title: Underestimation of mortality following lung volume reduction surgery resulting from incomplete follow-up.
abstract: OBJECTIVE
  Incomplete follow-up can bias interpretation of data that are collected in longitudinal studies. We noted that many patients failed to return for follow-up in a study of effect of lung volume reduction surgery (LVRS) on quality of life (QOL). Accordingly, we designed this investigation to determine the reasons patients dropped out, and to assess differences between those who continued in the study (attendees) and those who did not (nonattendees).
  
  
  METHODS
  Telephone survey.
  
  
  METHODS
  Patients with advanced emphysema who had undergone LVRS and had previously agreed to participate in a longitudinal QOL study.
  
  
  RESULTS
  No differences were found with regard to age, gender, preoperative pulmonary function, or oxygen use between attendees and nonattendees. Long-term mortality in nonattendees (27%) was considerably greater than that seen in attendees (3%, p < 0.05). Distance from the hospital, financial burden, and living out of the region were the most common reasons cited by surviving nonattendees for their failure to return for follow-up.
  
  
  CONCLUSIONS
  Studies reporting the long-term mortality after LVRS can be biased in the direction of underestimating the true value if they are compromised by incomplete follow-up.
authors: Department of Medicine, University of Washington, Seattle, WA, USA.
authors: C W
authors: CW
authors: Butler
authors: M
authors: M
authors: Snyder
authors: D E
authors: DE
authors: Wood
authors: J R
authors: JR
authors: Curtis
authors: R K
authors: RK
authors: Albert
authors: J O
authors: JO
authors: Benditt
mesh_terms: D000328:Adult; D000368:Aged; D015982:Bias; D015897:Comorbidity; D003625:Data Collection; D015991:Epidemiologic Measurements; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010352:Patient Dropouts; D011013:Pneumonectomy; D011656:Pulmonary Emphysema / Q000401:mortality* / Q000503:physiopathology / Q000601:surgery; D011788:Quality of Life; D015996:Survival Rate; D014109:Total Lung Capacity; D014797:Vital Capacity