Role of BMI, airflow obstruction, St George's Respiratory Questionnaire and age index in prognostication of Asian COPD.

BACKGROUND AND OBJECTIVE: COPD is a complex condition with a heavy burden of disease. Many multidimensional tools have been studied for their prognostic utility but none has been universally adopted as each has its own limitations. We hypothesize that a multidimensional tool examining four domains, health-related quality of life, disease severity, systemic effects of disease and patient factors, would better categorize and prognosticate these patients. METHODS: We first evaluated 300 patients and found four factors that predicted mortality: BMI, airflow obstruction, St George's Respiratory Questionnaire and age (BOSA). A 10-point index (BOSA index) was constructed and prospectively validated in a cohort of 772 patients with all-cause mortality as the primary outcome. Patients were categorized into their respective BOSA quartile group based on their BOSA score. Multivariate survival analyses and receiver operator characteristic (ROC) curves were used to assess the BOSA index. RESULTS: Patients in BOSA Group 4 were at higher risk of death compared with their counterparts in Group 1 (hazard ratio (HR): 0.29, 95% CI: 0.16-0.51, P < 0.001) and Group 2 (HR: 0.53, 95% CI: 0.34-0.82, P = 0.005). Race and gender did not affect mortality. The area under the ROC curve for BOSA index was 0.690 ± 0.025 while that for Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2011 was 0.641 ± 0.025 (P = 0.17). CONCLUSION: The BOSA index predicts mortality well and it has at least similar prognostic utility as GOLD 2011 in Asian patients. The BOSA index is a simple tool that does not require complex equipment or testing. It has the potential to be used widely.

Prognostic utility of the 2011 GOLD classification and other multidimensional tools in Asian COPD patients: a prospective cohort study.

BACKGROUND: How well the 2011 Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification prognosticates for Asian patients with COPD is unknown. OBJECTIVE: The authors aimed to study the predictive utility of the GOLD 2011 classification for exacerbations and mortality as compared with other multidimensional tools in an Asian population. METHODS: In all, 1,110 COPD patients were prospectively followed between March 2008 and March 2013. They were classified using the 2011 and 2007 GOLD guidelines, modified Medical Research Council score, St. George's Respiratory Questionnaire (SGRQ), and Body mass index, Obstruction, Dyspnea (BOD) index. Outcome measures were exacerbations and mortality. Multivariable survival analyses and receiver operating characteristic (ROC) curves were used to assess the different classification systems. RESULTS: Time-to-event analyses demonstrated earlier exacerbations in 2011's GOLD D when compared with GOLD A (hazard ratio [HR] 0.54, 95% confidence interval [CI]: 0.31-0.95, P=0.032) and GOLD B (HR 0.62, 95% CI: 0.45-0.85, P=0.003) and higher mortality when compared with GOLD A (HR 0.37, 95% CI: 0.16-0.88, P=0.025) and GOLD B (HR 0.46, 95% CI: 0.31-0.70, P<0.001). The areas under the ROC curve for GOLD 2011, GOLD 2007, modified Medical Research Council, St. George's Respiratory Questionnaire, and BOD index were 0.62, 0.59, 0.61, 0.60, and 0.61, respectively, for the prediction of exacerbations and 0.71, 0.70, 0.71, 0.71, and 0.72, respectively, for the prediction of mortality (ROC comparator, P>0.05). CONCLUSION: The 2011 GOLD classification predicts exacerbations and mortality moderately well in Asian COPD patients. Its prognostic utility is similar to that of other multidimensional systems.