Modified Yupingfeng formula for the treatment of stable chronic obstructive pulmonary disease: a systematic review of randomized controlled trials.

BACKGROUND

Chronic obstructive pulmonary disease (COPD), is a very common disease of respiratory system. An increasing number of clinical trials on Yupingfeng formula in the management of stable COPD have been performed. However, the evidence base for it remains unknown. This review aims at assessing the efficacy, and safety of modified Yupingfeng formula in the treatment of stable COPD through a systematic review of all available randomized controlled trials.

MATERIALS AND METHODS

Literature retrieval was conducted using four English databases (CENTRAL, PubMed, EMBASE, and ISI Web of Science), and four Chinese databases (CBM, CNKI, VIP, and WANFANG), from respective inception to January 2013, and supplemented with a manual search. Review authors independently extracted the trial data, and assessed the quality of each trial. Methodological quality was assessed by Cochrane risk of bias and Jadad's scale. The following outcomes were evaluated: (1) lung function; (2) 6-minute walk distance (6MWD); (3) effective rate; (4) serum levels of IgA, IgG and IgE; and (5) adverse events. Data were analyzed using STATA 12.0 software.

RESULTS

A total of nine studies involving 660, stable COPD patients were identified. Patients from all studies included in this review were randomized to receive Yupingfeng formula combined with Western medications in comparison with Western medications. In general, the methodological quality of the included trials was poor. The results of this systematic review indicates that, compared with Western medications alone, the use of Yupingfeng formula, if combined with Western medications could significantly improve FEV1 (WMD = 0.30L; 95%CI: 0.19, 0.42), FEV1/FVC ratio (SMD = 0.69; 95%CI: 0.48, 0.91), 6MWD (WMD = 31.73m; 95% CI: 19.29, 44.17), and effective rate (RR = 1.24; 95% CI: 1.10, 1.41), and increase the serum levels of IgA (WMD = 0.25; 95%CI: 0.16, 0.34) and IgG (WMD = 1.10; 95%CI: 0.53, 1.68), but no difference was found in the serum IgE levels (WMD = 0.47; 95%CI: -0.32, 1.27) between the two groups. No serious adverse events were reported.

CONCLUSIONS

Within the limitations of this systematic review, we may conclude that compared with Western medications alone, Yupingfeng formula, when combined with Western medications can provide more benefits for patients with stable COPD, without any serious adverse reactions being identified. However, these benefits need to be further confirmed through high-quality prospective placebo-controlled trials that should be strictly conducted in accordance with methodological principles and procedures.