Reply to Moran-Mendoza: Idiopathic Pulmonary Fibrosis Update. Reconciliation with Hypersensitivity Pneumonitis Guidelines Required?

From the Authors:

We thank Dr. Morán-Mendoza for bringing up the important point of reconciling the 2020 diagnosis of hypersensitivity pneumonitis (HP) guideline (1) with the recently updated 2022 diagnosis and management of idiopathic pulmonary fibrosis (IPF) guideline (2).

When the decision was made to update prior guidance on IPF, the 2018 diagnosis of IPF guidelines, the 2015 treatment of IPF guidelines, and the 2011 diagnosis and management of IPF guidelines were all reviewed for currency by the chair (3–5). A targeted update addressing outdated content was approved, consistent with Society policies limiting the number of questions that can be addressed in a guideline. Therefore, all content from prior IPF guidelines should be considered valid unless updated in the recent 2022 update. In retrospect, we agree that we should have been more explicit about the implications of the updated IPF guideline on prior guidance, perhaps by providing a table that lists both the unchanged recommendations from prior IPF guidelines and the updated recommendations from the 2022 IPF guideline. The diagnostic algorithm in Figure 10 in the 2022 IPF guideline is an updated version of Figure 9 in the 2018 diagnosis of IPF guideline, with the updated recommendation of transbronchial lung cryobiopsy inserted.

The letter from Dr. Moran-Mendoza gives us an important opportunity to reconcile IPF and HP guidelines by reiterating and emphasizing the need to rule out fibrotic HP in patients suspected of having IPF, as indicated by recommendations in the 2020 diagnosis of HP guideline. It is noteworthy that the need for BAL cellular analyses is included in the most recent diagnostic algorithm (Figure 10 in the 2022 guideline document) (2). We agree that integration of the diagnosis of IPF and fibrotic HP into a single guideline would have been useful to clinicians and patients confronted with patients manifesting fibrotic interstitial lung disease. Unfortunately, the high methodologic requirements expected of guidelines since the release of the National Academy of Medicine’s Standards for Trustworthy Guidelines (6) makes the development of such large comprehensive guidelines impractical.

In summary, we thank Dr. Moran-Mendoza for giving us the opportunity to emphasize our bottom line: known causes of pulmonary fibrosis should be eliminated in patients suspected of having IPF, which requires that the diagnostic process be conducted in a multidisciplinary environment. An exposure history and BAL cellular analysis, as outlined in both the 2018 diagnosis of IPF guideline (3) and the 2020 diagnosis of HP guideline (1), should inform the diagnostic algorithm published in the 2022 IPF guideline update (2) to achieve an accurate diagnosis of IPF.