Prehypertension Burden Of Disease And Medication Cost-effectiveness Analysis

ObjectiveSeveral cardiovascular risk factors were coexisted among prehypertensive population. Furthermore, it is also associated with an increased risk of the development of hypertension and its subsequent cardiovascular disease. According to the findings from the Chinese national nutrition and health survey in2002,34%was found to have prehypertension. However, as the aging and growth of the population, it may affect the number of prehypertensive individuals as well as its prevalence. So, it is very important to control prehypertension to lighten the disease burden, especially for the cardiovascular disease. Currently, several studies have demonstrated the benefits of the drug therapy among individuals with prehypertension, besides the lifestyle intervention. However, due to the large absolute number in China, it will cause a heavy economic burden if we carry on the drug intervention for whole population. Therefore, it is very necessary to evaluate the cost-effectiveness for different scenarios.MethodMarkov model was applied to calculate the expected life loss based on two simulated scenarios (risk existing or non-existing models). For the risk-existing model, prehypertension was not only associated with higher risk of death but also with the higher progression rate of hypertension. But for the non-risk model, we assumed that the individuals with prehypertenion had the same risk as those with normotension.Trend extrapolation was used to predict the prevalence of prehypertension and its numbers based on an assumption that the future changes for prehypertension was ascribed to the alternation from the whole population and its age structure.To predict the lifetime cost-effectiveness of prehypertension treatment, we used a Markov decision-analytic health model and combined data from several meta-analyses of randomized trials and other published sources such as epidemiology survey, health statistics report while taking account patients'preferences and different level of CVD risk by different age (e.g.30-39,40-49,50-59,60-69and70-79years) and sex.ResultsHypertension and prehypertension could both decrease life expectancy, though prehypertension may cause less life years lost (from2.16to5.21for male and0.84to1.93for female among hypertensive population versus0.54-2.14for male and0.26-0.86for female among prehypertensive population). Moreover, the estimated life years lost for the prehypertensive individuals aged15-24years was2.14years for male and0.86for female. However, the figures reduced to0.86years for male and0.26for female among those aged65years and older. The same pattern was observed among hypertensive population. While taking account patients'preferences, our study found that prehypertension is associated with loss of0.41to2.26QALYs for male and0.17to1.41QALYs for female. However, this may cause more losses among hypertensive population (1.7to4.21QALYs for male and0.63to1.49QALYs female).Based on the data from the Chinese national nutrition and health survey in2002and future population from2002-2030in China, we estimated that the prevalence of hypertension in2030will be28.1%(27.4%for male and28.1%for female), and the number will projected to0.323billion,0.16billion and0.163billion, respectively. Although, the prevalence of prehypertension will not change materially from2002-2030(around34%), the number will increase by0.068billion from0.333billion in2002to0.401billion.Using baseline estimates, the model predicted that lifetime antihypertensive treatment increased life expectancy in all age, sex and CVD risk subgroups from0.9to1.5. Moreover, the estimated additional life expectancy tended to be greater among younger individuals, especially for those within high-risk group. Taking account patients'preferences and the cost for the drug treatment, we further found that antihypertensive therapy was associated with the increased QALYs (0.7-1.3QALYs) and cost (5,677-29,211Yuan). These results persisted across all age, sex and CVD risk strata. Furthermore, compared with those within high-risk group, individuals with low risk cost more money and gained more QALYs. The average ICER for treatment ranged between8,494Yuan/QALY and38,311Yuan/QALY with a greater ICER in low-risk individuals than in high-risk subjects. A wide range of one-way or probabilistic sensitivity analysis varying the base-case assumption and inputs did not materially change the conclusion of the cost-effectiveness analysis. However, the average ICER was found to relative sensitivity to the variations in treatment effect, cost for drug treatment, especially for the low-risk women.ConclusionPrehypertension could not only reduce the expected life years but also decrease the quality-adjusted life years. With the increasing speed in aging population as well as its size in China, the absolute number of prehypertension will increase. So, it may be cost-effective to launch drug therapy among several high risk individuals, while performing active lifestyle intervention.