Use of Secondary Prevention Drugs for Cardiovascular Disease in the Community in High-Income, Middle-Income, and Low-Income Countries (The PURE Study): A Prospective Epidemiological Survey
What is the use of secondary preventive drugs (antiplatelet drugs, beta-blockers, angiotensin-converting enzyme [ACE] inhibitors or angiotensin-receptor blockers [ARBs], and statins) in individuals with a history of coronary heart disease or stroke in low-income and middle-income countries?
In the Prospective Urban Rural Epidemiological (PURE) study, the investigators recruited individuals ages 35-70 years from rural and urban communities in countries at various stages of economic development. They assessed rates of previous cardiovascular disease (coronary heart disease or stroke) and use of proven effective secondary preventive drugs and blood pressure-lowering drugs with standardized questionnaires, which were completed by telephone interviews, household visits, or on patient’s presentation to clinics. The authors report estimates of drug use at national, community, and individual levels. On the basis of partitioned error variance, the percentage of variance explained by country status (between-country variance), or individual factors and urban location versus rural location (within-country variance) was calculated as a percentage of the overall variance.
The investigators enrolled 153,996 adults from 628 urban and rural communities in countries with incomes classified as high (three countries), upper-middle (seven), lower-middle (three), or low (four) between January 2003, and December 2009. A total of 5,650 participants had a self-reported coronary heart disease event (median 5.0 years previously [interquartile range 2.0-10.0]) and 2,292 had a stroke (4.0 years previously [2.0-8.0]). Overall, few individuals with cardiovascular disease took antiplatelet drugs (25.3%), beta-blockers (17.4%), ACE inhibitors or ARBs (19.5%), or statins (14.6%). Use was highest in high-income countries (antiplatelet drugs 62.0%, beta-blockers 40.0%, ACE inhibitors or ARBs 49.8%, and statins 66.5%), lowest in low-income countries (8.8%, 9.7%, 5.2%, and 3.3%, respectively), and decreased in line with reduction of country economic status (ptrend < 0.0001 for every drug type). The fewest patients received no drugs in high-income countries (11.2%), compared with 45.1% in upper middle-income countries, 69.3% in lower middle-income countries, and 80.2% in low-income countries. Drug use was higher in urban than rural areas (antiplatelet drugs 28.7% urban vs. 21.3% rural, beta-blockers 23.5% vs. 15.6%, ACE inhibitors or ARBs 22.8% vs. 15.5%, and statins 19.9% vs. 11.6%; all p < 0.0001), with greatest variation in poorest countries (pinteraction < 0.0001 for urban vs. rural differences by country economic status). Country-level factors (e.g., economic status) affected rates of drug use more than did individual-level factors (e.g., age, sex, education, smoking status, body mass index, and hypertension and diabetes statuses).
The authors concluded that use of secondary prevention medications is low worldwide, especially so in low-income countries and rural areas.
This study highlights the large gap that exists in secondary prevention worldwide, with extremely low rates of use of effective therapies in middle-income and low-income countries. Even the use of accessible and inexpensive treatments such as aspirin varied seven-fold between low-income and high-income countries, but the use of statins varied 20-fold. It should be noted that substantial opportunities remain for enhancement of drug use, even in high-income countries, and systematic efforts are needed to understand why even inexpensive drugs are substantially underused globally. We need to make concerted efforts to increase the use of effective and inexpensive drugs for prevention of cardiovascular disease, which has the potential to substantially and rapidly reduce cardiovascular disease burden globally.
Keywords: Angiotensin Receptor Antagonists, Stroke, Platelet Aggregation Inhibitors, Secondary Prevention, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Income, Questionnaires
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