Acute exacerbation of IPF following diagnostic bronchoalveolar lavage procedures

Backgrounds: Bronchoalveolar lavage (BAL) is generally regarded as a safe diagnostic procedure. However, acute exacerbation after BAL is increasingly recognized as a specific complication for patients with idiopathic pulmonary fibrosis (IPF). So far little is known about the correlation between BAL and acute exacerbation of IPF (AE-IPF). Methods: A cohort of 112 IPF patients at a single institution was analyzed retrospectively. We defined BAL-related AE-IPF as development of AE-IPF within 30 days after the procedure. The incidence rate of AE-IPF per person-month during the post-BAL period was compared with that after the post-BAL period. The relative risk was estimated as the former rate divided by the latter. We also reviewed the previous literature. Results: Four AE-IPF cases occurred during the 201 person-month post-BAL period. The risk of AE-IPF was significantly elevated within 30 days after BAL (rate ratio = 4.12; 95% CI = 1.03-12.2). None of the 111 initial BAL procedures were followed by AE-IPF within a month. In a post hoc analysis, the relative risk of developing AE after second or later BAL procedures was estimated to be considerably higher (rate ratio = 9.10; 95% CI = 2.27-26.98). Twelve cases of BAL-induced AE-IPF were found in our study and in the literature review. Among them, nine showed moderate to severe functional impairment, and eight had either findings of leukocytosis, positive C-reactive protein, or neutrophilia in BAL. Conclusions: These results suggest that IPF patients should be carefully monitored after BAL, especially those with functional impairment or active inflammation.