title: The Presence of Diffuse Alveolar Damage on Open Lung Biopsy Is Associated With Mortality in Patients With Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis.
abstract: OBJECTIVE
  Diffuse alveolar damage (DAD) is considered the histologic hallmark of ARDS although DAD is absent in approximately half of patients with ARDS. The clinical implications of having the syndrome of ARDS with DAD vs other histologic patterns is unknown. To address this question, we conducted a meta-analysis of lung biopsy series for patients with ARDS.
  
  
  METHODS
  Studies were identified using MEDLINE, EMBASE, Cochrane Register of Controlled Trials, LILACS, and citation review from January 1, 1967, to September 1, 2015. Studies were included if they included all of the following: open lung biopsies (OLB) performed after ARDS diagnosis; a clear definition of ARDS and DAD; histologic results of the OLB indicated the presence or absence of DAD; and mortality reported for the DAD and non-DAD groups. We excluded studies conducted solely on a specific histology subgroup (eg, DAD) and studies with fewer than 5 patients. Two authors independently selected studies for inclusion, and there were no language restrictions.
  
  
  RESULTS
  Of 8 included studies, 4 were high-quality (n = 228) and 4 were middle-quality trials (n = 122). The meta proportion of DAD between all the groups was 0.45 (95% CI, 0.35-0.56; Q test, 21.1; I(2), 66.8%; P ≤ .01). The pooled OR for mortality in ARDS with DAD compared with ARDS without DAD was 1.81 (95% CI, 1.14-2.80; Q test, 8.8; I(2), 20.2%; P = .269). Age, sex, and days elapsed between ARDS diagnosis and OLB as well as sequential organ failure assessment score and Pao2/Fio2 ratio on the day of OLB did not differ between DAD and non-DAD groups.
  
  
  CONCLUSIONS
  This meta-analysis demonstrated that ARDS with DAD is associated with higher mortality than ARDS without DAD.
authors.affiliation: Emergency Department, Hospital Universitario HM Sanchinarro, Madrid, Spain. Electronic address: pablocardinal@hotmail.com.
authors.forename: Pablo
authors.initials: P
authors.lastname: Cardinal-Fernández
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston, MA.
authors.forename: Ednan K
authors.initials: EK
authors.lastname: Bajwa
authors.affiliation: Internal Medicine Department, Hospital Universitario HM Sanchinarro, Madrid, Spain.
authors.forename: Andrea
authors.initials: A
authors.lastname: Dominguez-Calvo
authors.affiliation: Emergency Department, Hospital Universitario HM Sanchinarro, Madrid, Spain; Internal Medicine Department, Hospital Universitario HM Sanchinarro, Madrid, Spain; Universidad CEU San Pablo, Madrid, Spain.
authors.forename: Justo M
authors.initials: JM
authors.lastname: Menéndez
authors.affiliation: Assistance Publique, Hôpitaux de Marseille, Hôpital Nord, Réanimation des Détresses Respiratoires et des Infections Sévères, Chemin des Bourrely, and the Faculté de Médecine, Aix-Marseille Université, Marseille, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Papazian
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston, MA.
authors.forename: B Taylor
authors.initials: BT
authors.lastname: Thompson
mesh_terms: D001706:Biopsy; D006801:Humans; D008168:Lung / Q000473:pathology; D009026:Mortality; D016017:Odds Ratio; D011379:Prognosis; D011650:Pulmonary Alveoli / Q000473:pathology*; D012128:Respiratory Distress Syndrome / Q000401:mortality / Q000473:pathology*
keywords: ARDS; diffuse alveolar damage; meta-analysis; open lung biopsy