Treating vitamin D deficiency may help prevent COPD attacks
Vitamin D supplements can help reduce the rate of moderate-to-severe COPD* exacerbations in patients with inadequate vitamin D levels (<25 nmol/L) at baseline, but not in those with higher levels, according to a meta-analysis of randomized controlled trials (RCTs).
“Vitamin D supplementation is safe, and it costs just a few pence to supplement a person for a year - so this is a potentially highly cost-effective treatment that could be targeted at those who have low vitamin D levels following routine testing,” suggested principal investigator Professor Adrian Martineau from Queen Mary University of London in London, UK.
The meta-analysis used individual participant data from three double-blind RCTs involving 469 patients with COPD who were randomized to either oral vitamin D3 supplementation or placebo. [Thorax 2019;doi10.1136/thoraxjnl-2018-212092]
In the overall study population, supplemental vitamin D had no effects on the rate of moderate/severe COPD exacerbations compared with placebo (adjusted incidence rate ratio [aIRR], 0.94; p=0.52).
However, subgroup analysis revealed that supplemental vitamin D benefits patients with baseline 25-hydroxyvitamin D levels <25 nmol/L, who saw the rates of moderate/severe COPD exacerbations significantly reduced by almost half (aIRR, 0.55; p=0.006).
In contrast, the protective effects were not seen in the patient subgroup whose baseline 25-hydroxyvitamin D [25(OH)D] levels were ≥25 nmol/L (aIRR, 1.04; p=0.71).
“Our study shows that giving supplements to vitamin D-deficient COPD patients nearly halves their rate of potentially fatal attacks,” said Martineau.
“Given the high prevalence of profound vitamin D deficiency in people with COPD, and the large reduction in exacerbation rates seen with vitamin D supplementation in [the subgroup with low baseline 25(OH)D], our findings support a strategy of routinely testing vitamin D status in patients with COPD who experience exacerbations and offering supplementation to [these patients],” the researchers stated.
There was no effect on COPD exacerbations with vitamin D supplementation when the analyses were prespecified by other factors such as baseline GOLD spirometric grade, BMI, concomitant use of inhaled corticosteroids, polymorphisms in genes involved in vitamin D metabolism (VDR and DBP), and the frequency of vitamin D dosing.
The proportion of patients who had at least one serious adverse event also did not change with vitamin D supplementation (adjusted odds ratio, 1.16, 95 percent confidence interval, 0.76–1.75), which according to the researchers, indicates that “vitamin D supplementation was safe at the doses administered.”
“Serious adverse events and occasional episodes of hypercalcaemia were evenly distributed between participants randomized to vitamin D versus placebo, and no instances of renal stones were seen,” they noted.
The findings echoed the results from previous studies by the same research team, which showed that vitamin D supplementation was protective against asthma attacks and acute respiratory infections in people with low baseline vitamin D levels. [BMJ 2017;356:i6583; Lancet Respir Med 2017;5:881-890]
“Since acute respiratory infections commonly precipitate exacerbations of both asthma and COPD, it may be that protective effects of vitamin D against these outcomes are mediated by a common mechanism, namely induction of antiviral and antimicrobial responses,” suggested Martineau and co-authors on the potential mechanism behind the protective effects of vitamin D.