Dongfeng Gu 1 , 2 , * , Jiang He 3 , 4 , Pamela G. Coxson 5 , Petra W. Rasmussen 6 , Chen Huang 1 , 2 , Anusorn Thanataveerat 6 , Keane Y. Tzong 6 , Juyang Xiong 7 , Miao Wang 8 , Dong Zhao 8 , Lee Goldman 9 , Andrew E. Moran 6 , 9 , *
4 August 2015
Hypertension is China’s leading cardiovascular disease risk factor. Improved hypertension control in China would result in result in enormous health gains in the world’s largest population. A computer simulation model projected the cost-effectiveness of hypertension treatment in Chinese adults, assuming a range of essential medicines list drug costs.
The Cardiovascular Disease Policy Model-China, a Markov-style computer simulation model, simulated hypertension screening, essential medicines program implementation, hypertension control program administration, drug treatment and monitoring costs, disease-related costs, and quality-adjusted life years (QALYs) gained by preventing cardiovascular disease or lost because of drug side effects in untreated hypertensive adults aged 35–84 y over 2015–2025. Cost-effectiveness was assessed in cardiovascular disease patients (secondary prevention) and for two blood pressure ranges in primary prevention (stage one, 140–159/90–99 mm Hg; stage two, ≥160/≥100 mm Hg). Treatment of isolated systolic hypertension and combined systolic and diastolic hypertension were modeled as a reduction in systolic blood pressure; treatment of isolated diastolic hypertension was modeled as a reduction in diastolic blood pressure. One-way and probabilistic sensitivity analyses explored ranges of antihypertensive drug effectiveness and costs, monitoring frequency, medication adherence, side effect severity, background hypertension prevalence, antihypertensive medication treatment, case fatality, incidence and prevalence, and cardiovascular disease treatment costs. Median antihypertensive costs from Shanghai and Yunnan province were entered into the model in order to estimate the effects of very low and high drug prices. Incremental cost-effectiveness ratios less than the per capita gross domestic product of China (11,900 international dollars [Int$] in 2015) were considered cost-effective. Treating hypertensive adults with prior cardiovascular disease for secondary prevention was projected to be cost saving in the main simulation and 100% of probabilistic simulation results. Treating all hypertension for primary and secondary prevention would prevent about 800,000 cardiovascular disease events annually (95% uncertainty interval, 0.6 to 1.0 million) and was borderline cost-effective incremental to treating only cardiovascular disease and stage two patients (2015 Int$13,000 per QALY gained [95% uncertainty interval, Int$10,000 to Int$18,000]). Of all one-way sensitivity analyses, assuming adherence to taking medications as low as 25%, high Shanghai drug costs, or low medication efficacy led to the most unfavorable results (treating all hypertension, about Int$47,000, Int$37,000, and Int$27,000 per QALY were gained, respectively). The strengths of this study were the use of a recent Chinese national health survey, vital statistics, health care costs, and cohort study outcomes data as model inputs and reliance on clinical-trial-based estimates of coronary heart disease and stroke risk reduction due to antihypertensive medication treatment. The limitations of the study were the use of several sources of data, limited clinical trial evidence for medication effectiveness and harms in the youngest and oldest age groups, lack of information about geographic and ethnic subgroups, lack of specific information about indirect costs borne by patients, and uncertainty about the future epidemiology of cardiovascular diseases in China.
In a Markov-style simulation model, Andrew Moran and colleagues estimate the reduction in cardiovascular disease and cost-effectiveness of broad provision of antihypertensive medications in China.
Worldwide, in 2008, more than one billion people had high blood pressure (hypertension), a condition that is responsible for about 10 million deaths annually from heart attacks, stroke, and other cardiovascular diseases (CVDs). Hypertension, which rarely has any symptoms, is diagnosed by measuring blood pressure (BP), the force that blood circulating in the body exerts on the inside of large blood vessels. BP is highest when the heart contracts to pump blood out (systolic BP) and lowest when the heart relaxes and refills (diastolic BP). Normal adult BP is defined as a systolic BP of less than 120 millimeters of mercury (mm Hg) and a diastolic BP of less than 80 mm Hg (a BP of <120/80 mm Hg). A BP of 140–159/90–99 mm Hg indicates mild (stage one) hypertension; a BP of ≥160/≥100 mg Hg indicates severe (stage two) hypertension. Many factors affect BP, but overweight people and individuals who eat fatty or salty food are at high risk of developing hypertension. Lifestyle changes and/or antihypertensive drugs can be used to control the condition.
Hypertension is the leading cardiovascular risk factor in China, the world’s most populous country. About 325 million adults in China have hypertension, but less than half are aware of their condition, only 34% of Chinese adults with hypertension are treated with antihypertensive drugs, and only 28% of treated individuals achieve a BP of <140/90 mm Hg. Improved hypertension control would yield enormous health gains in China, but would these gains outweigh the costs of this intervention? The World Health Organization defines a “highly cost-effective” intervention as one for which the incremental cost effectiveness ratio (ICER; in this case, the ratio of the cost difference between the intervention and no intervention to the difference in outcomes) is less than a country’s gross domestic product (GDP) per capita (a country’s total economic output divided by its number of inhabitants) per quality-adjusted life year gained (a QALY is a measure of disease burden that considers both the quality and quantity of life lived). Here, the researchers use a computer simulation model to project the cost-effectiveness of hypertension treatment in Chinese adults using the low-cost antihypertensive drugs included on the national essential medicines list. In China, most patients pay for drugs out-of-pocket, but several antihypertensive medications with affordable prices are available in government-sponsored primary health facilities.
The researchers used a computer model called the “Cardiovascular Disease Policy Model-China” to simulate the costs of hypertension screening, essential medicines program implementation, hypertension control program administration, drug treatment and monitoring, and the QALYs gained by preventing CVD in Chinese adults with untreated hypertension aged 35–84 y between 2015 and 2025. According to the model, treating hypertension for both primary prevention of CVD (reduction of hypertension in healthy individuals to prevent the development of CVD) and secondary prevention (reduction of hypertension in people who already have CVD to prevent further heart attacks or strokes) would prevent between 600,000 and a million CVD events annually. Treating only patients with CVD and patients with severe hypertension was borderline cost-effective. The ICER of this intervention was between Int$10,000 and Int$18,000 per QALY gained; China’s GDP per capita is Int$11,900.
These findings suggest that an expanded program of treatment for hypertension could prevent about 800,000 cardiovascular events every year in China. Such a program should be borderline cost-effective, provided low-cost essential antihypertensive drugs are used to control hypertension. As with all computer simulation studies, the numerous assumptions incorporated into the model limit the accuracy of these findings. For example, some model inputs were derived from studies of non-Chinese patients and may not accurately represent the Chinese population. Moreover, the model only considers the cost-effectiveness of using medications to control hypertension and does not consider the potential effects of lifestyle changes. Importantly, additional simulations indicate that the cost-effectiveness of the intervention would be greatly reduced if adherence to treatment were lowered or drug costs were increased. Thus, full implementation of the essential medicinesprogram and subsidized drug costs program will be needed to reap the full benefits of improved hypertension control in China.
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