This paper examines the prevalence of major risk factors in a developing country and the costs of one specific strategy to prevent CVD, i.e. the identification and drug treatment of persons at high risk. The analysis is restricted to direct costs of the intervention (medication and medical follow-up), an immediate and practical issue for health care providers and patients. The case of Seychelles is interesting because it is a middle-income developing country; the prevalence of risk factors is based on recent population data; at least one medication from all major medication classes are available in the public sector; and the national health system allows for providing treatment to all high-risk individuals.
The survey showed high levels of the major CVD risk factors in a rapidly developing middle-income country. Prevalence in 2004 can be compared with data of a similarly designed population survey in 1989 (20,21). Adjusted to the WHO standard population, the overall prevalence of HBP (BP ≥140/90) was lower in 2004 than 1989 (31.6% vs. 38.6%, population aged 25–64), probably reflecting the larger proportion of persons with HBP under treatment in 2004 than in 1989 (59.3% vs. 21.9%). The higher prevalence of overweight in 2004 than in 1989 can relate to rapid socio-economic development [22
], with large increase in motorised transport and service-oriented economy. This may account for the higher prevalence of diabetes and, to some extent, hypercholesterolemia (both higher in 2004 than in 1989). The prevalence of smoking was substantially lower in 2004 than in 1989, consistent with sustained government tobacco control interventions, including high taxes on tobacco products, advertising ban, education programs, ratification of the Framework Convention of Tobacco Control in 2003 and comprehensive legislation enacted in 2005.
We used conservative assumptions in our estimation model and costs for a treatment strategy provided in our study are likely to correspond to minimal figures. Our assessment of CVD risk did not include several indicators of CVD that are difficult to quantify, e.g. risk factors such as sedentary habits or family history of CVD and other markers of risk (target-organ damage, associated clinical conditions except for diabetes, or established CVD). Our cut-off values for age (≥55 years for men), total cholesterol (≥6.2 mmol/l) or HDL cholesterol in women (<1 mmol/l) are less stringent than in other guidelines. Measurement of blood pressure on one single visit tends to overestimate the prevalence of hypertension [23
] but this may be partially compensated by the use of blood pressure values unadjusted for antihypertensive treatment (i.e. another source of underestimation of an individual's CVD risk). Overall, it is likely that we assessed CVD risk conservatively so that medical treatment would be justified for most patients labeled in our study as 'medium' or 'high risk'. We also used conservative criteria for the nature and frequency of biochemical analyses assumed for medical follow-up of high risk patients in our estimation. In particular, we did not include urine analysis, electrocardiogram, fundoscopy and others tests usually found useful in the circumstances. Also, we did not include interventions, such as aspirin, intended mainly for secondary prevention of CVD.
The cost of medications accounted for approximately two thirds of the total cost of the treatment strategy. It follows that a decreased price of medications will reduce the total direct cost of the treatment strategy. We show that by using generic rather than proprietary medications, the cost of medications alone could be substantially reduced: from $30 to $11 per capita per year for hypertension and from $22 to $4 for diabetes. The cost of medication for dyslipidemia could potentially be similarly reduced if generic medications were used. Although new statins are more powerful than older ones, the majority of subjects with elevated blood cholesterol would get to target even with the older agents while only a minority of patients at very high risk would need the latter to reach recommended very low LDL targets.
