Dietary Vitamin C Deficiency Is Associated With Health-Related Quality of Life and Cardiac Event-free Survival in Adults With Heart Failure.
Jia-Rong Wu, Eun Kyeung Song, Debra K Moser and 1 others
PMID 30211815WHAT IT FOUND
Dietary vitamin C deficiency was associated with shorter time to first cardiac event and worse physical quality of life in adults with chronic heart failure.
Forty percent of patients were deficient. This is observational, not proof supplementation helps.
Key findings
01After adjustment, dietary vitamin C deficiency was associated with shorter time to first cardiac event (HR 1.95, 95% CI [1.08, 3.51]).
02Patients with dietary vitamin C deficiency had worse total Minnesota Living with Heart Failure scores (49.3 vs 37.9) and physical subscale scores (22.2 vs 16.5), but no emotional subscale difference (P = 0.21).
03One hundred patients (40%) had dietary vitamin C deficiency.
STILL TO COME
How it was doneWhat they foundWhat it means for RNs
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What it does not show
The study is observational, so it shows an association, not that low vitamin C caused worse quality of life or cardiac events. The study did not test vitamin C supplementation, so it cannot show that adding vitamin C improves outcomes. Dietary vitamin C intake was measured from a 4-day food diary at one time point, which may not reflect usual intake. Serum vitamin C levels were not measured, so dietary intake was not confirmed by blood levels. The sample was 251 patients, mostly male, white, and married, so the findings may not apply broadly. The authors note that randomized trials are still needed before vitamin C supplementation can be recommended as treatment.
Declared interests
The article lists NIH and non-U.S. government research support. The conflicts section states none.
The easy way to misread this
Do not conclude that vitamin C supplementation will improve heart failure quality of life or prevent cardiac events. This was an observational study of existing dietary intake, and the authors say randomized trials are still needed.