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
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