Identification of Diagnostic Criteria for Chronic Hypersensitivity Pneumonitis: An International Modified Delphi Survey

Abstract

Rationale: Current diagnosis of chronic hypersensitivity pneumonitis (cHP) involves considering a combination of clinical, radiological, and pathological information in multidisciplinary team discussions. However, this approach is highly variable with poor agreement between centers.

Objectives: We aimed to identify diagnostic criteria for cHP that reach consensus among international experts.

Methods: A 3-round modified Delphi survey was conducted between April and August 2017. Forty-five experts in interstitial lung disease from 14 countries participated in the online survey. Diagnostic items included in round 1 were generated using expert interviews and literature review. During rounds 1 and 2, experts rated the importance of each diagnostic item on a 5-point Likert scale. The a priori threshold of consensus was ≥ 75% of experts rating a diagnostic item as very important or important. In the third round, experts graded the items that met consensus as important and provided their level of diagnostic confidence for a series of clinical scenarios.

Measurements and main results: Consensus was achieved on 18 of the 40 diagnostic items. Among these, experts gave the highest level of importance to the identification of a causative antigen, time relation between exposure and disease, mosaic attenuation on chest imaging, and poorly formed non-necrotizing granulomas on pathology. In clinical scenarios, the diagnostic confidence of experts in cHP was heightened by the presence of these diagnostic items.

Conclusion: This consensus-based approach for the diagnosis of cHP represents a first step towards the development of international guidelines for the diagnosis of cHP.

Keywords: Delphi; Diagnosis; Hypersensitivity pneumonitis; Interstitial Lung Disease.

Figure 1.

Source of the 40 diagnosis items. Items that originated from multiples sources are positioned in overlapping areas. CTD = connective tissue disease; HP = hypersensitivity pneumonitis; ILD = interstitial lung disease; NSIP = nonspecific interstitial pneumonia; UIP = usual interstitial pneumonia.

Figure 2.

Approach to the diagnosis of chronic hypersensitivity pneumonitis. *Consider additional test: bronchoscopy with bronchoalveolar lavage, transbronchial lung biopsy, transbronchial lung cryobiopsy, or surgical lung biopsy. ^#Consider additional test: transbronchial lung biopsy, transbronchial lung cryobiopsy, or surgical lung biopsy. cHP = chronic hypersensitivity pneumonitis; HRCT = high-resolution computed tomography; UIP = usual interstitial pneumonia.