Hypersensitivity pneumonitis: application of a new diagnostic algorithm to a time series of the disease

ABSTRACT

Background

The diagnostic criteria for Hypersensitivity pneumonitis (HP) have changed over time. Our aim is to apply a recent diagnostic algorithm to a historical series of patients diagnosed with HP to assess its distribution according to current diagnostic criteria and the diagnostic confidence achieved.

Research design and methods

Application to each patient the algorithm criteria. The diagnosis was HP (≥90%), provisional high (70–89%) or low confidence (51–69%) or non-HP (unlikely) (≤50%); or HP, provisional or non-HP, if they had lung biopsy.

Results

129 patients [mean age 64 ± 12 years; 79 (61.2%) women] were included of which 16 (12.4%) were diagnosed on the basis of high clinical suspicion. After applying the algorithm, 106 patients (82.2%) could be evaluated and 83 (78.3%) had a diagnosis of HP or high confidence. Lung biopsy was able to establish a diagnosis of certainty in another 21 patients and a provisional diagnosis in 9 more [total, 113 (87.6%)]. The 16 patients without strict diagnostic criteria for HP had a low confidence diagnosis. A total of 56 lung biopsies (64.4%) could have been avoided according to the new guidelines.

Conclusions

The application of this algorithm achieves a high diagnostic yield in HP, significantly reducing the number of lung biopsies required.

KEYWORDS:

• Hypersensitivity pneumonitis
• diagnostic algorithm
• diagnostic certainty
• lung biopsy
• diagnostic yield

Abbreviations

BAL	=	bronchoalveolar lavage
DLCO	=	diffusing capacity for carbon monoxide
HP	=	hypersensitivity pneumonitis
HRCT	=	high-resolution computed tomography
ILD	=	interstitial lung disease
IPF	=	idiopathic pulmonary fibrosis

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

The authors would like to acknowledge all study participants and patients advisers.

Author contributions

A Casal, Author and drafting. Conception and design. Approval of the final manuscript.

J Suárez-Antelo, Co-author. Approval of the final manuscript.

V Riveiro, Co-author. Approval of the final manuscript.

L Ferreiro, Co-author. Approval of the final manuscript.

C Rodríguez-García, Co-author. Approval of the final manuscript.

A Martínez de Alegría, Co-author. Radiological review. Approval of the final manuscript.

J R Antúnez, Co-author. Pathological anatomy review. Approval of the final manuscript.

M E Toubes, Co-author. Approval of the final manuscript.

B Otero, Co-author. Approval of the final manuscript.

N Rodríguez-Núñez, Co-author. Approval of the final manuscript.

J M Álvarez-Dobaño, Co-author. Approval of the final manuscript.

K Vargas-Osorio, Co-author. Anatomical pathology review. Approval of the final manuscript.

F Gude, Co-author. Statistical design. Approval of the final manuscript.

L Valdés, Author and drafting. Conception and design. Approval of the final manuscript.

Additional information

Funding

This paper was not funded.