Prevalence of COPD in Trinidad and Tobago - A National Study

ABSTRACT

Purpose: Chronic Obstructive Pulmonary Disease (COPD) is preventable and treatable, yet it is the third leading cause of death and fifth leading cause of disability globally. Local studies in restricted settings have reported about 20% COPD prevalence, but the national prevalence and risk factors are unknown. We aimed to measure the prevalence of COPD and its risk factors in Trinidad and Tobago as part of the multicentre Burden of Obstructive Lung Disease (BOLD) Study. Research Design and Methodology Used A cross-sectional study was conducted during 2014-2015 using the BOLD standardised protocol. A stratified cluster sample of non-institutionalised males and females aged ≥ 40 years (N = 1104) and a sample of 18-39 year olds (N = 807) were selected. Questionnaires on respiratory symptoms, health status, and exposure to COPD risk factors were administered and spirometry conducted before and after bronchodilator. Spirometry quality control measures utilised were (1) direct spirometer feedback and (2) BOLD international centre review. Spirometry readings below international standards required technician retraining. Post- bronchodilator forced expiratory volume in the first second of expiration (FEV1) was expressed as a percentile of the forced vital capacity (FVC). COPD was defined by FEV1/FVC < 70% and a smoker as having smoked >200 cigarettes in a lifetime. Logistic regression was used to examine associations a (expressed as Odds Ratios (OR) and multivariate logistic regression to determine independent risk factors. Findings: There was a 95% response rate The mean age (SD) of these participants was 54 (11) years and Body Mass Index (BMI) 29 (7) kg/m2; with N (%) males, 443 (40) males; Afro-Trinidadians 400 (37), Indos 454(42), Mixed 234 (21), ever-smokers 302 (27), current smokers 157 (14), Adverse events 13(<1%)]. The prevalence of COPD was 9.5%, Of those with COPD, only 4% reported a previous doctor diagnosed COPD. COPD was more likely among those aged 60-69 years or over 70 (OR=4.15 and 5.88 respectively, p<0.001), among males (OR=1.64, p=0.023), ever smokers (OR=1.72, p=.016), retirees and the unemployed (OR=4.41 and 3.59 respectively, p<.001), with BMI<21 (OR=2.64, p=.001), asthma (OR=5.20, p<.001) or wheezing (OR=3.48, p<.001). Multivariate analysis showed significant risk factors for COPD were older age groups, low BMI, working over a year in dusty jobs, cigarette or cannabis smoking. There was no non-responder bias in age, gender, ethnicity, smoking or BMI but unacceptable spirometry was more likely in the elderly and smokers. Among the 807 participants aged 18-39 years old, 23% smoked with the prevalence of smoking in males being 32% vs. 11.7% in females (p < 0.001). Conclusions: COPD is prevalent yet under-diagnosed in the general population. Health care education and use of spirometry for prevention of COPD should target males, the elderly, smokers, those working in dusty jobs and those with a history of asthma or wheeze. We suggest spirometry measurements be available at all district health facilities.