| Background:Hypertension is the major risk factor of cardiovascular disease(CVD)and mortality all over the world,contributing to at least 7.6 million deaths annually(13.5%of all deaths).Due to the rapid economic development and the acceleration of the aging process,combined with sedentary behavior,unhealthy dietary habits,and other unfavorable lifestyle choices,the prevalence of cardiovascular disease continues to rise and has become the leading cause of death in China.Hypertension is one of the most important modifiable risk factors for cardiovascular disease.With the population rapidly aging,there has been a rise of interest in antihypertensive treatment for older hypertension patients.The SPRINT trial found that intensive blood pressure lowering in older hypertension individuals decreased cardiovascular events and all-cause mortality considerably.The recently published STEP trial revealed that intensive blood pressure treatment significantly reduced the incidence of cardiovascular events in Chinese older hypertensive patients.Compared with standard blood pressure treatment,intensive treatment may avert cardiovascular events and decrease events related treatment costs.However,this strategy is not without risks or costs,which must be taken into account in cost-effectiveness analysis.Moreover,the National Centralized Drug Procurement(NCDP)policy was launched in January 2019 by the General Office of the State Council of the People’s Republic of China with the aim of reducing medication burden and improving the affordability and accessibility of medications.The implementation of this policy throughout the nation has successfully reduced the medication cost for 245 million hypertensive individuals.Objective:The aim of this cost-effectiveness analysis was to evaluate the long-term health benefits and medical expenditures associated with intensive blood pressure treatment,while taking into consideration the reduced expense of anti-hypertensive drugs resulting from the recent implementation of the NCDP policy,utilizing the treatment and efficacy data from the STEP trial.Methods:A microsimulation model included 10,000 hypothetical samples of Chinese individuals aged 60 to 80 years old with baseline systolic blood pressure higher than 140 mmHg.This hypothetical cohort was established utilizing the identical inclusion criteria and baseline characteristics as witnessed in the STEP trial.In this context,a total of 5000 patients received intensive blood pressure intervention aiming to reduce systolic blood pressure to a range of 110-130 mmHg,whereas another 5000 patients were subjected to standard blood pressure intervention with a systolic blood pressure target of 130-150 mmHg.After entering the model,patients could have any of the following health status:(1)treated hypertension without events;(2)stroke;(3)post-stroke;(4)acute coronary syndrome;(5)post-acute coronary syndrome;(6)heart failure;(7)post-heart failure;(8)atrial fibrillation;(9)post-atrial fibrillation;(10)death from cardiovascular causes;(11)death from causes other than cardiovascular disease.To calculate the lifetime benefits of the two treatment strategies,all patients were tracked until death or the age of 100.The risks of the initial fatal or non-fatal cardiovascular events and treatment-related adverse events in patients who complied with the medication strategy were consistent with the STEP study.Additionally,the risk of death due to causes other than cardiovascular disease was acquired from the National Statistical Yearbook.Those patients who were nonadherent to the medication gradually reverted to their baseline systolic blood pressure.Furthermore,the China-PAR equation was used to evaluate the risks of the first fatal or non-fatal cardiovascular events for those non-adherent individuals.Primary outcome was the incremental cost-effectiveness ratio(ICER)from a payer’s perspective.Secondary outcome was composite endpoint of cardiovascular events,including acute coronary syndrome,stroke,acute decompensated heart failure,atrial fibrillation,and death from cardiovascular causes.We performed both short-term validations,in which we compared the observed risks of cardiovascular events in the STEP trial to the risks of cardiovascular events predicted by our model,and long-term validations,in which we compared the predicted outcomes of cardiovascular events and all-cause mortality rates in the base case to the long-term follow-up results of the Kailuan study.To investigate the influence of uncertainty in the model’s input parameters,we conducted one-way sensitivity analysis,which examined the effect of changes in individual parameters within a reasonable range on the study’s results while maintaining the values of others constant.The scenario analysis examined the effect of different assumptions regarding medication adherence and the cost of antihypertensive drugs.In the probabilistic sensitivity analysis,the model randomly selected values within a reasonable range of all parameters.Results:Short-term validation revealed that the incidence of the composite endpoint of cardiovascular events was 10.3 per 1,000 person-years in the base case for the intensive blood pressure treatment,and 13.7 per 1,000 person-years for the standard blood pressure treatment,respectively,and 10.3/1,000 and 13.5/1,000 person-years for the composite endpoint of cardiovascular events in the STEP trial.The hazard ratio(HR)for the composite endpoint of events was 0.75(95%CI 0.61-0.93)in the model,and 0.76(95%CI 0.61-0.95)in the STEP trial.In the long-term validation,the cumulative incidences of the composite endpoint of cardiovascular events and all-cause mortality were similar to the long-term follow-up results in the Kailuan study.According to the simulation,in the base case,36.88%of the 5,000 patients in the intensive blood pressure treatment group and 41.28%of the 5,000 patients in the standard blood pressure treatment group experienced cardiovascular events during the remaining lifespan,resulting in an absolute difference of 4.4 percentage points between the two groups.The patients’ mean remaining life expectancy was 17.71 years and 17.56 years in the two groups,respectively.Furthermore,the average number of quality-adjusted life years(QALYs)for patients receiving intensive blood pressure treatment was 0.16 higher compared to those receiving standard treatment.The intensive blood pressure treatment cost CNY12,614(Int$ 3018)more per QALY gained than standard blood pressure treatment.In 5000 probabilistic simulations,when the willingness-to-pay threshold was CNY 72,000 per QALY gained[one times the gross domestic product per capita in 2020],the probability of intensive blood pressure treatment being cost-effective was 91%.In one-way sensitivity analysis,the risk of death from cardiovascular causes in the intensive treatment group was the parameter that had the greatest impact on incremental cost-effectiveness ratio(ICER),reaching a maximum value of CNY 20,998 when the risk of death from cardiovascular disease in the intensive treatment group was taken as the minimum value.None of the other parameters in their range resulted in ICER value exceeding CNY 20,000 per QALY gained.The results of scenario analysis in which we made various assumptions regarding medication adherence and pharmaceutical expenses after the intervention period revealed that intensive blood pressure treatment remained cost-effectiveness.Conclusions:Compared with standard blood pressure treatment,the implementation of intensive blood pressure treatment averted cardiovascular events among the older hypertensive patients in China.Notably,it has been demonstrated to be cost-effective in a majority of the scenarios.Our research supports the implementation of intensive blood pressure intervention in the older population from an economic perspective,since this intervention can bring extra health benefits at a reasonable cost. |
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