Review study highlights AAV-ILD patients’ mortality risk factors
Older age, disease exacerbations, MPA indicative of greater risk
A higher risk of death among AAV patients with interstitial lung disease (ILD) is significantly associated with older age, episodes of sudden symptom worsening, and microscopic polyangiitis (MPA), a common type of anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV).
That’s according to a review of published studies that also pointed to a history of smoking and interstitial pneumonia, or inflammation affecting lungs’ structural tissue, as risk factors of death in this patient population.
“Early intervention and management of risk factors related to AAV-ILD [AAV-related ILD] will provide benefits to improve the poor prognosis of patients,” the researchers wrote. The study, “Risk factors for poor prognosis in ANCA-associated vasculitis with interstitial lung disease: a systematic review and meta-analysis,” was published in Clinical Rheumatology.
AAV is a group of autoimmune diseases marked by inflammation and damage to small blood vessels in tissues in organs, most often the lungs and kidneys. Most cases are caused by a type of self-reactive antibody called ANCAs.
Nearly half of AAV patients develop ILD, a group of inflammatory disorders characterized by scarring in lung tissue involved in gas transfer and the surrounding tissues. Specifically, AAV-related ILD occurs in up to 45% of those with MPA and 23% of those with granulomatosis with polyangiitis (GPA), another common type of AAV.
Mortality risk in AAV-ILD reviewed
While several factors can influence the prognosis of a person with AAV-related ILD, research on the risk factors of death in this patient population remains limited and the results inconsistent. To shed light on this, researchers in China systematically reviewed published studies up to May 2024 that reported on mortality risk factors among AAV-ILD patients.
Eight retrospective studies, covering 654 AAV-ILD patients, were included in the meta-analysis. Four studies were conducted in China, two in Japan, one in South Korea, and one in France and Belgium.
Pooled results showed older age was significantly associated with a 6% higher risk of death among AAV-ILD patients and a history of smoking was linked to a 61% higher risk.
Usual interstitial pneumonia (UIP), a common ILD subtype of AAV-ILD, and acute exacerbations, or episodes of symptom worsening, were each significantly associated with a twofold higher risk of death, while MPA was significantly linked to a fourfold increased risk.
Using immunosuppressive medications for inducing AAV remission was identified as a strong protective factor and was significantly associated with a 60% lower mortality risk in AAV-ILD patients. Another protective factor was higher predicted forced vital capacity (FVC%), reflecting better lung function, which was significantly linked to a 3% lower risk of death. FVC% measures how much air a person can forcibly exhale after a deep breath.
“We conducted a pooled analysis of potential risk factors for the first time, and demonstrating that age, ever smoker, FVC%, UIP pattern, [acute exacerbations], MPA and [initial immunosuppressive medications] were associated with AAV-ILD mortality,” wrote the researchers, who noted that “the candidate risk factors … need to be further clarified” by larger, multicenter studies following patients over time.”
“A systematic understanding of the risk factors for AAV-ILD may provide clues for developing effective interventions and managements to improve poor prognosis in [AAV-ILD] patients,” they wrote.
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