A study published online before the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine print edition shows that vitamin D levels are not related to acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in patients with severe COPD.

The cohort study of 973 North American patients showed no association between baseline Vitamin D levels and both time to first AECOPD or AECOPD exacerbation rates during a secondary evaluation of data from a randomized controlled trial of the effects of azithromycin on the frequency of AECOPD.

Ken M. Kunisaki, M.D., of the Minneapolis Veterans Affairs Medical Center commented:

“Vitamin D insufficiency and deficiency are common in patients with COPD, and patients with severe COPD are at the highest risk for exacerbations, so we hypothesized that low vitamin D levels might increase the risk of AECOPDs. Our negative results are in contrast with earlier studies in which lower vitamin D levels were associated with higher rates of respiratory infections in adults and more frequent asthma exacerbations in children.”

Results showed 1.12L as the mean forced expiratory volume in one second (FEV1), 40% of the predicted level. The average vitamin D level at baseline was 25.7 ± 12.8 ng/mL and researchers categorized 33.1% of the participants as vitamin D insufficient (≥20 ng/mL but

At 1-year follow up a total of 1,425 AECOPDs were experienced, showing that from a total of 973 participants 360 (37%) remained AECOPD-free, one participant developed the disease and 133 (14%) patients had 2 AECOPDs, whilst 202 (21%) of patients had 3 or more incidents of disease.

The primary analysis revealed that vitamin D levels were not associated with the time to first AECOPD. The estimated hazard ratio was 1.04 (95% confidence interval: 0.97-1.12) for a 10 ng/mL increment in vitamin D level.

The secondary analyses established that vitamin D levels were not associated with annualized rates of AECOPDs in either Poisson (p=0.82), or negative binomial analyses (p=0.87). Researchers discovered a higher average but statistically insignificant rate of AECOPDs in patients with severe vitamin D deficiency and observed that time to first AECOPD was not faster compared with other patients.

According to the researchers the study also had some limitations, for example seasonal changes in vitamin D levels in addition to levels only being assessed at baseline, meaning that they may have changed during the study period.

Dr. Kunisake concluded:

“Contrary to what we expected, baseline vitamin D levels were not related to the risk of subsequent AECOPDs in this large group of COPD patients at high risk of AECOPD. Vitamin D supplementation is unlikely to have an effect on AECOPD risk in these patients.”

Written by Petra Rattue