title: Proposed definitions for epidemiologic and clinical studies of Mycobacterium avium complex pulmonary disease.
abstract: BACKGROUND
  Epidemiologic and clinical studies of Mycobacterium avium complex (MAC) pulmonary disease typically use strict ATS/IDSA definitions designed for decisions about treatment. Studies based on these criteria may exclude a substantial number of patients with true disease. We reviewed patients treated for MAC pulmonary disease at an academic medical center to propose revised definitions encompass the full spectrum of MAC pulmonary disease.
  
  
  METHODS
  We conducted a retrospective review of patients with MAC pulmonary disease treated from 1993-2006 by pulmonary or infectious disease specialists to assess whether treated patients met current ATS/IDSA microbiologic criteria and dichotomous radiologic classification as nodular/bronchiectatic (NB) or fibrocavitary (FC) disease. We propose a revised set of definitions that include categories of both probable and definite disease to include all treated patients. We further classify patients into dichotomous clinical categories as: "primary MAC" (without antecedent lung disease) or "secondary MAC" (smoking history or antecedent lung disease).
  
  
  RESULTS
  Among 72 treated patients, 74% were female. Median age at diagnosis was 64 years; 41(57%) met ATS/IDSA criteria and 31 (43%) did not, most often for lack of multiple positive cultures. Dichotomous radiologic criteria were met by 48 (67%) patients (36 NB, 12 FC); the remaining 24 (33%) had both NB and FC findings or other abnormalities. Nineteen (26%) were classified as primary and 53 (74%) as secondary MAC (21 COPD, 4 bronchiectasis, 44 smoking history).
  
  
  CONCLUSIONS
  We propose revised definitions for epidemiologic and clinical studies of MAC pulmonary disease that describe the full spectrum of disease.
authors.affiliation: Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States of America ; Providence St. Vincent Medical Center, Portland, Oregon, United States of America.
authors.forename: Rachel N
authors.initials: RN
authors.lastname: Plotinsky
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Talbot
authors.forename: C Fordham
authors.initials: CF
authors.lastname: von Reyn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015269:Mycobacterium avium Complex / Q000502:physiology*; D015270:Mycobacterium avium-intracellulare Infection / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology / Q000628:therapy*; D009626:Terminology as Topic