BODE Index For COPD

Items considered in the method

The BODE index accounts for the following four variables in predicting long term respiratory outcomes in patients with COPD:

■ Body mass index (BMI), which is dependent on patient height and weight;

■ Obstruction of airflow is the forced expiratory volume in one second or the FEV1. This is staged from 1 to 4, where 1 is mild and 4 is very severe;

■ Dyspnea status is based on the modified MRC dyspnea scale:

- Grade 0 means breathless only with strenuous exercise.

- Grade 1 means shortness of breath when hurrying on the level or walking up a slight hill.

- Grade 2 means a slower pace than most people of the same age on the level because of breathlessness.

- Grade 3: Stop for breath after walking about 100 meters or after a few minutes at my own pace on the level.

■ Exercise capacity is the treadmill test for six minutes.

COPD is one of the respiratory disease important to monitor and to predict outcome for. It is amongst the most common causes of death after heart disease, stroke and cancer.

The index can also be used in the differential diagnosis of COPD with other diseases such as bronchiectasis, pneumoconiosis, allergic fibrosis or bronchopulmonary dysplasia.

BODE score interpretation

After the four items are applied to the patient status, each of the choices is awarded a number of points, as explained in the table below.

The final score represents the sum of those points and ranges between 0 and 10. There are four mortality rates, that increase as the final score increases:

About the study

The BODE index was created by Celli et al. in 2004 following a study on 207 patients with COPD. The resultant index, a multidimensional 10 point scale which was further validated in a cohort of 625 patients.

The hazard ratio for all-cause mortality is set at 1.34 and for respiratory disease at 1.62, for every one increment increase in the index.

The index was found to have a higher predictive accuracy than the FEV1 which is not sensible to the systemic manifestations of COPD.

The GOLD classification

The Global Initiative on Obstructive Lung Disease classifies the severity of chronic obstructive pulmonary disease in 5 stages:

■ Stage 0 means negative diagnosis with normal spirometry but the patient is at risk with chronic cough and sputum production present;

■ Stage I presents with mild COPD characterized by mild airflow limitation (FEV1/FVC less than 70% but FEV1 80% or more than predicted);

■ Stage II means moderate COPD, indicated by worsening airflow limitation (FEV1 50 - 79% predicted) and shortness of breath on exertion;

■ Stage III presents with severe COPD characterized by further worsening of airflow limitation (FEV1 30 - 50% predicted), increased shortness of breath and repeated exacerbations;

■ Stage IV is the most severe one with serious airflow limitation (FEV1 less than 30% predicted) or the presence of chronic respiratory failure.

Original source

Celli BR, Cote CG, Marin JM, et. al. The body-mass index, airflow obstruction, dyspnea and exercise capacity index in chronic obstructive pulmonary disease. N Engl J Med. 2004; 350(10):1005-12.

Other references

1. Celli BR, Cote CG, Lareau SC, Meek PM. Predictors of Survival in COPD: more than just the FEV1. Respir Med. 2008; 102 Suppl 1:S27-35.

2. Marin JM, Cote CG, Diaz O, Lisboa C, Casanova C, Lopez MV, Carrizo SJ, Pinto-Plata V, Dordelly LJ, Nekach H, Celli BR. Prognostic assessment in COPD: health related quality of life and the BODE index. Respir Med. 2011; 105(6):916-21.