A new score, the ADO index, for predicting a patient's risk of dying from chronic obstructive pulmonary disease (COPD) performs better than the current test and is much more applicable in clinical practice. It could help doctors target suitable treatment options to individual patients, finds an Article to be published in this week's COPD special edition of the Lancet.
The BODE index is a widely used estimate of how likely a patient is to die from COPD based on an assessment of major risk factors for COPD such as body-mass index, airflow obstruction, shortness of breath, and exercise capacity. However, since exercise capacity is often not available in practice the BODE index is rarely used in primary care settings where most COPD patients are managed. In addition, the index fails to calculate an individual's absolute risk* accurately and is therefore not ready for doctors to use as a prognostic tool when trying to identify which treatment option to use in individual patients.
To verify if the BODE index accurately predicts those most at risk, Milo Puhan from Johns Hopkins Bloomberg School of Public Health in the USA and colleagues compared whether a patient's risk of death predicted by the BODE index matched the observed 3-year risk of all-cause mortality in two different COPD populations from Switzerland and Spain. The authors then aimed to modify the index to improve its predictive accuracy and develop a new simple score using age, shortness of breath, and airflow obstruction (ADO index), to make it more useful for doctors in primary care settings.
In total, 232 patients with longstanding and severe COPD from the Swiss Barmelweid cohort were studied, along with 342 patients from the Spanish Phenotype and Course of COPD cohort study who had their first hospital admission due to moderate-to-severe COPD. Findings showed that the original BODE index was poor at predicting 3-year risk of mortality—with a 36% relative underprediction in the Swiss cohort (median predicted risk 21.7% compared with 34.1% observed risk) and a 39% relative overprediction in the Spanish cohort (median predicted risk 16.7% compared with 12.0% observed risk). Importantly, the updated BODE and ADO indices gave more accurate predictions of 3-year mortality and matched the observed mortality in the Spanish cohort well with little difference between predicted and observed mortality.
The authors comment: "The simplified points system for the updated BODE and ADO indices…[is] easy to use to obtain the 3-year mortality risk in an individual patient…[and] allows clinicians to identify patients at moderate or high risk of mortality, for which more comprehensive treatment with respiratory rehabilitation, for example, might be appropriate to reduce their risk."
They conclude: "Both the updated BODE and ADO indices could lend support to the prognostic assessment of patients with COPD in specialised and in primary care settings. Such assessment enhances the targeting of treatments to individual patients."
In an accompanying Comment, Holger Schünemann from McMaster University Health Sciences Centre in Canada says the results suggest that: "Identification of baseline risks through prognostic studies might help to target therapy and can make important and long-needed contributions to, for instance, guideline development."
Dr Milo Puhan, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA. T) +1 443 287 8777 E) mpuhan@jhsph.edu
Dr Holger Schünemann, McMaster University Health Sciences Centre, Ontario, Canada. T) +1 905 525 9140 E) schuneh@mcmaster.ca
For full Article and Comment, see: http://press.thelancet.com/copdbode.pdf
Notes to Editors: *To calibrate the index the absolute risks as predicted by risk scores need to be compared with the observed risks in at least one other population.
Journal
The Lancet