Summary

2022 ATS/ERS/JRS/ALAT guideline updates IPF diagnosis and management and introduces the new entity of progressive pulmonary fibrosis (PPF) in non-IPF fibrotic ILD. Key updates: transbronchial lung cryobiopsy (TBLC) is now an acceptable alternative to surgical lung biopsy in experienced centers; conditional recommendations against antacid medication and antireflux surgery for the sole purpose of improving respiratory outcomes in IPF; no recommendation on genomic classifier testing. PPF is defined by ≥2 of 3 criteria (symptoms, physiologic decline, radiologic progression) within 1 year, and nintedanib is conditionally recommended for PPF after failure of standard ILD-directed therapy, while pirfenidone requires further research.

Key Recommendations

TBLC is an acceptable alternative to surgical lung biopsy for histopathologic diagnosis of ILD of undetermined type in centers with appropriate expertise (conditional, very low quality).
Make no recommendation for or against genomic classifier testing for diagnosing UIP in patients undergoing transbronchial forceps biopsy.
Do not treat IPF with antacid medication solely to improve respiratory outcomes; antacids remain appropriate for GERD-related indications (conditional, very low quality).
Do not refer patients with IPF for antireflux surgery solely to improve respiratory outcomes (conditional, very low quality).
Maintain four HRCT categories (UIP, probable UIP, indeterminate, alternative diagnosis); patients with probable UIP can be diagnosed with IPF via MDD without biopsy in the appropriate clinical context.
Define PPF in non-IPF fibrotic ILD as ≥2 of 3 criteria within the past year: worsening symptoms, physiologic progression, or radiologic progression, with no alternative explanation.
Use nintedanib for PPF in patients who have failed standard management for their underlying fibrotic ILD (conditional, low quality).
Further research is recommended before routine use of pirfenidone in PPF; insufficient evidence to issue a treatment recommendation.
Refer patients with IPF at increased mortality risk for lung transplantation at the time of diagnosis; reassess every 3–6 months for progression.
Treat IPF acute exacerbations with corticosteroids; mechanical ventilation is not recommended for most patients with IPF respiratory failure.
Evaluate and treat IPF comorbidities (pulmonary hypertension, GERD, OSA, lung cancer) and incorporate pulmonary rehabilitation, oxygen, and palliative care.
Avoid TBLC when FVC <50% predicted, DLCO <35%, sPAP >40 mm Hg, uncorrectable bleeding risk, or PaO2 <55–60 mm Hg (relative contraindications).

Thresholds & Doses

PPF physiologic criterion: absolute decline in FVC ≥5% predicted within 1 year.
PPF physiologic criterion: absolute decline in DLCO (Hb-corrected) ≥10% predicted within 1 year.
TBLC relative contraindications: FVC <50% predicted, DLCO <35%, sPAP >40 mm Hg, PaO2 <55–60 mm Hg.
TBLC diagnostic yield ~79%; rises to ~85% with ≥3 samples; SLB yield ~90%.
TBLC complication rates: pneumothorax ~9%, any bleeding ~30%; SLB pneumothorax ~6%.
Antireflux surgery aggregate 30-day complication rate ~15%, severe ~9%.
Honeycomb cysts: clustered, thick-walled, 3–10 mm (up to 2.5 cm); paraseptal emphysema cysts typically >1 cm.
Nintedanib in PPF (INBUILD): reduced annual FVC decline by ~107 mL/yr overall; ~128 mL/yr in UIP pattern, ~75 mL/yr in non-UIP pattern.
Pirfenidone in PPF: reduced FVC decline by ~100 mL and ~2.3% predicted over 24 weeks; attenuated 6MWD decline by ~25 m.
Pleuroparenchymal fibroelastosis occurs in 6–10% of IPF cases.
IPF reassessment interval: every 3–6 months for disease progression.
Clinically suspected IPF: age >60 yr (rarely 40–60 yr if familial features), bibasilar inspiratory crackles, unexplained bilateral fibrosis.

Citations

Evidence-based Recommendations for Diagnosis of IPF — TBLC as acceptable alternative to SLB (conditional, very low quality)
Evidence-based Recommendations for Diagnosis of IPF — no recommendation on genomic classifier testing
Evidence-based Recommendations for Treatment of IPF — antacid medication and antireflux surgery conditional recommendations against
Table 3 — HRCT patterns in IPF (UIP, probable UIP, indeterminate, alternative diagnosis)
Table 4 — Definition of Progressive Pulmonary Fibrosis (2 of 3 criteria within 1 year)
Part II Evidence-based Recommendations — nintedanib conditional recommendation for PPF; pirfenidone research recommendation
Figure 10 — Diagnostic algorithm for IPF
Figure 11 — Management pathway for IPF including antifibrotics, transplant referral, comorbidity care