Predictive Factors of Mortality in Chronic Obstructive Pulmonary Disease Subjects: A Monocenter Prospective Observational Study in Algeria

Abstract

Background and Aim: To assess the prevalence of mortality and identify predictive factors for mortality in chronic obstructive pulmonary disease (COPD) subjects, we conducted a prospective and observational study of a cohort of COPD patients, followed over 3 years. In addition to providing appropriate therapeutic care for each stage of the disease, we annually conducted clinical evaluations (assessing dyspnea, body mass index [BMI], comorbidities, and exacerbations) and functional assessments (spirometry and the 6-minute walk test [6MWT]) for our patients. Materials and Methods: Over a 3-year period, we conducted a prospective and observational study of a cohort of patients with COPD. Clinical evaluation (dyspnea, assessed using the modified Medical Research Council [mMRC] scale, BMI, comorbidities, and exacerbations) and functional evaluation (spirometry and 6MWT) were conducted annually. A threshold of three exacerbations per year was established to identify frequent exacerbators. In addition, we assessed the quality of life using the COPD Assessment Test questionnaire. Results: Our series consists of 132 men and 3 women, with an average age of 61 ± 9 years. Smoking is found in 95% with an average consumption of 50 P/A. The average stage of dyspnea according to mMRC was 1.8 ± 0.7 and the average BMI was 22.1 ± 3.7 kg/m2. Comorbidities were recorded at 64% with a predominance of cardiovascular factors. The functional outcomes were as follows: the mean postbronchodilator forced expiratory volume in 1 s was 58.25% ±15%, the mean distance covered in 6 min was 366 ± 107 m, and the mean Body Mass Index, Airflow Obstruction, Dyspnea, and Exercise Capacity (BODE) index was 2.7 ± 1. The mortality rate during our follow-up period was 12.6%. Univariate analyses have shown a significant relationship between mortality and the factors traditionally recognized as factors of COPD severity: age, Global Initiative for Chronic Obstructive Lung Disease stage, dyspnea stage, 6MWT, frequency of exacerbations, BMI, and comorbidities. However, in multivariate analysis, mortality is significantly correlated with three factors (BODE index, 6MWT, and frequency of exacerbations). Conclusion: Mortality among COPD patients in stable condition remains high despite adequate therapeutic care. This mortality rate is very significantly linked to the frequency of exacerbations.

Keywords

• 6-min walk test
• body mass index
• airflow obstruction
• dyspnea
• and exercise capacity index
• chronic obstructive pulmonary disease
• exacerbations
• mortality