Impact of chronic obstructive pulmonary disease (COPD) in the Asia-Pacific region: the EPIC Asia population-based survey

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a clinical syndrome encompassing a group of chronic, progressive, and debilitating respiratory conditions, that are characterized by incompletely reversible airflow limitation. Within the Asia-Pacific region, prevalence estimates have been derived using various protocols and study methods, and there is little data on the impact of COPD exacerbations. This study aimed to provide a comprehensive picture of the current prevalence and burden of COPD in this region.

Methods: A population-based survey was conducted in nine Asia-Pacific territories between 01 February 2012 and 16 May 2012. Overall, 112,330 households were screened to identify eligible subjects (aged ≥40 years, with a physician diagnosis of COPD, chronic bronchitis or emphysema, or with identifiable symptoms of chronic bronchitis). Out of a sample of 69,279 individuals aged ≥40 years, 4,289 subjects with COPD were identified. Data were collected via face-to-face interviews or by fixed-line telephone, using a structured questionnaire. A total of 1,841 completed questionnaires were analyzed.

Results: The overall estimated COPD prevalence was 6.2%, with 19.1% of subjects having severe COPD. In the 12 months prior to the survey, nearly half of all subjects (46%) had experienced exacerbations, and 19% had been hospitalized as a result of their condition. When subjects were asked about the impact of their condition on employment, 23% said their condition kept them from working, and 42% felt that their condition limited their ability to work or their activities. Of those who reported taking prescription drugs, 20% did not know the name of the drugs they were taking. Prescription of oral corticosteroids was common, with 44% of subjects having used these during the previous year to manage their respiratory symptoms; in contrast, inhaler use was low (25%). Only 37% of subjects had taken a lung function test, and the majority (89%) of those tested did not know their test results.

Conclusions: Across the Asia-Pacific territories surveyed, the prevalence of COPD is high, indicating a substantial socioeconomic burden. Our findings suggest that there is considerable room for improvement in the management of COPD, and highlight a need to enhance patient and physician education in the region.

Keywords: Asia-Pacific; Chronic obstructive pulmonary disease (COPD); Exacerbations; Impact; Population-based; Prevalence; Quality of life (QoL); Survey.

Figure 1

Sampling strategy and response rate for the EPIC Asia survey. ‘Study subjects’ refers to the subset of individuals aged ≥40 years who were identified as having COPD, based on the definitions used in this study (see Methods), and who completed the questionnaire.

Figure 2

Prevalence, frequency, and seasonal variation of exacerbations. (A) Proportion of study subjects who reported experiencing one or more exacerbations within the 12 months prior to the survey. (B) Median number of exacerbations reported by subjects over this period. (C) Proportion of subjects who reported exacerbations within each month over this period.

Figure 3

Unplanned healthcare utilization. (A) Proportion of subjects who either visited a hospital emergency room or made unscheduled visit(s) to a doctor or clinic as a result of their condition, in the 12 months prior to the survey. (B) Subjects who had ever been hospitalized because of their condition (n; %) were asked how many times they had been hospitalized in the previous 12 months. The proportions of subjects who had been hospitalized 0, 1, 2, or 3 or more times are indicated by the shading within each bar. Results are shown only for subjects who were able to report the number of times they had been hospitalized.

Figure 4

Impact of disease on employment and work productivity. (A) Employment status of study subjects. (B) Proportion of subjects who reported that their condition kept them from working, limited the kind or amount of work they could do, or limited their activities. (C) Subjects’ estimated level of productivity on a typical day, and on a day when symptoms are at their worst. Upper row of n values: subjects who answered the question regarding productivity on a typical day; lower row of n values: subjects who answered the question regarding their worst day.

Figure 5

Delivery format of prescribed medication. Subjects who reported taking a prescription drug were asked about the delivery format of their medication. Numbers below the bars indicate the total number of valid answers for this question, for the corresponding territory. Results are shown only for subjects who were able to report the delivery format of their medication.

Figure 6

Use of oral corticosteroids. All study subjects (upper row of n values) were asked if they had been told to use oral steroids to manage their respiratory symptoms in the past 12 months. Those who had been prescribed steroids (lower row of n values) were asked if they had been told to take the steroids for three days or longer.