Inhibitory effect of pirfenidone on pulmonary fibrosis in patients with acute paraquat poisoning

Objective: To study the efficacy of pirfenidone (PFD) on patients with pulmonary fibrosis caused by acute paraquat (PQ) poisoning. Methods: A total of 86 patients with pulmonary fibrosis caused by acute PQ poisoning admitted to our hospital were analyzed retrospectively. All of them successfully received the standard 21-day treatment based on "Taishan Consensus", and they were assigned to the PFD group or the NO-PFD group according to whether they received PFD treatment (at 200 mg/time, 3 times/day) for 6 months after discharge. The two groups were compared in effective treatment rate, mortality and incidence of adverse reactions such as liver and kidney function damage, pulmonary fibrosis-associated indexes, pulmonary function-associated indexes, and arterial blood gas indexes before and after therapy. Results: The PFD group showed a notably higher effective treatment rate than the NO-PFD group (P<0.05). Additionally, the PFD group showed notably lower levels of serum hyaluronic acid (HA), laminin (LN), type IV collagen (CIV), and type III procollagen (PCIII), and notably higher levels of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC than the NO-PFD group (all P<0.001), and the PFD group also showed significantly higher levels of arterial blood gas indexes including arterial partial pressure of oxygen (PaO,) and PaO2/inspired oxygen (FIO2) than the NO-PFD group (both P<0.001). Moreover, the Kaplan-Meier survival curves showed that the survival rate of the patients in PFD group was significantly higher than that in the NO-PFD group (P<0.05). Conclusion: With a high safety, PFD can effectively improve the treatment efficacy in patients with pulmonary fibrosis caused by acute PQ poisoning. PFD can improve the pulmonary function and arterial blood gas status of patients, without causing obvious liver and kidney damage.