Takuya Kotani, Shogo Matsuda, Ayana Okazaki, Yuichi Masuda, Atsushi Manabe, Tsuneyasu Yoshida, Keiichiro Kadoba, Ryosuke Hiwa, Muneyuki Hatta, Mayu Shiomi, Ryu Watanabe, Motomu Hashimoto, Hirofumi Miyake, Nahoko Suwa, Yohei Fujiki, Wataru Yamamoto, Tohru Takeuchi
This multicentre study highlights the peripheral neutrophil count as a simple and readily available biomarker for risk stratification in AAV-DAH. Recognising neutrophilia at diagnosis may facilitate closer monitoring, early escalation of supportive care, and timely adjustment to immunosuppressive therapy. These findings provide a rationale for integrating neutrophil count into the prognostic assessment and therapeutic decision-making for AAV-related DAH.
OBJECTIVES: Diffuse alveolar haemorrhage (DAH) is a life-threatening complication of antineutrophil cytoplasmic antibody-associated vasculitis (AAV). This study aimed to clarify the incidence, timing, and predictors of severe respiratory distress (SRD) in patients with AAV-related DAH.
METHODS: This multicentre retrospective study included 50 consecutive patients with AAV-related DAH enrolled in the multicentre REVEAL cohort. Baseline demographic characteristics, laboratory parameters, and respiratory indices were recorded. The primary outcome was the development of SRD, defined as respiratory failure requiring ventilatory support (high-flow oxygen therapy, non-invasive ventilation, or invasive mechanical ventilation) or DAH-related death within 30 days. Cox proportional hazards models were used to identify independent predictors.
RESULTS: SRD occurred in 14 patients (28%), typically within several days of immunosuppressive therapy initiation, and was associated with early mortality. Patients who developed SRD exhibited significantly higher baseline neutrophil counts, lower haemoglobin levels, higher C-reactive protein concentrations, and impaired oxygenation (lower PaO2/FiO2 ratio). Multivariate analysis identified the peripheral neutrophil count as an independent predictor of SRD. A cut-off of 8,800/μL effectively discriminated between high- and low-risk patients. Notably, neutrophilia was associated with early progression to SRD, highlighting its potential as an early indicator of fulminant disease progression.
CONCLUSIONS: This multicentre study highlights the peripheral neutrophil count as a simple and readily available biomarker for risk stratification in AAV-DAH. Recognising neutrophilia at diagnosis may facilitate closer monitoring, early escalation of supportive care, and timely adjustment to immunosuppressive therapy. These findings provide a rationale for integrating neutrophil count into the prognostic assessment and therapeutic decision-making for AAV-related DAH.