Cost-Effectiveness of Blood Pressure Control Efforts

Chronic disease has been a focus for health system improvement and hypertension is the most prevalent chronic disease in the US.  Although there has been debate about what the guideline should be for effective blood pressure control and some balance is needed between reducing blood pressure and medication side effects, controlling hypertension is a priority for quality improvement work.    A study published in the New England Journal of Medicine attempts to ascertain whether controlling hypertension to guideline limits is cost-effective. (NEJM Article)   There are a couple of ways of thinking about cost-effectiveness.  One is whether the present value of the health and administrative costs related to the intervention are greater than the present value of the net future health costs.  Another approach might also try to assign some value to quality or length of life effects.

Recent studies have shown that intensive control of blood pressure (i.e., seeking a lower pressure) leads to less mortality and fewer cardiovascular events than standard control, so the study sought to identify the value of this extra lowering.  The researchers created a model which used data about costs, mortality gains, adverse events from medications and created scenarios of patient adherence to treatment recommendations.  They did also attempt to assign a value to added years and quality of life, which I personally find much less useful than the pure health costs analysis, or an analysis which might include other economic effects like ability to work or avoiding being on disability payments.  A basic finding was, in the scenario which assumed some lessening of adherence after five years, that for 10,000 patients, intensive control would result in 190 fewer deaths from cardiovascular disease and 170 other serious health incidents would be avoided.  In the best-case scenario in which patients remain adherent indefinitely, 464 deaths from cardiovascular disease and 929 serious incidents would be avoided.

Direct health costs were higher, both because of treatment and because of longevity, offset somewhat by decreased costs for treating cardiovascular disease.  In the best-case scenario, the cost of intensive control was best estimated at $28,000 per quality-adjusted year.   The cost was obviously higher in other scenarios.  The article’s discussion is somewhat misleading in failing to clearly identify purely economic cost/benefit, versus one including assumptions about the value of living longer in better health.  What is apparent, however, is that this intensive control of hypertension does raise overall health spending.  Doesn’t mean it isn’t the right thing to do, since it clearly appears to improve people’s health, but we should be very cautious about believing that better management of chronic diseases will result in lower total health spending.  Better diagnostics to determine who benefits most from this intensive control, or those who clearly don’t benefit from it, would help to limit spending and make the intervention cost-effective on a purely economic basis.