Herbal medicine for adults with asthma: A systematic review.

BACKGROUND

Many people with asthma use herbal medicines to help reduce symptoms and improve asthma control.

OBJECTIVE

To update the systematic review and meta-analysis of randomised controlled trials of herbal medicine for adult asthma.

DATA SOURCES

Nine English and Chinese databases were searched (PubMed, Embase, CINAHL, CENTRAL, AMED, CBM, CNKI, CQVIP, Wanfang).

STUDY SELECTIONS

Herbal medicines combined with routine pharmacotherapies compared with the same pharmacotherapies alone or placebo. Cochrane Risk of Bias Tool and GRADE Summary of Findings tables were used to evaluate methodological quality.

RESULTS

Twenty-nine (29) studies involving 3,001 participants were included. Herbal interventions used multi-ingredients such as licorice root, crow-dipper, astragali, and angelica. Compared with routine pharmacotherapies alone, herbal medicines as add-on therapy improved lung function (FEV1: MD 7.81%, 95% CI 5.79, 9.83, I(2) = 63%; PEFR: MD 65.14 L/min, 95% CI 58.87, 71.41, I(2) = 21%); asthma control (MD 2.47 points, 95% CI 1.64, 3.29, I(2) = 55%); reduced salbutamol usage (MD -1.14 puffs/day, 95% CI -2.20, -0.09, I(2) = 92%); and reduced acute asthma exacerbations over one year (MD -1.20, 95% CI -1.82, -0.58, one study). Compared with placebo plus pharmacotherapies herbal medicines as add-on therapy improved lung function (FEV1: MD 15.83%, 95% CI 13.54, 18.12 and PEFR: MD 55.20 L/min, 95% CI 33.41, 76.99). Other outcomes were not reported in these placebo studies. Included studies were low to moderate quality. Adverse events were rare.

CONCLUSIONS

Herbal medicines combined with routine pharmacotherapies improved asthma outcomes greater than pharmacotherapies alone. Included studies did not blind participants therefore more studies that address such weaknesses are warranted.