Xiaoqinglong granules as add-on therapy for asthma: latent class analysis of symptom predictors of response

Abstract

Xiaoqinglong granules (XQLG) has been shown to be an effective therapy in asthma animal models. We reviewed the literature and conducted this study to assess the impact of XQLG as an add-on therapy to treatment with fluticasone/salmeterol (seretide) in adult patients with mild-to-moderate, persistent asthma. A total of 178 patients were randomly assigned to receive XQLG and seretide or seretide plus placebo for 90 days. Asthma control was assessed by asthma control test (ACT), symptoms scores, FEV(1), and PEF. Baseline patient-reported Chinese medicine (CM)-specific symptoms were analyzed to determine whether the symptoms may be possible indicators of treatment response by conducting latent class analysis (LCA). There was no statistically significant difference in ACT score between two groups. In the subset of 70 patients with symptoms defined by CM criteria, XQLG add-on therapy was found to significantly increase the levels of asthma control according to global initiative for asthma (GINA) guidelines (P = 0.0329). There was no significant difference in another subset of 100 patients with relatively low levels of the above-mentioned symptoms (P = 0.1291). Results of LCA suggest that patients with the six typical symptoms defined in CM may benefit from XQLG.

Figure 1

Flow Diagram of the enrollment progress through the phases of XQLG randomized trial of the two groups.

Figure 2

Adjusted mean change from baseline in forced expiratory volume (FEV₁%) and peak expiratory flow (PEF%) during the entire 90-day treatment period.

Figure 3

Conditional probabilities for each item endorsement according to latent class for asthma participants in subjects (n = 170).