Abstract MP019: Should Global Cardiovascular Risk Guide Treatment of Stage One Hypertension? A Cost-effectiveness Analysis

Abstract

Introduction: Current U.S. hypertension guidelines base treatment on clinic blood pressure (BP) alone. International guidelines recommend adding global cardiovascular disease (CVD) risk to guide treatment. We projected incremental effectiveness and costs of treating stage 1 hypertension based on CVD risk assessment. Methods: We used the Coronary Heart Disease (CHD) Policy Model, a validated state-transition simulation of the CVD epidemic in the US, to model CHD and stroke events, costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness (ICE) of increasingly aggressive treatment of hypertensive patients. Census and national survey data were used to estimate joint distributions of risk factors by age and sex; the CVD risk function was based on Framingham. We modeled treatment of BP to an approximate target <140/90 mmHg using standard dose medications, including averaged annual drug costs (e.g., $253 for a systolic BP reduction of 11.5 mmHg; $1,036 for reduction of 36.7 mmHg) and monitoring costs (2 or 4 visits/year for stage 1 or 2 plus 1 lab test/year for all). We compared a strategy in which only stage 2 hypertensives (≥160/≥100 mmHg) were treated to increasingly aggressive strategies in which stage 1 hypertensives (140-159/90-99 mmHg) with successively lower global CVD risk (15%, 10%, 5% risk, then all of stage 1) were also treated. Results: Reaching hypertension treatment targets with any policy simulated would prevent between 389,000 and 478,000 CVD events annually ( Table ). Treating all stage 2 and ≥15% CVD risk stage 1 hypertensives would be cost-saving and treating stage 1 with ≥10% or ≥5% CVD risk would incur modest costs. Treating all stage 1 would cost $161,000/QALY more than treating only ≥5% CVD risk. Conclusions: Treatment of low risk stage 1 hypertensives appears to come at high cost and limited added benefit unless treatment costs can be minimized. Using global CVD risk assessment might allow re-allocation of resources toward controlling hypertension in the highest risk patients. Table Simulated CVD outcomes, costs, and cost-effectiveness, 2010-2011, the CHD Policy Model Scenario Annual number hypertensives treated Annual CVD events Annual QALYs (millions) Annual costs (millions, $US) ICER * Base case, no intervention - 2,387,000 127.67 $827,313 reference Treat only stage 2 23,364,180 1,997,000 128.78 $825,264 cost saving Treat stage 2 + stage 1 >=15% CVD risk 30,654,361 1,943,000 128.93 $824,541 cost saving Treat stage 2 + stage 1 >=10% CVD risk 34,947,200 1,928,000 128.97 $824,898 $9,381 Treat stage 2 + stage 1 >= 5% CVD risk 44,321,985 1,913,000 129.02 $826,433 $28,931 Treat stage 2 + all stage 1 50,863,390 1,909,000 129.04 $828,290 $160,630 *ICER = difference in cost/difference in QALY in comparison with the next less effective strategy