title: Predictors of survival in COPD patients with chronic hypercapnic respiratory failure receiving noninvasive home ventilation.
abstract: BACKGROUND
  Patients with COPD and chronic hypercapnic respiratory failure (CHRF) are at high risk, and noninvasive ventilation at home is increasingly being used. Knowledge of prognostic parameters under these conditions is limited but may be clinically helpful and highlight the role of noninvasive ventilation.
  
  
  METHODS
  In 188 patients with COPD (mean +/- SD FEV1, 31.0 +/- 9.6% of predicted; PaCo2, 56.3 +/- 9.4 mm Hg) discharged from the hospital receiving NIV between July 1994 and July 2004, the prognostic value of body mass index (BMI), lung function, laboratory parameters, and blood gas levels was assessed by univariate and multivariate Cox regression analyses. Moreover, the impact of changes in risk factors on mortality assessed 6.7 +/- 2.8 months after the initiation of noninvasive ventilation was evaluated.
  
  
  RESULTS
  Overall, the mortality rate during follow-up (duration, 32.2 +/- 24.3 months) was 44.7%, with 1-year, 2-year, and 5-year survival rates of 84.0%, 65.3%, and 26.4%. Deaths resulted predominantly from respiratory causes (73.8%). Univariate regression analyses revealed age, BMI, hemoglobin, FEV1, specific airway resistance, residual volume (RV)/total lung capacity (TLC), pH, and base excess (BE) to be associated with prognosis (p < 0.01 each), whereas multivariate analysis identified only age, BMI, RV/TLC, and BE as independent predictors (p < 0.05). In patients at risk (BMI < 25 km/m2, RV/TLC >or= 73%, or BE >or= 9 mmol/L), changes in these predictors were also associated with survival.
  
  
  CONCLUSIONS
  In patients with COPD and CHRF, nutritional status, hyperinflation, and BE, which turned out to be reliable and consistent markers in CHRF, were independent prognostic factors for mortality. These data favor a multidimensional approach in these patients, including the use of noninvasive ventilation.
authors.affiliation: Center for Pneumology, Donaustauf Hospital, Donaustauf, Germany. stephan.budweiser@klinik.uni-regensburg.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Budweiser
authors.forename: Rudolf A
authors.initials: RA
authors.lastname: Jörres
authors.forename: Theresa
authors.initials: T
authors.lastname: Riedl
authors.forename: Frank
authors.initials: F
authors.lastname: Heinemann
authors.forename: André P
authors.initials: AP
authors.lastname: Hitzl
authors.forename: Wolfram
authors.initials: W
authors.lastname: Windisch
authors.forename: Michael
authors.initials: M
authors.lastname: Pfeifer
mesh_terms: D000368:Aged; D015992:Body Mass Index; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000150:complications* / Q000503:physiopathology; D007320:Inspiratory Capacity / Q000502:physiology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009752:Nutritional Status; D011175:Positive-Pressure Respiration / Q000379:methods* / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000401:mortality* / Q000503:physiopathology; D012131:Respiratory Insufficiency / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy*; D012307:Risk Factors