Secondary outcome
INTERACTION
The estimation of models aimed to determine the impact of Q-SRP and timing of treatment on GDF-15, GPx-1, hs-CRP, and SP-D concentration changes at 6 months using a two-way ANOVA test revealed that Q-SRP had a significant effect on the reduction of serum GDF-15 (p = 0.015), GPx-1 (p = 0.045), and SP-D (p = 0.045) together with the timing of treatment for GDF-15 (p = 0.028) and GPx-1 (p < 0.001) concentrations. More specifically, patients with high GDF-15, GPx-1, and SP-D baseline concentrations gained more benefits from Q-SRP at 6-month follow-up (Table 
Results of two-way ANOVA for the dependent variable GDF-15, GPx-1, hs-CRP and SP-D. GDF-15, growth differentiation factor 15; GPx-1, glutathione peroxidase 1; hs-CRP, c-reactive proteins; SP-D, surfactant protein DMS: Mean of Square. F: Fisher test; Group*Timing: Interaction term