Background and importance Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive disease. Its treatment with antifibrotic drugs (pirfenidone and nintedanib) is characterised by a high incidence of adverse effects (AE) that together with the progression of the disease make therapeutic persistence difficult.

Aim and objectives The objective was to compare pirfenidone and nintedanib in terms of effectiveness, safety, and durability of treatment in a tertiary hospital.

Material and methods Retrospective observational study of patients treated with pirfenidone and/or nintedanib between November 2012 nd May 2021.

Variables collected: age, sex, forced vital capacity (FVC), dose, duration of treatment, reason for suspension, AE and adherence. Effectiveness was measured as a <10% reduction in FVC at 12 and 24 months. Data sources: outpatient dispensing program and clinical history. Analysis with SPSS Statistics 21.

Results 83 patients received pirfenidone and 58 nintedanib (76% and 69% men, respectively). Mean age 73 years with pirfenidone and 72 years with nintedanib. Dose reductions were greater with nintedanib (38% vs 18% pirfenidone, p=0.008), and more patients switched drugs with nintedanib (26%) than with pirfenidone (17%) without statistically significant differences (p=0.194).

The percentage of patients who progressed was higher with pirfenidone (38% vs 23%) without statistically significant differences (p=0.132). The speed of progression was also higher with pirfenidone (within the first 12 months: 73% vs 38%, p=0.028).

The median durability by Kaplan–Meier was greater with nintedanib: 23 months (95% CI 12 to 33) versus 22 months (95% CI 11 to 33), although without statistical significance (p=0.689).

Reasons for suspension: with pirfenidone 23/45 death, 19/45 AE, 2/45 change of hospital and 1/45 lung transplantation; with nintedanib 9/23 death, 8/23 AE, 3/23 anticoagulant treatment and 3/23 change of hospital.

The percentage of patients with AE was practically the same: 45% (37/83) pirfenidone and 43% (25/58) nintedanib.

Adherence was similar in both groups (92% for pirfenidone and 87% for nintedanib).

Conclusion and relevance Pirfenidone and nintedanib have very similar safety and durability profiles, and it seems that with pirfenidone a greater number of patients progress and do so faster; however, larger sample size studies would be necessary to achieve statistical significance.

Conflict of interest No conflict of interest