reduce PRA and PRC?
The researchers enrolled 101 participants in their study (99 completed the study). All received best current care for heart failure. Half of the participants knowingly took 2,000 IU/day, while the other half did not and served as controls. The open label trial lasted for 6 weeks.
So did vitamin D lower PRA and PRC? Here is what they found:
- Vitamin D levels rose from 19 ng/ml to 32 ng/ml in the vitamin D group after 6 weeks. The control group’s vitamin D levels remained the same, around 19 ng/ml.
- In the vitamin D group, PRA decreased from a mean 6.3 ng/ml per hour to 5.2 ng/ml per hour. The control group on the other hand, experienced an increase from a mean of 5.1 ng/ml/h to 7.3 ng/ml/h. This was statistically significant (p= .002).
- In the vitamin D group, PRC decreased from a mean 63 ng/l to 55 ng/l. The control group on the other hand, experienced an increase from a mean of 56 ng/l to 72 ng/l. This was statistically significant (p= .020).
The researchers concluded,
“Most chronic heart failure patients are vitamin D deficient. Supplementation with dietary vitamin D3 (daily intake 2,000 IU) effectively increased vitamin D levels and lowered both PRA and PRC compared with control.”
Limitations of this study include small number of participants and short follow-up period. It was also not a randomized placebo controlled trial, although since the researchers were just looking at blood markers, it’s hard to believe that a placebo pill would have an effect on the PRA and PRC levels.
The researchers recommend further research for longer duration and possibly using higher doses. In the meantime, the study may provide some explanation why vitamin D sufficiency helps with chances of survival in chronic heart failure.
Schroten NF et al. Short-term vitamin D3 supplementation lowers plasma renin activity in patients with stable chronic heart failure: An open-label, blinded end point, randomized prospective trial (VitD-CHF trial). American Heart Journal, 2013.