The cost of basic medical follow-up for high-risk patients, both investigations and medical visits ($23 per capita per year) is less compressible and indeed likely to increase under the pressure of increasing patients' expectations and other factors such as rising health care personnel costs. This emphasizes the need for guidelines to ensure that utilization of scarce resources is not unduly influenced by local or global commercial interests but used in a cost-effective way [24
At a minimum of $68 per capita, the estimated direct costs for medications and basic medical follow-up for all high-risk individuals is a major burden on the health budget. Even at half of that cost to account for half of the prevalence of risk factors found in this study -a situation more typical of populations at earlier stages of the epidemiological transition-, treating risk factors in the population would remain out of reach for many developing countries. Indeed, many developing countries rely on government health budget lower than $50 per capita per year -vs. $3000–5000 in western countries- [10
] and a large proportion is absorbed to control the persisting large burden of infectious diseases. There has been much debate as to whether medical treatment for chronic conditions can be afforded in low resource settings, in view of high cost of life-long medication and, indeed, high cost per year of life saved compared to interventions for other conditions [25
]. It has been argued that scarce resources could be better invested in more cost-effective or urgent medical or other interventions [26
]. It would however be inequitable to deny treatment of demonstrated efficacy to some or all individuals who would benefit of it [28
We considered costs in the public sector, which provides universal coverage for health care in Seychelles. We have not investigated or compared costs and prices in the private sector, which remains relatively small. Currently, the public services are financed from taxation revenue, an approach aimed at providing more equitable provision of care to the population. Increasing pressure for the introduction of user fees is likely to impact negatively on those who are most vulnerable and least able or willing to pay.
Furthermore, direct cost for medical treatment of elevated risk factors is of course only one component in the spectrum of medical care required and, more generally, in cost-benefit analysis. Costs can be averted as well, such as hospitalization and loss of productivity, therefore potentially reducing the overall cost of a high-risk strategy. In Seychelles, where some special care is available -e.g. hemodialysis but not revascularization-, the costs averted can be significant. However, these costs may not be immediate in many low and middle income countries, since hospitalization and surgery may not be available and low formal employment makes evaluation of the cost of lost productivity uncertain. Clearly, comprehensive cost-benefit analysis is a greater challenge in developing countries in the absence of documented evidence on the magnitude of such factors. While adopting a simplified approach, the analysis presented in this paper does provide approximate direct costs that must actually be borne in providing high-risk individuals with medication and care.
The high cost of a treatment strategy stresses the need to identify alternative and more affordable strategies. Emphasis has been put on the need to inform individual clinical treatment based on the probable size of absolute treatment benefits, i.e. based on an individual's CVD total risk, not just risk factor levels [29
]. A major issue is to choose CVD risk thresholds that can maximize events prevented without increasing the total numbers treated in a defined population. However, assessing CVD risk is challenging in populations for which cohort data are not available and calculation of CVD risk along current western-based risk functions cannot be calibrated. A radically different strategy, recently proposed, would consist of providing a low-cost "polypill" combining several medications (e.g. three antihypertensive drugs, a statin, aspirin) to all persons aged 55 years and above, given that CVD risk is predominantly driven by age [31
]. This approach may well be far less expensive than traditional treatment strategies because of expectedly much lower cost of such a polypill (use of generic drugs, economy of scale) and the avoidance of medical follow-up. However, clinical trials will have first to demonstrate the effectiveness, safety, and acceptability of such a strategy.
Even if drug prices are reduced, strategies relying on medications may still be unaffordable for many low or middle income countries. In addition, several factors inherently limit the impact of treatment strategies at a population level, e.g. poor compliance to medications for asymptomatic chronic conditions [32
] and limited control of hypertension or diabetes in many instances, even with multi-drug combinations. Furthermore, approaches based on the assessment of lifetime CVD risk imply that individuals will have accumulated much of their risk (e.g. developed substantial atherosclerosis) before they become eligible for treatment [33
Although a high-risk approach can be an important component of a global strategy to reduce CVD [34
], evidence strongly supports the predominant role of primary prevention[35
]. Interventions typically include policies aimed at changing the societal milieu to enable a broad adoption of healthy lifestyles [36
]. In addition, by decreasing risk factor levels in the population (or maintaining favorable levels in some developing countries in early epidemiological transition), primary prevention can substantially minimize the number of persons at high CVD risk in need of medical treatment for hypertension, dyslipidemia or type II diabetes. Ultimately, the interests of the population at large are served by broad improvements in the quality of life, which includes both a reduction in morbidity as well as a decrease in fatal events. Since prevention delivers the best results in terms of quality of life, that should be sufficient reason to rank it as the top priority for public health interventions. Economic considerations alone cannot be the primary criteria that lead to the choice of the primary prevention strategy vs. the high risk strategy.