Immune diffuse alveolar hemorrhage: a retrospective assessment of a diagnostic scale

Initiating early steroid treatment in patients with immune diffuse alveolar hemorrhage (DAH) is a key aspect of early management. However, steroid initiation is often delayed until the results of immunological markers and/or tissue biopsy have been obtained, which could contribute to poor outcomes. We previously developed a clinical score allowing for the early diagnosis of DAH of immune causes. However, this score has not been validated in an independent cohort of patients. The aim of this study was to assess the validity of this diagnostic score using an independent cohort of patients admitted for DAH of immune and nonimmune causes.

We conducted a retrospective cohort study of patients admitted between January 2002 and December 2009 for DAH of immune and nonimmune causes.

Forty-six patients were included in the study, with 12 patients having immune DAH and 34 patients with nonimmune DAH. Application of our previously validated clinical scale of immune DAH to this independent population of patients yielded an area under the ROC curve of 0.95 [0.90-1.01]. A score ≥4/10 was associated with the best performances of this scale: sensitivity = 1.00 [0.73-1.00], specificity = 0.88 [0.72-0.97], positive predictive value = 0.75 [0.48-0.93], and negative predictive value = 1.00 [0.88-1.00].

While immunological tests and tissue biopsy results are pending, deciding whether to initiate an immunosuppressive treatment is challenging. The initiation of early corticosteroid treatment is warranted in patients with immune DAH and could improve outcomes. This study confirms that this score allows for a good discrimination between patients with immune and nonimmune DAH. Because this series has several limitations, including its single-center and retrospective nature, the small number of patients included, and the lack of therapeutic intervention, a prospective evaluation of this score is warranted to ascertain whether it can improve the adequacy of early treatment strategies and thus improve the outcomes of DAH patients.