PDE4A and chronic obstructive pulmonary disease: In this study, CS was predicted to affect COPD by targeting genes such as PARP1, PDE4A, PDE4B, PDE4C, PDE4D, PTGDR2 (p = 4.61e‐03, TTD), HMOX1, and MMP1 (p = 3.65e‐02, OMIM).