Background: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with a poor prognosis. Pirfenidone is approved and widely used for the treatment of IPF and reduces lung function decline. The aim of this study was to evaluate the efficacy of different doses of pirfenidone for the prevention of disease progression in patients with IPF. Methods: This was a prospective, observational, single-center cohort study conducted in Haeundae Paik Hospital, Republic of Korea, from April 2021 to March 2023. IPF patients were assigned to three groups according to the dose of pirfenidone (600mg, 1,200mg, 1,800mg). The primary endpoint was the efficacy of pirfenidone according to dose for the prevention of disease progression over 12 months. The secondary endpoint was the role of Krebs von den Lungen-6 (KL-6) in predicting disease progression. Results: A total of 44 patients were enrolled, of whom 39 completed the study, with 13 patients assigned to each of the three groups. The median age was 71.7 years, and 79.5% of patients were men. The baseline characteristics were similar across groups, except the 600mg group was older (75.9 vs. 69.2 vs. 68.2 years, p = 0.016). Fourteen patients (35.9%) suffered disease progression. The rate of disease progression did not differ according to the dose of pirfenidone (38.5 vs. 38.5 vs. 30.8%, p = 1.000). In multivariable logistic regression analysis, KL-6 was not a statistically significant predictor of disease progression. Conclusions: In our study, regardless of dose, consistent pirfenidone use for 12 months resulted in similar efficacy for the prevention of disease progression in patients with IPF. Large-scale, randomized, double-blind, placebo-controlled clinical trials are needed.

This study was conducted to investigate the prevalence of Coxiella burnetii infection according to cattle breeds and growth types. A total of 491 cattle [cattle breed: 216 dairy cattle and 275 beef cattle; according to growth type: indoor housing (n = 294) and grazing (n = 197)] were tested for the presence of C. burnetii DNA and antibodies against C. burnetii using a commercial enzyme-linked immunosorbent assay (ELISA). Overall, 10.8% and 8.8% of the cattle were positive by PCR and for C. burnetii antibodies, respectively. The prevalence of C. burnetii was significantly higher in beef cattle than in dairy cattle using PCR (13.6% vs 7.4%; P = 0.032) and ELISA (14.6% vs 1.4%; P = 0.000), respectively. The overall infection rate of C. burnetii was significantly high in grazing cattle (PCR: 24.9%, ELSIA: 21.3%; P = 0.000) compared with housing cattle (PCR: 1.4%, ELISA: 0.3%). The results indicate that beef cattle have a significantly higher risk of contracting C. burnetii infection compared with dairy cattle (21.5% vs. 7.9%, χ2 = 5.82, P = 0.000, odds ratio = 3.197, 95% CI: 1.80-5.67). In addition, the infection of C. burnetii was significantly associated with grazing (P = 0.000). Moreover, a risk of contracting C. burnetii infection in grazing cattle was increased by 32.57-fold (95% CI: 12.84-82.60, P = 0.000) compared with indoor housed cattle. The phylogenetic analysis based on the IS111 gene revealed that our isolates were grouped together with humans, ticks, goats, and cattle isolates found in several countries. C. burnetii isolates circulating in the Republic of Korea exhibit genetic variations. Consequently, our results suggest that cattle are potential reservoirs for C. burnetii infection and most importantly, grazing acts as a high risk factor for the occurrence and transmission of this infection.