title: Comparison of exercise capacity in COPD and other etiologies of chronic respiratory failure requiring non-invasive mechanical ventilation at home: retrospective analysis of 1-year follow-up.
abstract: BACKGROUND
  The objective of this study was to compare the change in 6-minute walking distance (6MWD) in 1 year as an indicator of exercise capacity among patients undergoing home non-invasive mechanical ventilation (NIMV) due to chronic hypercapnic respiratory failure (CHRF) caused by different etiologies.
  
  
  METHODS
  This retrospective cohort study was conducted in a tertiary pulmonary disease hospital in patients who had completed 1-year follow-up under home NIMV because of CHRF with different etiologies (ie, chronic obstructive pulmonary disease [COPD], obesity hypoventilation syndrome [OHS], kyphoscoliosis [KS], and diffuse parenchymal lung disease [DPLD]), between January 2011 and January 2012. The results of arterial blood gas (ABG) analyses and spirometry, and 6MWD measurements with 12-month interval were recorded from the patient files, in addition to demographics, comorbidities, and body mass indices. The groups were compared in terms of 6MWD via analysis of variance (ANOVA) and multiple linear regression (MLR) analysis (independent variables: analysis age, sex, baseline 6MWD, baseline forced expiratory volume in 1 second, and baseline partial carbon dioxide pressure, in reference to COPD group).
  
  
  RESULTS
  A total of 105 patients with a mean age (± standard deviation) of 61±12 years of whom 37 had COPD, 34 had OHS, 20 had KS, and 14 had DPLD were included in statistical analysis. There were no significant differences between groups in the baseline and delta values of ABG and spirometry findings. Both univariate ANOVA and MLR showed that the OHS group had the lowest baseline 6MWD and the highest decrease in 1 year (linear regression coefficient -24.48; 95% CI -48.74 to -0.21, P=0.048); while the KS group had the best baseline values and the biggest improvement under home NIMV (linear regression coefficient 26.94; 95% CI -3.79 to 57.66, P=0.085).
  
  
  CONCLUSIONS
  The 6MWD measurements revealed improvement in exercise capacity test in CHRF patients receiving home NIMV treatment on long-term depends on etiological diagnoses.
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Cuneyt
authors.initials: C
authors.lastname: Salturk
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Zuhal
authors.initials: Z
authors.lastname: Karakurt
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Huriye Berk
authors.initials: HB
authors.lastname: Takir
authors.affiliation: Respiratory Intensive Care Unit, Kartal Kosuyolu Cardiovascular Disease and Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Merih
authors.initials: M
authors.lastname: Balci
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Feyza
authors.initials: F
authors.lastname: Kargin
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Ozlem Yazıcıoglu
authors.initials: OY
authors.lastname: Mocin
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Gokay
authors.initials: G
authors.lastname: Gungor
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Ipek
authors.initials: I
authors.lastname: Ozmen
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Selahattin
authors.initials: S
authors.lastname: Oztas
authors.affiliation: Respiratory Intensive Care Unit, Department of Chest Disease and Pulmonology, Inonu University Medical Faculty, Malatya, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Yalcinsoy
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Ruya
authors.initials: R
authors.lastname: Evin
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Ozturk
authors.affiliation: Respiratory Intensive Care Unit, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, Turkey.
authors.forename: Nalan
authors.initials: N
authors.lastname: Adiguzel
mesh_terms: D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D016009:Chi-Square Distribution; D002908:Chronic Disease; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume; D006699:Home Care Services; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D063087:Noninvasive Ventilation / Q000379:methods*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D020127:Recovery of Function; D012131:Respiratory Insufficiency / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy; D012189:Retrospective Studies; D012307:Risk Factors; D013147:Spirometry; D062606:Tertiary Care Centers; D013997:Time Factors; D016896:Treatment Outcome; D016138:Walking
keywords: 6-minute walking test; chronic respiratory failure; exercise capacity; non-invasive ventilation