21st European Meeting on Hypertension and Cardiovascular Prevention
Ralph Hughes, a Health Economist with the National Clinical Guidelines Centre, London, United Kingdom, discussed the results of a recent re-evaluation of the cost-effectiveness of several classes of blood pressure (BP) lowering drugs for the management of essential hypertension. According to this latest model, treating hypertension with first-line therapies is cheaper than doing nothing. The evaluation was conducted as part of the development of the 2011 UK National Institute for Health and Clinical Excellence (NICE) guideline for hypertension.
The model used to evaluate first-line therapies included primary care patients with essential hypertension. The base case patient was defined as men and women 65 years of age with a 2% risk for cardiovascular disease, a 1% risk for heart failure, and 1.1% risk for diabetes. The model compared no intervention and treatment with thiazide-type diuretics (TD), calcium channel blockers (CCB), beta blockers (BB), and angiotensin-converting enzymes/angiotensin-II receptor antagonists (ACE/ARB). A Markov model was used to estimate lifetime costs and quality-adjusted life years (QALYs) from a UK health service perspective. The model incorporated the relative risks of myocardial infarction, stroke, unstable angina, heart failure and diabetes. Drug effectiveness was based on based on a systematic review and meta-analysis of head-to-head randomized clinical trials of BP lowering therapies conducted between 2004 to 2009. Costs included were for first-line drugs and management of cardiovascular events. Drug costs were based on generic UK list prices.
In the UK, guidelines must consider both clinical and cost effectiveness when making recommendations. Cost effectiveness is defined as the ratio of cost and health outcomes. For economic evaluations, health is measure in quality adjusted life years (QALYs). These two items are then used to develop an incremental cost-effectiveness ratio or ICER. In the UK a therapy costing less that £ 20K (€ 24,900) per QALY gained is considered cost effective (Figure 1).
Figure 1. Cost-Effectiveness Ratio.
Incremental cost- Difference in costs
effectiveness ratio = —————————
(ICER) Difference in QALYs
= Cost per QALY gained
Based on the 2011 model, the investigators concluded that treating hypertension is highly cost-effective, resulting in improved health outcomes and cost savings with all drug classes compared to no treatment. Thiazide-type diuretics were the lowest cost therapy while calcium channel blockers were the most cost effective (Table 1).
Table 1. Cost-Effectiveness
|Thiazide-type diuretics||€4,873||10.22||Lowest cost|
|Angiotensin-converting enzymes/angiotensin-II receptor antagonists||€4,998||10.21|
|Calcium channel blockers||€5,023||10.28||€2,443|
|Thiazide-type diuretics||€5,372||10.65||Lowest cost|
|Calcium channel blockers||€4,472||10.71||€1,894|
|Angiotensin-converting enzymes/angiotensin-II receptor antagonists||€5,484||10.63|
ICER =Incremental cost effectiveness ratio; QALY = quality adjusted life year