Chronic obstructive pulmonary disease (COPD) prevalence surveys in low- and middle-income countries (LMICs): A systematic scoping review of methodologies

Abstract

<b>Introduction:</b> Determining the prevalence of COPD is a challenge in community-based surveys as this varies depending on epidemiological, clinical or spirometric diagnostic criteria used. <b>Aim:</b> We aimed to identify strategies used in conducting prevalence surveys for COPD in LMICs. <b>Methods:</b> We conducted a systematic scoping review to map prevalence surveys on COPD, conducted in LMICs published between 1995 and 2018. We searched OVID Medline, EMBASE, ISI Web of Science, Global Health and WHO Global Index Medicus databases, limiting the search to adults. After an initial title sift, eight trained reviewers undertook study selection and data extraction. We charted findings focusing on criteria used to diagnose COPD. <b>Results:</b> Our search returned 36,872 publications; 281 publications on CRD prevalence were included. Among these studies, the prevalence of COPD was reported in 112 publications. COPD diagnosis was typically based on spirometry findings (n=90). Other methods, which were sometimes used in combination, were reference to GOLD guidelines (n=87), symptoms (n=44), self-reported diagnosis (n=14) and doctor’s diagnosis (n=3). As for spirometric criteria, 59 used fixed FEV1/FVC thresholds, 28 reported both fixed-ratio and the lower limit of normal (LLN) values and three used only the LLN values as diagnostic criteria. LLN values was used in more recent studies (published since 2008). <b>Conclusion:</b> Our scoping review identified substantial heterogeneity and multitude of criteria used to define COPD in prevalence surveys. There is a need for a more uniform criteria to diagnose and in turn estimate the true prevalence of COPD.