Correlation of BODE index with quality of life in stable Chronic Obstructive Pulmonary Disease (COPD) patients – A prospective study

Background and Aims: Chronic obstructive pulmonary disease (COPD) is characterized by slow progressive deterioration of respiratory function with systemic effects which have a great impact on health-related quality of life (HRQoL). The severity of airflow limitation in COPD, as reflected by forced expiratory volume in one second (FEV1) does not represent the systemic consequences of COPD. Hence, a multidimensional grading system, BODE index (Body mass index, Airflow obstruction, Dyspnea and Exercise capacity) that assessed both the pulmonary and systemic manifestations has recently been proposed to provide useful prognostic information and predict the outcome in COPD patients. The objective of this study was to evaluate the relationship between BODE index and health-related quality of life (HRQOL) in stable COPD patients and its usefulness in predicting the disease exacerbations. Materials and Methods: Sixty stable COPD patients who presented in the out-patient departments of Medicine and Pulmonology were recruited over one year period. We evaluated them by body-mass index, forced expiratory volume in one second (FEV1), Modified Medical Research Council dyspnea scale and six minute walk test (6MWT). BODE index was calculated using these variables. Disease duration, number of exacerbations and hospitalization in the previous year were recorded. We also administered the St. George's Respiratory Questionnaire (SGRQ) to assess the health related quality of life (HRQoL) in these patients. BODE scores were categorized into four quartiles, quartile one to four with scores of 0-2, 3-4, 5-6 and 7-10, respectively. Results: According to BODE score, (16) 26.7% of patients were BODE 1, (27) 45% BODE 2, (15) 25% BODE 3 and (2) 3.3% were BODE 4. Higher BODE quartiles were associated with higher total SGRQ scores and SGRQ subscale scores (symptom, activity and impact). Very strong correlations were found between BODE quartiles and total SGRQ scores ( P < 0.01). Among the components of BODE index, the decrease in the FEV1 (%predicted) and 6MWD, and the increase of MMRC dyspnea grade were associated with worsening of health status (increase in total SGRQ and SGRQ subscales). BODE index also correlated with the acute exacerbations ( P < 0.0012) during one year follow-up. Conclusion: BODE index strongly correlated with the HRQoL and also reliably predicted acute exacerbations in stable COPD patients.