Longitudinal change in the BODE index predicts mortality in severe emphysema

Am J Respir Crit Care Med. 2008 Sep 1;178(5):491-9. doi: 10.1164/rccm.200709-1383OC. Epub 2008 Jun 5.

Abstract

Rationale: The predictive value of longitudinal change in BODE (Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity) index has received limited attention. We hypothesized that decrease in a modified BODE (mBODE) would predict survival in National Emphysema Treatment Trial (NETT) patients.

Objectives: To determine how the mBODE score changes in patients with lung volume reduction surgery versus medical therapy and correlations with survival.

Methods: Clinical data were recorded using standardized instruments. The mBODE was calculated and patient-specific mBODE trajectories during 6, 12, and 24 months of follow-up were estimated using separate regressions for each patient. Patients were classified as having decreasing, stable, increasing, or missing mBODE based on their absolute change from baseline. The predictive ability of mBODE change on survival was assessed using multivariate Cox regression models. The index of concordance was used to directly compare the predictive ability of mBODE and its separate components.

Measurements and main results: The entire cohort (610 treated medically and 608 treated surgically) was characterized by severe airflow obstruction, moderate breathlessness, and increased mBODE at baseline. A wide distribution of change in mBODE was seen at follow-up. An increase in mBODE of more than 1 point was associated with increased mortality in surgically and medically treated patients. Surgically treated patients were less likely to experience death or an increase greater than 1 in mBODE. Indices of concordance showed that mBODE change predicted survival better than its separate components.

Conclusions: The mBODE demonstrates short- and intermediate-term responsiveness to intervention in severe chronic obstructive pulmonary disease. Increase in mBODE of more than 1 point from baseline to 6, 12, and 24 months of follow-up was predictive of subsequent mortality. Change in mBODE may prove a good surrogate measure of survival in therapeutic trials in severe chronic obstructive pulmonary disease. Clinical trial registered with www.clinicaltrials.gov (NCT 00000606).

Trial registration: ClinicalTrials.gov NCT00000606.

Publication types

  • Comparative Study
  • Evaluation Study
  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Female
  • Humans
  • Kaplan-Meier Estimate
  • Longitudinal Studies
  • Male
  • Multivariate Analysis
  • Pneumonectomy
  • Predictive Value of Tests
  • Prognosis
  • Proportional Hazards Models
  • Pulmonary Disease, Chronic Obstructive / diagnosis
  • Pulmonary Disease, Chronic Obstructive / mortality
  • Pulmonary Disease, Chronic Obstructive / therapy
  • Pulmonary Emphysema / diagnosis*
  • Pulmonary Emphysema / mortality*
  • Pulmonary Emphysema / therapy
  • Randomized Controlled Trials as Topic
  • Severity of Illness Index*
  • Survival Rate
  • United States / epidemiology

Associated data

  • ClinicalTrials.gov/NCT00000606